H7N9 influenza A virus transmission in a multispecies barnyard model.

Influenza A viruses are a diverse group of pathogens that have been responsible for millions of human and avian deaths throughout history. Here, we illustrate the transmission potential of H7N9 influenza A virus between Coturnix quail (Coturnix sp.), domestic ducks (Anas platyrhynchos domesticus), chickens (Gallus gallus domesticus), and house sparrows (Passer domesticus) co-housed in an artificial barnyard setting. In each of four replicates, individuals from a single species were infected with the virus. Quail shed virus orally and were a source of infection for both chickens and ducks. Infected chickens transmitted the virus to quail but not to ducks or house sparrows. Infected ducks transmitted to chickens, resulting in seroconversion without viral shedding. House sparrows did not shed virus sufficiently to transmit to other species. These results demonstrate that onward transmission varies by index species, and that gallinaceous birds are more likely to maintain H7N9 than ducks or passerines.