EPIZOOTIC HEMORRHAGIC-DISEASE VIRUS AND BLUETONGUE VIRUS SEROTYPE DISTRIBUTION IN WHITE-TAILED DEER IN GEORGIA

Serum samples collected from 1,396 white-tailed deer (Odocoileus virgi nianus) in five areas of Georgia (USA) from 1989 to 1991 were tested f or precipitating and serum neutralizing (SN) antibodies to the enzooti c North American epizootic hemorrhagic disease virus (EHDV) and blueto ngue virus (BTV) serotypes. Precipitating antibodies to the EHDV or BT V serogroups, as detected by agar gel immunodiffusion (AGID) tests, we re present in 35%, 29%, and 39% of deer sampled in 1989, 1990, and 199 1, respectively. Significant differences (P < 0.05) in precipitating a ntibody prevalence were detected between physiographic regions during all years. Antibody prevalence consistently was highest in deer sample d from the Coastal Plain (77%), followed by the Piedmont (33%), Ridge and Valley (29%), Barrier Island (5%), and Blue Ridge (2%) regions. Al l AGID-positive samples were tested by SN tests for antibodies against all North American EHDV and BTV serotypes (EHDV serotypes 1 and 2, BT V serotypes 2, 10, 11, 13, and 17). Criteria for previous exposure to a specific serotype were either detection of monospecific results or c lusters of positive results against that serotype. Serologic evidence of previous exposure to EHDV serotypes 1 and 2, and BTV serotypes 11 a nd 13 was detected during all years. Predominant serotypes varied amon g years. In general, evidence of exposure to EHDV serotype 2 appeared annually while exposure to BTV serotype 13 and EHDV serotype 1 decreas ed and increased, respectively. To determine serotype diversity prior to 1989, 134 ACID-positive white-tailed deer serum samples collected f rom 1967 to 1988 also were tested by SN. Evidence of exposure to EHDV serotypes 1 and 2 and BTV serotypes 11, 13, and 17 was detected.