High prevalence of highly pathogenic avian influenza A virus found in Vietnam’s live bird markets
A long term study of Vietnam’s live bird markets has found a high prevalence of highly pathogenic avian influenza A virus in these food outlets, which could pose health risks for consumers in the country.
Published in Open Forum Infectious Diseases, the study calls for urgent and continued surveillance measures to mitigate the risks posed by the avian influenza viruses to both poultry and humans.
The research analysed 3,493 samples from northern Vietnam, including poultry oral swabs, pig oral secretion samples, bioaerosol and faecal samples from animal farms, and nasal washes from animal workers in live bird markets and swine farms between January 2019 and April 2021.
A significant prevalence of avian influenza A viruses, particularly the highly pathogenic H5N6 strains, was found in these markets. Close to 38% of poultry oropharyngeal swabs, 25% of bioaerosol samples, and 35% of poultry fecal swabs tested positive. However less than 1% of samples from swine farms were positive for influenza A virus. Human nasal washes also showed a lower positivity rate of about 2%. These findings mean that avian influenza A viruses are rare in swine herds.
‘Our findings of a large reservoir of highly pathogenic avian influenza virus in Vietnam’s live bird markets underscores the pressing need to work not just in the country but also internationally to reduce the prevalence of these viruses,’ said Professor Gregory C. Gray of the University of Texas Medical Branch (UTMB), who led the study.
Dao Duy Tung from the National Institute of Veterinary Research (NIVR), said the ‘findings highlight the need for continued and enhanced surveillance of avian influenza viruses in live bird markets’.
Hung Nguyen, leader of Health program at the International Livestock Research Institute (ILRI) called for the ‘adoption of the One Health approach for pathogen surveillance (in people, animal and the environment at the same time) to address the health threats facing humans, animals, and the environment, including from avian influenza outbreaks which have been causing mortality cases among human and poultry in Southeast Asia and Vietnam.’
Researchers from the Vietnam National Institute of Veterinary Research (NIVR), the Hanoi University of Public Health (HUPH), the International Livestock Research Institute (ILRI) and Duke One Health Team (USA, China and Singapore) and the University of Texas Medical Branch (UTMB) conducted the study.
Download the full paper: https://hdl.handle.net/10568/149074
Citation: Duy Tung Dao, Coleman, K.K., Vuong N. Bui, Anh N. Bui, Long H. Tran, Quy D. Nguyen, Son Than, Pulscher, L.A., Marushchak, L.V., Robie, E.R., Hung Nguyen-Viet, Phuc Duc Pham, Christy, N.C., Brooks, J.S., Huy C. Nguyen, Rubrum, A.M., Webby, R.J., and Gray, G.C. 2024. High prevalence of highly pathogenic avian influenza A virus in Vietnam’s live bird markets. Open Forum Infectious Diseases 11(7): ofae355.
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Collaborators begin new One Health study of avian influenza viruses in Vietnam | ILRI Asia
