Poultry trading behaviours in Vietnamese live bird markets as risk factors for avian influenza infection in chickens

Abstract

Vietnamese poultry are host to co‐circulating subtypes of avian influenza viruses, including H5N1 and H9N2, which pose a great risk to poultry productivity and to human health. AIVs circulate throughout the poultry trade network in Vietnam, with live bird markets being an integral component to this network. Traders at LBMs exhibit a variety of trading practices, which may influence the transmission of AIVs. We identified trading practices that impacted on AIV prevalence in chickens marketed in northern Vietnamese LBMs. We generated sequencing data for 31 H9N2 and two H5N6 viruses. Viruses isolated in the same LBM or from chickens sourced from the same province were genetically closer than viruses isolated in different LBMs or from chickens sourced in different provinces. The position of a vendor in the trading network impacted on their odds of having AIV‐infected chickens. Being a retailer and purchasing chickens from middlemen was associated with increased odds of infection, whereas odds decreased if vendors purchased chickens directly from large farms. Odds of infection were also higher for vendors having a greater volume of ducks unsold per day. These results indicate how the spread of AIVs is influenced by the structure of the live poultry trading network.

Contribution of Segment 3 to the Acquisition of Virulence in Contemporary H9N2 Avian Influenza Viruses

“…(A, B) One-way analysis of variance (ANOVA) with multiple comparisons (all 293T and WF10 panel in DF-1) or Kruskal-Wallis with multiple comparisons (UDL-01 panel in DF-1). (C, D) Primary chicken embryonic fibroblasts (CEF) were infected with a high MOI ( 3 ) of virus. At 7 h postinfection, cells were pulsed with 35 S methionine for 1 h, then lysed, and proteins were separated by SDS-PAGE.…”

“…H9N2 avian influenza viruses (AIVs) are low pathogenicity avian influenza (LPAI) viruses that are enzootic in poultry in many countries across Asia, Africa and the Middle East (3)(4)(5)(6).…”

“…H9N2 avian influenza viruses (AIVs) are low-pathogenicity avian influenza (LPAI) viruses that are enzootic in poultry in many countries across Asia, Africa, and the Middle East ( 3 – 6 ). In afflicted countries they cause a constant burden on poultry production systems through mortality, often associated with coinfection, or through morbidity that leads to reduced egg production and bird growth rates ( 7 – 9 ).…”

The Evolution, Spread and Global Threat of H6Nx Avian Influenza Viruses

“…In the East Asian sub-region, H6N1, H6N2, H6N5, H6N6, H6N8 and H6N9 co-circulate in chicken and duck populations, undergoing frequent reassortment with other subtypes [ 23 , 39 , 40 ]. The migratory waterfowl reservoir is the most common source of H6 introduction into domestic poultry but is typically restricted in their ability to spread further [ 33 ].…”

Preparing for Emerging Zoonotic Viruses

“…The main type of production system, as well as the organization of the trade chain, and the degree and frequency of human and wildlife contact differs greatly between regions. In South East Asia, the majority of poultry is reared in backyard farms, with complicated subsequent trade chains, involving many traders and live poultry markets ( Moyen et al ., 2018 ; Sealy et al ., 2019 ). This influences infectious disease risk and possible spread.…”