Epidemiologic Studies of the 1975 Avian Influenza Outbreak in Chickens in Alabama

Abstract

The epidemiology of the 1st reported non-fowl-plague avian influenza (AI) virus A/Chicken/Alabama/75 (Hav4Neq2) isolated from chickens in the USA is discussed. The signs and pathologic changes were described. The environment, nutrition and stress factors are discussed as possible contributors to the disease syndrome observed in 3 commercial egg-laying flocks. Avian influenza antibody was demonstrated by agar-gel precipitation in convalescent chickens through 83 days postinfection. A serological survey of 321 additional poultry flocks was negative for antibodies against avian influenza. A survey was made by serology and virus isolation techniques on 387 wild, free-flying birds that fed and roosted in the area. Wild waterfowl are discussed as a possible source of the AI virus.