Have you ever wondered why you are required by law to vaccinate your pet for rabies? The rabies virus is carried in a number of different wild animal species here in the US. Although it is rare, cases do occur in our domestic animals as a result of exposure to infected wildlife. This then places humans at risk of exposure – that is the reason for current rabies laws! This month a horse was diagnosed with rabies, so it does happen from time to time. In addition, a well-meaning Mom brought a dead bat to school for her child’s class to inspect. Unfortunately, it turned out to have died from rabies and the entire class had to get post-exposure vaccinations!!! Ouch!
Rabies causes serious neurologic disease in all mammals. If left untreated before symptoms occur, the disease if invariably fatal. In the wild, rabies is carried by skunks, foxes, raccoons and bats. Exposures occur most commonly through bites but transmission can also occur when infected saliva, blood or neural tissue contacts mucous membranes or breaks in the skin. The incubation period is highly variable with clinical signs appearing anywhere from 10 days to 6 months after exposure! Most cases however, become apparent within 2-8 weeks. The location and severity of the exposure, as well as the amount of virus transmitted affect how quickly clinical signs appear.
Symptoms of rabies are nonspecific and can range from apprehension, restlessness, fever, loss of or an increase in appetite, dilation of the pupils, hyper-reactivity to stimulus and of course, excessive salivation – the classic symptom better known as “foaming at the mouth”. Following initial signs, rabies usually manifests itself in one of two ways: paralytic or “dumb” rabies, or “furious” rabies. The paralytic form is characterized by gradual paralysis (inability to move) of all muscles beginning with those required for chewing and swallowing. The animal is unable to swallow correctly and thus drools excessively. Clumsiness and depression may also occur. Biting and aggression is uncommon with this form of the disease. Death usually occurs in 2-6 days after signs occur. The furious form is characterized by restlessness, wandering, howling, rapid breathing and unprovoked attacks on humans and other animals. Unfortunately, the majority of viral shedding occurs 1-5 days before symptoms become apparent so transmission could occur before you are even aware that they have the contracted the virus!
There is no known treatment once symptoms have appeared and survival is exceedingly rare. If a known or probable human exposure has occurred, the unvaccinated victim is treated with human immunoglobulins and a long course of vaccinations. If the victim has been vaccinated and is current, then only a shortened course of booster vaccinations is administered. There is currently no post-exposure treatment protocol recommended in animals. Vaccination and prevention of exposure to wildlife form the cornerstones of protection for your animals!
Current regulations require that all dogs be vaccinated against rabies in order to be eligible for license in their county of residence. All healthy pets that bite humans should be confined and observed for 10 days. If signs of rabies do occur, the animal will be euthanized and tested for rabies. Recommendations for probable exposures are much more stringent: vaccinated pets are re-vaccinated and confined under the owner’s control for a period of at least 45 days. Unvaccinated pets should be euthanized and tested immediately.
While human cases of rabies are rare, they do occur. The variability of clinical signs and high fatality rate in infected humans and animals make this disease a true threat. Keeping your pets current of their rabies vaccinations keeps everyone safe!