Abstract Title
Infection dynamics of avian influenza A virus in mallards: implications for environmental contamination and disease spread
Abstract
Influenza A viruses (IAVs) infect a variety of avian and mammalian species, including humans, with aquatic waterbirds, especially from the orders Anseriformes and Charadriiformes, serving as primary reservoirs. Mallards (Anas platyrhynchos) are a key species for the maintenance of IAVs among aquatic birds, depositing viruses into the environment and playing an important role in influenza transmission and ecology. Although it is known that IAVs can replicate in both the respiratory and gastrointestinal (GI) tracts of mallards, the dynamics of replication and shedding are not fully understood. In this study, we generated a hemagglutinin-green fluorescent protein (HA-GFP) subtype H4N6 low-pathogenic avian IAV with characteristics comparable to the wild-type virus. In a cohort of 8-week-old ducks intranasally inoculated with 10^6 TCID50 of the HA-GFP virus, viral replication occurs predominantly in the small intestine, with limited but detectable activity in the upper respiratory tract. Viral replication initiated in the jejunum, maintaining high levels through the ileum, while rapidly declining in the cecum, colon, and cloaca. As the virus traverses the GI tract, a substantial accumulation of viral particles occurs in the lumen, where the solubility of gut fluids facilitates mixing and subsequent shedding of the virus through feces. Further studies will investigate molecular mechanisms driving tissue-specific replication and viral shedding patterns to improve insights on environmental deposition. These findings enhance understanding of IAV dynamics in mallards, highlighting the role of the GI tract in viral replication and environmental spread, with implications for monitoring and mitigating influenza in wild birds and aquatic habitats.
Co-Author(s)
Bac Le1,2,3, Emily Giri1,2,3, Moran Li1,2,3,4, Andrew Ramey5, Xiu-Feng Wan1,2,3,4,6
1Center for Influenza and Emerging Infectious Diseases, University of Missouri, Columbia, Missouri 65211, USA; 2Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, Missouri 65211, USA; 3Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA; 4Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, USA; 5US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA; 6Department of Electrical Engineering & Computer Science, University of Missouri, Columbia 65211, Missouri, USA.
Abstract Category
Transmission pathways, pathobiology, immune responses