Reassortant Avian Influenza A(H5N1) Viruses with H9N2-PB1 Gene in Poultry, Bangladesh

Isabella Monne

, Mat Yamage, Gwenaëlle Dauphin, Filip Claes, Garba Ahmed, Mohammed Giasuddin, Annalisa Salviato, Silvia Ormelli, Francesco Bonfante, Alessia Schivo, and Giovanni Cattoli

Author affiliations: Istituto Zooprofilattico Sperimentale delle Venezie, Padova, Italy (I. Monne, A. Salviato, S. Ormelli, F. Bonfante, A. Schivo, G. Cattoli); Food and Agriculture Organization of the United Nations Emergency Center for Transboundary Animal Diseases, Dhaka, Bangladesh (M. Yamage, G. Ahmed); Food and Agriculture Organization of the United Nations Animal Health Service, Rome, Italy (G. Dauphin, F. Claes); Bangladesh Livestock Research Institute National Reference Laboratory for Avian Influenza, Dhaka (M. Giasuddin)

Abstract

Bangladesh has reported a high number of outbreaks of highly pathogenic avian influenza (HPAI) (H5N1) in poultry. We identified a natural reassortant HPAI (H5N1) virus containing a H9N2-PB1 gene in poultry in Bangladesh. Our findings highlight the risks for prolonged co-circulation of avian influenza viruses and the need to monitor their evolution.

Bangladesh has one of the highest reported number of outbreaks of highly pathogenic avian influenza (HPAI) (H5N1) in poultry (1). As of May 26, 2013, a total of 548 outbreaks of HPAI (H5N1) have been reported (1); these outbreaks have resulted in serious economic repercussions in the poultry sector in this country. Furthermore, 7 cases of human infection with HPAI (H5N1) were confirmed, most recently a fatal case in a 2-year-old child in April 2013 (2).
In addition to the HPAI (H5N1) virus, the H9N2 subtype is widely circulating in poultry in Bangladesh, which raises concerns about the possible implications of the extensive co-circulation of these viruses (3,4). Their coexistence in the same susceptible population is likely to generate appropriate conditions for the emergence of novel reassortant variants, with unknown epizootic and zoonotic potential. We characterized the complete genome of 18 HPAI (H5N1) virus strains from Bangladesh and report the identification and characterization of a novel natural reassortant HPAI (H5N1) virus that contains an H9N2-PB1 gene in poultry.