title: West Nile virus infection of birds, Mexico.
abstract: West Nile virus (WNV) has caused disease in humans, equids, and birds at lower frequency in Mexico than in the United States. We hypothesized that the seemingly reduced virulence in Mexico was caused by attenuation of the Tabasco strain from southeastern Mexico, resulting in lower viremia than that caused by the Tecate strain from the more northern location of Baja California. During 2006-2008, we tested this hypothesis in candidate avian amplifying hosts: domestic chickens, rock pigeons, house sparrows, great-tailed grackles, and clay-colored thrushes. Only great-tailed grackles and house sparrows were competent amplifying hosts for both strains, and deaths occurred in each species. Tecate strain viremia levels were higher for thrushes. Both strains produced low-level viremia in pigeons and chickens. Our results suggest that certain avian hosts within Mexico are competent for efficient amplification of both northern and southern WNV strains and that both strains likely contribute to bird deaths.
authors.affiliation: Zoológico Miguel Alvarez del Toro, Tuxtla Gutiérrez, Mexico.
authors.forename: Sergio
authors.initials: S
authors.lastname: Guerrero-Sánchez
authors.forename: Sandra
authors.initials: S
authors.lastname: Cuevas-Romero
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Nemeth
authors.forename: María Teresa Jesús
authors.initials: MT
authors.lastname: Trujillo-Olivera
authors.forename: Gabriella
authors.initials: G
authors.lastname: Worwa
authors.forename: Alan
authors.initials: A
authors.lastname: Dupuis
authors.forename: Aaron C
authors.initials: AC
authors.lastname: Brault
authors.forename: Laura D
authors.initials: LD
authors.lastname: Kramer
authors.forename: Nicholas
authors.initials: N
authors.lastname: Komar
authors.forename: José Guillermo
authors.initials: JG
authors.lastname: Estrada-Franco
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000821:virology*; D001717:Birds / Q000821:virology*; D021821:Communicable Diseases, Emerging / Q000662:veterinary / Q000821:virology; D004197:Disease Reservoirs / Q000662:veterinary / Q000821:virology; D006801:Humans; D008800:Mexico; D046109:Passeriformes / Q000821:virology; D014766:Viremia / Q000662:veterinary / Q000821:virology; D014774:Virulence; D017201:Virus Shedding; D014901:West Nile Fever / Q000662:veterinary* / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity