What Is AI?
Avian influenza (AI) viruses can infect chickens, turkeys, pheasants, quail, ducks, geese and guinea fowl, as well as a wide variety of other birds. Migratory waterfowl have proved to be a natural reservoir for the less infectious strains of the disease known as low pathogenicity avian influenza. AI viruses can be classified into low pathogenicity (LPAI) and high pathogenicity (HPAI) based on the severity of the illness they cause. HPAI is an extremely infectious and fatal form of the disease that, once established, can spread rapidly from flock to flock. However, some LPAI virus strains are capable of mutating under field conditions into HPAI viruses.The U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) works to keep HPAI from becoming established in the U.S. poultry population.

What Are the Signs?
The clinical signs of birds affected with all forms of AI may show one or more of the following: Sudden death without clinical signs; Lack of energy and appetite; Decreased egg production; Soft-shelled or misshapen eggs; Swelling of the head, eyelids, comb, wattles, and hocks; Purple discoloration of the wattles, combs, and legs; Nasal discharge; Coughing, sneezing; Lack of coordination; and Diarrhea. Note: Many birds with LPAI may not show any signs of disease.

How Is AI Spread?
Exposure of poultry to migratory waterfowl and the international movement of poultry, poultry equipment, and people pose risks for introducing AI into U.S. poultry. Once introduced, the disease can be spread from bird to bird by direct contact. AI viruses can also be spread by manure, equipment, vehicles, egg flats, crates, and people whose clothing or shoes have come in contact with the virus. AI viruses can remain viable at moderate temperatures for long periods in the environment and can survive indefinitely in frozen material.