Meeting Abstract
The 2015 outbreak of highly pathogenic avian influenza virus (AIV) among domestic poultry in the Midwest was the worst in US history. Because the strain of AIV responsible had been previously found in wild ducks, and because waterfowl are known to be reservoirs of AIV in general, these species were widely reported as a likely cause of the outbreak. Waterfowl, however, are rarely found in or near commercial poultry barns, raising the question of how AIV would move from its natural reservoir into poultry. One possibility is that small terrestrial birds or mammals served as vectors, moving the virus from wetland to farm. To assess the likelihood of this scenario, we sampled over 400 individuals from 39 species of small birds and mammals at sites across Iowa during the fall of 2015 and spring of 2016, after the AIV epidemic had subsided in poultry. We swabbed both internally (mouth and cloaca/anus) and externally (feet and feathers/fur) to test for the virus via qPCR. In addition, we drew blood to test for prior exposure via antibodies against AIV. We found no evidence of current or prior exposure to AIV in small birds and mammals, estimating a 95% confidence interval of true prevalence to be 0.00-0.74%. During our surveillance, governmental organizations did detect AIV in waterfowl across Iowa, at an observed prevalence of up to 15%. So, even though AIV was present on the landscape, small birds and mammals were unlikely to play a major role in moving the virus from wild to domestic species.
