Overview of the 1971 Texas Venezeulan Equine Encephalomyelitis Epizootic
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
Pagination or Media Count:
The etiologic agent of Venezuelan equine encephalomyelitis VEE is a member of Casals group A arboviruses. There are currently 4 major antigenic subtypes, of which the first is subdivided into 5 minor antigenic variants. The present epidemic of highly virulent subtype 1B probably had its origin in Ecuador, and was introduced into Guatemala in 1969. From there, the disease spread rapidly through El Salvador and portions of Honduras and Nicaragua. In 1970, VEE reoccurred in Honduras and spread into Costa Rica and Mexico. Although slowed in 1970, VEE continued its inexorable spread toward the United States, and by April, 1971, was occurring near Tampico, Mexico. The first recognized encephalitis horse in South Texas was sick on 23 June. Vaccination was begun on a voluntary basis on 25 June in a 13-county area of South Texas. After confirmation of VEE by virus isolation on 9 July, vaccination was extended statewide in Texas on 13 July, and to New Mexico, Oklahoma, Arkansas, and Louisiana on 17 July.
- Animal Husbandry and Veterinary Medicine