Animal bites and suspected human rabies exposures
Animal bites are a public health concern because of the potential for transmission of rabies, a viral infection of the nervous system and brain of humans and other mammals that is almost always fatal. A suspected human rabies exposure occurs when saliva or other possibly infectious material (such as central nervous system tissue) from a potentially infected animal penetrates the skin or comes into contact with mucosal surfaces. Rabies is not transmitted by contact with blood, urine, feces, or fur.
Bats are a special case because bat variant rabies has been documented in persons with no history of a scratch or a bite. Any potential human exposure to a bat requires careful assessment because bat teeth are razor sharp and tiny, so a bite wound may not be detectable on physical examination.
Although terrestrial carnivores such as raccoons, skunks, foxes and coyotes are known to harbor rabies in other parts of the country, bats are the only known reservoir for rabies in Washington state. Over the past several decades, only four non-bat animals have tested positive for rabies in Washington (one each of a cat, dog, llama and horse), two of which were infected with a bat-variant of rabies (the strain type was unknown for the other two animals).
If a person is exposed to rabies, infection can be prevented by administering rabies immune globulin and a series of rabies vaccine doses. To be effective, preventive treatment must be started before symptoms appear and must be given according to a specific schedule.
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|Suspected rabies exposure in King County
Purpose of surveillance:
- To identify persons potentially exposed to rabies and to ensure appropriate evaluation and preventive treatment if necessary
- To ensure that potentially rabid animals are managed appropriately
- To identify animal sources of rabies and risk factors for rabies transmission
In 2014, 93 suspected rabies exposures were reported of which 71 occurred within the United States. Bat exposures accounted for 68 (96%) of the domestic exposures. Two exposures were associated with bats that tested positive for rabies; for the remainder of cases, the bat was not available for testing. Twenty-two (24%) exposures to animals including bats, dogs, cats and monkeys occurred outside the United States.
In Washington state, almost all cases of animal rabies occur in bats, however, most bats do not carry rabies. Five to ten percent of the sick or injured bats tested are positive for rabies each year.
The last identified cases of rabies in humans in Washington occurred in 1995 and 1997, both attributed to bat exposures. Prior to that, the last identified human case of rabies occurred in 1939 from the bite of a rabid dog. In February of 2011, reporting requirements were changed so that only animal bites that are suspected rabies exposures are immediately notifiable.