Rabies

Definition:

An acute viral infection affecting the nervous system of animals. It can be transmitted to humans by a bite or the exposure of broken skin to the animal's saliva

Causes, incidence, and risk factors:

Rabies is transmitted by infected saliva that enters the body by a bite or open wound. The virus travels from the wound along nerve pathways to the brain where it causes inflammation that results in the symptoms of the disease. The incubation period ranges from 10 days to 7 years, with the average period 3 to 7 weeks. In the past human cases usually resulted from a dog bite but most recently cases of human rabies have been linked to rabies virus carried by bats. Bats, skunks, raccoons, foxes, and other animals are other sources of rabies virus. There are an estimated 15,000 cases of rabies worldwide each year. Few cases occur in the U.S. (only 3 reported in 1991 and 9 in 1994) because of the extensive animal-vaccination programs.

The threat of rabies causes extreme fear on the part of people who think they may have been exposed and health care workers who must contend with possible exposures. In New Hampshire, October of 1994, an unknown number of individuals were exposed to a rabid kitten. Because exposure could not be well documented 665 individuals received rabies postexposure prophylaxis at a cost of $1.5 million. This was an extreme reaction by the public to possible exposure. The Centers for Disease Control is presently making recommendations to help prevent unnecessary treatment in questionably exposed individuals.