* Arthropod-Borne Animal Diseases Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, P.O. Box 3965, University Station, Laramie, Wyoming 82071
** Division of Vector-Borne Viral Diseases, Center for Infectious Diseases, Centers for Disease Control, Public Health Service, U.S. Department of Health and Human Services, P.O. Box 2087, Fort Collins, Colorado 80522
† Nebraska State Health Department, P.O. Box 95007, Lincoln, Nebraska 68509
‡ Colorado Department of Health, 4210 East 11th Avenue, Denver, Colorado 80220
§ Veterinary Services, Animal and Plant Health Inspection Service, U.S. Department of Agriculture, Eckert, Colorado 81418
An epizootic of vesicular stomatitis (VS) caused by the New Jersey serotype of VS virus affected livestock and humans in 14 western states in 1982–1983. Epidemiological observations were made on at least 10% of the cattle in 4 dairy herds that were located in the vicinity of Grand Junction, Colorado. High rates of neutralizing antibody to the New Jersey serotype were seen in all cattle regardless of whether livestock in the dairy had clinical VS or a decrease in milk production. Antibody titers remained high in these cattle for as long as 2 years after the epizootic. No virus isolations were made from 32 humans with clinical signs compatible with viral disease. Entomological information was obtained during the epizootic from 23 premises in northwestern Colorado. Insect collections yielded 4 isolates from Culicoides spp. midges, 2 from C. variipennis, and 1 each from C. stellifer and C. (Selfia) spp. This is the first report of VS virus isolations from field-collected Culicoides.