title: Unusually High Mortality in Waterfowl Caused by Highly Pathogenic Avian Influenza A(H5N1) in Bangladesh.
abstract: Mortality in ducks and geese caused by highly pathogenic avian influenza A(H5N1) infection had not been previously identified in Bangladesh. In June-July 2011, we investigated mortality in ducks, geese and chickens with suspected H5N1 infection in a north-eastern district of the country to identify the aetiologic agent and extent of the outbreak and identify possible associated human infections. We surveyed households and farms with affected poultry flocks in six villages in Netrokona district and collected cloacal and oropharyngeal swabs from sick birds and tissue samples from dead poultry. We conducted a survey in three of these villages to identify suspected human influenza-like illness cases and collected nasopharyngeal and throat swabs. We tested all swabs by real-time RT-PCR, sequenced cultured viruses, and examined tissue samples by histopathology and immunohistochemistry to detect and characterize influenza virus infection. In the six villages, among the 240 surveyed households and 11 small-scale farms, 61% (1789/2930) of chickens, 47% (4816/10 184) of ducks and 73% (358/493) of geese died within 14 days preceding the investigation. Of 70 sick poultry swabbed, 80% (56/70) had detectable RNA for influenza A/H5, including 89% (49/55) of ducks, 40% (2/5) of geese and 50% (5/10) of chickens. We isolated virus from six of 25 samples; sequence analysis of the hemagglutinin and neuraminidase gene of these six isolates indicated clade 2.3.2.1a of H5N1 virus. Histopathological changes and immunohistochemistry staining of avian influenza viral antigens were recognized in the brain, pancreas and intestines of ducks and chickens. We identified ten human cases showing signs compatible with influenza-like illness; four were positive for influenza A/H3; however, none were positive for influenza A/H5. The recently introduced H5N1 clade 2.3.2.1a virus caused unusually high mortality in ducks and geese. Heightened surveillance in poultry is warranted to guide appropriate diagnostic testing and detect novel influenza strains.
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.|Section for Epidemiology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark.
authors.forename: N
authors.initials: N
authors.lastname: Haider
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.|Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
authors.forename: K
authors.initials: K
authors.lastname: Sturm-Ramirez
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.|College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA.
authors.forename: S U
authors.initials: SU
authors.lastname: Khan
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
authors.forename: M Z
authors.initials: MZ
authors.lastname: Rahman
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
authors.forename: S
authors.initials: S
authors.lastname: Sarkar
authors.affiliation: Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Poh
authors.affiliation: University of California, Davis, Tulare, CA, USA.
authors.forename: H L
authors.initials: HL
authors.lastname: Shivaprasad
authors.affiliation: Department of Livestock Services, Ministry of Fisheries and Livestock, Dhaka, Bangladesh.
authors.forename: M A
authors.initials: MA
authors.lastname: Kalam
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
authors.forename: S K
authors.initials: SK
authors.lastname: Paul
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
authors.forename: P C
authors.initials: PC
authors.lastname: Karmakar
authors.affiliation: Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Balish
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
authors.forename: A
authors.initials: A
authors.lastname: Chakraborty
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
authors.forename: A A
authors.initials: AA
authors.lastname: Mamun
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.|United States Department of Agriculture (USDA), Hawthorne, CA, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Mikolon
authors.affiliation: Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
authors.forename: C T
authors.initials: CT
authors.lastname: Davis
authors.affiliation: Institute of Epidemiology, Diseases Control and Research (IEDCR), Dhaka, Bangladesh.
authors.forename: M
authors.initials: M
authors.lastname: Rahman
authors.affiliation: Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
authors.forename: R O
authors.initials: RO
authors.lastname: Donis
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.|Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Heffelfinger
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.|Division of Infectious Disease and Geographic Medicine, Stanford University, Stanford, CA, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Luby
authors.affiliation: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.|Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA.
authors.forename: N
authors.initials: N
authors.lastname: Zeidner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001459:Bangladesh / Q000453:epidemiology; D002645:Chickens; D002648:Child; D004196:Disease Outbreaks / Q000662:veterinary*; D004372:Ducks; D005260:Female; D005777:Geese; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000401:mortality / Q000821:virology; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D011201:Poultry Diseases / Q000453:epidemiology* / Q000401:mortality / Q000821:virology; D017422:Sequence Analysis, DNA / Q000662:veterinary; D055815:Young Adult
keywords: Bangladesh; H5N1 subtype; clade 2.3.2.1a; duck; goose; histopathology; immunohistochemistry; influenza A virus; outbreaks