The orbiviruses, epizootic hemorrhagic disease (EHD) virus or bluetongue (BT) virus, cause a disease syndrome termed hemorrhagic disease (HD) in white-tailed deer (Odocoileus virginianus) and several other wild ruminants. An annual mail survey of state wildlife agencies was conducted from 1980-1989 to estimate the occurrence of HD in the continental United States. Thirty-one states reported confirmed or suspected HD activity, and 1,608 occurrences were reported in 880 counties or parishes. Cases of HD were reported throughout most of the Southeast and much of the Midwest and northern Great Plains. Reports also were received from the Pacific Coast states. Death losses of deer accounted for 33.8% of the reports, whereas chronic, post-infection lesions alone were seen in 55.0%. Virus isolations were reported in 57 counties in 21 states; EHD virus was identified twice as often as BT virus. Recurrences of HD were noted during the 10-year period at both the state and county level. There was a strong geographic difference in the frequency of occurrence and clinical type of HD; the disease syndrome was milder but more frequent in the southernmost states of the southeastern United States.
