Rabies

Preparing for Overseas Animal Bites

Rabies

Rabies is defined as an acute viral encephalitis (brain infection) transmitted from animal to animal or by animal to humans by exposure to saliva. Virus in the saliva attaches to the ends of nerves and travels to the brain. Rabies is 100% fatal (although at least 3 documented cases of survivors are known).

Rabies causes 60,000 deaths worldwide, half of which are in India. There are no Rabies in Australia, New Zealand, Japan, Hong Kong, Singapore, Great Britain, and some islands. All mammals are capable of transmitting rabies, although 99% are from dogs.

Dogs in developing countries must be assumed to be rabid. Even if docile, they should be avoided. Dogs who are provoked or disturbed are less likely to be rabid but…

THIS IS NOT A RELIABLE INDICATOR OF RABIES !

Whether a bite is provoked or not; if a country is known to have rabies the wound must be assumed to be rabid. Bats also carry rabies. If a bat is found in a sleeping person's room, rabies must be suspected. Bat teeth are like needles and can feed on people without tem being aware of this.

Dogs or other animals may lick a small child. This is also a high-risk exposure. If he skin is broken or the child is unable to properly communicate, rabies cannot be ruled out. Children are often embarrassed that they have been playing with dogs and may not admit they have been bitten.

Characteristics of encephalitis (furious) rabies:

•  Fluctuating consciousness from agitation to depression, which will gradually progress to coma.

•  Phobic spasms-aerophobia and hydrophobia the fear of air and water.

•  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 b 70% alcohol, or tincture of iodine.

Rabies exposure is graded as:

Type of Contact

•  Touching, feeding, or licks (animal) on intact skin.

•  Nibbling of uncovered skin. Minor scratches or abrasions without bleeding, licks on broken skin.

Recommended Treatment- Give vaccine. Stop treatment if animal observed to be healthy after 10 days in quarantine or lab tests are negative.

•  Single or multiple bites or scratches. Contaminated mucous membrane by saliva (licks).

Recommended Treatment- Give vaccine and rabies immuno globulin. May stop treatment if rabies tests result comes 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 I the gluteal muscle because there is poor absorption of the vaccine when given in the gluteal area.

Rabies immunoglobin 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 vaccinated. The immuno globulin 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.

Many people who are bitten by proven rabid animals still do not develop rabies but this cannot be relied on to prevent such a terrible disease. Still, proper early wound management will help prevent rabies (and other infections).

Wound Management Algorithm

•  Scrub with soap and water at 5 minutes.

•  Wash in running water.

•  Debridement of damaged tissue if available.

•  Alcohol, iodine.

•  Do not suture, wound must drain open.

•  Tetanus shot.

•  Antibiotics given early after bite to cover.

•  Must travel ASAP to nearest major medical centre.

•  Find the name of nearest city where good rabies vaccine exist (contact nearest embassy for this city).

Getting Help Overseas

Unfortunately, good rabies treatment is not universal and in some countries the traveler may actually have to leave the country to get the proper care. Some vaccines routinely used in developing countries are simply not safe or effective.

Some vaccines available overseas are not safe, avoid the following:

•  Semple vaccine (SV)

•  Sucking Mouse Brain Vaccine (SMB)

•  Duck Embryo Vaccine (DEV)

These vaccines are cheap but have too many side effects.

The following tissue cell culture vaccines are reasonable:

•  PDEV-Purified Duck Embryo Vaccine

•  PVCRV-Purified Vero Cell Rabies Vaccine

•  PCECV-Purified Chick Embryo Culture Vaccine

•  RVA-Rabies Vaccine Absorbed

•  HDCV-Human Diploid Cell Vaccine (Immovax)

Some clinics administer 1/10 th of a regular rabies vaccine intradermally instead of intramuscular injections. This regimen is not widely available nor recommended for travelers or post-bite series, as it may not give reliable antibodies.

In Summary:

•  Rabies is present in many developing countries and kills many.

•  Pre-vaccination is recommended for high-risk travelers going to areas where rabies is likely, and medical facilities are unable to help them (remoteness, no available immune globulin or good quality cell derived vaccine).

•  The risk of being bitten by a rabid animal must be balanced with the likelihood of availability and quality of the vaccine can be assured.

•  This pamphlet is intended to give general information only. If you have a concern about a wild animal bite you must see an emergency department immediately.

References:

•  Vaccines

Stanley Plotkin 1999

•  Rabies in 60 questions

Pasteur Meriux Cannaught 2002

http://www.pasteur.fr/recherche/rage/init-eng.html

•  Dog Owner's site: Rabies: http://www.canismajor.com/dog/rabies.html

•  CDC Rabies Page http://www.cdc.gov/ncidod/dvrd/rabies/

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Winnipeg, MB R2H 1Z9

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Website: www.skylarkmedicalclinic.com

Information current as of Feb 22,2006

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