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Active #Surveillance for Emerging #Influenza A Viruses – Findings from a #OneHealth Study in #Vietnam’s Live Bird #Markets

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By G.M.

 


Highlights

-- We conducted surveillance for influenza A viruses at live bird markets in northern Vietnam.

-- Six different subtypes of influenza A virus were found co-circulating in the markets.

-- Notable genetic mutations were found across many genes.

-- These markets have great potential to generate new pandemic influenza A virus strains.


Abstract

Objectives

Live bird markets (LBMs) in Asia have often been the source of human infections with avian influenza virus (AIV).

Methods

From July 2021 to August 2023, we employed a One Health approach in conducting periodic surveillance for novel influenza A viruses in five LBMs in northern Vietnam. Specimens were studied with egg culture, molecular assays, Sanger sequencing, and next-generation sequencing.

Results

We studied a total of 688 human, avian, and bioaerosol specimens. Among these, 118 (17.2%) were found to have molecular evidence of AIVs. Next-generation sequencing of 92 isolates revealed multiple AIV subtypes, including H4N6 (n=1), H5N1 (n=3), H5N8 (n=6), H6N2 (n=3), H6N6 (n=18), and H9N2 (n=61) and mix infections (n=7). Our H5Nx sequences belonged to the Eurasian lineage clade 2.3.4.4b, while our H6N2 sequences were of group III, H6N6 of group II, and H9N2 of the BJ94-lineage clade 4.6.14.

Conclusions

The relatively high prevalence of AIV, particularly highly pathogenic H5N1 and H5N8 viruses, along with the subtype diversity, frequent co-infections and notable mutations, highlights the urgent need for continued monitoring and control of AIV in Vietnam’s poultry farms and LBMs.

Source: International Journal of Infectious Diseases, https://www.ijidonline.com/article/S1201-9712(25)00354-6/fulltext

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