Survey of potential viral pathogens in the ceca of pen-raised mallards

The threat posed by infectious diseases are a major concern for global public health and the role of migratory birds in pathogen transmission is increasingly under scrutiny. Enteric viral pathogen surveillance in migratory birds is a critical component of outbreak preparedness. The shedding of such pathogens through excrement into bodies of water located at migratory stop-over sites and breeding and wintering grounds creates conditions to potentially infect millions of birds annually. The mallard is the most abundant of all duck species and migratory across much of its range. Here we characterized enteric viral pathogens from the cecum of 16 captive raised mallards (Anas platyrhynchos) from Wisconsin, USA using metagenomics. Four families of viral pathogens from our study of Mallard cecum viromes - Picobirnaviridae (Genogroup I), Caliciviridae (Duck Nacovirus), Picornaviridae (Duck Aalivirus) and Sedoreoviridae (Duck Rotavirus G) - were recovered. To our knowledge, this is the first report of Aalivirus in the Americas, and the first report of Calicivirus in wild birds in the United States.