Highly Pathogenic Avian Influenza

Highly pathogenic avian influenza virus was confirmed in wild geese in Northeastern Colorado on March 24, 2022. Colorado Parks and Wildlife (CPW) is working with the Colorado Department of Agriculture, the United States Department of Agriculture, and other agencies to monitor and respond to additional cases of highly pathogenic avian influenza.

What is Avian Influenza?
Avian influenza is an infectious disease of birds caused by a group of influenza viruses. These viruses naturally circulate in wild birds, such as waterfowl and shorebirds, which can carry the virus without showing any signs of disease. There are many strains of avian influenza, which are classified into two categories: low pathogenic (LPAI) strains which typically cause little or no clinical signs in domestic poultry, and highly pathogenic (HPAI) strains which can cause severe disease and potentially high mortality in domestic poultry.

Does Avian Influenza cause disease in wild birds?
Most wild birds that are infected with avian influenza viruses do not show signs of disease. However, HPAI strains can occasionally cause disease in some wildlife species including swans, diving ducks, gulls, geese, grebes, raptors, vultures, cranes and terns. In these birds, typical symptoms include swimming in circles, head tilt and lack of coordination. Game bird species such as turkeys, grouse, and quail may also be susceptible to HPAI with signs more similar to poultry such as swelling of the head, diarrhea, moving slowly, ruffled feathers, respiratory signs, and not eating. Some affected wild birds are found dead.

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