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Genetically related highly pathogenic avian influenza viruses (HPAIVs) of H5N6 subtype caused outbreaks simultaneously in East Asia and Europe—geographically distinct regions—during winter 2017–2018. This situation prompted us to consider whether the application of phylogeographic analysis to a particular gene segment of AIVs could provide clues for understanding how AIV had been disseminated across the continent. Here, the N6 NA genes of influenza viruses isolated across the world were subjected to phylogeographic analysis to illustrate the inter- and intracontinental dissemination of AIVs. Those isolated in East Asia during winter and in Mongolia/Siberia during summer were comingled within particular clades of the phylogeographic tree. For AIVs in one clade, their dissemination in eastern Eurasia extended from Yakutia, Russia, in the north to East Asia in the south. AIVs in western Asia, Europe, and Mongolia were also comingled within other clades, indicating that Mongolia/Siberia plays an important role in the dissemination of AIVs across the Eurasian continent. Mongolia/Siberia may therefore have played a role in the simultaneous outbreaks of H5N6 HPAIVs in Europe and East Asia during the winter of 2017–2018. In addition to the long-distance intracontinental disseminations described above, intercontinental disseminations of AIVs between Eurasia and Africa and between Eurasia and North America were also observed. Integrating these results and known migration flyways suggested that the migration of wild birds and the overlap of flyways, such as that observed in Mongolia/Siberia and along the Alaskan Peninsula, contributed to the long-distance intra- and intercontinental dissemination of AIVs. These findings highlight the importance of understanding the movement of migratory birds and the dynamics of AIVs in breeding areas—especially where several migration flyways overlap—in forecasting outbreaks caused by HPAIVs. [ABSTRACT FROM AUTHOR]

Background: Acute respiratory infections (ARIs) cause a considerable morbidity and mortality worldwide especially in children. However, there are few studies of the etiological structure of ARIs in Russia. In this work, we analyzed the etiology of ARIs in children (0–15 years old) admitted to Novosibirsk Children’s Municipal Clinical Hospital in 2013–2017. Methods: We tested nasal and throat swabs of 1560 children with upper or lower respiratory infection for main respiratory viruses (influenza viruses A and B, parainfluenza virus types 1–4, respiratory syncytial virus, metapneumovirus, four human coronaviruses, rhinovirus, adenovirus and bocavirus) using a RT-PCR Kit. Results: We detected 1128 (72.3%) samples were positive for at least one virus. The most frequently detected pathogens were respiratory syncytial virus (358/1560, 23.0%), influenza virus (344/1560, 22.1%), and rhinovirus (235/1560, 15.1%). Viral co-infections were found in 163 out of the 1128 (14.5%) positive samples. We detected significant decrease of the respiratory syncytial virus-infection incidence in children with increasing age, while the reverse relationship was observed for influenza viruses. Conclusions: We evaluated the distribution of respiratory viruses in children with ARIs and showed the prevalence of respiratory syncytial virus and influenza virus in the etiological structure of infections. This study is important for the improvement and optimization of diagnostic tactics, control and prevention of the respiratory viral infections. [ABSTRACT FROM AUTHOR]

Background: Wild aquatic birds, reservoir of low-pathogenicity (LP) avian influenza viruses (AIVs), congregate in huge numbers in Western Siberia wetlands, where major intra- and inter-continental bird flyways overlap. In 2005 and 2006, highly pathogenic (HP) AIV H5N1 epizootics affected wild and domestic birds in the Novosibirsk Region. In 2012, we evaluated AIV persistence in Siberian natural and anthropic ecosystems. Methodology/Principal Findings: In Novosibirsk Region, 166 wild birds ecologically linked to aquatic environments and 152 domestic waterfowl were examined for AIV isolation in embryonating chicken eggs. Biological samples were obtained by integrating the conventional cloacal swab collection with the harvesting of samples from birds' plumage. Haemagglutinating allantoic fluids were further characterized by serological and molecular methods. In August-September 2012, 17 AIVs, including three H3N8, eight H4N6, two H4N?, one H2N?, one H?N2, and two unsubtyped LPAIVs, were isolated from 15 wild ducks. Whereas comparable proportions of wild Anseriformes (n.118) tested virus isolation (VI)-positive from cloaca and feathers (5.9% vs 8.5%) were detected, the overall prevalence of virus isolation, obtained from both sampling methods, was 2.4 times higher than that calculated on results from cloacal swab examination only (14.4% vs 5.9%). Unlike previously described in this area, the H4N6 antigenic subtype was found to be the prevalent one in 2012. Both cloacal and feather samples collected from domestic waterfowl tested VI-negative. Conclusion/Significance: We found lack of evidence for the H5N1 HPAIV circulation, explainable by the poor environmental fitness of HPAIVs in natural ecosystems. Our LPAIV isolation data emphasise the importance of Siberia wetlands in influenza A virus ecology, providing evidence of changes in circulation dynamics of HN antigenic subtypes harboured in wild bird reservoirs. Further studies of isolates, based on bioinformatic approaches to virus molecular evolution and phylogenesis, will be needed to better elucidate mechanisms involved in AIV perpetuation in this area. [ABSTRACT FROM AUTHOR]