Natural Infection of Chicks with Chicken Anemia Agent

Abstract

A disease, that was characterized by very early mortality after hatching, occurred in two commercial broiler chicken flocks which were derived from the same breeder flock. Anemia, thymic atrophy, and anemic bone marrow were recognized in affected chicks. Microscopic examination showed lesions which were characterized by lymphocyte depletion in the thymus, and hyperplasia of immature granulocytic series or hypoplasia of hematopoietic cells in the bone marrow. The disease was produced by inoculating liver emulsions prepared from the field cases into SPF one-dayold chicks. An agent was isolated from the livers of chicks infected experimentally and it was identified as chicken anemia agent (CAA). On the basis of these results, the present cases were diagnosed as CAA infection.