Precursor genes of future pandemic influenza viruses are perpetuated in ducks nesting in Siberia

Abstract

Influenza A viruses of different subtypes were isolated from fecal samples of ducks in their nesting areas in Siberia in summer from 1996 to 1998. Phylogenetic analysis of the NP genes of the isolates in Siberia and those in Hokkaido, Japan on their flyway of migration from Siberia to the south in autumn revealed that they belong to the Eurasian lineage of avian influenza viruses. It is noted that the genes of the isolates in Siberia are closely related to those of H5N1 influenza virus strains isolated from chickens and humans in Hong Kong in 1997 as well as to those of isolates from domestic birds in southern China. The results indicate that influenza viruses perpetuated in ducks nesting in Siberia should have contributed genes in the emergence of the H5N1 virus in Hong Kong. Vaccine prepared from avirulent A/duck/Hokkaido/4/96 (H5N3) influenza virus was potent enough to protect mice from challenge with lethal dose of the pathogenic H5N1 virus [19]. Intensive surveillance study of aquatic birds especially in Siberia is, therefore, stressed to provide information on the future pandemic influenza virus strains and for vaccine preparation.

Antibodies to Influenza A Virus in Wild Birds across Mongolia, 2006–2009

“…Extensive surveillance studies of wild ducks in the northern hemisphere have revealed high prevalence of influenza virus primarily in HY birds, with a peak in virus recovery in early fall prior to southbound migration (Krauss etal., 2004;Fouchier et al, 2007;Wallensten et al, 2007). Similar patterns have been observed in northern Europe and Siberiaprior to winter migration (Okazaki et al, 2000). Given this timing of AI transmission, our sampling period (July-September) should have coincided with the increased seasonal transmission of AI virus; however, HY Great Cormorants, Ruddy Shelducks, and Mongolian Gulls showed either no or low prevalence of antibodies to AI.…”

Ecophysiology of avian migration in the face of current global hazards

“…Importantly, migratory waterbirds (waterfowl Anseriformes and waders/gulls Charadriiformes) are considered an important reservoir for low-pathogenic avian influenza viruses, certain strains of which represent precursors for highly pathogenic avian influenza viruses [34,35]. Although avian influenza is currently in the spotlight, there are numerous other diseases for which migratory birds may be important vectors [36].…”

Evaluation of Replication and Cross-Reactive Antibody Responses of H2 Subtype Influenza Viruses in Mice and Ferrets

“…Given the potential for live attenuated influenza virus vaccines to confer a great breadth of heterologous cross-protection (1,2,6,35), we recently conducted a study evaluating cold-adapted A/Ann Arbor/6/1960 (AA CA), an H2 influenza virus used as the backbone of the seasonal live attenuated influenza A virus vaccine currently licensed in the United States (3). However, as H2 influenza virus continues to circulate widely and appear in migratory birds (10,24,26), in poultry markets (20), and in swine (21), with evidence of interregional gene transmission (19,22), a more extensive evaluation of recent isolates may be warranted in the selection of a potential H2 pandemic vaccine candidate.…”