title: West Nile encephalitis.
abstract: WNV encephalitis in horses, previously reported in Africa, Asia, and Europe, occurred for the first time in the Western Hemisphere in 1999. The causative agent, WNV, is a flavivirus maintained in nature by a bird-mosquito cycle. The disease in horses is manifested primarily by ataxia of variable severity. Outbreaks of encephalitis may have a case fatality rate in excess of 40%, although this virus infection is inapparent in some horses. Early evidence indicates that WNV has overwintered in the northeastern United States and poses a threat for future disease occurrences in horses. No vaccine is available to protect against WNV infection in horses; disease control is predicated on mosquito abatement.
authors.affiliation: Equine and Ovine Viruses Section, Diagnostic Virology Laboratory, National Veterinary Services Laboratories, United States Department of Agriculture , Ames, Iowa, USA.
authors.forename: E N
authors.initials: EN
authors.lastname: Ostlund
authors.forename: J E
authors.initials: JE
authors.lastname: Andresen
authors.forename: M
authors.initials: M
authors.lastname: Andresen
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D001921:Brain / Q000821:virology; D004196:Disease Outbreaks / Q000662:veterinary*; D006734:Horse Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D006736:Horses; D009032:Mosquito Control; D014481:United States / Q000453:epidemiology; D014901:West Nile Fever / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy / Q000662:veterinary*
chemical_list: D000914:Antibodies, Viral