The Continuing Evolution of H5N1 and H9N2 Influenza Viruses in Bangladesh Between 2013 and 2014.
In 2011, avian influenza surveillance at the Bangladesh live bird markets (LBMs) showed complete replacement of the highly pathogenic avian influenza (HPAI) H5N1 virus of clade 2.2.2 (Qinghai-like H5N1 lineage) by the HPAI H5N1 clade 2.3.2.1. This clade, which continues to circulate in Bangladesh and neighboring countries, is an intra-and interclade reassortant; its HA, polymerase basic 1 (PB1), polymerase (PA), and nonstructural (NS) genes come from subclade 2.3.2.1a; the polymerase basic 2 (PB2) comes from subclade 2.3.2.1c; and the NA, nucleocapsid protein (NP), and matrix (M) gene from clade 2.3.4.2. The H9N2 influenza viruses cocirculating in the Bangladesh LBMs are also reassortants, possessing five genes (NS, M, NP, PA, and PB1) from an HPAI H7N3 virus previously isolated in Pakistan. Despite frequent coinfection of chickens and ducks, reassortment between these H5N1 and H9N2 viruses has been rare. However, all such reassortants detected in 2011 through 2013 have carried seven genes from the local HPAI H5N1 lineage and the PB1 gene from the Bangladeshi H9N2 clade G1 Mideast, itself derived from HPAI H7N3 virus. Although the live birds we sampled in Bangladesh showed no clinical signs of morbidity, the emergence of this reassortant HPAI H5N1 lineage further complicates endemic circulation of H5N1 viruses in Bangladesh, posing a threat to both poultry and humans.
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
Atanaska
A
Marinova-Petkova
Karthik
K
Shanmuganatham
B Department of Zoology, Jahangirnagar University, Savar, Dhaka, Bangladesh 1342.
Mohammed M
MM
Feeroz
C National Primate Research Center, University of Washington, Seattle, WA 98195.
Lisa
L
Jones-Engel
B Department of Zoology, Jahangirnagar University, Savar, Dhaka, Bangladesh 1342.
M Kamrul
MK
Hasan
B Department of Zoology, Jahangirnagar University, Savar, Dhaka, Bangladesh 1342.
Sharmin
S
Akhtar
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
Jasmine
J
Turner
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
David
D
Walker
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
Patrick
P
Seiler
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
John
J
Franks
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
Pamela
P
McKenzie
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
Scott
S
Krauss
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.
Richard J
RJ
Webby
A Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105.|D Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia 21589.
Robert G
RG
Webster
D000818:Animals; D001459:Bangladesh / Q000453:epidemiology; D002645:Chickens; D004372:Ducks; D019143:Evolution, Molecular; D005777:Geese; D053124:Influenza A Virus, H5N1 Subtype / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D053127:Influenza A Virus, H9N2 Subtype / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D005585:Influenza in Birds / Q000453:epidemiology / Q000821:virology*; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology / Q000821:virology*; D011784:Quail; D014764:Viral Proteins / Q000235:genetics
D014764:Viral Proteins
Bangladesh; H5N1 clade 2.3.2.1a; H9N2 clade G1-Mideast; highly pathogenic avian influenza; live-bird markets; reassortants