RESUMO
Influenza A viruses occur worldwide in wild birds and are occasionally associated with outbreaks in commercial chickens and turkeys. However, avian influenza viruses have not been isolated from wild birds or poultry in South America. A recent outbreak in chickens of H7N3 low pathogenic avian influenza (LPAI) occurred in Chile. One month later, after a sudden increase in deaths, H7N3 highly pathogenic avian influenza (HPAI) virus was isolated. Sequence analysis of all eight genes of the LPAI virus and the HPAI viruses showed minor differences between the viruses except at the hemagglutinin (HA) cleavage site. The LPAI virus had a cleavage site similar to other low pathogenic H7 viruses, but the HPAI isolates had a 30-nucleotide insert. The insertion likely occurred by recombination between the HA and nucleoprotein genes of the LPAI virus, resulting in a virulence shift. Sequence comparison of all eight gene segments showed the Chilean viruses were also distinct from all other avian influenza viruses and represent a distinct South American clade.
Assuntos
Surtos de Doenças , Vírus da Influenza A/genética , Influenza Aviária/epidemiologia , Recombinação Genética , Sequência de Aminoácidos , Animais , Aves , Chile/epidemiologia , Vírus da Influenza A/classificação , Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Dados de Sequência Molecular , Filogenia , VirulênciaRESUMO
Virus isolation attempts were carried out on wild-caught Xenosaurus grandis, X. platyceps, and Abronia graminea from Mexico. These animals were also tested for exposure to paramyxoviruses and reoviruses. Pharyngeal and cloacal swabs were collected from 30 lizards, and blood was collected from 23 lizards. A cytopathogenic virus was isolated from the cloacal swab of one of the X. platyceps. The isolate was identified as a paramyxovirus on the basis of its sensitivity to chloroform, resistance to 5-iodo-2'-deoxyuridine, size and morphology of the viral particles, hemagglutination of chicken erythrocytes, and serologic reaction with paramyxovirus-specific antisera. Antibodies against the paramyxovirus isolated in this study were found in four animals from three species. Antibodies against a different paramyxovirus isolated from a monitor lizard were found in seven animals from three species, showing that all the species tested are susceptible to paramyxovirus infections. Antibodies to a reptilian reovirus were found in three of the X. grandis.