Avian influenza, commonly referred to as H5N1 or "bird flu", is caused by a virus found among various species of birds. It is highly contagious among domestic poultry and has a mortality rate of nearly 100%, It can infect domestic poultry, including chickens, turkeys, quail, geese, ducks, pheasants, and guinea fowl. Since January 2025, Connecticut has had two poultry outbreaks in non-commercial "backyard" poultry flocks. H5N1 has been more frequently detected in wild birds. No additional H5N1 virus cases have occurred in people, livestock, or other domestic animals in Connecticut.