What is the role of migratory birds in the spread of HPAI H5N1?
The role of migratory birds in spread of HPAI H5N1 is not fully understood. Only a very few live wild birds out of hundreds of thousands tested have been found to be carrying HPAI H5N1. Most were found dead, usually near outbreaks in domestic poultry. It is unclear whether wild birds can carry HPAI H5N1 long distances, especially beyond the incubation period of the virus, which is around three to seven days. This is because HPAI H5N1 appears to be fatal to many wild birds. It is also unknown how easily infected wild birds can pass on the virus to other wild birds. The geographic spread of HPAI H5N1 does not correlate well with migratory bird routes or seasons. HPAI H5N1 has not been found in areas or at an intensity that might be expected if migratory birds were the main carriers. Most outbreaks of HPAI H5N1 appear to have been spread by the movement of poultry, poultry products, and waste rather than by movements of migratory birds. Is HPAI H5N1 in the United States? Various forms of
