Canine Rabies
Rabies is a very serious, most often fatal, viral disease affecting the central nervous system. It is most frequently transmitted through the bite of an infected animal. In the United States, because of the high rate of rabies vaccinations, canine rabies rarely occurs. When it does, it is almost always the result of a dog being bitten by a wild animal such a raccoon or bat. If a previously vaccinated dog is bitten by a possibly rabid animal, the dog should receive an immediate rabies booster and be kept under observation for 45 days.
Rabies is a zoonotic illness, meaning that it can be transferred from animals to humans as well as among other animal species. While it is highly preventable disease, in Asia and Africa over 50,000 people die annually of the disease. Once symptoms of rabies appear, the prognosis is very poor. Most patients dies within days.
Transmission of Canine Rabies
Although all species of mammals may contract rabies, only a few species seem to harbor the illness. In the United States, these species are raccoons, skunks, foxes, coyotes and bats. Typically, rabies is transmitted through contact with the infected saliva of the host animal. Most commonly, the disease is spread through bites, but other transmissions, via mucous membranes other than the mouth, and through inhalation, have also been documented. There have also been rare cases of rabies transmission through corneal and organ transplant.
Symptoms of Canine Rabies
The symptoms of canine rabies are progressive. At first, the dog may run a fever for several days and appear weak and uncomfortable. As the illness progresses, some or all of the following symptoms may appear:
- Anxiety or agitation
- Insomnia
- Confusion or delirium
- Abnormally aggressive behavior
- Excessive salivation and difficulty swallowing
- Hydrophobia (a fear of water)
- Partial paralysis
Canine rabies, once symptoms appear, is almost always fatal. The acute symptoms may last up to 10 days during which the only available treatment is supportive care or euthanasia..
Diagnosis of Canine Rabies
It is essential that rabies be diagnosed quickly and accurately so that steps can be taken to prevent the spread of the virus. The test requires that the animal be euthanized. Canine rabies is diagnosed using the direct fluorescent antibody (DFA) test, which looks for the presence of rabies virus antigens in brain tissue, especially in the brain stem and cerebellum. Rabies test results are usually available within 1 to 3 days. Fortunately, test results within this time frame are more than sufficient to determine whether an exposed patient requires post-exposure vaccinations. In recent years, such vaccinations are not as painful or troublesome as they were in the past.
It is important that rabies tests be performed on possibly infected animals in order to promote public safety. Out of the large number (approximately 120,000) animals tested for the disease each year in the United States, only a small percentage are found to be rabid and most of these are wild animals. Only 1 percent of domestic animals test positively for rabies. Because the incidence of canine rabies is so low, most often euthanasia for testing is not necessary; it is sufficient to keep the animal contained for 10 days under close observation. Public health officials must be notified when a case of rabies is suspected.
Prevention of Canine Rabies
Canine rabies is best prevented by regular vaccinations. It is important to keep dogs under direct supervision while they are outdoors to prevent them for having contact with wild animals. Neutering or spaying pets is also helpful because it limits the number of animals who may not be properly vaccinated and therefore may spread the illness. Stray animals or wild animals who are behaving peculiarly should be reported to the authorities.