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Title: Isolation of H15N7 influenza virus from wild birds in Eastern Europe and its relationship to viruses from other regions

Author
item MUZYKA, DENYS - National Scientific Center
item Pantin Jackwood, Mary
item FEREIDOUNI, SASAN - Wesca Wildlife Network

Submitted to: European Scientific Working Group on Influenza
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2014
Publication Date: 9/14/2014
Citation: Muzyka, D., Pantin Jackwood, M.J., Fereidouni, S. 2014. Isolation of H15N7 influenza virus from wild birds in Eastern Europe and its relationship to viruses from other regions [abstract]. Fifth European Scientific Working Group on Influenza Conference, September 14-17, 2014, Riga, Latvia. CDROM.

Interpretive Summary: Influenza viruses circulating in the natural reservoir in wild birds are monitored to obtain valuable information on the viruses, including new ecological niches, seasons of virus circulation, to detect new variants of the virus and to establish their introduction into new geographic regions. As part of the monitoring of wild bird influenza viruses in the Azov-Black Sea region of Ukraine in 2010 an influenza virus subtype H15N7 was isolated (A/mallard/Novomychalivka/2-23-12/10) from a clinically healthy wild mallard duck. This subtype of virus circulated only in wild birds in Australia, but in 2008 the virus A/teal/Chany/7119/2008 (H15N4) was isolated from wild birds in Western Siberia (Russia). We conducted the sequencing of all genes of the H15N7 influenza virus and found that the HA15 gene was closely related to the virus A/teal/Chany/7119/2008 (H15N4) from Russia, and the N7 gene it was related to avian influenza viruses of H7N7 and H10N7 subtypes circulating in wild birds in Western Europe. The M gene sequencing revealed a close relationship with influenza viruses of different subtypes from Altai (Russia) and Mongolia, and analysis of the NP, NS, and PB1 genes revealed that the Ukrainian virus was similar to influenza viruses of different subtypes from Norway and Sweden, and the PB2 gene sequence was similar to viruses of Asian origin. In conclusion, the H15N7 avian influenza subtype was isolated for the first time from wild birds in Eastern Europe. This virus is a reasortant between influenza viruses of different subtypes from Western Europe, Western Siberia and Asia.

Technical Abstract: Background: Continuous monitoring of influenza viruses circulating in the natural reservoir in wild birds is important for early warning and forecasting of epizootic and epidemiological situation with influenza. These studies allow getting much valuable information on the environmental features of influenza viruses’ circulation, new ecological niches of viruses, to detect new variants of the virus and establish their introduction into new geographic regions. Methods: Monitoring of influenza viruses in wild birds of 27 families and 11 genera was conducted in 2006-2012 in the Azov-Black Sea region of Ukraine. Virological studies of the biological material (cloacal, nasal swabs and fecal samples) collected from 6281 wild birds of 84 species were conducted as recommended by the OIE. Results: As part of the monitoring of wild bird influenza in 2010 an influenza virus subtype H15N7 was isolated (A/mallard/Novomychalivka/2-23-12/10) from a clinically healthy wild mallard (Anas platyrhynchos) in the Azov-Black Sea region of Ukraine. This virus grew well in chicken embryos without causing their death. The HA titer was 1:512, and the infectious titer was 6,5 lg EID50/0.2 ml. This subtype of virus circulated only in wild birds in Australia, but in 2008 the virus A/teal/Chany/7119/2008 (H15N4) was isolated from wild birds in Western Siberia (Russia). We conducted the sequencing of all genes of the H15N7 influenza virus. Phylogenetic analysis of HA15 gene showed that the virus was closely related to the virus A/teal/Chany/7119/2008 (H15N4) from Russia, and the N7 gene it was related to avian influenza viruses of H7N7 and H10N7 subtypes circulating in wild birds in Western Europe. M gene sequencing revealed a close relationship with influenza viruses of different subtypes from Altai (Russia) and Mongolia, and analysis of the NP, NS, and PB1 genes revealed that the Ukrainian virus was similar to influenza viruses of different subtypes from Norway and Sweden, and the PB2 gene sequence was similar to viruses of Asian origin. Conclusions: The H15N7 avian influenza subtype was isolated for the first time from wild birds in Eastern Europe. This virus is a reasortant between influenza viruses of different subtypes from Western Europe, Western Siberia and Asia. These results support the need for monitoring continuing of influenza viruses circulating in the Azov-Black Sea region in order to study the characteristics of their circulation and the possible introduction of new genetic variants of the virus.