There tends to be confusion about what happens when an animal bites or is bitten, and rabies is being considered. Most of the confusion revolves around how long an animal is quarantined or observed. Yet, it’s actually pretty straightforward if you think about why quarantine/observation is being performed and some basics about the virus and the disease itself.
Scenario 1: A dog bites a person
This one’s easy.
- The response: 10 day quarantine or observation. Basically, we need to ensure that the dog is normal 10 days after the bite.
- To see if it develops signs of rabies. Based on the nature of rabies virus infection, by the time a dog is infectious (shedding rabies virus in saliva) the infection is well advanced. If the dog is neurologically normal 10 days after the bite, it could not have had rabies virus in its saliva at the time of the bite
What if the dog was vaccinated against rabies?
- That doesn’t have any impact. Vaccination is highly effective but not 100% protective. Since you can’t guarantee a vaccinated dog doesn’t have rabies, even vaccinated dogs may be placed under a 10-day observation period.
One variable here is whether the offending animal is available for testing. If it is killed/euthanized and tested, and shown not to have rabies virus in its brain, the bitten dog is in the clear (same applies if a person is bitten by a wild animal). In a large proportion of cases the offending animal is not available for testing, and the rabies status of the animal is never known at the time of the bite.
Why is there a response?
- Unlike scenario 1, the goal here isn’t to see if the dog was incubating rabies virus when it was bitten. The goal is to determine if there is a reasonable risk that the dog will develop rabies, and to keep it contained during the period when rabies is most likely to develop so it can’t infect someone else. The incubation period for rabies in dogs can be long (months) so the quarantine/observation period has to be longer.
What is the response?
- The first step is to perform a risk assessment to determine the likelihood that the offending animal transmitted rabies to the dog. Although the risk from a bite from another mammal is never zero, if the risk is deemed to be very low then no specific action is taken other than to ensure the dog’s vaccination status is up-to-date. Pet owners must always be vigilant for neurologic signs in their animals that may be consistent with rabies. Even indoor animals can have contact with potential rabies vectors such as bats.
- If the risk assessment is that there is a significant risk of rabies transmission, unlike scenario 1, the dog’s vaccination status then plays a role in determining the subsequent response. (Note: These rules are for Ontario. There’s some variation between jurisdictions).
If the dog was full vaccinated, according to the intervals specified by the vaccine manufacturer, and is not overdue for a booster:
- The dog still requires a rabies booster is given within 7 days of the bite. If this is done, there is no confinement period, although an informal observation period (45 days) is recommended out of an abundance of caution.
- If a booster isn’t given within 7 days, then the dog gets a 3 month precautionary confinement period (PCP). During this time, they have to stay on the owner’s property (except for medical care), have contact only with one caregiver, have no contact with other animals, can only go outside on a leash and in a fenced area and must be cordoned off when inside with a double barrier (e.g. kept in a room with a closed door in a house with a closed door).
If the dog received an initial rabies vaccine but is not yet due for its first booster (i.e. within 12 months but no less than 14 days after initial vaccination):
- Same as for fully vaccinated dogs. The key is getting to booster done within 7 days.
If the dog has been vaccinated in the past but is overdue for a booster:
- This is handled on a case-by-case basis, thinking about the time since vaccination, the number of vaccines the dog has had in the past and other things that might influence protection. Usually, the response is a booster within 7 days and a 3 month PCP. Without a booster, a 6 month PCP is used.
If the dog has never been vaccinated against rabies or rabies vaccination history is unknown:
- If the dog gets a rabies shot within 7 days of the bite, it gets a 3 month PCP. If not, it’s 6 months. Euthanasia is the other option and is sometimes chosen because of the issues with long quarantines. That’s particularly true with puppies (who are more likely to be unvaccinated), where long confinement periods can be very difficult and impact socialization.
Incidentally, the same rules apply to cats in Ontario. Don’t forget, all dogs, cats and ferrets over 3 months of age in Southern Ontario are legally required to be fully vaccinated for rabies at all times. Failure to do so can result in a fine (which usually costs more than the vaccination!)