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 |