Transmission dynamics of avian influenza viruses in Egyptian poultry markets

Live bird markets (LBMs) are considered hotspots for Avian Influenza Viruses (AIVs). In such markets, AIVs pose threats to both poultry and public health. Within LBMs, AIVs spread through various routes, including direct contact, environmental contamination, and aerosol transmission. Unique factors in Egyptian LBMs, such as the coexistence of wild and domestic birds, increase transmission risks between birds as well as spill-overs into exposed humans. Understanding the transmission dynamics of AIVs is vital for implementing effective control measures. We conducted a study in four Egyptian LBMs located in Mediterranean coast cities from November 2021 to March 2023. In this study we tested 3,971 samples from poultry, wild birds, and the environment, out of which 692 (17.4%) were positive for AIV. Poultry exhibited a higher prevalence (42.2%) than wild birds (34.4%). Environmental samples, including water (30.8%), surfaces (17.2%), and air (18.2%), also tested positive for AIV. Diverse AIV subtypes, including H5N1, H9N2, H5/H9 co-infection, and H5N8, were detected among avian species and the environment. Temporal analysis revealed fluctuating IAV positivity rates from November 2021 to March 2023. These results emphasize the importance of continuous surveillance, resource allocation, and multisectoral collaboration to protect poultry and human health, and prevent novel influenza strains' emergence in Egyptian LBMs.