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Rabies

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To establish category of animal bite

Rabies in Animals

Observing 10 day rule - Is it justifiable?

Exposed patients who turn up after considerable delay

Exposure of pregnant/ lactating woman to a suspected or rabid animal bite

Vaccination & Immunoglobulin

One of the important consideration in initiating anti Rabies treatment is to establish the category of the animal bite. This categarisation helps in deciding the future course of action. The table below can be used as a guide to facilitate the management of rabies exposure.
Management of Rabies Exposure in Rabies Endemic Countries
WHO CATEGORY	Nature of Contact	Recommended Treatment	Healthy Animal
WHO CATEGORY	Nature of Contact	Unknown, Sick, Proven or Wild Mammal	Healthy Animal
I	Petting, feeding,licking on healthy skin, no mucous membrane exposure	None	None +
II	Superficial scrach, lick on broken skin	Modern tissue culture Rabies Vaccine	Modern tissue culture Rabies Vaccine ++
III	Single or multiple transdermal bites or scratches at any location, or lick over mucous membrane	Modern Rabies Vaccine and Rabies Immunoglobulin	Modern Rabies Vaccine and Rabies Immunoglobulin

+ This is a good time to start pre-exposure vaccination, particularly in children and others likely to have repeated contact, such as postmen, vets and others that are at a risk of dog bite.

++ Start full treatment on the first day and discontinue vaccine if animal is alive and well on day 10, or it has been found rabies negative on reliable laboratory examination. Encourge patient to return for another dose of vaccine on day 21, so that a full course of pre-exposure series has been completed.

If there is significant delay in presentation and if the patient is immunosuppressed, it may be appropriate to double the first dose of vaccine. Administration of two ampules of vaccine , one on each arm, on day 0.

Is observing the dog for 10 days without initiating treatment risky or justifiable?.

In view of the extremely high fatality rate of human rabies, the prevention of rabies infection after exposure is of the utmost importance.

The practice of first observing a dog that has bitten man before starting treatment is encouraged in America, Australia & Europe and could be accepted where the likelihood of such a dog being rabid is small. This is however not the case in a country where there is rabies among a large stray dog population, where 50% of the dogs that had bitten man and were taken for examination proved to be positive for rabies (under fluorescent microscopy).

Here, it is mandatory to start treatment and discontinue it after the dog remains healthy, or has been found laboratory negative.

For example: If the dog is available for observation we say that the risk can be reassessed, but start the immunisation and observe the dog for 10 days. If the dog is well on day 7 (by which time the third vaccine dose is due), the day 7 vaccine is postponed to day 8; if the dog is well on day 8, it is postponed to day 9 and so on; if the dog is well on day 1 0 no further vaccine is given and post-exposure schedule is converted into a pre-exposure vaccine schedules.

If the dog is not available for observation, a vaccine has to be given because risk cannot be reassessed later.

What should he done with a patient who has had exposure,

but only goes for treatment after considerable delay (weeks to months)?

Since prolonged incubation periods have been noted, persons who present themselves for evaluation and treatment should be dealt with in the same mammer as if the contact has occured recently.

No one knows what happens to the rabies virus during the prolonged incubation periods. Does the virus reside at the bite site before suddenly replicating and rnigrating centrally, or is it already in nervial tissue? There is no way to determine whether such a patient is infected and whether he or she is now silently incubating the disease.

Patients incubating rabies usually do not show a detectable antibody response and do not have antibodies during the silent phase.

It may be that the ptient who comes long after bitten or otherwise exposed, already has replicating virus in an immuno protected intraneural location, and that he or she may die within days or weeks of consulting the physician. Starting a post-exposure series would then be futile. Nevertheless, this is not known for sure and ethical and medicolegal considerations mandate that such a patient be given full post exposure

	Vaccination in Pregnant women
Exposure of pregnant/ lactating woman to a suspected/ rabid animal bite - can the modern tissue culture rabies vaccine he given?		Pregnancy and infancy are never contraindications to post-exposure rabies vaccination. "Now more convenient and painless tissue culture vaccines are available, which can easily be administered in the deltoid region. It must be remembered that the anti-rabies immunization takes preference over any other consideration since it is a life saving procedure. The anti-rabies vaccines and the inactivated rabies virus do not have any teratogenic properties. These do not induce abortion and have no influence on the progress of pregnancy, mother-to-be or the foetus.

Dr. Manbir Singh