Retrospective Examinations on Cryptosporidium in the Bursa of Fabricius in Growing Layers

Abstract

In order to see a fringe of cryptosporidium (Cr) infection in the past, retrospective histologic examinations were carried out on the bursae of Fabricius from 200 growing layer chickens collected in 1977 and 1978. As a result, Cr infection was recognized in 5% of the chickens examined, suggesting a relatively wide prevalence of the infection for a long time in Japan. Most of chickens with Cr infection in their bursa of Fabricius concurrently exhibited histologic bursal lesions similar to those of infectious bursal disease. This indicates a possible relationship between both infections.