Ecology and epidemiology of raccoon rabies.

Two areas of the United States presently are experiencing epizootics of raccoon rabies, which have been followed by the development of an enzootic state. These include four southeastern and five mid-Atlantic states. Information was obtained from 1,610 raccoons submitted for rabies testing in four of the affected mid-Atlantic states during 1982 and 1983 and from 798 raccoons from Virginia during 1984 and 1985. Analysis of the two sets of data provided an opportunity to characterize certain aspects of the epizootic. Raccoons collected during the day or at dusk and those that behaved abnormally were more likely to be rabid. Many human exposures to raccoons were preventable or may not have necessitated treatment. Eight (3%) of 291 serum samples from raccoons in an epizootic area had titers of antibody to rabies virus (complete neutralization) of greater than or equal to 1:25. Field trials of baiting systems incorporating an oral raccoon rabies vaccine are being conducted in Virginia, Washington, D.C., and Pennsylvania.