RESUMO
Molecular characterization studies of a diverse collection of avian influenza viruses (AIVs) have demonstrated that AIVs' greatest genetic variability lies in the HA, NA, and NS genes. The objective here was to quantify the association between geographical locations, periods of time, and host species and pairwise nucleotide variation in the HA, NA, and NS genes of 70 isolates of H5N1 highly pathogenic avian influenza virus (HPAIV) collected from October 2005 to December 2007 from birds in Romania. A mixed-binomial Bayesian regression model was used to quantify the probability of nucleotide variation between isolates and its association with space, time, and host species. As expected for the three target genes, a higher probability of nucleotide differences (odds ratios [ORs] > 1) was found between viruses sampled from places at greater geographical distances from each other, viruses sampled over greater periods of time, and viruses derived from different species. The modeling approach in the present study maybe useful in further understanding the molecular epidemiology of H5N1 HPAI virus in bird populations. The methodology presented here will be useful in predicting the most likely genetic distance for any of the three gene segments of viruses that have not yet been isolated or sequenced based on space, time, and host species during the course of an epidemic.
Assuntos
Variação Genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1/genética , Epidemiologia Molecular/métodos , Neuraminidase/genética , Proteínas não Estruturais Virais/genética , Proteínas Virais/genética , Animais , Teorema de Bayes , Aves , Geografia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Virus da Influenza A Subtipo H5N1/metabolismo , Influenza Aviária/virologia , Modelos Teóricos , Neuraminidase/metabolismo , Análise de Regressão , Romênia , Análise de Sequência de RNA/veterinária , Especificidade da Espécie , Fatores de Tempo , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais/metabolismoRESUMO
In this study, we have analyzed 23 PCV2 ORF2 sequences recovered from wild boar population in Romania. The PCV2 sequences were originated from different geographical regions in Romania, and collected between 2008 and 2009 during the classical swine fever virus (CSFV) surveillance campaign. Complete open reading frame 2 (ORF2) nucleotide sequences were obtained and compared with sequences mainly from European and Asian isolates. The Romanian sequences were identified as belonging to previously described clusters 2a and 2b, with high degree of heterogeneity (PCV2 ORF2 nucleotide homology ranged between 90.1% and 100%). Interestingly, for cluster 2a, the majority of the sequences (8 from a total number of 9) clustered mainly with the Asian isolates (especially China, but also India and South Korea), with three exceptions from Europe previously reported in Germany, Belgium and The Netherlands.