Which animals are recognized as the primary reservoirs for influenza A viruses?

The primary reservoirs for influenza A viruses are waterfowl and shorebirds. These birds are crucial as they harbor various subtypes of the virus in their intestines without showing signs of illness, allowing the viruses to persist and be spread through their droppings. The presence of these viruses in wild waterfowl is central to the ecology and evolution of influenza A, as they can infect domestic birds and other species, leading to outbreaks of avian influenza.

While domestic chickens, turkeys, feral swine, and Asian backyard poultry can all be affected by influenza A viruses and play roles in transmission pathways, they are not recognized as the primary reservoirs of the virus. The transmission dynamics and host interactions begin with the wild waterfowl populations, which makes them the focal point of concern for animal health and public health regarding influenza A viruses.