title: Western Equine Encephalitis submergence: lack of evidence for a decline in virus virulence.
abstract: The incidence of Western Equine Encephalitis (WEE) in humans and equids peaked during the mid-20th century and has declined to fewer than 1-2 human cases annually during the past 20 years. Using the mouse model, changes in WEE virus (WEEV) virulence were investigated as a potential explanation for the decline in the number of cases. Evaluation of 10 WEEV strains representing a variety of isolation locations, hosts, and all decades from the 1940's to the 1990's yielded no evidence of a decline in virulence. These results suggest that ecological factors affecting human and equine exposure should be investigated to explain the decline in WEE.
authors.affiliation: Center for Biodefense and Emerging Infectious Diseases, Sealy Center for Vaccine Development and Department of Pathology, University of Texas Medical Branch, TX 77555-0609, USA.
authors.forename: Naomi L
authors.initials: NL
authors.lastname: Forrester
authors.forename: Joan L
authors.initials: JL
authors.lastname: Kenney
authors.forename: Eleanor
authors.initials: E
authors.lastname: Deardorff
authors.forename: Eryu
authors.initials: E
authors.lastname: Wang
authors.forename: Scott C
authors.initials: SC
authors.lastname: Weaver
mesh_terms: D000818:Animals; D001835:Body Weight; D004667:Encephalitis Virus, Western Equine / Q000472:pathogenicity*; D020241:Encephalomyelitis, Western Equine / Q000453:epidemiology / Q000821:virology*; D006801:Humans; D015994:Incidence; D051379:Mice; D016019:Survival Analysis; D014774:Virulence
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