Avian influenza and coronaviruses in live animal and wet markets in Laos: prevalence and public health considerations

Background: Live animal and wet markets (LWM) serve as critical interfaces where humans closely interact with domestic and peri-domestic animals, facilitating the spillover of zoonotic pathogens. Previous outbreaks of avian influenza viruses (AIV) and coronaviruses (CoV) linked to these markets underscore their significant public health risks. Despite the high density of LWM and historical viral spillovers in Southeast Asia, studies on the prevalence of respiratory viruses in LWM in Laos remain limited. Methods: To address this gap, we conducted a study across 20 LWM in the capital region of Laos in 2023. A total of 266 oropharyngeal swab samples from live and slaughtered ducks and chickens, the environment, and the air, were collected and screened for AIV and CoV. Furthermore, a questionnaire assessed the knowledge and attitudes of vendors and shoppers regarding disease risks at LWM. Results: We found a higher prevalence of AIV in swabs from live ducks (72%) compared to chickens (18%), while CoV was more common in chickens (13%) than ducks (5%). Air samples showed a prevalence of 38% for AIV and 8% for CoV. Subtyping of AIV revealed the circulation of the high pathogenicity H5N1 strain which is genetically characterized as clade 2.3.2.1e. Conclusions: These findings highlight the significant public health risks associated with LWM in Laos and emphasize the need for continuous surveillance and control measures to mitigate the risk of future zoonotic outbreaks.