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Genetic Diversity and Phylogenetic Analysis of Highly Pathogenic Avian Influenza ( HPAI ) H5N1 Viruses Circulating in B angladesh from 2007–2011
Author(s) -
Mondal S. P.,
Balasuriya U. B. R.,
Yamage M.
Publication year - 2013
Publication title -
transboundary and emerging diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.392
H-Index - 63
eISSN - 1865-1682
pISSN - 1865-1674
DOI - 10.1111/tbed.12173
Subject(s) - clade , influenza a virus subtype h5n1 , biology , phylogenetic tree , virology , highly pathogenic , genetic diversity , antigenic drift , virus , influenza a virus , gene , genetics , population , demography , sociology
Summary Highly pathogenic avian influenza ( HPAI ) H5N1 virus has been endemic in Bangladesh since its first isolation in February 2007. Phylogenetic analysis of the haemagglutinin ( HA ) gene of HPAI H5N1 viruses demonstrated that 25 B angladeshi isolates including two human isolates from 2007–2011 along with some isolates from neighbouring A sian countries (India, Bhutan, Myanmar, Nepal, China and Vietnam) segregate into two distinct clades (2.2 and 2.3). There was clear evidence of introduction of clade 2.3.2 and 2.3.4 viruses in 2011 in addition to clade 2.2 viruses that had been in circulation in Bangladesh since 2007. The data clearly demonstrated the movement of H5N1 strains between Asian countries included in this study due to migration of wild birds and/or illegal movement of poultry across borders. Interestingly, the two human isolates were closely related to the clade 2.2 Bangladeshi chicken isolates indicating that they have originated from chickens. Furthermore, comparative amino acid sequence analysis revealed several substitutions (including 189R>K and 282I>V) in HA protein of some clade 2.2 Bangladeshi viruses including the human isolates, suggesting there was antigenic drift in clade 2.2.3 viruses that were circulating between 2008 and 2011. Overall, the data imply genetic diversity among circulating viruses and multiple introductions of H5N1 viruses with an increased risk of human infections in Bangladesh, and establishment of H5N1 virus in wild and domestic bird populations, which demands active surveillance.