Bio-molecular Diagnosis of Avian Influenza Virus from Different Species of Birds in Bangladesh

Highly pathogenic avian influenza (HPAI) causes enormous losses to the poultry industry of Bangladesh every year since the detection of first outbreak in 2007. In this study biomolecular diagnosis of avian influenza virus in Bangladesh from different species of birds was carried. A total of 1135 samples including 280 from migratory birds, 680 from live bird market (LBM) chickens, 118 from ducks and 57 from pigeons were collected from different locations of Bangladesh during the period from July 2013 to June 2014. Out of 1135 samples, 69 were found positive for influenza A by real time RT-PCR. In addition, 741 Influenza A positive samples collected by different institutes from different species of birds under the FAO-led surveillance program were also received at Bangladesh Livestock Research Institute (BLRI) for further analysis. The real time RT-PCR positive samples were inoculated in 10-day-old embryonated chicken eggs. Out of 810 (741+ 69) influenza A positive samples, 110 were selected on the basis of species and region to cover the whole country and were sent to the OIE reference laboratory for detailed study. The bio-molecular results revealed that in case of migratory bird samples one was H5 (HPAI), two were H9 and eight were of undetermined subtype. Among the LBM chicken samples, seven were H5 (HPAI), 51 were H9, six were mixed infection with H5 & H9 and three were of undermined subtype. In case of duck samples, one was H2, six were H4, six were H5 (HPAI), one with mixed infection with H5 & H2, one with both H5 & H4, two were H9 and one was H7N5, though H7 was genetically distinct from that of the novel H7N9 virus of China. Among quail samples, one was H5 (HPAI) and one was H9. In case of pigeon samples, all three contained H9. From this study it was revealed that HPAI (H5N1) is still circulating in our poultry population. The novel avian influenza virus H7N9 was not found during this study.