Avian influenza

Avian influenza is a viral infection found in domestic poultry and a wide range of other birds. Wild waterfowl and shorebirds are often subclinically affected carriers of the virus. In poultry, low-pathogenicity strains can cause subclinical infections; however, some strains typically cause respiratory signs or decreased egg production. Highly pathogenic strains may cause widespread organ failure and sudden death, often with high mortality rates. Diagnosis is based on detection of the viral genome or specific antibodies or on virus isolation. Antimicrobials may help control secondary bacterial infection in flocks affected by low-pathogenicity strains. Antiviral drugs are not approved or recommended. Prevention is best accomplished by biosecurity measures. Vaccines matched for antigenic type can greatly increase resistance to infection, prevent clinical signs, and decrease viral shedding in infected flocks.