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).
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.
vaccine is given in three doses
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
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
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.
should be given as soon as possible after being bitten since
rabies has developed a few days after being bitten.
will begin to produce their own antibodies 7-10 days after
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.
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.
CDC Rabies http://www.cdc.gov/ncidod/dvrd/rabies/
Aventis Pasteur http://www.rabies.com/