title: Highly Pathogenic Avian Influenza Virus A/H5N1 Infection in Vaccinated Meat Duck Flocks in the Mekong Delta of Vietnam.
abstract: We investigated episodes of suspected highly pathogenic avian influenza (HPAI)-like illness among 12 meat duck flocks in two districts in Tien Giang province (Mekong Delta, Vietnam) in November 2013. In total, duck samples from 8 of 12 farms tested positive for HPAI virus subtype A/haemagglutinin 5 and neuraminidase 1 (H5N1) by real-time RT-PCR. Sequencing results confirmed clade of 2.3.2.1.c as the cause of the outbreaks. Most (7/8) laboratory-confirmed positive flocks had been vaccinated with inactivated HPAI H5N1 clade 2.3.4 vaccines <6 days prior to onset of clinical signs. A review of vaccination data in relation to estimated production in the area suggested that vaccination efforts were biased towards larger flocks and that vaccination coverage was low [21.2% ducks vaccinated with two shots (range by district 7.4-34.9%)]. The low-coverage data, the experimental evidence of lack of cross-protection conferred by the currently used vaccines based on clade 2.3.4 together with the short lifespan of meat duck flocks (60-70 days), suggest that vaccination is not likely to be effective as a tool for control of H5N1 infection in meat duck flocks in the area.
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.
authors.forename: N V
authors.initials: NV
authors.lastname: Cuong
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.|University of Science, Ho Chi Minh City, Vietnam.
authors.forename: V N T
authors.initials: VN
authors.lastname: Truc
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.
authors.forename: N T
authors.initials: NT
authors.lastname: Nhung
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.
authors.forename: T T
authors.initials: TT
authors.lastname: Thanh
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.
authors.forename: T T B
authors.initials: TT
authors.lastname: Chieu
authors.affiliation: Sub-Department of Animal Health, Tien Giang Province, Vietnam.
authors.forename: T Q
authors.initials: TQ
authors.lastname: Hieu
authors.affiliation: Sub-Department of Animal Health, Tien Giang Province, Vietnam.
authors.forename: N T
authors.initials: NT
authors.lastname: Men
authors.affiliation: Sub-Department of Animal Health, Tien Giang Province, Vietnam.
authors.forename: H H
authors.initials: HH
authors.lastname: Mai
authors.affiliation: Sub-Department of Animal Health, Tien Giang Province, Vietnam.
authors.forename: H T
authors.initials: HT
authors.lastname: Chi
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, UK.
authors.forename: M F
authors.initials: MF
authors.lastname: Boni
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, UK.
authors.forename: H R
authors.initials: HR
authors.lastname: van Doorn
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, UK.
authors.forename: G E
authors.initials: GE
authors.lastname: Thwaites
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Carrique-Mas
authors.affiliation: Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Hospital for Tropical Disease, Ho Chi Minh City, Vietnam.|Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, UK.
authors.forename: N T
authors.initials: NT
authors.lastname: Hoa
mesh_terms: D000818:Animals; D004196:Disease Outbreaks / Q000517:prevention & control / Q000662:veterinary*; D004372:Ducks; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology; D008460:Meat; D014611:Vaccination / Q000662:veterinary; D014744:Vietnam / Q000453:epidemiology
keywords: H5N1; avian influenza virus; duck; one health; vaccine; veterinary epidemiology; zoonoses