AI Surveillance in Wild Birds in Argentina

AGUSTINA RIMONDI; KEMIN XU; LUCAS FERRERI; MARIA ISABEL CRAIG; TROY SUTTON; DANIEL R. PEREZ; ARIEL PEREDA

Simposio; 8th International Symposium on Avian influenza; 2012

Until recently, influenza A viruses from wild waterfowl in South America were rarely isolated and/or characterized. To explore the ecology of influenza A viruses in this region, a long-term surveillance program was established in 2006 for resident and migratory water birds in Argentina. We report the characterization of avian influenza viruses mostly isolated from Anseriforms. These isolates corresponds to different HA and NA subtypes. Sixteen isolates corresponds to H5, H6, H7 and H9 subtypes. Genetic and phylogenetic analysis of the internal gene segments of these viruses form a unique clade supporting the notion of independent evolution from influenza A viruses in this latitude. The presence of NS alleles A and B were also identified. Mostly of these isolates also formed unique HA and NA clades separate from North American and Eurasian viruses with the exception of the HA gene of one H6 isolate that was more closely related to the North American lineage, suggesting possible interactions between viruses of North American and South American lineages. Animal studies using H6 isolates suggested that these viruses could replicate and transmit inefficiently in chickens, indicating limited adaptation to poultry. Our results highlight the importance of continued influenza surveillance in wild birds of South America, especially considering the unique evolution of these viruses.