title: Migratory birds and the dispersal of arboviruses in California.
abstract: Each spring large numbers of neotropical migrants traversing the Pacific flyway pass through the Coachella Valley enroute to northern destinations, providing an opportunity to test the hypothesis that mosquito-borne encephalitis viruses are introduced annually into California by migratory birds. A total of 5,632 sera were collected from 43 species of migrants during spring (April-June), of which 34 (0.61%) comprised of 14 species tested positive by enzyme immunoassay; only 10 were confirmed by plaque reduction neutralization tests (PRNT). In addition, of 1,109 migrants comprised of 76 species that were reported dead by the public and necropsied, 126 (11%) were positive for West Nile virus (WNV) RNA; however, only three (0.7%) of 428 birds tested during the spring were positive. Limited experimental infection studies with WNV showed that Orange-crowned Warblers were highly susceptible and frequently died, whereas most Yellow Warblers survived. Our results indicated that birds entering California rarely exhibited a history of infection and that most birds probably became infected after entering California.
authors.affiliation: Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California 95616, USA. wkreisen@ucdavis.edu
authors.forename: William K
authors.initials: WK
authors.lastname: Reisen
authors.forename: Sarah S
authors.initials: SS
authors.lastname: Wheeler
authors.forename: Sandra
authors.initials: S
authors.lastname: Garcia
authors.forename: Ying
authors.initials: Y
authors.lastname: Fang
mesh_terms: D025041:Animal Migration; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001715:Bird Diseases / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D001717:Birds; D002140:California / Q000453:epidemiology; D004665:Encephalitis Virus, St. Louis / Q000276:immunology / Q000302:isolation & purification; D004667:Encephalitis Virus, Western Equine / Q000276:immunology / Q000302:isolation & purification; D004674:Encephalitis, St. Louis / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D020241:Encephalomyelitis, Western Equine / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D012367:RNA, Viral / Q000032:analysis; D012621:Seasons; D013997:Time Factors; D014901:West Nile Fever / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D014902:West Nile virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral