African Trypanosomiasis is an infectious disease caused by the parasite transmitted by tse-tse flies? There are two types, the Gambian type in the West and Central Africa, and the Rhodesian type in East Africa caused by two species of Trypanosama brucei, which are transmitted by tse tse flies. Rhodesian form is quicker than the Gambian.
Tse-tse flies like the savannah and fresh water. After a bit, a painful inflamed boil will occur. Symptoms begin after 3 weeks of being bitten and include: fever, rapid pulse, headache, weakness, joint pain, and itching. The liver, spleen, and lymph nodes become enlarged. With progression the brain is affected causing behavioral changes, lethargy, and apathy and eventually coma hence the "sleeping sickness".
Blood tests will test for the parasite or anti bodies against it. A lumbar puncture may be necessary; IV drugs can treat the disease.
West African type is mostly a human disease-affecting people living close to woodlands along riverbanks where tse-tse flies prefer. Countries such as Uganda, Zaire, and Sudan are affected. One reason for an increase is that much of the population had to ride near thickets and bush during the recent wars exposing themselves to the tse-tse flies, where as they would have been otherwise safer in their villages. A traveler passing through these countries would be at minimal risk.
East African type affects wild animal on open Savannah grasslands. People at risk include fisherman, hunters, and sometimes safari tourists.
Symptoms include fever and may be hard to distinguish from other infections. Usually a painless chancre or boil occurs at the bite of the tse tse flie followed by fever and a rash. Late stages include neurological symptoms. Prevention includes insect avoidance, spraying, destroying infected germ life as well as personal protection and DEET. The tse tse flies are attracted to bright colors especially blue and subdued clothing that blends is preferred.
Present from Mexico to Argentina and affects 20 million people worldwide. Caused by protozoa, transmitted from assassin or kissing bugs (reduviid bugs). It also can be caught during birth (mother to infant), breast-feeding and by transfusion. No vaccine exists. People should avoid adobe huts where these buds like to live in the walls and come out at night. Insect repellent and screens will help stop them.
Symptoms include: swelling at bite and sometimes at eyes and fever in the first 10 days. Itchy rash and lymph enlargement also occur. The heart, brain and intestinal tract are affected, causing chronic and fatal disease. A blood test diagnosis this disease. Drug treatment helps in the early symptoms.
Triatomine bugs are found in the cracks of adobe houses, in palm leaf roots; and in woodpiles, chicken coops and goat pens.
Most commonly occurs in Africa, Central Asia, South America, and the former U.S.S.R states. It is transmitted to people by bacterial spores from infected sheep, goats, cattle, horses, or pigs, usually after close contact. Canada customs restricts the importation of certain produces (products made from goat) because of their risk.
The 3 types of disease are:
1. Cutaneous anthrax (after handling animals or their hides). Usually symptoms begin 1-5 days after exposure with ulcerations of the skin at points of contact. The ulcers are dark red, itchy but rarely painful, and the adjacent lymph nodes may be inflamed. Other symptoms are fever, headache, nausea and anorexia. If untreated, uncontrolled infection may make the individual severely ill.
2. Pulmonary anthrax occurs after inhaling spores and manifests as a dry cough, high fever, and chest pain.
3. Intestinal anthrax occurs after eating infected meat causing diarrhea, vomiting and fever.
Both 2 and 3 are more severe but more rare than Cutaneous anthrax.
Diagnosis is made by culture. A mild skin infection will respond to antibiotics, but severe types require hospitalization. The anthrax vaccine is an exotic vaccine, mostly used by the military. It gives protection but this needs to be boosted. It is unavailable for travelers.
A tropical, bacterial infection, causing diarrhea, that last 1-2 weeks. It is acquired from drinking water contaminated by animal or human fesses.
Symptoms are short-lived and treatment often not needed but it will also respond to antibiotics (doxycycline or flagyl).
Is a viral disease from Northern Australia (Victoria), similar to Ross River virus? The risk to travelers is low. The symptoms are similar to that of Dengue Fever - a flu-like illness (fever, chills, aches, headache). The symptoms will disappear with time. Only symptomatic treatment exists.
Exists in Andes (SW Colombia, Equator, and Peru). Transmitted by sand flies that bit between dusk and dawn, and are most common in valleys between 1000m and 3000m altitude.
Initial symptoms include acute anorexia, thirst, bone pain, anemia (causing fatigue) and fever. The fever is high at night and could last 6 weeks. Next wart like eruptions occurs on face and limbs, but will heal without scarring. People affected are particularly vulnerable to overwhelming salmonella infections.
This is another sandfly-transmitted disease caused by bacteria. It is found on the Western Slopes of the Andes and is rare. Symptoms include fever, bone aches, anemia and sometimes skin eruptions.
Is a bacterial infection that affects children under 10 years of age and occurs in Brazil and Australia? It starts as a severe conjunctivitis but some cases develop fever, vomiting and purpuric rash which can lead to death. It can be treated with antibiotics.
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Bloodsucking
Insects (Flying)
General Precaution in Avoiding Bloodsucking Insects / Personal Protection |
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|
Mosquitoes
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Transmit
|
Rural
or Urban
|
Bite
indoor or outdoor
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Bite
in Day
or night |
Insect-
Proof Rooms
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Aerosol
sprays + vaporizers
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Mosquito
Bednets With Insecticides
|
| Anopheles |
Malaria,
Lymphatic Filiariasis
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Both
|
Both
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Night
|
Yes
|
Yes
|
Yes
|
| Culex |
Arboviruses
|
Both
|
Both
|
Night
|
Yes
|
Yes
|
Yes
|
| Aedes |
Dengue/Yellow
Fever
|
Both
|
Both
|
Day
|
Not
Needed
|
Yes
|
Yes
|
| Masonia |
Arboviruses
|
Both
|
Both
|
Day
|
Yes
|
Yes
|
Yes
|
Small Flies |
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| Black Flies (near streams) |
Onchocerciasis
|
Rural
|
Outside
|
Both
|
No
|
No
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Yes
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| Midges (mangroves + wetlands) |
Mansmellosis
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Rural
|
Both
|
Both
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Yes
|
Yes
|
Yes
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| Sandflies |
Leishmanisis
+ Sandfly Fever
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Rural
|
Both
|
Both
|
Not
Applicable
|
Yes
|
Yes
|
Flies |
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| Horseflies |
Loasis
(central+west Africa)
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Rural
|
Outside
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Day
|
No
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No
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Yes
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| Tse Tse Flies (Africa) |
Sleeping
Sickness (Trypsanosomiasis)
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Rural
|
Outside
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Day
|
No
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No
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Yes
|
|
Bloodsucking
Insects (Crawling)
General Precaution In Avoiding Bloodsucking Insects / Personal Protection |
||||||||
|
Insect
|
Transmit
|
Rural
or Urban
|
Bite
Indoor
or Outdoor |
Bite
in Day
or Night |
Insect
Proof Rooms
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Sprays
and Vapourizers
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Mosquito
Bed Nets |
Repellent
Treated Clothes
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| Triatomine Bugs(latin America) |
Chaga's
Disease
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Both
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Both
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Night
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N/A
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Spay
Mattress
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Yes
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Not
Helpful
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| Bed Bugs |
Nuisance
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Both
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Indoor
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Night
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N/A
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Spay
Mattress
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Yes
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No
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| Fleas |
Nuisance
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Both
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Both
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Both
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N/A
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Flea
Collar
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Yes
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Yes
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| Rat Fleas |
Plague
+ Murine Typhus
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Both
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Both
|
Both
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N/A
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Flea
Collar
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Yes
|
Yes
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| Body Louse, Head and pubic Lice |
Typhus
Relapsing Fever
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Transmitted
By person to person
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N/A
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N/A
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N/A
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In
Epidemic Yes
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| Hard Ticks |
Lyme
disease, Rickettsial Fevers, Arbovirus
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Rural
|
Both
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Day
|
N/A
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N/A
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N/A
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Check
body for quick removal
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| Soft Ticks |
Relapsing
Fever
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Rural
|
Both
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Night
|
Sleep
high off ground
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Yes
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Yes
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Check
body for quick removal
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| Biting Mites |
Scrab
Typhus (Asia and Australlia)
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Rural
|
Outdoor
|
Day
|
N/A
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N/A
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N/A
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Yes
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Acquired from drinking unpasteurized milk from infected cattle, goats, and sheep. People working with animals are also at risk.
After 1-3 weeks or longer, symptoms develop including malaise, headache, high sweats, anorexia and generalized aches. Chronic Brucellosis involves muscle aches, easy fatigability, fever and depression.
Diagnosis is confirmed by blood tests, and Brucellosis is treated with high dose antibiotics. Acquired from ingesting infected milk or milk products. Occasionally acquired via respirations and veterinarians can catch it through skin abrasions. Incubation time to illness is 1-3 weeks.
Human Brucellosis is acquired from cattle milk and is caused by brucella abortus. Brucella melliteis affects goats, sheep and camels. Brucella Suis affects pigs.
Symptoms include: dramatic fever, sweats, aches and pains. Fever can be intermittent. Lymph nodes, spleen and liver can get enlarged. More chronically it can cause arthritis, bone infection, meningitis and heart disease.
Disease is diagnosed from serology and biopsy. Treatment is difficult and could involve over 6 weeks of antibiotics.
The best prevention is mild pasteurization.
A rare skin infection acquired in Benin, Cote d'Ivoire (Ivory Coast), Gabon, Ghana and Uganda. It is similar to tuberculosis bacteria. It is spread through scratches or cuts on the skin. It is found in women and children living near wetlands or rivers in tropical/subtropical areas. Risk to travelers is low. The BCG vaccine gives some short-term immunity against the Buruli bacteria.
Symptoms start as a painless but itchy skin swelling which turns to a destructive ulcer after 4-8 weeks. The ulcer can remain, disappear or cause local destruction.
Treatment with drugs is unsatisfactory and surgery with skin grafting is often done.
Is a mosquito borne viral illness found in Africa, India and SE Asia? Chikungunya is Swahili for 'that which bends up' which refers to affected people's stooped posture caused by joint pains. Symptoms are similar to dengue fever - fever, headache, nausea, rash and joint pains that last for 3-7 days. It is not life threatening, but some people may have joint stiffness that can last for months.
Diagnosis can be made with a blood test although it is treated with symptomatic measures. It is important to rule out the more serious malaria or dengue fever, which have similar features.
Cholera is a severe diarrhea disease caused by the bacteria Vibro cholerae.
There are presently 5.5 million cases reported worldwide. Untreated it has a 40% mortality rate. Within Africa 20,000 people die per-year and about 100,000-die per-year in Asia.
The cholera vaccine is about 50% effective and causes local reactions such as; fever, flu symptoms, and headache. The vaccine is felt to be effective in controlling cholera epidemics but is not recommended for travelers because of car effectiveness and severe side effects.
Cholera is characterized by severe diarrhea (early to rapid dehydration), and if left untreated death occurs within 24 hours. Cholera is transmitted through food or water contaminated by cat, dog or human feces. It is also transmitted by direct person-to-person contact. To avoid transmission of cholera drink provided water and consume well cooked food. Seek help early on if symptomatic. Rehydration with oral or IV fluids may be necessary.
Pilgrims going to Mecca may require proof of vaccination against cholera. In Canada this vaccine is currently unavailable but we will provide a letter of exemption since that will allow travelers to go to Mecca. Other countries may require proof of vaccination for travelers arriving from countries where cholera is endemic.
Occurs after eating reef dwelling fish that have fed on toxic plankton. This can occur sporadically in the Pacific and Caribbean
Affected fish cannot de distinguished by inspection, smell or taste, and cooking does not neutralize the toxin. The best way to avoid during outbreaks is by avoiding large predatory - type reef dwelling fish that would be more likely to bio-accumulate the toxin. The toxin is more concentrated in the head, liver, and gut of these fish.
Examples of commonly affected species include: red snapper, grouper, barracuda, coral trout, cod and amberjack.
Symptoms usually occur after 1-6 hours (but have been up to 30 hours) after eating. Mostly people are mildly affected with gastrointestinal symptoms (diarrhea, vomiting, and abdominal pain) but neurological also occur (muscle aches, weakness, blurry vision and burning). Ciguatera poisoning also has particularly bizarre symptoms in that some will report a reversal of hot and cold sensations. Symptoms usually last less than 2 weeks.
Diagnosis is bored on history. Treatments involve antihistamines and sometimes mannitol (a medication that can be useful as a partial antidote).
Occurs in Africa, Asia, and the Middle East. It is common in many animals but rare, yet serious in people.
It is caused by a virus transmitted by infected ticks or by direct contact with infected animal body fluids. There is no vaccine. Risk to travelers in low.
Symptoms start after an incubation period of 1-3 days. Non-specific symptoms like fever, dizziness, headache, neck stiffness; aches, abdominal pain, diarrhea, nausea, sore eyes and photophobia develop. Generalized bleeding can develop.
Diagnosis is confirmed with a blood test. Treatment is supportive only.
Dengue is an arbovirus consisting of 4 serotypes (DEN 1,2,3,4) all of which can cause severe and fatal disease. After an infection with one subtype an individual will gain lifelong immunity to that subtype. There are estimated 50-100 million cases of Dengue fever/year. 250-500,000 cases of Dengue hemorrhagic fever worldwide. Most deaths are in children 5-15 years.
Risk to travelers is estimated 1/1,000 in countries where it is present but could be worse in outbreaks.
Aedes Egypti is a mosquito adapted to city like and typically feeds in early morning and late afternoon. Adults lay eggs as floating egg rafts in puddles. These mosquitoes thrive on small puddles.
Aedes egypti has a tropical and subtropical distinction and one single mosquito will feed many times so that many people could become infected at the same time. These mosquitoes are found active in the daytime and are found in and around human habitation. They lay eggs in shallow containers that rainwater has collected in.
Dengue infection involves a spectrum of different symptoms, which range from a non-specific fever, classical dengue fever, dengue hemorrhagic fever, and dengue shock. Dengue fever may begin suddenly.
Symptoms include high fever, severe headache, and joint and muscle pain. Nausea, vomiting and anorexia may also occur. A rash may also appear 3-4 days after the onset of fever spreading from the torso to the arms, legs and face.
Dengue hemorrhagic fever is usually defined as having a rash, hemorrhage and fever. Patients should be checked for evidence of bleeding, their hydration status, and their blood pressure. Bleeding is evidenced by petechiae, purpura, increased bleeding from gums and increased menstrual flow.
The W.H.O criteria for diagnosis are: fever, bleeding, platelets less than 100,000; and evidence of ' leaky capillaries'. Co-factors that will worsen the severity of dengue include having a prior infection with one or more of the other 3 serotypes (and how long ago, and how severe); age; and host genetics. The strain of serotype is also important with the lethality ranked: DEN 2>3>4>1. Unusual complications of dengue are encephalopathy, liver and heart damage; and gastrointestinal bleeds.
Treatment of dengue hemorrhagic fever includes fluids, rest, anti-pyretics (acetaminophen but no ASA or NSAIDS), and to check blood pressure, hemoglobin and platelets. Patients may be treated at home if there is no bleeding and well hydrated. Observation is warranted if sicker and ICU admission if bleeding. Serial hemoglobin and platelets are done until afebrile for 1-2 days. Other treatments include IV fluids and avoidance of invasive procedures. Steroids and gammaglobulin are unproven treatments.
Clinical tests for dengue fever: CBC- WBC, Hb, and platelets; albumen, liver function tests, urinalysis (to check for hematuria), and direct tests to look for virus isolation and serology. Blood serology should be taken during the acute phase (less than 5 days after start of fever) to check for acute serology and virus isolation; and again after 6-21 days to check for convalescent serology and confirm the diagnosis. A rapid diagnostic test for dengue fever is at present not approved. Check to see if traveler has recently been to a dengue area. If the fever starts greater than 2 weeks after the end of traveling then this is not dengue fever.
Differential diagnosis includes influenza, rubella, measles, malaria, typhoid, leptospirosis, meningococinemia, rickettsia, bacterial sepsis, and other viral hemorrhagic illnesses.
Personal protection against Dengue:
Use DEET 20-30%, spray clothing with permethrin, and spray insecticide over bed. Wear long sleeved pants and shirts. Persons may also decrease risk by spending less time in areas where dengue more frequent. Residential areas are the most affected while industrialized or commercialized areas (like beaches, forests, and tennis courts) have less Aedes mosquitoes. Air conditioning helps remove mosquitoes.
Infection caused by Dengue virus (4 types), is transmitted by specific mosquitoes. Ades Egypti and more recently also Ades Albopictus.
New mosquitoes, Aedes Albopictus (Asian Tiger mosquitoes) were recently introduced to Hawaii and Texas. This mosquito also causes Eastern Equine Encephalitis and Cack Valley viruses, but not Yellow Fever.
A transmission of Dengue fever occurs with increased urbanization, low altitude (<4500ft), introduced by travelers, floods and hurricanes, and increased temperature and humidity.
Symptoms of Dengue Fever:
Young children mostly get a febrile upper respiratory infection. Older children and adults get Dengue fever. Dengue hemorrhagic fever, and Dengue shock are severe manifestations of Dengue.
Dengue incubates in 2-7 days. Abrupt fever 41° with chills and a slow pulse. Biphasic fever lasts an average of 6 days. Other symptoms include; sore throat, runny nose, and cough, similar to the flu, pronounced headache behind eyes. Also lumbosacral and calf muscle aches, bone/joint pain. (giving Dengue the name break bone fever)
The fever of Dengue fever is 50%. It usually transmits a faint, macular rash or molting rash in 1st 1-2 days. 1-2 days after defervecsence (days 3-6) a second dark red confluent maculopapular rash (islands of white in a sea of red) or measle-like non-itchy rash may occur. The rash usually starts on the trunk then goes to the limbs and face (usually sparing palms and soles) lasting 2-3 days.
Other Symptoms
Bleeding from the gums, nose, or bond. May have enlarged liver and lymph nodes, spleen enlargement not usual. Platelets decreased, liver enzymes (transaminases), no jaundice.
Dengue fever resolves in 2nd week after illness. As with similar viral infections, patients may have fatigue and depression for months but no long-term problems
Dengue Hemorrhagic Fever
Usually less than 15 years. Travelers are at risk if:
1) Infants who have pre-existing maternal dengue antibodies (usually<6-18 months)
2) A second dengue infection of a 2nd type of dengue stereotype
Dengue Hemorrhagic Fever during the acute phase (2-5) behaves like dengue fever but a critical stage occurs 1 day, after fever decreases and there is onset bleeding, circulatory failure and plasma leaking into spaces. The usual cause of death is hypovolemic shock, but can be treated with aggressive IV fluids.
Also, after 2-5 days, rapid pulse and respiratory rate, low blood pressure, cool extremities with warm face and trunk. Sweating, irritability, and bleeding into the skin and bone also occur.
Dengue shock involves the most severe spectrum of disease - loss of 20% of circulating volume, pleural effusion, edema, ascites, and hypoproteinemia. Liver enlargement and bowel bleeding also occurs. Convalescence usually occurs after 24-36 hours.
A tourniquet test can be used to test for vascular fragility in dengue. A blood pressure is inflated midway between distal and subtle for 5 minutes. It is considered positive if there is greater than 20 petecinave (small bleeds) per square inch of skin.
Neurologic Symptoms of DHF:
- Encephalitis
- Isolated nerve plaster
- Taste abnormalities
- Reye's Syndrome
- Prolonged sensations
Risk factors for DHF:
Is greater is if > 2 serotypes of dengue are circulating in a population DHF also has low ubc, low platelets, and increased hematocit as fluid leakage occurs. An increasing hamatocit is an important test for Dengue Hemorrhagic Fever.
Diagnosis of Dengue - Four fold increase in serology in blood taken initially and then again at follow-up.
Management of Dengue fever and DHF
- avoid ASA
- fluid and electrolyte replacement
- patients should be isolated from another dengue infection from
a different serotype, so mosquito netting essential
- if DIC, may need fresh frozen plasma platelets and heparin
- steroids are not helpful because this is a hypovolemic shock
Prevention of Dengue Fever
- destroy mosquito breeding grounds by eliminating unused containers
- stock small fish that will eat mosquito larvae
- insecticides - Permethrin and DEET
- clothing
- new concepts - Mesocyclops (organisms that eat larvae)
- vaccines being developed
Reference: Dr. Bill Kennedy - Wilderness and Travel Medicine April 25, 2002, Santa Fe, NM
Is a bacteria illness spread person to person? It is rare except in countries where there is poor immunization. People require a booster every 10 years.
The bacteria incubation after 2-6 days and symptoms such as sore throat, fever and chills develop. A foul odor to the breath is present. it is difficult to swallow because of a leathery membrane over the tonsils and back of throat. Their bacteria also secrete a toxin that causes heart disease and paralyses. Diphtheria is contagious for 10 days after the onset of fever.
Treatment with antibiotics is important and possibly an antitoxin.
Most cases are now from Sudan, Yemen and other sub-Saharan African countries. Infection is acquired by drinking water contaminated with Cyclopes water fleas carrying the guinea worm larvae. These larvae penetrate the intestine and mature into adult worms that then start moving. These worms will travel, and can exit through skin (feet, genitalia, hands or breasts). It can take 3 weeks to emerge. While they are emerging, embryos are shed into water while the infected person is bathing.
Dracunculiasis is acquired in poor rural communities as is prevented by drinking boiled water (which kills the fleas and larvae
Symptoms may be absent until emergance. If a joint is entered there will be localized pain and swelling. Skin will blister at the worm exit point, and then ulcers can take weeks to heal. Sometimes generalized symptoms (nausea, vomiting, diarrhea, swelling, itchy rash) occur during worm emergance, more so if multiple worms are expelled.
When visible the worm can be sped up by repeating to immersing it in water where it releases its larval (as a milky fluid). After it produces enough its thread-like head can be wrapped around a stick and gently pulled, but it can still take two weeks to remove.
Metranidazole (Flagyl) 400mg for 5 days can speed up the removal of the worm.
Is a virus that affects birds and horses and rarely humans? Mosquito spreads it. A vaccine exists for horses but not people.
Symptoms are a high fever, headache, lethargy and vomiting. Some may progress to coma and death. This disease can be detected by blood tests but no specific treatments exist. It affects roughly 10 people per year in the U.S.A.
No one knows exactly how Ebola is maintained as a reservoir in the wild. Outbreaks have occurred in Zaire, the Democratic Republic of Congo, Gabon, Sudan, and Ivory Coast, affecting humans, monkeys, and chimpanzees.
The virus is spread by direct contact with blood, secretions, or organs of those infected. Hospital workers in those countries are at risk, but travelers have a relatively low risk.
Symptoms occur a few days after contamination with high fever, sore throat, headache and muscle aches, stomach pains, diarrhea and fatigue. On day 5 an itchy pink rash spreads first on the face then the rest of the body. Other symptoms include a dry cough, red and irritable eyes and vomiting blood and bloody diarrhea. After a week severe cases of bleeding may occur. It is survivable and the individual factors that allow some to survive are still poorly understood.
Blood test can confirm Ebola if suspected. There is no specific treatment although IV anti-viral may help. It should be noted that Ebola while flashy is very rare and many more people die of measles and other diseases each day.
Do ticks transmit a bacterial infection?
Symptoms are similar to Rocky Mountain spotted fever and Lyme disease. Onset of symptoms occurs 5-10 days after the tick bite with sudden fever, headache, chills, aches and nausea and vomiting. A generalized rash occurs more often in affected children compared to adults. Untreated meningitis, kidney and liver disease may occur, and rarely it is fatal.
Diagnosis is with blood tests, which may take some time. Doxycycline is effective treatment (which will also cover Rocky Mountain Spotted Fever and Lyme disease), while waiting for confirmation of blood work.
This fluke infects cattle, sheep and goats worldwide, humans are infected after eating food or water contaminated by feces.
Larval will penetrate the intestine and migrate to the liver and biliary tract and produce eggs. Sometime they are also found in the brain, lungs, and skin.
Initial symptoms are non-specific - malaise, fever, weight loss, diarrhea, abdominal pain (near liver) and itching about 2-3 months after infection. Jaundice may occur if the flukes block the biliary flow.
Diagnosis - eggs are seen in stool or blood tests can confirm the diagnosis. Anti-worm medication is effective in eradicating their infection.
This fluke is found in pigs and humans in South China, Taiwan, Vietnam, Thailand, Indonesia, India and Bangladesh.
Humans are affected after eating water chestnuts or water caltops contaminated by larval cysts. These cysts release the flukes inside the large intestine where they mature into adults (3 months). Eggs are shed in stools, which enter the fresh water table, penetrate into larval inside fresh water snails and then become cysts, which go to fresh water plants.
Symptoms may be absent. Severe cases cause abdominal pain, diarrhea/constipation, anorexia, nausea and severe malnutrition is a high worm load is present. Swelling of the face is sometimes observed and anemia can also be present. Diagnosis is done by stool examination. Anti-worm medication will clear this infection.
Filarial infections are caused by parasitic worms and spread by biting insects.
Filiasis is a group of parasitic diseases consisting of Uncherieria bancrofti (bancroftian filariasis), Onchocerciasis volvulus (Onchocerciasis), and Loa Loa. Mosquitoes in urban and rural areas transmit Bancroftian type. Classic elephantitis occurs in legs and genitals after heavy worm load over many years, which affects lymph drainage.
Acute infections may develop 3 months after exposure with fever, lymphadenopathy, cellulites, Lymphangitis, epididymo-orchitis and edema. Fever may be on and off.
Suspicion, peripheral eosinophilia, filiaviral antibodies and micrfilaria on blood film confirm diagnosis. Some people with uncheriria bancofti infection will exhibit cough, wheeze and transient pulmonary infiltrates
There are 3 main diseases:
1) Onchocerciasis (River Blindness, Robie's Disease, Volvalosis, Mal Morado). This is mostly found in Africa but some in Central and South America and Arabic Peninsula. Is caused by worm transmitted by black fly found near fast-flowing water. The larval are deposited by the black fly and mature. After 1 year the worm matures and reproduces as small microfilariae that migrate through the body. Symptoms include: widespread itchy rash (caused by large numbers of the microfilariae). Nodules 'boney bumps' occur where the adult worm is. The microfilariae also causes fever, headache, lymphatic swelling, and fatigue. While migrating they may lodge in the eyes causing irritation, redness and possible blindness.
Diagnosis is either by the clinical pattern or microfilariae seen on a tissue biopsy.
Treatment with the drug ivermectin once yearly kills the microfilariae but not the adult worm, which can live for 20 years!
Onchocerciasis is rare in travelers staying less than 3 months even if they are in high-risk areas. River blindness occurs to people living long term with heavy infection. Onchocerciasis is a leading cause of blindness, and is also known as river blindness. It is acquired through simulium (black) flies that breed near fast flowing rivers. The most common symptoms are itchiness and blurred visions. Repeated exposure and high worm loads may lead to blindness.
Signs of infections will show minor skin changes and nodules (skin snips are biopsied from shoulder, buttocks, and thigh areas), and corneal inflammation. No vaccination exists but anti-parasitic medication exists. Highly suspicious cases may need serologic screening, checking skin biopsies and peripheral eosinophilia in complete blood count.
Onchocerca volvulus occurs mostly in West Africa but is found in many sub-Saharan countries.
2) Filarial Lymphangitis occurs by transmission of worms by mosquitoes. The adult worms live in lymph tissue and produce microfilariae, which the mosquitoes irrigate while feeding. The mosquitoes deposit their new larval to the next victim. Present in Sub-Sahara Africa, Egypt, Southern Asia, Western Pacific Islands, Central and tropical South America, and Caribbean.
Symptoms appear 5-18 months after being bitten. Local inflammation of the lymphatic network occurs, with later scarring. Lymph may block leading to swelling; which in its extreme turn becomes elephantitis (which is permanent). Other complications include fever, rashes, blindness, and tropical pulmonary eosinophilia (an inflammation of the lung causing coughing and wheezing).
A blood test confirms infection and a drug treatment will eradicate infection. Bancroftian filariasis is a remote risk for travelers, but more so in back packers. There is no vaccine available and general mosquito avoidance should be practiced.
3) Loasis (Loa Loa) occurs in Western and Central Africa in forested areas such as Sudan and Cameroon. The Loa worm transmitted by the daytime biting tabarid fly causes it. The eggs take 1 year to mature after deposited and as adults migrate freely under the skin. They can be up to 6cm 1mg and .5mm diameter.
The female worm release more microfilarial which tabarid flies take up. The risk of infection to travelers is low (although not routinely given a weekly dose of the drug directly carbamazine 300mg will prevent disease).
Loasis rarely is serious and worms are first noticed crossing the bridge of the nose or under the conjunctiva. People can actually even see the worm more across their eye. Some people develop painless skin swellings 'Calabar swelling' near joints during hot weather, which is probably caused by a toxin released by the worm as it passes along. Loa Loa is acquired by the bite of the day feeding Chryops flies. Infection is mostly asymptomatic but the worm can migrate under the conjuctiva. Other symptoms include tender swellings over pressure points (called Calabar swellings) and joint effusion.
The Chryops flies are found in the rain forest areas of West and Central Africa and are attracted to dark colours Diagnosis can be confirmed with a blood test and treated with medication. If a worm is observed at the eye or bridge of the nose, a skilled doctor with local anesthesia can remove it.
Is found worldwide. Protozoan cysts that can remain for 3 months in water, which people irrigate, cause it.
Symptoms occur 2-4 weeks after with diarrhea, nausea, weight loss, and bloating. Usually symptoms resolve after 2 weeks but some will have chronic problems that may last for months.
Diagnosis is with stool analysis. Treatment is with Flagyl 500mg BID X 7 days.
Is a worm infection caused after eating raw fresh water fish contaminated with worm larval? Usually in Thailand and Japan.
After being eaten the larval migrate outside the intestine. In the skin they cause itching but also can affect the lung (causing coughing), bladder (causing blood in urine) and brain (causing meningitis).
Blood tests help but sometimes-surgical removal of the worms helps identification. Treatment may require both medical and surgical.
Hanta viruses are a group of viruses spread to people from rodents causing viral hemorrhagic fever. They are transmitted, by inhaling dried rat feces (usually from brushing or beating carpets). There is no person-to-person transmission and no vaccine exists. It is rare but serious with symptoms of high fever, chills, increased bleeding, and shock and kidney failure. Also in the Americas, a Hanta Virus Pulmonary Syndrome exists with fluid developing in the lungs usually in the first 10 days. Hantavirus Pulmonary Syndrome
This is caused by Sin Nombie virus (Hantavirus family), which is transmitted by deer mouse (which do not become diseased). Humans are accidental hosts and risk depends on climate. Deer mice spread this virus through their urine and feces.
Peak season is usually May and June. Distribution is throughout the U.S. Other similar diseases are in the Eastern U.S but different viruses cause these.
Clinical Symptoms
- early Influenza type symptoms
- develop ARDS after
Lab Findings
- all patients have significant thrombocytopenia
- high hematocrit (sever hemo-concentration)
- immunoblasts, elevated, LDH, hypoxemia (fatality rate 50% usually in 1st wk)
- immunoblasts - clue to Hantavirus - this will not be seen as an automated CBC
- needs to be reviewed by a lab technologist
- Diagnosis confirmed with serology (Elisa, Western Blot)
- Treatment is supportive only
- Prevention - must focus on avoidance of mouse urine and feces, abandoned dirty buildings. Be careful if cleaning these buildings
Notes based on a lecture by Dr. Rodney Adams Wilderness and Travel Medicine Conference, April 2002.
Hepatitis A is a virus that will cause infectious inflammation of the liver. It is common in developing countries and transmitted from food and water that has been contaminated.
Many people will have mild symptoms including nausea, vomiting and diarrhea. Active hepatic disease may last up to 90 days. Some people may become jaundiced and rarely it is a cause of death more notably in older travelers. Infection with Hepatitis A has recently been determined to be a risk factor for arteriosclerosis. People who have grown up in developing countries where Hepatitis A was present may already have an immunity built up to it. If a person has had Hepatitis A at any time in their life they are felt to be immune to it. If there is any doubt whether a previous infection was actually Hepatitis A or not, a blood test can be done to determine this.
Hepatitis A may infect food and water. Uncooked shellfish (especially oysters) may cause Hepatitis A. Hepatitis A also affects children and a vaccination is recommended for children 1 year and over. Risk is estimated to be 3-6 per 1000 per month to 20-1000 per month in higher risk travelers.
Individuals who are at high risk include: ethnic populations, homosexual or bisexual men, IV drug users, military personnel, individuals with liver disease, who routinely receive blood products, lab workers, and primate handlers.
One dose of the Hepatitis A vaccine will provide protection for up to twelve month. A booster can be given between 6 - 12 months after the initial shot. The second shot will boost the response for 10 years and it is felt it may even last longer.
Hepatitis A vaccine is also recommended and considered safe for pregnant women who plan to travel. Pregnant women are more likely to become sick from a Hepatitis A infection.
Recently expanded indications for vaccination include: fast food workers, all children, daycare workers, and medical people. It is recommended for ALL non-immunes going to developing countries. These countries include: All of Latin America, Caribbean, Africa, and Asia (except for Singapore and Japan). Eastern Europe including Russia, Ukraine, Belarus, Albania is also included (but not Greece or Southern Europe in General).
Although the vaccine provides protection against Hepatitis A caution should still be taken when infectious agents may be present in both food and water, because of the other infections or pollutants that may be present as well.
Other information on the Hepatitis A vaccine:
SIDE EFFECTS:
These are reactions you may or may not experience after the injection.
1. At injection site: pain, tenderness, warmth, and swelling.
2. Other: headache and fatigue.
3. Muscular activity increases these effects, so avoid strenuous activities for 24-48 hours. No other change in your normal activities is needed. Wash site as usual.
Hepatitis E is similar to Hepatitis A although there is no immunization to protect against it yet. Hepatitis E is also transmitted through food and water.
Hepatitis B is a virus that infects the liver causing infectious Hepatitis, which may lead to liver disease and liver cancer. Hepatitis B is transmitted through blood products, IV drug use and sexual contact with infected partners.
Less commonly it can be transmitted through unclean medical and dental procedures as well as living closely with a person who has been infected. Children playing together with cuts and scrapes may also transmit this. Athletes have been known to transmit Hepatitis B cuts and body fluids are present.
Hepatitis B virus is more common and easier to transmit than AIDS. It also kills more people yearly. Fortunately there is a vaccine available for people who are at potential risk.
It is recommended that travelers have the Hepatitis B vaccine if they are traveling to a country where it is common or if a traveler is planning to send three months or more in a certain area. People involved with medical centers, sanitation and sewage projects, or day care positions should consider being immunized. Although travelers often deny planning risky sexual behavior on vacation it is well known that many do so and therefore they should consider immunization.
The Hepatitis B vaccine is currently available to grade four students in Manitoba as part of their vaccination schedule. Adults and teens that have not yet been vaccinated should consider doing so. Younger children that may be traveling abroad for extended periods should also consider being vaccinated.
The Hepatitis B vaccine is considered safe and there is no evidence to link it with multiple sclerosis, diabetes, or autism as been suggested by anti-vaccination groups. These groups have issued many misleading statements about vaccinations. Health Canada and the World Health Organization advocate the use of vaccinations to prevent further spread of Hepatitis B.
Hepatitis B is available in several brands and is given on visit one, then again in one month and the final booster is given in five to six months.
Two doses are necessary to initiate enough antibodies to provide adequate protection while traveling. After having the third dose the vaccine is effective for at least ten years. There are no guidelines for boosting people past ten years, as it is believed they still have long-term immunity.
A variation of the vaccination schedule can be given during the initial visit, seven days later and the in twenty-one days. A final booster should be given in twelve months to provide coverage for the following ten years.
A sore arm and low-grade fever are the most common side effects of the vaccine and may last anywhere from 1 - 3 days.
Often Hepatitis A and B are combined together (Twinrix) to give both vaccines at once in the same needle.
Hepatitis B infections may be almost asymptomatic or actively involving the liver. People may die from liver failure or they may be more prone to liver cancer in the future. People with diagnosed Hepatitis B should be under the care of a specialist and should do everything possible to avoid further liver damage. This may include avoiding alcohol and Tylenol (as well as other drugs that either effect the liver or are metabolized). People with Hepatitis B may also consider immunization with Hepatitis A since any further liver damage from a potential 2nd liver infection could be very serious. Conversely all individuals with any liver disease should consider vaccination for both Hepatitis A and B
Hepatitis B should be considered for travelers when:
1) To cover accidents requiring medical intervention
2) Exposed to non-sterile medical equipment and unscreened blood or blood products
3) Cosmetic practices (body piercing) and tattoos
4) Casual sexual liaisons
5) Exposure to poor food, hygiene and sanitation
Estimated rate of infection of Hepatitis B in travelers .8-2.4/1000 per month Risk is dependant on exposure, destination and duration.
Other information on the Hepatitis B vaccine:
General: Hepatitis B is a viral liver infection that is spread from person to person by blood and body fluids. To be immunized against it you will need a series of three injections
SIDE EFFECTS:
- These are reactions you may or may not experience after the injection. These generally last for 24-48 hours. At the injection site: swelling, redness, and tenderness.
- Other: There is no proof that this causes autism, diabetes, multiple sclerosis or other autoimmune diseases. A recent study showed the incidence of multiple sclerosis less in people vaccinated with Hepatitis B.
- Muscular activity increases these side effects; avoid strenuous activities for 24-48 hours after injection. No other change in normal activity is needed. Wash site as usual.
TREATMENT FOR SIDE EFFECTS:
- Tylenol, as directed on label.
- Cool compress to site may be soothing.
BOOSTER: Not required after completion of three shot series.
- incubation period 2wks-6mos
- is a flavirus
- usually from iv drugs, sometimes sexually
- Egypt has the highest rate in the world -mass immunizations against Schistomiasis with dirty needles gave 2
million people Hep C
- immune globulin doesn't work
- same precautions as with Hep B
Hepatitis D is a plant virus that can infect only people who are positive with Hepatitis B. The Hepatitis D infection will make their liver disease much worse. There is currently no vaccine for this type of Hepatitis.
- incubation period of 15-60 days
- case fatality 0,5-3%, pregnant women 25%
- common in young adults
- children rarely get it
- no chronic liver disease
- water borne illness
- low person to person contagiousness
- humans are not the reservoir (swine, rats)
- boiling water helps
- vaccines seem to be helping (SKB)
- immune globulin does not work
unclear if causes disease
flavirus-does not cause disease
Is caused by a tick borne protozoan infection. Rodents, wild animals and cattle are its natural reservoir, with humans rarely infected.
Symptoms start 1-4 weeks after bit and may be mild to severe. In severe cases - high fever, chills, nausea and vomiting, may even mimic malaria with future complications such as lung edema, anemia, kidney failure and bleeding.
There parasites may be seen on a blood smear (as with malaria) and treatment may be supportive or if severe symptoms, several drugs are used.
This disease often co-exists with Lyme disease in the same ticks, although it is rare.
Is worldwide, yet rare in humans. This tapeworm infection is acquired through milk, vegetables or water contaminated with animal feces or by direct contact with infected animals (dog, fox, sheep, and cattle).
The tapeworm larval then encrypts in the liver, lungs, and other organs. Years can pass before symptoms develop depending on the size and location of the parasites
Liver cysts are abdominal discomfort, nausea, and vomiting. If a cyst ruptures, bleeding can cause sudden death. Cysts in lungs may cause a cough, shortness of breath, and even pneumonia or lung abscess.
Blood tests may defect tapeworm antibodies and chest x-rays or abdominal ultrasound may visualize the cysts. Surgical treatment is often necessary but drugs can also regress the cysts.
Influenza (which is a different disease from the similarly named Haemophilus Influenza type B mentioned above) is a highly contagious virus disease with epidemics regularly occurring. Infection causes sudden onset of fever, chills, muscle aches, cough, headache, and may lead to pneumonia. It is spread by sneezing, coughing or direct contact with the infected person. Children and adults with long-term illness like asthmas and diabetes are more prone to serious flu complications such as pneumonia, dehydration, meningitis, and even death. Influenza infection is a major cause of death in the elderly.
The virus has 3 subtypes A, B, and C. Type A causes moderate to severe disease, affects only humans and affects all age groups. Type B causes mild disease affects only humans, mostly children. Type C affects animals and rarely humans and is not associated with epidemics. The influenza virus also mutate frequently. Antigenic shifts and drifts are major and minor changes in the antigens, or parts of the virus recognized by the body's immune system.
These changes allow the virus to persist in the population and give rise to epidemics of the flu. Epidemics occur when incidence of influenza cases increase and mortality rises. Pandemics occur with high incidence in all age groups and increased mortality. An influenza pandemic could affect up to 200 million people with an estimated 400,000 deaths. Sporadic outbreaks occur when clusters of cases occur in families, schools or small communities.
The virus is acquired from respiratory droplets. It replicated in the trachea and bronchi causing local destruction and is shed for 5-10 days. Maximal communicatability occurs 1-2 days before onset and 4-5 days after. Symptoms appear after an incubation of 1-2 days. Abrupt onset of fever, muscle aches, non-productive coughs, and headaches occur. Severity is less if the person has encountered a similar antigened virus before. Only 50% of people have the above classical symptoms of influenza. Symptoms last 2-3 days and rarely more than 5. Aspirin should not be taken because of its association with Reye's syndrome, an often-fatal affliction
Complications of the flu include pneumonia (either a bacterial superinfection on top of the influenza or an influenza pneumonia which is rarer). Reye's syndrome is a rare complication in children with the development of coma and brain swelling. Other complications include myocarditis (heart inflammation), and worsening of chronic bronchitis. Death occurs in 0.5-1 cases per 1000 cases, usually in ages >65 years.
Diagnosing influenza can be difficult and is largely on the clinical appearance along with its prevalence in the community. Influenza peaks between December and March in temperate climates but can vary. It is year long in the tropics and outbreaks are common aboard cruise ships.
Vaccination
Vaccination is done with an inactivated virus of circulating strains of type A and B influenza. Egg protein is present. The vaccine is effective in protecting 90% of healthy adults but only 30-40% of the elderly. It is not highly effective in preventing illness but is effective in preventing complications and death particularly in the elderly. The vaccine is most effective if given 2-4 months prior to flu exposure and is usually available in September. The vaccine may be given annually for people older than 9 years. Children from 6 months to 9 years receiving it for the first time should receive 2 doses 1 month apart.
Flu shots are recommended for all people over 50 (over 65 are covered by Manitoba Health), children >6 months with chronic disease, long term care residents, health care workers, students, travelers, pregnant women, and persons 6 months to 18 years taking chronic aspirin therapy (so that they do not develop Reye's Syndrome). Any person who wishes to decrease the likelihood of becoming ill from influenza should receive the flu shot although Manitoba Health does not cover all the above groups.
Adverse effects of the Flu Vaccine
Local reactions occur at the site if vaccination with soreness and redness lasting 1-2 days in 15-20% of people. Non-specific fever and aches last 1-2 days in <1% of people. Hives and allergic reactions occur rarely particularly in people allergic to eggs. People with egg allergies should not receive the vaccine. At present the flu vaccine is injected but a nasal preparation is being developed.
For people with flu like symptoms antiviral therapy is available with new drugs that can block viral replication and prevent illness if started as early as possible (within 48 hrs). Vaccination still remains the best way of controlling the flu.
This is a mosquito acquired flavovirus infection that occurs in Asia. At least 35,000 cases with 10,000 deaths are reported yearly. The virus is similar to Yellow Fever and other flavoviruses.
Most infections are not symptomatic. 1 in 250 infections cause illness after 5-15 days of incubation. Illness begins with a high fever, change in mental status, gastrointestinal symptoms, headache and followed by disturbances in speech, gout or other motor problems. Symptoms progress to stupor and coma. 5-30% of cases are fatal and 1/3 of survivors may have neurologic injury. Treatment of Japanese Encephalitis is mostly supportive for affected people.
Japanese Encephalitis Vaccine
Japanese Encephalitis Vaccine is used to protect local populations in Asia who are mostly at risk. Others such as military personnel or expatriates (people who live as residents during a transmission season) may consider the vaccine. In most Asian countries the peak Japanese Encephalitis season lasts about 5 months and traveler's need only be vaccinated if at high risk during that time.
Risk factors for traveler's include:
1. Travel to endemic country
2. Travel during transmission season
3. Travel to rural areas (worse in rice paddies or near pig farms)
4. Extended period of residence or travel >4wks.
5. Advanced age 6. Pregnancy (risk to developing fetus)
Protective factors:
1. Repellants
2. Protective clothing
3. Residence in air conditioned or well-screened areas
4. Permethrin mosquito nets
The Japanese Encephalitis vaccine is given in 3 dose administered at 0,7, and 14-21 days, with a booster at 3 years. Side effects of vaccination include local redness and soreness at vaccination site, low grade fever, and muscle aches. Allergic reactions to JEV have occurred up to 20-336 hours after vaccination, which are treatable with Corticosteroids and antihistamines.
In conclusion, Japanese Encephalitis is extremely rare in traveler's but may be indicated in select people.
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Risk
of Japanese Encephalitis By Country, Region, and Season
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Country
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Affected
Area
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Transmission
Season
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Comments
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| Bangladesh | Few data, probably widespread | Possible July-December as in northern India | Outbreak reported from Tangail district, Dacca division; sporadic cases in Rajshahi division |
| Bhutan | No data | No data; presumed to be similar to Nepal presumed year-round transmission | Not applicable |
| Brunei | Pressumed to be sporadic-endemic as in Malaysia | Presumed year-round transmission | Not applicable |
| Cambodia | Endemic-hyperendemic countrywide | Presumed to be May-October | Highly prevalent in rural areas near Phnom Penh; some JE cases confirmed in epidemics of uncertain etiology, Oct-Dec 1993-1998 |
| Democratic Republic of Korea | Presumed countrywide chiefly in rural areas <800m | July-October | Epidemics reported in the 1970's few recent data |
| India | Reported cases from all states except Arunachal, Dadra, Daman, Diu, Gujarat, Himachal, Jammu, Kashmir, Lakshadweep, Meghalaya, Nagar Haveli, Orissa, Punjab, Rajasthan and Sikkim | South India: May-Oct, Goa: Oct-Jan, Tamil Nadu: Aug-Dec, Karnataka: second peak (April-June in Mandya district) Andrha Pradesh: Sept-Dec, North India: July-Dec | Outbreaks in West Bengal, Bihar, Karnataka, Tamil Nadu, Andrha Pradesh, Assam, Uttar Pradesh, Maharashtra Manipure, Kerala, and Goa Urban cases reported (e.g. Lucknow) |
| Indonesia | Kalimantan, Bali, Nusa Tenggara, Sulawesi, Mollucas, and West Irian Java, Lombok | Probably year-round risk; varies by island; peak risks associated with rainfall, rice cultivation, and presence of pigs. Peak periods of risk, Nov-Mar; June-July in some years | Hyperendemic on Bali. Sporadic cases recognized elsewhere. Vaccine not recommended if travel is to only urban areas. |
| Japan | Rare sporadic cases on all islands, except Hokkaido | Jun-Sep except Ryukyu islands (Okinawa) Apr-Oct | Vaccine not routinely recommended for travel to Tokyo and other major cities. Enzootic transmission without human cases observed on Hokkaido. |
| Laos | Presumed to be endemic-hyperendemic countrywide | Presumed to be May-Oct | No data available |
| Malaysia | Sporadic-endemic in all states of Peninsula, Sarawak, and probably Sabah | Nov-Jan peak on peninsula | Most cases from Penang, Perak, Salangor, Johore, and Sarawak; differentiate cases from Nipah encephalitis |
| Myanmar | Presumed to be endemic-hyperendemic countrywide | Presumed to be May-Oct | Repeated outbreaks in Shan State in Chiang Mai Valley |
| Nepal | Hyperendemic in southern lowlands (Terai). Sporadic cases in Kathmandu Valley | July-December | Vaccine not routinely recommended for travelers visiting high-altitude areas only |
| Papua New Guinea | Sporadic cases reported from D'entrecasteaux islands, Gulf, Milne Bay, Shouth Highland, West Sepik, Western provinces | Unknown | Vaccine not routinely recommended |
| People's Republic Of China | Cases in all provinces except Xizang (Tibet), Xinjiang, Qinghai. Hyperendemic in southern China; endemic-periodically epidemic in temperate areas. Rare cases in Hong Kong. New territories. | Northern China: May-Sept, Southern China: Apr-Oct, (Guangshi, Ynnan, Gwangdong, and Southern Fujian, Szechuan, Guizhou, Hunan, Jiangsi provinces) | Vaccine not routinely recommended for travelers to urban areas only, including Hong Kong |
| Pakistan | May be transmitted in central deltas | Presumed to be Jun-Jan | Cases reported near Karachi Endemic areas overlap those for West Nile virus. |
| Philippines | Presumed to be endemic on all islands | Uncertain, speculations based on locations and agroecosystems: West Luzon, Mindoro, Negro Palowan: Apr-Nov; Elsewhere: year-round-greatest risk: April-January | Outbreaks described in Nueva Ecija, Luzon, and in Manila |
| Republic of Korea | Rare sporadic cases | July-October | Last major outbreaks 1982-1983 |
| Russia | Far eastern maritime areas south of Khabarousk | Peak period Jul-Sep | Sporadic transmission; differentiate cases from RSSE |
| Singapore | Rare cases; last indigenous cases in 1992 | Year-round transmission no longer detected | Vaccine not routinely recommended |
| Sri Lanka | Rare cases; last indigenous cases in 1992 | Oct-Jan; secondary peak of enzootic transmission May-June | Recent outbreaks in central (Anuradhapura) and northwestern provinces |
| Taiwan | Endemic, sporadic cases; island wide | Apr-Oct, June peak | Cases reported in and around Taipei |
| Thailand | Hyperendeimic in north; sporadic-endemic in south | May-October | Annual outbreaks in Chiang Mai Valley; sporadic cases in Bangkok suburbs |
| Vietnam | Endemic hyperendemic in all provinces | May-October | Highest rates in and near Hanoi |
| Western Pacific and Australia | Discrete epidemics reported on Guam, Saipan (Northern Mariana Islands) Sporadic cases in the Torres Strait and Cape York, Australia | Uncertain, possible September-January in the Pacific; February-April in northern Australia | Enzootic Cycle may not be sustainable; epidemics may follow introductions of the virus. Single Australian mainland case reported in 1998 |
Reference: The Textbook of Travel Medicine and Health, Second Edition 2001 Herbert L. Dupont, M.D., Robert Steffen, M.D.
Epidemics occur in dry seasons in West Africa, Nigeria, Sierre Leonne, and Democratic Republic of Congo. This virus is transmitted to humans by infected rat body fluids, and then highly contagious between people. Up to 30% of those infected have no symptoms. Others have symptoms beginning after an incubation period of 1-3 weeks.
Symptoms are high fever, vomiting, diarrhea, cough, pains and generalized weakness. Inflammation of eyes, throat, face and neck may occur. After 3-6 days bleeding occurs. Survivors may be left with hair loss, deafness, and loss of coordination. Diagnosis is initially difficult to differentiate. White patches are present on the tousle. A blood test helps confirm cases. IV treatment, with anti-viral helps. Since there may be some time before people exhibit symptoms a strong suspicion should be kept in returning travelers with high fever, who have been to endemic areas, no matter how short their stay.
Lassa fever is an arena virus and is transmitted to people by contact with infected rat urine and also by person -to- person contact. It can cause severe illness including bleeding and meningo-encephalitis with lack of effective therapy, but the vast majority of people infected exhibit minimal symptoms
Risk to travelers is very small but exists for health care workers. Usually infected people will exhibit symptoms within 21 days of return.
Differential diagnosis includes other viruses caught from mosquitoes or other insects(Dengue fever, Yellow fever, O'nyong-nyong, Chikungunya, Rift valley fever, Crimean-Cango fever and Hantaon fevers.
Although leeches are distasteful they do not carry any serious diseases. Their bite may cause secondary infections. Covering up exposed skin, and tucking in trousers helps deter them, but most can still penetrate this.
To remove a leech a person can wait until it is sated with blood and it will naturally fall off. To speed up removal applying a lighted cigar, vinegar, salt or chili help. Direct pulling may leave the leech mouth wide inside. Because leeches use an anticoagulant to help them, their bites bleed for a while after removed. Direct pressure is the best way to control bleeding.
Is caused from inhaling certain bacteria from infected water, present through hot showers, air conditioning, or steam rooms, but not by person to person. The elderly are more susceptible to infections.
Symptoms occur after 2-10 days, and include chest infection, high fever, headache, and shortness of breath, bloody cough, nausea, vomiting, confusion, and loss of weight.
Diagnosis may be made with blood, urine, or sputum sample. Antibiotics are an infective treatment. Often outbreaks follow patterns, so avoiding places known to have outbreaks help to present cases.
Is found near the Mediterranean, Africa, China and Central and South America. Female Sandflies transmit this protozoa infection to humans from dogs or rodents. Other ways to catch it are from blood transfusions, sexual intercourse or from mother to child.
Sandflies bite at night. They only fly at laver altitudes above ground so being bitten can be avoided by sleeping above ground (hammock or second story of a house). They may be small enough to slip between mosquito nets, but if the nets are treated with permethracin they will deter flies.
Sand flies are tiny flies that breed in moist debris, like humid places, or damp soil rich in humus. They are also linked to poor housing conditions or forest/rain forest ecosystems where they like to breed in rotting leaves between the buttresses of tree trunks. Usually a sandfly bite has a non- swollen circle around it. Sometimes biting midges, near beach resorts, are referred to as sandflies, but are in fact not.
Leishmaniasis is grouped into 3 types:
1. Cutaneous (Aleppo boil or button, Baghdad boil, Baune ulcer, Delhi boil, oriental sore, tropical sore). The Sandflies bite first appears as red patches that gradually enlarge and ulcerate. Next nodules form that are itchy, firm, yet painless. Without treatment these heal slowly, often with scarring. Cutaneous Leishmaniasis is diagnosed by biopsy. Intravenous medication is needed to treat this.
2. Visceral Leishmaniasis (dumdum fever, Kala-azar). Most cases of this type are in India, Bangladesh, Nepal, Sudan, and at the Mediterranean. 'Kala-azar' is Hindu for black sickness as the disease causes darkening of the face, limbs and abdomen. They tend to affect young people and the incubation period can last months to years. Symptoms may start during incubation period, which can last months to years. Initially a mild fever with bouts of extreme sweating. With progression - weight loss, fatigue, anorexia, nausea, abdominal pain and diarrhea develop. Enlargement of the spleen, liver and lymph nodes occur. Untreated disease is fatal. Diagnosis is confirmed with blood tests. Intravenous drugs teat this disease.
3. Mucocutaneous Leishmaniasis (American Leishmaniasis, Chiclero ulcer, Espundia, Forest yaws, Uta). Present in South and Central America. Initially painful, itchy nodules occur, which heal within a few months. Years late 40% of these develop ulcers at face and mouth, which cause disfigurement. Diagnosis may be made from biopsy or blood tests. Medication and surgery are often unsatisfactory.
Leishmaniasis is acquired through the bite of the female sandfly, which generally bite at night. They are inactive during the day and like to breed in moist dark areas. Bites can be prevented through protective clothing at evening and night, elevation of bedding so it is not on the ground and DEET.
Cutaneous Leishmaniasis involves skin infection and is caused by Leishmaniasis major, Leishmaniasis aethiopia, and Leishmania tropica. Leishmania minor is a rural disease affecting wild rodents. Tourists, hunters and others living in these areas are vulnerable. Skin lesions are large, wet and multiple and rarely spread.
Leishmania aethiopia is found in Ethiopia and Kenya and typically infects the animal reservoir, the rock hyrax. Infection by tourists is rare. Leishmania tropica is an urban disease found in the Middle East and Asia. Leishmania brazilensis (in South America) can lead to distinctive mucocutaneous lesions.
Visceral Leishmaniasis (also known as Kala-azar) is caused by Leishmania donovani. It is common in Kenya and Sudan. Transmission may be human to human but outbreaks are usually in isolated areas so tourists are not usually affected. Infected patients may present with an acute illness after 4-6 months. Symptoms include high fever and severe sweats.
Progression to splenomegaly, hepatomegaly, lymphadenopathy and wasting with anemia, but only 5% go on to more severe symptoms.
HIV infected travelers and immunocompromised people will be affected more.
Leptospirosis
Leptospirosis is a spirochete bacterium and has a worldwide distribution.
It occurs in farmers, rice, sugar cane, taro and rubber plantations, veterinarians,
sewage workers, miners, and outdoorsmen. One half of U.S cases are from Hawaii.
People will acquire Leptospirosis from contact via water or moist soil, contaminated
with the urine of infected animals or the bodily fluids of infected animals.
There is an increased incidence in Hawaii (worse on wetter-windward side).
Leptospires enter the body from abrasions or contact with mucous membranes.
Leptospirosis in travelers is under-recognized and increasing. Worse in floods
and river rafting.
Symptoms of Leptospirosis with out jaundice. Incubation period can be 7-14
(Sometimes 2-21 days). Usually no symptoms and 90-95% are self-limited but
5-10% are severely sick. Symptoms of affected people follow 2 phases:
Phase 1: Leptospiremic phase (3-7 days)
-Sudden onset, severe frontal headache, muscle aches (calf and thighs), high
fever, abdominal pain, nausea, vomiting, diarrhea, rashes (maculopapular,
urticarial, hemorrhagic), enlarged liver, spleen and lymph nodes, conjunctival
suffusion
- very red eye. (A suffusion is an increased prominence of the vessels of
the eye and not the same as a conjunctivitis)
Phase 2: Immune phase (0-30 days)
-coincides with antibodies, and low grade fever
-Meningitis and uveitis (which can occur later)
Severe Leptospirosis (Weil's Disease)
- involves jaundice, kidney failure, bleeding and cardiovascular collapse
- possible biphasic phase, mild phase - no usual " mortality in severe disease
is 4-40% but may increase in the elderly
- worse prognosis with dyspnea, decreased urine output, elevated wbc and abnormal
EKG or chest x-rays
- pulmonary hemorrhage has increased mortality with epidemics in China, Brazil,
and Nicaragua. These cases don't have jaundice and represent a different variant
of Leptospirosis
Diagnosis
- confirmed with serology taken from 2 samples of blood, taken 10-14 days
apart
- a positive test is a 4-fold increase in antibodies in that time period
- compared with a 4-fold increase, 10-14 days apart
- lgM anti-bodies can appear after 4 days and peak at week 3-4
- white blood count can be normal but with elevated neutrophils, lower platelets
- CSF antibodies appear by day 10 - ESR elevated
- culture should be attempted with special media (check with lab) culture
blood and CSF in 1st phase
- urine in 2nd phase - specimens should be mid-stream and alkalinized after
collection
- dialysis fluid - good culture
- culture may take 6wks to become positive
Other Tests
- CSF fluid is usually normal in second phase, elevated protein, normal glucose
and pleocytosis with PMN cells, 1st and later lymphocytes
- Liver function tests - high bilirubin, alkaline phosphates, and transaminase
- Elevated amylase (but not pancreatitis
- Urinalysis - has proteinuria
Differential Diagnosis
- Malaria, Rickettsia, Typhoid, Hemorrhagic disease
Diagnostic Red Flags
- history of mud, water, or animal contact
- history of skin, cuts, or abrasions
- conjunctival suffusion (This can be confused with conjunctivitis)
- severe myalgia (calf and back) " acute severe headache
- fever and new onset arterial fibrillation
- Hepatitis and elevated wbc
- fever and elevated creatine kinase
- fever and elevated amylase
- elevated with bilirubin levels and mild transaminase
Treatment
- start treatment as soon as suspicious
- antibiotics given within 4 days of symptoms, reduce multi-organ complications
- late antibiotics also helpful
- Penicillin, Doxycycline, Erythromycin, for 7-10 days, Ceftriaxone is a good
choice as it may cover other infections
- Quinolones are also good (some resistance to chloramphenicol, vancomycin,
and aminoglycoside
- must have strict attention to fluids and electrolytes to prevent kidney
failure
- connect coagulation abnormalities
- dialysis may be necessary
Bottom Line
- high
index of suspicion
- early treatment
- good supportive treatment
Prevention
- identify high risk travelers such as adventure travelers or those water
rafting
- avoid contaminated water and soil
- wear protective clothing
- cover cuts and abrasions
- treat drinking water (iodination works well, maybe better than filters)
- shower after possible exposure
- avoid submersion
Vaccine
- Exists and is used for high risk groups in some countries
-Paris uses it for sewage workers, but this is only specific to specific types
of Leptospirosis, not useful at all for travelers
Chemoprophylaxis
- 200mg of Doxycycline once weekly is effective for short- term, high-risk
activity -start 1wk before and continue 1wk after, Zithromax works well for
children
Dengue Fever - overlaps with Leptospirosis but Dengue pain is more boney pain.
Leptospirosis is more of a severe muscular pain.
Based on a lecture by: Dr. Vernon Ansdell, University of Hawaii
Wilderness Medical Society April 2002
Lyme's Disease
Ticks harbor many infectious diseases. Ticks typically lie on shrubbery and
will crawl onto people. People infected are usually bitten by the nymph stage,
which can be small.
Rarely an adult tick will cause problem. Lyme disease incidence peaks in June
and July, which corresponds to when the nymph tick is most active in May,
and June.
Lyme Disease Stage 1: Fever, muscle aches, flu-like symptoms, enlarged
lymph nodes.
Erythema Migrams
- as symptomatic 5-20cm round or oral rash with central clearing occurs <50%
of the time
- occurs 7-10 days after bite at bite site (usually the margins of underwear
will stop the ticks ascend up a leg.
- 90% of Lyme patients have erythema migrams, less than ½ are recognized
- diagnosis is clinical. Serology is often negative. This is the best opportunity
for diagnosis and treatment. (Do not miss this window of opportunity)
- organisms can be cultured from the leading edge of rash, but this requires
special media that is not readily available.
Stage 2: Acute Disseminated Phase
1-secondary skin lesions
2-cardiac disorders
3-CNS disorders
4-neurological diseases
Skin Lesions
- look like red spots
-10-20% of time in untreated people
-usually smaller and less migrations may occur anywhere in the body
Neurologic Lesions
- 15-20% of untreated
-Facial nerve palsy not common
-"Aseptic" meningitis
- headache
-photophobia, neck, stiffness
-CSF fluid (pleocytosis - 10-100) and elevated protein
-chronic confusional state
-leukoencephalitis very rare, similar to multiple sclerosis
-some reversible CT scan abnormalities
Cardiac Lesions
- 8-10% of untreated
-1st-3rd degree heart block
-myocarditis or pericarditis by EKG (60%)
-mild left ventricular dysfunction (50%)
-may require hospitalization for cardiac pacing or observation
-most common cause of death in Lyme Disease
Stage 3: Chronic Widespread Arthritis (60%)
-recruitment a symptomatic pain
-usually 1 joint, lasting about 8 days
-predispostion forknee>shoulder>elbow>TMJ
-Inflammatory synorial fluid, organisms may be detected
-becomes chronic and destructive in 10%
-people with haplotype DRA may be predisposed to developing arthritis
Diagnosis
- Erythema Migrans rash
- pathognomatic for Lyme disease
If no skin lesions:
-thorough examination
-check if history consistent with tick bite and get lab confirmation
Lab Studies
- lgM presents 2 wks, peaks 3-4 wks then declines
- lgg presents 4-6 wks, peaks 8 wks, then may be elevated for years
Early Removal of Tick (is best)
-clean wound
-meticulous search for other ticks which may be very small
-follow-up for fever, headache and rash
"Risk of adverse reaction to antibiotics is greater than risk of Lyme disease".
- Dr. Steeve: denies relation with chronic fatigue, and fibromyalgen.
- Lyme Disease advocacy groups and the media have great influence regarding
Lyme Disease, and this has led to confusion as to what Lyme disease is and
is not
Arthropod Avoidance
DEET - effective against mosquitoes, not as good against ticks
Permethrin - very effective -spray lasts 1 or 2 washings
-soaking clothing in solution 1.5cc of 13% solution/L lasts 50 washings
-strong smell but disappears when dried
Vaccine
- from protein (recombinent vaccines)
- effectiveness 49% after 2 injections, 76% after 3 injections
- duration of protection unknown
- vaccinations in outer membrane in Europe, so European Lyme Disease is not
prevented
- vaccinees will not develop erythema migrans rash if infected
Babesiosis
- concurrent parasite = with Lyme Disease
-same distribution
-co-infected patients have headache, fever, chills, anorexia, and conjunctivitis
symptoms for 3 months or longer
- also Ehrlichosis also has similar distribution as Lyme Disease
Treatment of Lyme Disease
Primary (Stage 1)
Infections where erythema chronicum migrans is seen, can be treated with
one of the following:
- Doxycycline 100mg po BID x 10-21days
- Amoxil 500mg po BID x 10-21 days
- Cefuroxime 50mg po BID x 10-21 days
- Zithromax 500mg po BID then 250mg po od x 4 (12 pack)
Arthritis - treat with one of the following:
- Doxycycline 100mg po BID x 30 days
- Amoxil 500mg TID x 30 days
- Ceftriaxone 2g IV q4h x 14-21 days
- Pan G 4million units IV q4h x 14-21 days
Isolate facial palsy (where Lyme disease suspected)
- Doxycycline 100mg po BID x 30 days
- Amoxil 500mg TID x 30 days
Other neurologic SX:
- Ceftriaxone
2g IV od x 14-21 days
- Pan G 4million units q4h x 14-21 days
References:
New Front Against Lyme Disease
www.gene.com/ae/WN/SU/front_against_lyme_disease.html
Centre for Disease Control
http://www.cdc.gov/ncidod/diseases/submenus/sub_lyme.htm
European Union Concerned in Action on Lyme Borreliosis (EUCACB)
www.dis.strath.ac.uk/vie/lymeEU/
Malaria affects 500 million people worldwide and kills at least 2 million per year. Over one million Africans die yearly (mostly children). 30,000 Europeans and North Americans are affected. Anopheles mosquitoes are responsible. They carry malarial parasites, (plasmodium falciparum, vivax, oval, or malaria), which are four different species.
Anopheles mosquitoes are sometimes identifiable by the way they bite (head downward when biting), compared with culex mosquitoes that stand parallel. Female mosquitoes of Anopheles type bite at night or twilight. Urbanization may create areas where mosquitoes may breed close to people (stagnant water).
Mosquitoes don't travel more than two miles from where they are bred. Weird exceptions are airport malaria acquired by passengers being bitten by mosquitoes indoors during stopovers. Wind could also blow mosquitoes further away. Only female mosquitoes drain blood. Males eat nectars and fluids.
Malaria is caused by a parasite transmitted by certain species of mosquito. Once a mosquito bites a parasite, a gamocyte enters the mosquito and breeds internally creating oocytes and then sporocites, which travel to the salivary glands of the mosquito. These sporocites can penetrate the liver of an infected human within 45 minutes. Within 9-16 days the sporocites differentiate into merozites, which invade red blood and liver cells. Blood cells rupture, releases gametocytes and merozites, which cause the cycle of fevers and chills.
Different malarial species have different severity of diseases all of which are bad. Sometimes malaria may be easy to recognize, but also sometimes difficult.
Symptoms of malaria may be very subtle - flu like attack, fever and chills which may lead to multi-organ failure and death. Important to note that malaria medication will lessen symptoms of malaria but does not guarantee immunity. Malaria chemoproplylaxis helps prevent life threatening malaria that will kill people before seeking medical attention. Any symptoms should be investigated with thick and thin malarial smear. This can still lead to misdiagnosis, as a smear may not "catch" parasites on microscopic analysis. If malaria is suspected, one normal smear does not rule it out. It is generally assumed that any returning traveler with fever has malaria until proven otherwise. Many other infectious diseases may also manifest as flu like symptoms but malaria is the one diagnosis not to miss.
Many other mosquitoes co-exist with the Anopheles mosquito-Aedes aegypti, Culex, Haemogogus, Sabethes, and Masonia, which cause other diseases like yellow fever, filariasis, viral encephalitis, dengue and other hemorrhagic fevers. Other insects (tse-tse flies, black flies, deerflies, sand flies, lice, ticks and mites) cause a variety of illnesses many of which have no known vaccine or medication to prevent illness as well as no good treatment. General recommendations are to avoid all insects similarly to malarial mosquitoes.
Prevention is best accomplished by avoiding being bitten. Wear long sleeved shirts and long pants. Use insect repellent, sleep under a mosquito net, use mosquito coils, don't sleep on ground, and check for ticks and insect bites daily. Be knowledgeable of the signs and symptoms of the disease you may likely encounter where you are traveling.
Types of medication to prevent malaria (chemoproplylaxis) include
Chloroquine: (Avalen): Cheap, well tolerated but bitter taste, can upset stomach and blur vision. There are many areas resistant to chloroquine. Medication is started one week prior to travel, and taken weekly during and for four weeks after trip.
Mefloquine: (larium): More expensive, but 2-5% of people reported side effects (anxiety, nausea, hair loss, poor sleep, irritation). It is used where chloroquine resistance. Medication is also weekly, starting one week before, during trip and for four weeks after trip.
Doxycycline: Daily medication used where mefloquine resistance or as alternative to above. Side effects include stomach irritation and photosensitivity. It is started four days prior to trip, and continues for four weeks after leaving area.
Chloroquine, mefloquine and doxycycline should be taken for 4 additional weeks after leaving the malarious area because they are only effective for malaria in the blood. Since the parasite may be in the liver for 4 weeks, they must also be taken for that long. Long-term use should be monitored for adverse effects but has been used for years in expatriates
Malarone: (Atoraquine/Proquinil): Is new, but expensive and can cause nausea and vomiting. This drug may be started 2 days before the trip. It is taken daily and then discontinued 7 days after the trip. It is discontinued sooner because it is effective at killing malaria in the liver. So there is no need to take this medication as long as mefloquine, chloroquine or doxycycline.
Self-treat malaria kits are available. Many travelers would do self-testing and then treat themselves. Also large doses of malaria drugs in a sick person are not without side effects. Self-treatment is not recommended. Instead preventative measures are best and to seek medical attention if ill.
90% of travelers with malaria do not become ill until after they return home. This illusion of good health may foster urban myths among travelers on laxity of mosquito precautions.
Taking medications to prevent malaria is not a perfect solution but is still the over all best way to prevent malaria. All the malaria medications have some type of side effects but the benefits of them preventing malaria far outweigh these effects.
Other information on malaria:
General:
Infection caused by a parasite that is transmitted through the bite of an infected Mosquitoes. Malaria enters the body through the blood stream, once in the blood stream parasites travel to the liver and destroy red blood cells. Other complications include anemia caused by blood cell destruction, and clumping of blood cells that may cause brain and kidney damage.
Signs & Symptoms:
1. Headaches
2. Shakes and chills caused by fever
3. Fatigue
4. Rapid breathing
5. Nausea
6. Extremes sweating with a drop in temperature
Prevention:
1. Anti-malarial drugs
2. While in mosquito infested areas use mosquito netting
3. Avoid crowded or unsanitary conditions
4. Wear long pants and long sleeved shirts
Treatment:
Anti-malarial drugs to kill the parasites
This virus occurs in small outbreaks in Sudan, Kenya, and Democratic Republic of Congo and is passed between people by intimate contact. It is rare and low risk for travelers.
It is a viral hemorrhagic fever, which may cause fatal bleeding. A blood test confirms the diagnosis. Careful support 'barrier nursing' is required for affected people.
The bacteria that cause this are rare, but outbreaks have occurred in Vietnam, the Far East and Northern Australia. These bacteria enter through cuts and abrasion, injecting contaminated water and inhalation. It is more common in animals than people usually.
Bacterial infection that causes meningitis,(an inflammation of the brain membranes). Can occur world wide, but more prevalent in the 'meningitis belt' which covers consists of Sub-Sahara African countries, often worse during dry seasons, and potentiated by war, and famine.
A vaccine is present against the A, C, W, and Y forms of their disease. At this point there is no vaccine for the B subtype although researchers are working on it. This vaccine is mandatory for travelers during the Hay to Mecca. Saudi Arabia used to use the C type vaccine, but uses W-135 vaccine now.
Symptoms incubate after 2-10 days. Cold like symptoms develop into malaise, fever, headache, neck irritation and a rash. The rash is indicator of widespread blood infection (septicemia). It is a collection of bleeds under the skin. If suspected meningitis MUST be treated with penicillin (or other suitable antibiotics) as soon as vaccine is recommended for all individuals over 2 months.
Vaccine is given to younger individuals, but the response may not be great.
Treatment for menigococal infection is to treat with penicillin. If penicillin is given prior to admission, patient will have a 50% better prognosis. If menigococal disease is suspected patient should be given penicillin (benzyl penicillin).
BEDSIDE GLASS TEST: Is used to detect menigococal infection. Skin will not blanch from pressure. If menigococal is suspected it must be treated immediately.
Menigococal infection produces fever and a non-blanching rash.
A chronic fungal infection, usually affecting the lower extremity involving skin, muscle, and bone. These fungi enter the body through a scrap or cut. At first small firm painless nodules develop over weeks to months. They will enlarge and ulcerate in their centers.
Treatment with drugs and often surgery is necessary.
Is the infestation of bodily tissues by the larvae of flying insects? In Africa the tumbu fly and Lund's fly are responsible. Tumbu flies like to lay eggs on drying laundry and the larvae enter the skin when clothes are worn.
In Central and South America the human botfly and new world screwworm cause disease. Human botfly affects people and cattle. A botfly catches blood-feeding insect, lays eggs into it and that insect later injects the eggs into the human when it feeds. These larvae usually stay where they penetrated. After 12 weeks the larvae leave the skin and mature in soil. New world screwworm flies lay eggs on the edges of wounds and healthy mucous membranes (mouth or nose) and the larvae then burrow in and incubate about 1 week.
Myiasis is a rare condition in travelers. Symptoms are mainly itchy sores or oozing boils, but there are no long-term effects. Sometimes maggots are seen by their air hole they create in the skin. Closing the hole with Vaseline forces it closer to the surface, making extraction easier.
Insect borne virus spread by mosquitoes in East and West Africa, as well as Zimbabwe.
Symptoms include high fever, joint pain, headache and swollen lymph nodes. Sometimes there is a general rash. Recovery can take two weeks.
There have been no serious long-term problems after an infection but pregnant women have had increased miscarriage because of infection. There is no specific treatment but general mosquito precautions should be observed. This disease co-exists with malaria so general precautions against malaria should be observed.
3 main species exist:
1) Clonorchis sinenis in China, Taiwan, Korea, Japan and Vietnam carried by cats and dogs.
2) Opistriorchis felineus in Eastern Europe and carried by many animals.
3) Opisthorchis viverrini in Thailand carried by dogs and cats.
Humans acquire the parasite after eating raw, dried, or pickled fresh water fish. Millions of people are infected but only some have problems.
Symptoms include liver pain, fever, nausea, vomiting, and jaundice can occur. Diagnosis is by eggs in the stool. An anti-worm medication will cure this disease.
Oroponche
Virus
Virus transmitted by midges present in Peru, Brazil, Trinidad and Panama. Natural reservoir is the sloth. Symptoms include headache, fever, aches, nausea, vomiting and sometimes meningitis. Blood tests confirm the diagnosis although no specific treatment exists.
Virus transmitted by midges present in Peru, Brazil, Trinidad and Panama. Natural reservoir is the sloth. Symptoms include headache, fever, aches, nausea, vomiting and sometimes meningitis. Blood tests confirm the diagnosis although no specific treatment exists.
Acquired from eating infected crabs or crayfish. Flukes migrate from intestine into lungs and other organs. The adult worm matures and produces eggs after 6 weeks, which are coughed up. Particularly risky foods include 'drunken crabs' - crabs that are immersed in rice wine before eaten or raw, pickled, or undercooked fresh water crustations.
Symptoms include mild cough, fever and blood stained sputum. Later night sweats and chest pain develop. Medication is effective although surgery is sometimes needed.
Is a mild disease related to typhoid caused by similar bacteria?
Symptoms include malaise, fever, headache, anorexia and cough. Sometimes bleeding, confusion and hearing loss occurs. It is acquired after eating contaminated food or water.
The vaccination against typhoid does not give protection, but ciprofloxacin (an antibiotic) is effective treatment.
The pneumococcal bacteria are the most common cause of pneumonia, meningitis, sepsis, sinusitis, and ear infection in children under 2 years.
A pneumococcal vaccine has been available for many years but had not been recommended for children under 2 years old because it was not effective in this age group. A new pneumococcal conjugate vaccine has recently became available. This vaccine targets the 7 most common disease-causing types of Pneumococcus. Pneumococcal Disease is the leading cause of bacterial meningitis (swelling of the brain and spinal cord) of children 5 and younger. It can also cause severe blood infections (bacteremia) and lung infections (pneumonia).
This is spread to people by droplets of bacteria that are breathed in. For bacteremia and meningitis fatality per case is 10-20% in infants and up to 80% in elderly people. Pneumococcal infections can be treated with antibiotics but vaccination is becoming an important method of prevention since bacteria resistance to antibiotics is becoming a problem.
There are two types of pneumocoocal vaccines:
1. The Pneumococcal polysaccharide vaccine is recommended for children over 2 years with high risk of disease (lack of spleen, sickle cell disease, nephritic syndrome, CSF leak, and immunosuppression including HIV infection). This vaccine is also recommended for adults 65 years and older, those with chronic diseases, immunocompromization, HIV infection, and those in high-risk occupations. One vaccination is enough but people at very high risk may have a single booster after 5 years. This vaccine is not effective in children under 2 years.
2. The pneumococcal conjugate vaccine is recommended for children <24 months and is given at 2,4,6 and 12-15 months. Unvaccinated children >7 most need fewer boosters. It is recommended to consider vaccinating all children aged 24-59 months as well.
Adverse effects include local reactions (polysaccharide 30-50%, Conjugate 10-20% and fever or muscle aches (polysaccharide <1%, conjugate 5-24%) but there are no severe reactions. For children, the vaccination with the conjugate vaccine (Prevnar) is:
For Healthy children :
Three doses are given in the first year of life followed by one booster in the second year.
Dose 1 at 2 months
Dose 2 at 4 months
Dose 3 at 6 months
Dose 4 at 12-15 months.
(The recommended interval between doses is 4-8weeks)
|
Vaccination
for Healthy Children after 7 months until 9 years of age
|
||
|
Age
at first dose
|
Total
number of doses
|
Dosing
information
|
|
7-11
months
|
3
|
-2
doses 4wks apart
-3rd dose after 12mos old -3rd dose 2mos after 2nd |
|
12-23
months
|
2
|
-2
doses 2mos apart
|
|
24mos
to 9yrs
|
1
|
-1
dose
|
Occurs after earthquakes, and natural disasters where there is increased contact with wild rodents. Often a plague is heralded by large amounts of dead rats. A flea transmits the bacteria from rats to people. The plague vaccine is not given for travelers (more so for lab personnel).
Symptoms start between hours to as long as 17 days after the initial flea bite, and include headache, high fever, muscle aches, and nausea. Lymph nodes become inflamed and become buboes, which may enlarge and develop abscesses. The infection may spread to blood (causing septicemia) or lungs (pneumonic plague), which is then contagious by coughing. The patient may also have increased bleeding.
Diagnosis is with a blood test and treatment includes tetracycline or similar antibiotics.
General: Polio is an infectious disease that attacks the central nervous system, injuring or destroying nerve cells that control the muscles.
Side Effects: None. The oral polio vaccine had more side effects but is no longer used in Canada
.
Booster: Required ten years after the initial vaccine and is then said to be good for life.
The W. H. O.' s goal is to eradicate polio by year 2005. Vaccinations may discontinue after this date.
Caused by ricketssia an infection microbe carried by sheep, cattle and goats. It can be acquired by contact with milk, urine, and feces and by breathing it in. people who work with animals are at the greatest risk (not travelers). A vaccine exists but is only recommended for high-risk occupations.
This illness occurs worldwide but greater in rural areas.
Symptoms begin after 10-20 days of incubation with headache, fever, shivering, muscle aches, loss of appetite, fatiguability, and nausea. Also sharp pain with deep breathes. Usually symptoms last 2 weeks but rarely heart, liver and brain complications can happen.
Diagnosis is confirmed with a blood test but may not be suspected because it is rare and hard to differentiate clinically from other viral illnesses. Medications (doxycycline) can speed up reduction of symptoms although usually the disease is self-limited.
Rabies causes 60,000 deaths worldwide, half of which are in India. Countries completely free of rabies include: Australia, New Zealand, Japan, Honk Kong, Singapore, Great Britain, and some Scandinavian countries. The virus Rhabdoviridae Lyssavirus causes rabies. All mammals are capable of transmitting disease to other animals or people. 99% are from dogs.
Animal commonly carrying rabies:
1. Dogs: Major vector of rabies especially in Asia, Latin America, and Africa.
2. Foxes: Europe, Arctic, and North America.
3. Raccoons: Eastern USA.
4. Skunks: Mid Western USA and Western Canada
5. Mongooses: Yellow mongoose in Asia and Africa, Indian mongoose in Caribbean Island.
6. Coyotes: Asia, Africa, and North America.
7. Bats: Vampire bats from Northern Mexico to Argentina. Insectiverous bats in Northern America and Europe. Man to man transmission is possible (3 cases) but precautions for medical or paramedical personnel receiving routine vaccination is not needed.
Infections with rabies occur when the virus is first inoculated into the victim and then absorbed into a susceptible cell where it multiplies. The virus then enters nerve endings. The virus will migrate to the brain and once the virus has then entered the brain, rabies symptoms begin to occur. Rabies is almost universally fatal afterwards. The term rabies refers only to when the person has the fatal condition.
The average incubation time before the development of symptoms is 90 days, although is has occurred is as little as 7-10 days to greater than a year. Rarely only a few days resulted in rabies and 1 case was over 6 years.
Children tend to develop symptoms faster because bites are closer to the brain (the virus have less to travel towards the brain), and often more severe.
Symptoms of rabies in people are divided into 2 types - encephalitic (furious) and paralytic (dumb). Early symptoms may be vague and non-specific (fever, upset stomach), local symptoms may occur at bite site (burning, numbness, tingling or itching).
Characteristics of encephalitic (furious) rabies:
1. Fluctuating consciousness from agitation to depression, which will gradually progress to coma.
2. Phobic spasms - aerophobia and hydrophobia, (the fear of water and air).
3. Signs of autonomic dysfunction like fixed dilated pupils, increased salivation, excessive sweating and priapism.
Rabies is 100% fatal although four people to date have survived but all with neurological damage.
PREVENTION AND TREATMENT OF RABIES
Pre-exposure vaccination is giving the rabies vaccine to people who might be exposed to rabies. The vaccine is given in three doses as days 0, 7, 28, (or 21) with a booster at 1 year and every 5 years after. It eliminates the need for post exposure immunoglobulin treatment after a rabid bite, which may not even be available in certain countries. It also simplifies post exposure treatment to only 2 vaccine doses after being bitten.
People who should be vaccinated include researchers working with rabies, veterinarians, and remote travelers. Spulunkers may also be at risk of rabies from bats. Children of long-term travelers might also be at high risk of rabies in developing countries.
POST BIT TREATMENT
Cleaning bites is the most important step in preventing rabies. This should be done as soon as possible, first by flushing the wound with soap and water, followed by 70% alcohol, or tincture of iodine.
Rabies exposure is graded as:Type of Contact - Recommended Treatment
1. Touching, feeding, or licks, (animal)on intact skin - No treatment necessary.
2. Nibbling of uncovered skin, minor scratches or abrasions without bleeding, licks on broken skin. - Give vaccine. Stop treatment if animal observed to be healthy after 10 days in quarantine or lab tests are negative
3. Single or multiple bites Or scratches.Contaminated mucous membrane by saliva (Licks). - Give vaccine and rabies immunoglobulin. May stop treatment if rabies tests result come up negative for the animal.
After a rabid bite the rabies vaccine is usually given on days 0, 3, 7, 21, and 28. The vaccine is given in the deltoid (or thigh in children). It is not to be given in the gluteal muscle because there is poor absorption of the vaccine when given in the gluteal area.
Sometimes a double dose of the vaccine is given on day 0 if the patient is immune deficient or had a very bad bite. If a person who had been previously vaccinated within 5 years is bitten they only require 2 booster doses at days 0, 3 but do not need rabies immunoglobulin.
Rabies immunoglobulin is given to those people with severe bite(s) who have no prior antibodies that will bind to the virus to prevent them from entering the nerve tissue and spreading to the brain. This should be given as soon as possible after being bitten since rabies has developed a few days after being bitten. People will begin to produce their own antibodies 7-10 days after being vaccinated. The immunoglobulin should be injected into the wound with a separate syringe from the rabies vaccine. Treatment should not be withheld while waiting tests or quarantined animals.
Intradermal injection of vaccine for post rabies exposure is done in some developing countries, which is much cheaper since less vaccine is given intradermally. The vaccine is given in day 0,3, and 7 in double doses; and days 28 and 90 at single doses. Some North American centers will give intradermal injections for pre-exposure since this is likewise cheaper. However when doing this these patients have to be followed closely by lab tests to confirm the effectiveness of this type of immunization with extra injections if a low immunoglobins titre is found. In Canada, there is at least one center that uses the intradermal approach but not in Manitoba.
Complied by Gary Podolsky
June 2001 Reference 1. Pasteur Merieux Connaught monograph 2001
W.H.O- guidelines on rabies.
Relapsing fever is a bacterial illness called so because of the unresolved recurrent fever in untreated people. There are two types:
1) The louse-borne variety is found in areas of poverty with epidemic occurring after natural disasters. There live proliferate in the clothing.
2) The tick-borne variety is found in Africa, Southern Europe, Middle East, Asia, Western U.S.A. and Canada.
The risk for travelers is generally low. Person to person infections does not occur except by the method of infected body lice infesting people.
Symptoms occur after an incubation period of 2-10 days with abruptly starting fevers chills, aches, headaches and profound weakness, which last for about a week. A remission period then takes place for the duration of one week with no symptoms. Next a relapse period occurs with resumption of symptoms for another week.
Without treatment the cycle continues. Additionally lymph nodes, liver and spleen may swell and sometimes jaundice and a purpuric rash develop. A cough is also noted. Each time the fever drops the blood pressure can drop very significantly. With long lasting disease inflammation of the heart and brain can occur. Untreated relapsing fever can be very dangerous but it does respond to treatment well.
Diagnosis occurs with a blood test. Treatment with antibiotics must be maintained, as often there will be complications during treatment (the bacteria while dying interact with the medication causing more symptoms).
Outbreaks have occurred in Sub-Sahara Africa, Egypt, Kenya, and Somalia and are usually associated with heavy rainfall and flooding.
This disease is a viral hemorrhagic fever type transmitted by mosquitoes. It also infects cattle, sheep, goats and camels. People may also be infected through blood, meat, bodily fluids and milk of infected animals. Some vaccines have been developed which are used for researchers but all are not widely available and the average traveler is at very low risk for this disease. Avoiding potentially diseased carrying mosquitoes and livestock is still the best preventative measure.
Symptoms are similar to other infectious diseases and can be confused with meningitis. Usually after an incubation period of 2-7 days a fever develops that peaks twice (the first occurring for 2-4 days followed by a break and then again). Headache, muscle aches, and back pains are common. Neck stiffness, vomiting and pain from bright lights (photophobia) can also occur. Very severe cases may cause brain, liver or eye complications, usually in the first 3 weeks of illness with a high mortality rate. Diagnosis can be confirmed with blood tests for this virus's antigen. There is no specific treatment for Rift Valley Fever since most are mild and limited infections, but supportive care can be done for the rare severe cases.
(Choix fever, New world spotted fever, Pink fever, Tick fever)
This is a tick-borne illness and usually affects 600-800 people per year in the United States, mostly in the southeast states (Oklahoma, Tennessee, the Carolinas, Georgia and Virginia). It is also in Central and South America.
The tick responsible is more active in spring and summer. Children between 5-9 years are most commonly bitten. One reason is that they are more likely to brush against tick carrying shrubbery and get bitten.
Rocky Mountain Spotted Fever is related to typhus and caused by a rickettsia (bacteria-like organism) transmitted by ticks (in the eastern U.S it is the deer tick, while in the western U.S it is the wood tick).
The longer a tick is attached the greater the chance of infection. That is why daily surveillance (especially for children) when traveling in tick borne areas is essential. Tucking pant legs into trousers and insect repellants also help. Ticks should be carefully removed to not leave body parts in the wound.
Symptoms of Rocky Mountain Spotted start 1-2 weeks after the tick bite and are usually sudden with high fever, chills, muscle aches, severe headache and vomiting. A crusted, raised, lump may be at the inoculum (insect bite) with lymph nodes swollen. The characteristic rash of Rocky Mountain spotted fever begins 1-10 days after the onset of fever.
Small red spots begin at the extremities (hands, feet, ankles) and spread centrally (towards the trunk) while usually sparing the face. With progression these rashes became purpuric (bleeding under the skin) so that they will not blanch with pressure. Complications of this disease can lead to brain, kidney, liver, lung failure, and death, if untreated. Treatment is with tetracycline or a suitable alternative.
Diagnosis is on history and collection of symptoms. Blood tests take days to develop. It is important to note that although this rash is typical, not all cases have the rash or it may be very faint or hard to see, so its absence does not rule out the disease. Prognosis related to speed of treatment so an antibiotic may be started without a specific diagnosis (many of the tick borne diseases have similar treatments).
Different types of rickettsia cause other spotted fevers and their name usually tells of their location. Avoidance, diagnosis and treatment are similar to Rocky Mountain spotted fever, although the severity of symptoms can vary between them.
Examples are:
- Mediterranean Spotted Fever
- Kenyan Tick Typhus
- African Tick Bite Fever
- Israeli Spotted Fever
- Astrakhan Fever (found in the Caspian sea),
- Siberian Tick Typhus
- Indian Tick Typhus
- Japanese Spotted Fever
- Queensland Tick Typhus
- Flinders Island Spotted Fever (Australia)
Ross River Virus is found in Australia and South Pacific Islands. It is mosquito-borne and spreads by the insect after flooding during the rainy season. It affects wild (kangaroos and wallabies) and domestic animals. There is no vaccine, and risk for travelers is low unless an active epidemic is occurring.
Ross River Virus is similar to Dengue Fever. After 2-21 days of incubation, flu-like symptoms (fever, chills, aches, headaches, and lethargy) occur with sometimes a rash. Painful stiff joints may occur. The acute symptoms resolve quickly but joint aches may persist for months. Blood tests will confirm the viral antibodies. There is no specific treatment other than supportive. Unlike Dengue Fever there are no sever symptoms.
Sandfly Fever is found in the Balkans, Middle East, Central and South East Asia, parts of the Mediterranean, and Central America. It is a viral illness transmitted by the same sandflies that transmit Leishmaniasis.
There is no vaccine but since sandflies cannot fly above 3m. Sleeping above the ground helps. Sandfly fever has an incubation of 3-8 days with abrupt onset of fever, chills, headache (retro orbital - behind the eyes), muscle and joint pains. Usually symptoms are intense, followed by weakness and then recovery.
Diagnosis is by history although more severe infections like Dengue Fever and Malaria should be ruled out. A blood test will confirm infection. Specific treatment for the relief of symptoms is recommended.
This is the most common form of seafood poisoning. This is caused by fish with dark or red meat (mackerel, tuna, bouito, albacore, and skip jack), which contain a large amount of histadine. If the fish spoils bacteria will convert histadine into histamine. These fish have a peppery, metallic, taste. The histamine is not affected by cooking.
Symptoms start 3 hours after eating fish and include flushing, burning, tingling of the mouth, abdominal pain, nausea, vomiting, headache, thirst, wheezing, and itchy hives. All these symptoms are of severe allergies, which may last 3-4 hours.
The diagnosis is made on history and symptoms. Anti-histamine.
The St. Louis Virus is found throughout the U.S.A in the summer, roughly 100-200 cases per year. This virus occurs in birds and is transmitted to people by mosquitoes. It is similar to the Japanese Encephalitis Virus. Most cases are asymptomatic, flu-like illness erupts after 5-15 days. Severe cases cause paralysis and fatalities may occur in the elderly and very young.
Diagnosis is by blood tests and treatment is supportive.
Related to yellow fever, dengue fever and Japanese encephalitis virus. Is caused by several species of ticks living in Central and Eastern Europe and parts of Asia. Tick activity starts when soil temperature rises to 5-70C in March or April and ends in Fall. In Mediterranean countries ticks are more active November-January. Ticks are worse in wet summers and mild winters.
The risk of infection from specific tick bites ranges from 1:200-1:900. People at highest risk of being bitten include agriculture/forestry workers, hikers/ outdoorsmen and collectors of berries and mushrooms. These ticks attach to humans at hair covered portions of the scalp, ears, arms, knee joints, and hands and feet.
DIAGNOSIS:
- 1gM Elisa on serum (acute)
- Confirmation requires acute and convalescent serum to check for immunity check serology.
CLINICAL SYMPTOMS:
- Incubation 2-28 days
- Biphasic symptom
- 1st Stage (viraemia): fever, headache, myalgia and leuko and thrombocytopenia for 1-8 days. Latency stage then occurs lasting 1-33 days before the 2nd stage.
- 2nd Stage Up to 25% of cases develops meningitis, meningo-encephalitis, and transmyelitits. Case fatality rate of 1-5%. Paresis in acute stage- (3-23%) usually involves shoulder or hemiparesis and may sometimes involve cranial nerve pulses.
SYMPTOMS:
- Mild disease (55%) meningeal/encephalitis.
- Moderate (37%) moderate meningeal symptoms.
- Severe (8%) severe encephalitis.
TREATMENT: Gammaglobulin and Corticosteroids do not appear to work well. Strict bed rest and observations recommended
LONG TERM SEQUALAE:
- Prolonged hospital stay.
- 50 days- 40% still on sick leave.
- 40% of patients had chronic residual symptoms.
DIVERSITY OF LONG TERM SYMPTOMS:
Include neuropsychiatric symptoms (memory loss, stress intolerance, decreased concentration), balance, dysphagia, hearing, headache, and paresis. Negative prognostic factors include middle to high age and the severity of the acute phase.
3 CLINICAL COURSES:
1) Full recovery in 3 months.
2) Prolonged clinical return with neuropsychiatric and neurological problems.
3) Residual paresis.
In epidemic areas, TBE is one of the most important causes of viral CNS infections. Case fatality and severe effects still is very low (0.5-5%).
TICK BORNE ENCEPHALITIS VACCINE:
1) Common in Austria/Germany/Balkan. Invented in 1971 by Dr Kunz.
2) Indicated for long-term residents.
3) Short-term travelers? May consider if significant exposure.
4) Recommended for endemic areas in the Alps
5) People receive 90%protection after the 2nd dose.
6) Vaccine not available in North America
TBE VACCINATION FOR TRAVELLERS:
1. Consider epidemology of travelers and the disease. Austria has 84% of the population vaccinated. Goal is to have no more than 5-10 hospitalizations per year. Vaccination occurs in schools. Travelers to Austria, Western Europe should consider vaccination if they plan to be outside even including stays in urban parks.
2. Schedule: Day 0 1st, day 14-90 2nd, and 10-12 mos 3rd .5ml for adults and .25ml for children <12 yrs. Boost every 3 yrs.
3. Alternative for travelers arriving into Central /Western Europe: Double dose at day 0 on 2 arms and 2nd dose at day 7 (0R, 0L, 7 day schedule '007') If a person is at a very high risk at exposure the TBE vaccine is available upon arrival at many European clinics.
Compiled June 2001
1. 8th ISTM meeting in Austria
2. Lecture by Dr. Kunz
3. Baxter monograph on TBE.
Tick Typhus is transmitted to humans by ixodid ticks. An eschar scar develops at the bite site and the rickettsia (small bacteria like organism) incubates for about 1 week. A fever develops with a maculopapular rash (which may be very small). This rash and eschar are very typical of tick typhus but often this illness is confused with malaria or a traveler's diarrhea infection. A headache is also noted.
Usually symptoms are mild but kidney, liver and neurological damage can occur.
Doxycycline is an effective treatment and doxycycline when given daily for the prevention of malaria will prevent typhus.
Infective ticks infest domestic and wild animals particularly dogs in cities. Walking or carrying in brush is risky. Preventative measures for ticks include wearing the trouser cuffs inside the socks, DEET use, sleeping on elevated cots and checking each other for ticks.
Epidemic typhus is more severe but rarer and is caused by human lice. It is seen in poverty stricken areas (Rwanda, Uganda, and Ethiopia). Travelers are unlikely to experience epidemic typhus even if backpacking.
Trachoma is the most common form of blindness worldwide. It is present in Central America, The Middle East, and some Mediterranean countries.
This infection is transmitted to the eyes by contaminated hands or towels. After 1 week the eye is irritated and inflamed with discharge. After 1 month gray lumps form on the inside of the upper eyelids and scarring of the cornea may develop.
Diagnosis is by analysis of cells spread from the infection. Antibiotic ointment, medication, and sometimes surgery may be needed.
No vaccine exists yet but antibiotics can be taken for self treatment abroad.
|
Children
may take Pepto-Bismol providing no allergy to ASA
|
|
|
AGE
|
DOSE
|
|
7-12
yrs
|
2tbs
(30ml)
|
|
9-12
yrs
|
1tbs
(15ml)
|
|
6-9
yrs
|
2tsp
(10ml)
|
|
3-6
yrs
0-3 yrs |
1tsp
(5ml)
½ tsp (2.5ml) |
Tropical Sprue is a generalized condition where absorption from the small intestine is impaired following a trip to a tropical country. The specific cause is unknown but it usually follows an infection. It is present in Asia, the Caribbean, Africa, India, Puerto Rico, South and Central America, Fiji, Middle East and Northern Australia.
Symptoms occur months to years after returning and vary. Usually diarrhea, abdominal bloating, weights loss and anorexia. Other infectious agents need to be excluded. Endoscopy can confirm the diagnosis. Treatment may include: vitamin supplements and a long course of antibiotics.
Tuberculosis is a severe bacterial infection of the lungs and other organs. One in three people in the world are infected with Tb. Two million deaths occur each year from infection. Contagiousness is related to the length of exposure to and infectivity of the contact person Infection is contracted by droplet nuclei from coughing. The bacteria are then ingested by alveolar macrophages in the lungs causing the primary infection. This then spreads through the blood (hematogenously) and becomes a latent Tb infection.
Active Tb disease will develop in 10% of these latent infections (usually this occurs within 2 yrs in 80% of those who do develop disease). The lungs are most commonly infected (about 50%). On x-ray cavitations, caseation, and fibrosis can be seen. Only pulmonary TB is infectious to others. A direct stain for acid-fast bacilli diagnoses active TB and this is confirmed by culture. Chest X-ray will show lung infection. Two of the worst types of Tb infection occur more in children under 5 yrs and are miliary (generalized infection) and Tb meningitis.
Latent Tb by definition is symptomless and is diagnosed with the tuberculin skin test (the Mantoux test) where tuberculin protein is injected intradermally on the forearm to see if that person has been sensitized to tuberculin in the past (either with a prior exposure to the disease or vaccination with BCG). Immunodiagnosis techniques may be used in the future. Treatment of latent Tb can be months on anti-tuberculosis drugs
Risk Factors:
Tb is poverty related. As soon as living conditions improve the Tb incidence goes down. HIV and AIDS ca accelerate the symptoms of Tb. HIV increases the progression of Tb from 10% of latent infections towards active per life to 10% per year of those affected. With the rise of HIV Tb has risen and is expected to rise further.
There is an under appreciated risk to the traveler of Tb infection but little hard data on this. There are reports of Tb outbreaks among airplane passengers who had sat next to heavily infected individuals who were actively coughing during long flights. Travelers are at risk to exposure. There are outbreaks of TB, especially among air travel although this is felt to be very low.
Risk to travelers of Tb exposure can be expressed from the rate of Mantoux skin test conversions from negative to positive indicating that exposure has occurred. A Peace Corps study showed 15 per 1000 traveler years skin test conversions. In another study health care volunteers had a conversion rate 7.9 while tourists had a rate of 3.5. Expatriates and long term tourists have a risk of Tb that becomes similar to the host country (1-3 %?).
The risk of catching the disease is relative. In order of frequency diseases are; HEPATITIS A (0.3%-2%) > LATENT Tb INFECTION > HEPATITIS B > ACTIVE Tb > TYPHOID (~0.003%)> MENINGITIS> CHOLERA (1 in 500,000) per travel month
TB PREVENTION FOCUSES ON:
1) Avoiding exposure.
2) BCG vaccination.
3) Identifying and treating latent Tb infections.
BCG (Bacille Calmette-Guerin) vaccination is a live attenuated vaccine of Mycobacterium Bovis (cow tuberculosis) which protects against disease but not infection. It will induce Tb sensitivity but not infection. Studies compare different effectiveness and opinions vary from country to country from 0-80%. In better - designed studies it appears to have a more proven benefit. Closer to the equator studies have shown less protection. BCG does protect against the military and meningeal Tb infections. Duration is thought to be about 10-15 yrs. Although used in the past with high- risk population (native children and military personnel) it is not presently given routinely in Manitoba. In some countries where it is given it is administered at least 6 wks before travel. Contraindications to its use are: immune suppression, any HIV infection regardless of their CD4 counts, and a positive Mantoux test. Complications include having an abscess formation at inoculum site.
1) BCG Vaccine: Mycobacterium Bovis protects against disease but not against the infection. Studies conclude 0-80% protection.
2) Closer to the equator there is less protection. Protection cannot be predicted, (0-80%). BCG protects against miliary (widespread disseminated), and meningeal Tb. Although BCG is used in certain parts it is not given in Manitoba. High- risk aboriginal children may receive BCG.
IDENTIFICATION OF TB EXPOSURE:
The Mantoux test consists of injecting 0.1 ml of purified tuberculin protein intradermally. The injection site must be read by an experienced doctor or nurse 48hrs later. This protein is not infectious and there is no risk of acquiring Tb from this test. The immune system will recognize the tuberculin protein if that person has been sensitized (either be exposure to Tb or with the BCG vaccine) and mount an immune response at the injection site (which becomes red and indurated).
Local guidelines should for interpretation should be followed, as tuberculin doses are not universally standardized. In Manitoba 10mm of induration is felt to be a positive test. Sensitivity of this test may be affected by insulin dependant diabetes and pregnancy although these people should still be tested if indicated.
There also exists a booster effect from having a recent Mantoux test if given recently. Doing a 2 step Mantoux test can detect this. This test checks to see if a boosting effect occurs from the first injection of tuberculin rather than because of true exposure to tuberculosis.
The manitoux test is done once and then again 1-3 weeks later to see if a boosting effect takes place. If a boosting effect does take place then this can be noted and compared with that patients Mantoux when checked again after their trip. By doing this 2- step test there is increased sensitivity for catching new cases of Tb and treating them soon to prevent further contagion.
Individuals who had been vaccinated with the BCG vaccine will have a positive Mantoux although if vaccinated in their first year of life they may be Mantoux negative. If a BCG has been done in the past it is recommended to do the 2 step Mantoux. Individuals with weakened immune response may show anergy or the inability to mount an immune response against the Mantoux test and will be false negative.
TREATMENT OF POSITIVE CONVERSIONS (New Latent Infections) WHEN TO TREAT?
All new suspected conversions should be referred to a local Tuberculosis Treatment Program for further assessment and follow-up. Anti-tuberculosis drugs need to be taken for months and patients need to be followed.
BCG MAY BE RECOMMENDED FOR:
1. If patient is under 5 years and at high risk(these are more likely to develop meningeal or military Tb - 2 conditions that are prevented by the vaccine.)
2. Poor compliance for follow up i.e. They never return to get their Mantoux done properly or would be noncompliant with Tb medications.
3. Individual would be at risk for severe side effects from anti-Tb drugs.
TUBERCULOSIS CONCLUSIONS:
1. Long- term travelers have a risk for Tb
2. BCG may be recommended for high- risk travelers (although not in Canada).
3. Serology may replace skin tests in future, which could aid in detection much easier.
4. Newer vaccines unlikely to come out in near future.
At present the best way to control Tb is to promptly treat new cases and have people educated in high risk situations.
Source: 8th ISTM Scientific Assembly 2001,Yellow Book 2001, The CDC Pink Book 2000.
Tularaemia is caused by bacteria in wild animals and is found worldwide. It is caught by handling animal carcasses, hides, fur, or feces; and sometimes by insects. Incubation takes 1-14 days. If bacteria enters through the skin by cuts or bites an ulcer will form with localized lymph node swelling followed by fever and generalized symptoms.
If inhaled, pneumonia will develop, if neglected people develop tonsillitis, pharyngitis, nausea, vomiting, and gastrointestinal bleeding. Generalized symptoms are fever, leader lymph nodes, aches and rash.
Untreated serious complications (meningitis, septeaemin, paitentis and osteanyelitis) can happen. A blood test will confirm this diagnosis. Treatment is with antibiotics.
Tungiasis: is caused by the chigger (a pregnant female flea) that penetrates the skin (especially near the toenail) to lay eggs. The flea releases enzymes to weaken skin (so it doesn't have to burrow to penetrate skin). Their enzyme causes local pain, swelling, and itchiness. Sometimes gangrene or a generalized infection may develop.
Diagnosis is confirmed when the skin is removed showing the flea with her eggs. Use a sterile surgical technique to remove these fleas. Their wounds are very prone to infection, so coverage with an antibiotic is recommended.
Chiggers occur in Central and South America, Western India and Africa. Tungiasis tends to be seasonal when vegetation is lush and their fleas are more active. Risk factors to getting bitten are walking barefoot or sitting or lying on the ground. Bathing feet in hot water also will remove them before they enter themselves. Footwear is obviously the best protection.
Typhoid is a bacterial illness spread by contaminated food and water. There are 17 million cases per year, with 600,000 deaths.
This bacterium lives only in people and contaminated food or drinking water. The more bacteria ingested the sicker a person may get. Typhoid vaccines are available but are only about 80% effective and the immune system can be overwhelmed if ingested with a very large dose of typhoid.
Symptoms occur after about 2 weeks and gradually worsen after another 2 weeks. High fever, headaches, stomachache, anorexia, and constipation (and or diarrhea), coughing, and deafness can occur. Rose spots may develop on the trunk. Diarrhea usually occurs on the second week. In extreme cases meningitis and coma may occur.
Other complications include: increased bleeding, pneumonia, deep vein thrombosis, joint pain, and bone infections. Mortality is about 10% in untreated cases and 1% in treated cases.
Diagnosis is with blood tests. Treatment includes fluids and antibiotics. After symptoms resolve, people should be reviewed to make sure they are not carriers.
Typhoid causes 600,000 deaths annually in developing countries. Presently there is emerging resistance to previously used antibiotics. Vaccination is recommended in the face of increasing drug resistances, increasing incidence, and a high cost benefit for the traveler since illness will last 4-8 weeks (as compared with cholera which will be over in4-5 days). The vaccine may be given with yellow fever vaccine. Paratyphoid is a separate disease from typhoid in which the vaccine is not effective.
GENERAL: Typhoid fever is a severe illness caused by bacteria. It is usually Transmitted by contaminated food and drink.
SIDE EFFECTS: Theses are reactions you may or may not experience. These effects are infrequent and mild. They include stomach discomfort, nausea vomiting.
NOTE:
1. Antibiotics and anti-malaria drugs may interfere with this vaccine.
2. Keep capsules refrigerated at all times.
BOOSTER: Required every seven years.
Typhus is a collective term for diseases caused by the rickettsia bacteria, and are transmitted by louse or flea- bites; and have symptoms of a high fever followed by a rash.
The 4 main types are:
1. Epidemic louse-borne Typhus
2. Epidemic tick-borne Typhus
3. Rocky Mountain Spotted Fever
4. Scrub Typhus
No vaccination is available.
Diagnosis is confirmed with blood tests and treatment is with a tetracycline antibiotic (which will treat all types of typhus except some resistant strains found in Thailand, which are susceptible to ciprofloxacin).
Occurs in Africa, Central and South America, Asia, Eastern Europe, and Mexico. Epidemics occur in poverty and war stricken areas. The rickettsia is transmitted by body lice, which live in clothing and feed on blood. Their feces enter wounds or are inhaled. This disease is not transmitted person to person.
Symptoms of epidemic louse-borne typhus include: high fever, headache, dry cough, muscle pain, and nausea with vomiting. All symptoms occur within 2 weeks of being bitten.
Symptoms of epidemic louse-borne typhus include: high fever, headache, dry cough, muscle pain, and nausea with vomiting. All symptoms occur within 2 weeks of being bitten. Afterwards a rash appears on the torso and then spreads to the rest of the body (the rash of Rocky Mountain Spotted Fever starts in the extremities first). This disease can cause multiple organ disease and death.
Occurs worldwide and is common in ports and central areas. The disease is carried by rats and transmitted to people by flea bites (in the U.S the disease is found in dogs, cats, and opossums). Symptoms occur gradually over 2 weeks and are similar through milder than epidemic typhus (see above). Full recovery is usual even without treatment and fatalities are rare.
Occurs in south east Asia, Australia, India, and the Western Pacific Rim. It is transmitted by mite bites. Travelers are at risk if hiking through cleared forests or jungle. Darkened scabs where the mites have bitten may be visible. After 5-10 days people develop a sudden fever, headache, dry cough and swollen lymph nodes. A rash appears on the torso and limbs. Permanent neurological damage can occur. In both scrub typhus and epidemic typhus disease can sometime return even after treatment.
This is a mosquito-borne viral disease affecting rodents, horses, and people in Trinidad, Central America, Florida, and South America. Epidemics occur during rainy seasons.
After an incubation time of less than a week, a flu-like illness with fever, chills, nausea, vomiting, and diarrhea, will occur. The fever lasts up to 4 days but is followed by profound weakness of up to several weeks. Some people develop encephalitis.
Antibody tests confirm the diagnosis. There is no specific treatment, only supportive measures. A vaccine exists for lab personnel, but is unavailable to travelers as the disease is rare.
This is one disease the U.S military is concerned with being weaponized by terrorists because it incapacitates people, although there is no firm evidence of this having ever happened.
Measles: Infant younger than 6 months is protected, if 6-11 months he\she should have MMR or separate measles. If a child is 12 months and traveling to an area of high risk, a first does should be administered and a second at 28 days.
Mumps and Rubella: Not needed for infants less than 12 months.
Varicella (Chicken pox): recommended if 12 months or older.
Haemophilis Influenza Type B (Hib): Never given less than 6 weeks old. Begin series at 2 months. If previously not vaccinated children under 15 months should have 2 doses of Hib before travel (there should be 4 weeks between doses). Unvaccinated children 15-59 months should have single dose.
Hepatitis B: Vaccination may begin at birth or by 2 months. Second dose should be given after 1-2 months. Third dose should be given at least 2 months later and not before 6 months of age.
Typhoid: Breastfeeding children are likely to protect infants. Vaccine is recommended for children 2 years or older.
Yellow Fever: Never given below 4 months, rarely given to children 4-6 years of age , unless a special situation. 6-9 years of age are vaccinated only if traveling to areas of ongoing yellow fever epidemic.
Hepatitis A: Recommended for children over 2 years old.
Vaccines for Children Traveling
Children going traveling with their parents may need their vaccinations adjusted - either because of the decreased availability of pediatric follow-up where they are going or because of the increased visit of the new area.
Changes in Schedule for Routine Immunization due to Travel
|
Vaccine
|
Age
Routinely Given
|
Accelerated
Schedule
|
|
DTaP
- Diphtheria, Tetanus, Pertussis
|
2,4,and
6 months
|
6wks,
10wks, and 14wks
|
|
Hepatitis
B (note: Hep B is given much earlier in U.S than in Canada)
|
Birth,
1, 6-12 months
|
0,1
month, 2 months, booster-12 months (Hep B is given much earlier in U.S
than Canada.
|
|
MMR
- Measles, Mumps, Rubella
|
12-15
months
|
6
months
|
|
Polio
|
2,
4, and 6 months
|
6wks,
9wks,and 12 wks
|
Note:
When vaccines are given younger than routinely recommended or intervals are
shortened, vaccinations may need to be repeated at a later date.
Special Notes on Vaccines in Children
Cholera Vaccine - Is no longer available in North America. Risk of Cholera
to travelers is very low. Breast-feeding protects children. In older children,
close attention to food and water will protect.
Hepatitis A - Is given to children over 1 yrs old. Breast-feeding protects
small infants with passive immunoglobins from mother's milk.
Japanese Encephalitis Virus - Is given to children over 1yrs old traveling
to rural areas endemic in this infection during the peak transmission season.
Japanese Encephalitis is recommended only if staying in areas around rice
paddies or pig farms, where the risk of JEV mosquitoes is high.
Rabies - Children may be more susceptible to rabid animal attacks than
adults. Parents may consider this vaccine if their child is staying in a high-risk
area for rabies.
Typhoid - Breast fed infants are protected from this. For older children
careful boiling or chlorinating water prevents this disease. The new injectable
vaccine is given to children between ages 2-6. An oral typhoid vaccine is
available for older children.
Yellow Fever - This mosquito borne infection is required for travel to
some countries. It is never recommended to children under 4 months, and only
in exceptional circumstances for children 6-9 months. Infants 7-9 months may
be vaccinated if they require it.
Children and Bugs
Preventing insect bites is very important in preventing many diseases. The
following are recommended:
1. Placing nets over baby carriages and cribs
2. Eliminating standing water around living quarters
3. Stay inside between dusk and after dark
4. Dressing children carefully in long sleeved clothing over neck,
wrists, and ankles
5. Not allowing children to go barefoot
6.
Covering skin with DEET 20-35% - This is higher than what many other recommend.
DEET is safe to use on children when used correctly. Apply on exposed skin,
but not on irritated skin and wash it off after use.
7. Use a flying insect spray in living and sleeping quarters
8. Sleep in air-conditioned area when possible
Malaria Medication and Children
Chloroquine is self and well tolerated but has a bitter taste. Eating adult
strength doses can harm children. Chloroquine should be kept in safe place
away from children.
Mefloquine (Larium)
Is very safe in children. Neurological agitation from mefloquine is not seen
in children as with adults.
Malarone
Is a new medication and is more expensive. It is taken daily according to
weight.
|
WEIGHT
|
DOSE
|
|
10-20
kg
|
1
Pediatric strength tablet
|
|
21-30
kg
|
2
Pediatric strength tablet
|
|
31-40
kg
|
3
Pediatric strength tablet
|
|
40+
kg
|
1
Adult strength tablet
|
Safe for ages 9+. Also safe in lactating mothers, but not in pregnant woman..
West Nile Virus (WNV) is an arborovirus or insect borne infection. It has a 3 -15 day incubation period with viraemia on days 4-8. Symptoms can be none to meningitis or encephalitis. The mean age of those affected is 65 yrs. It is more severe with advancing age.
Potential cause for the New York outbreak migratory birds (unlikely), imported birds, infected humans, imported mosquitoes, or bioterrorism (unlikely).
Seventy- eight bird species will carry the WNV. In 2000 there were 21 human cases (fatalities of 11%.) West Nile Virus has occurred in France, Israel, and Russia.
West Nile virus is transmitted through the bite of a mosquito, which has become infected with virus by feeding on an infected bird. While there is currently no evidence of WNV in Canada, an outbreak in the New York City area in the summer of 1999 prompted health officials in Canada and the U.S. to enhance surveillance mechanisms in an effort to detect any potential virus was detected in 17 states in the northeastern United States, with 18 persons hospitalized and 2 subsequent deaths.
Infections with WNV are usually mild or unapparent. Symptoms can range from a slight fever and mild headache to the acute onset of severe headache, high fever, stiff neck, muscle weakness, focal neurological signs, and disorientation with alterations in the level of consciousness, and death.
Symptoms could begin 3 to 12 days following the bite of an infected mosquito. In the New York outbreak, the elderly tended to be at risk for more serious forms of the disease. Travel to endemic areas should be considered when individuals present with the above symptoms.
Role of the Physician:
If you should see patients where you suspect encephalitis, please order 2 blood samples, 3 weeks apart (acute and convalescent blood samples) for antibody titres. For cerebrospinal fluid (CSF) specimens, send 1to 2 cc on ice for the presence of antibody, and WNV by polymerase chain reaction (PCR) and also include one blood sample (10 cc for adults; 1 to 2 cc for young children). For brain biopsy specimens, in a sterile container on crushed ice, not formalin fixed specimens.
These worms are common in the tropics and sub-tropics. The eggs are passed in feces and hatch to larvae in soil. They penetrate bare feet and migrate to the lungs. They are then swallowed into the intestines and mature to adults 1 cm long. They start producing eggs after 5 weeks.
Symptoms are: an itchy lump on the skin where penetrated.
In some worms that are more meant for dogs or cats they go no further and cause Cutaneous Larva Migrans as they are trapped in the skin. This "creeping eruption" is an itchy line shaped eruption, which advances a few millimeters each day.
Those that do get to the lungs may cause an irritable cough or wheezing. In the gut they may cause nausea, vomiting, diarrhea and abdominal pain. Blood loss can lead to anemia. Further loss of protein can lead to edema.
Diagnosis: Eggs are seen in stool. Drug treatment is then used.
Strongyloidiasis (thread worms)
These worms affect only humans and lodge in the small intestine. They produce eggs, which pass into stool and then soil. Larva will infect people similar to hook worms as they will penetrate skin and then migrate from the lungs to the intestine.
It takes years for the worm to mature. Sometimes there is a rash at the skin entry and a wandering rash as they migrate in the skin. They also cause cough, wheezing, and abdominal complaints. They are diagnosed as stool analysis and treated with anti-worm medication.
Enterobiasis (pin worms)
This is the most common worm infection. They can be transmitted by linen, toys, and unwashed fingers. Most common symptoms is vaginal itching. Worms are sometimes visualized at the anus. Anti-worm medication is effective and all household members should be tested. All clothing and linen should also be washed.
Ascariosis (round worms)
These worms are found worldwide but more so in poor countries. This worm is about 15-40 cm and looks like an earthworm. They inhabit the small intestine, and do not usually cause bleeding or bowel damage.
Eggs pass in stool and can remain infective for even year. After hatching they hatch into larvae, go into bloodstream, lungs, and then back to the small intestine. Symptoms may be absent or if there is a heavy worm load, nausea, vomiting, abdominal pain, and rarely obstructed bowel or malnourishment.
Eggs are identified in stool and treatment with mebendazole is effective.
Trichuriosis (whipworm)
These worms are common in poor communities in warm, humid, climates. Whipworms embed themselves in the lining of the intestine causing significant blood and protein loss. They mature in 3 months growing up to 5 cm. Their eggs are released into the stool and mature in the soil.
Symptoms are uncommon. Heavy infestation leads to diarrhea with blood and mucus. Stool analysis will show this infection.
Trichinosis
Trichinosis is worldwide but cases are common in Europe, U.S and Northern Thailand. Cysts with larvae are present in under-cooked meat usually pork. The stomach acids release the larvae from the cyst and they then mature into mature worms in the intestine. New larvae are released in the blood and form cysts in the muscles.
Cysts are killed by cooking all parts >65°C, freezing to -27°C for 36 hours or microwaving. Pricking, smoking, or salting does not affect them.
Most people are asymptomatic. Abdominal pain and vomiting may happen within 72 hours. Larvae are released into the circulation between 2-8 weeks later. Symptoms include fever with chills, conjunctivitis, eye swelling, itchy rash, and shortness of breath, chest pain, diarrhea, muscle pains, muscle spasm, and photophobia. Symptoms can resolve but muscle pains can last for weeks.
Diagnosis is either made with a blood test or muscle biopsy. Bad rent and antihistamines help. If severe symptoms involving the heart or brain then high dose corticosteroids are used. Treatment against the worms is best in the first few weeks to prevent them from multiplying and producing migrating larvae.
Tapeworms
The Beef tapeworm is common in Mexico, South America, Eastern Europe, Middle East, and Africa. Pork tapeworm is common in South America, Asia, Africa, and Eastern Europe. Fish tapeworm occurs worldwide. The arrival has infective cysts in its flesh. If inadequately cooked, they enter the gut.
Beef tapeworms are acquired from beef and can be up to 10 cm long. They may cause vague abdominal symptoms with diarrhea, vomiting, and weight loss. Sometimes they can also cause physical obstruction. Pork tapeworms cause similar symptoms as beef tapeworms when the larvae are eaten, but different diseases are caused.
Pork tapeworm eggs are ingested. Hatching larvae will invade the gut and get into the bloodstream, acting like trichinosis. This disease, human cysticerosis may not be apparent for years but there cysts can be present in the brain, eye, and skin.
Fish tapeworm usually causes only mild symptoms but can interfere with the body's absorption of vitamin B12 causing pernicious anemia.
Diagnosis of tapeworm is by stool analysis.
Yellow fever is a flavivirus that can cause severe symptoms in travelers.
There are 200,000 cases of yellow fever per year with 30,000 deaths. There are 3 modes of transmission of this virus by mosquito: sylvatic, intermediate and urban. The sylvatic cycle occurs in tropical rain forests. The virus is found in monkeys who mosquitoes bite and spread to people. The intermediate cycle occurs in the humid / semi humid savannahs of Africa. Both humans and monkeys are reservoirs for yellow fever. The urban cycle occurs when immigrants infected will introduce the virus into a population where mosquitoes that were formerly virus free pick it up. Many countries that are yellow- fever visit on a certification of vaccination from travelers owing to their country to protect them by not introducing yellow fever into their mosquitoes.
Symptoms of yellow fever, range from none, to full blown cases. The incubation period after being bitten is 3-6 days followed by fever, headache, muscle aches, and protein in urine. Usually a slow pulse with fever is noted and abdominal tenderness. After 3-5 days people get better or may deteriorate with liver and kidney failure,(causing the yellow jaundice), abdominal pain and bleeding.
Fatality has been 50% for adults, 70% for children. No treatment is other than supportive is available.
The yellow fever vaccine can only be given through specialized clinics. Yellow Fever must be kept frozen and be given to a patient within one hour of being thawed and reconstituted. It is a live vaccine that may cause 1-3 days of muscle aches, low-grade fever or malaise (flu symptoms), but is effective after 7-10 days. These side effects are rare and sometimes happen within the first 2 weeks after vaccination. It is not given to children under 9-12 months (unless an overwhelming need), immune compromised individuals and pregnant women. The yellow fever certificate should be kept with the traveler's passport and is valid for 10 years.
References:
Travel Medicine and Migrant Health
International Society Travel Medicine, General Meeting, 2001
Baxter monograph on Tick Borne Encephalitits
The Rough Guide to Travel Health:
Dr Nick Jones Rough Guides 2001
International Travel Health Guide 2001 - Twelfth Edition:
Stuart Rose, M.D.
Textbook of Travel Medicine and Health- Second Edition:
Herbert L. Dupont, M.D., Robert Steffen, M.D.
Vaccines
Plotkin
Canada Communicable Disease Report
Volume 27, No.15 - August 1, 2001
Key Travel Health Information Sites for Canadians
World Health Organization
http://www.who.int
International Travel and Health: Vaccination Requirements and Health Advice,
January 2000 edition - www.who.int/it.english.index.htm
Detailed country by country yellow fever vaccination and malaria requirements
Disease Outbreak News - http://www.who.int.emc/outbreak_news/index.html
Listings of current outbreaks, along with archives dating back to 1996
International Immunization Profiles - http://www.who.int/gpv-surv/intro.html
Listing of international immunization profiles and schedules from the
Global Programme for Vaccines and Immunization .
Centers for Disease Control and Prevention
http://www.cdc.gov/travel/index.html
Includes information on disease outbreaks around the world, geographic
health recommendations, and information on specific diseases.
Health Information for International Travel (Yellow Book) - http:/www.cdc.gov/travel/reference.htm
Complete text of the 19999-2000 edition available electronically at the
above URL.
Includes in-depth information on: vaccination and disease prevention;
yellow fever vaccine requirements and malaria risk and prophylaxis by
country; and information for travelers with special needs
The Blue Sheet - www.cdc.gov/travel.bluesheet.htm
Summary of Health Information for International Travel " Lists cholera,
yellow fever, and plague infected countries.
Morbidity and Morality Weekly Report - http://www2.cdc.gov/mmwr/mmwr_wk.html
Weekly CDC publication containing information useful for travel health
practitioners
International Society of Travel Medicine http://www.istm.org/
Listings of travel clinics in over 50 countries around the world
Website Resources
High Altitude-
www.high-altitude.com
www.etravel.org
