RESUMO
The commercial flocks in Yucatan, Mexico are free of Newcastle disease virus (NDV) in its velogenic viscerotropic form, but little is known about the disease status of backyard poultry. A seroprevalence survey in 30 villages using haemagglutination inhibition (HI) tests for infectious bronchitis virus (IBV) and NDV antibodies was carried out from December 1997 to June 1998. The seroprevalences were 56.5% (95% CI 50-63%) for IBV and 2.2% (95% CI 0.5-3.8%) for NDV. All the villages had chickens that were positive for antibodies to IBV and nine of the villages had chickens that were positive for antibodies to NDV. This suggests that IBV may be responsible for a large proportion of the respiratory disease observed in backyard chickens in Yucatan. The implications of these findings are discussed, including the highly susceptible status of the backyard chickens in Yucatan to NDV and the possibility of this virus being one cause of the syndrome known as mortandad by the local people.
Assuntos
Anticorpos Antivirais/sangue , Galinhas , Vírus da Bronquite Infecciosa/imunologia , Vírus da Doença de Newcastle/imunologia , Doenças das Aves Domésticas/epidemiologia , Animais , Análise por Conglomerados , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/veterinária , Testes de Inibição da Hemaglutinação/veterinária , Vírus da Bronquite Infecciosa/isolamento & purificação , México/epidemiologia , Doença de Newcastle/epidemiologia , Doença de Newcastle/imunologia , Vírus da Doença de Newcastle/isolamento & purificação , Doenças das Aves Domésticas/sangue , Doenças das Aves Domésticas/virologia , Estudos SoroepidemiológicosRESUMO
Forty-four haemagglutinating viruses were isolated from the pooled tracheal/cloacal swabs of the dead birds from 170 consignments of caged birds arriving at Heathrow Airport over a period of 6 months. Two isolates were identified as Newcastle disease virus but the remaining 42 were all identified as influenza viruses with Hav 7 Neq 2 antigens. All the consignments from which influenza viruses were isolated originated in India but had widespread destinations. The NDV isolates were from birds originating in central America and destined for Japan.