PREVALENCE OF RABIES IN BATS IN MICHIGAN, 1981-1993

Objectives-To analyze the species distribution of animals submitted to the Michigan Department of Public Health (MDPH) for rabies testing du ring 1993. To determine whether any of the 9 species of bats residing in Michigan carries a disproportionate rabies burden, and to determine whether bats contributed the most cases of confirmed rabies during 19 81 through 1992. Design-Epidemiologic study. Procedure-Records of anim als submitted to the MDPH for rabies testing during 1993, and between 1981 and 1992, were reviewed. information regarding type of animal sub mitted, specific species if the animal was a bat, county from which th e animal was obtained, the identity of the submitting individual, spec ies of the animal exposed, month of the submission, and results of rab ies testing was extracted from these reords. Results-During 1993, the MDPH received 2,045 submissions for rabies testing. Seventeen rabid an imals were identified: 1 cat, 1 skunk, and 15 bats. Two hundred forty- six bats were submitted for testing. Eptesicus fuscus, the big brown b at, accounted for 97.2% (239) of bat submissions and was the only spec ies of bat that had positive results of testing for rabies. Annual per centages of submitted bats found to be rabid ranged from 2.0 to 11.0%, with a 13-year mean of 6.2%. Conclusions-100% of the confirmed cases of rabies in bats reported in Michigan in 1993 were associated with in E fuscus. During 1981 through 1992, most of Michigan's confirmed case s of rabies in animals developed in bats.