As I mentioned a few days ago, eliminating the risk of rabies in animal shelters is pretty much impossible. Another shelter-associated rabies exposure situation highlights the problems.

A cat at the Washington Area Humane Society was recently diagnosed with rabies, resulting in three people receiving post-exposure prophylaxis (i.e. rabies antibodies and a series of rabies vaccines). What’s quite interesting here is the fact that the cat had been in the shelter since May. So, unless the cat was exposed to rabies in the shelter (possible, but very unlikely), that means the incubation period was at least 6-7 months. That’s not unheard of, but it’s pretty long for a cat. We don’t know exactly how long the incubation period can be, except that it’s long. In humans, cases have been identified a few years after the presumed exposure. This situation shows how the 6 month quarantine that is used after exposure of unvaccinated animals is very reasonable, but still not a guarantee. It also shows how short-term isolation of animals in a shelter after arrival can’t guarantee there will be no rabies exposure (although it’s good for many other reasons).


  • Maureen Anderson

    It is worth noting that the 6-month interval for quarantine of unvaccinated animals has been the recommendation for over a century, and all evidence is that is has been quite reliable other than an odd case report here or there of an animal that develops rabies over six months after its last *presumed* exposure to rabies. However, at least in the last several decades, exposed animals are required to receive a rabies vaccine within 7-10 days of the incident, before being placed in quarantine (though that’s not to say this was always successfully done), which acts like post-exposure prophylaxis for the animal. With this regime, the animals that still go on to develop rabies (which certainly can happen) tend to develop signs sooner than later, making the 6 month quarantine in these cases quite reliable.

    I suspect the cat in this case did not receive a rabies vaccine when it entered the shelter. If it had, it’s possible (though still no guarantee) that this case could have been prevented.