Rabies virus infection in bats was first recognized in the US in 1953, and the first rabid bat was identified in New York State in 1956. Since then, the disease has been identified in each of New York's nine species of insectivorous bats and is widely distributed geographically within the state.
Among bats encountered by people and pets that are submitted to the rabies laboratory for testing, about 4% are found to be rabid. Among normally behaving bats collected in their natural habitats, a fraction of 1% are rabid. Outbreaks of rabies in bat populations have not been observed, and finding one rabid bat in a colony of bats is not evidence of greater prevalence of rabies in that population.
Rabies infection in bats is similar to the disease in other mammals. It is characterized by a variable incubation period that can be months long, a clinical period of about a week with behavioral changes and progressive paralysis leading to death. and the capacity to transmit the virus by bites inflicted during the clinical period.
Well documented instances of transmission of rabies from bats to terrestrial mammals have occurred in the State, particularly to domestic cats, grey foxes and horses.
There have also been two human rabies deaths attributable to bat rabies in New York State: in 1993 in an 11-year-old Sullivan County resident, and in 1995 in a 13-year-old resident of a nearby Connecticut community that was being treated in a Westchester County hospital. Since 1990, 20 of 22 domestically acquired human rabies infections in the United States have resulted from infection with bat rabies variants, and in only one of these cases was there a clearly documented bat bite. !n many of the other cases there had been a bat encounter where direct contact was probable, but no bite was detected.
Because of these observations, and because bat bites may result in limited injury, rabies post exposure treatment may be provided following encounters with bats where there is a probability a bite may have occurred and gone undetected, unless the bat can be captured and tests negative for evidence of rabies infection. These changing practices have resulted in an increase in the number of bats received for testing at the Wadsworth Rabies Laboratory.
Questions may be addressed to the Cattaraugus County Health Department at 716-373-8050, or at our free number, 1-800-251-2584.