Studies on Acute Marek's Disease: 2. The Role of Coccidia in Transmission and Induction

Abstract

INTRODUCTIONTHE role of parasites in the transmission or induction of fowl leukosis has been the object of much speculation as far back as 1926 (Pappenheimer et al.). Nine responses from 49 states or territorial agencies questioned at the time expressed the opinion that coccidiosis might be involved in the etiology of leukosis. An often-quoted reference of this period was that of Beach and Davis (1925) who pictured “a chronic type of coccidiosis” as inducing leg weakness and paralysis in chickens typical of neural leukosis. Since no reference was made to neural examination it may be assumed that their conclusions were probably based on incorrect diagnosis.Well-designed controlled experiments on interrelationships between coccidiosis and leukosis are totally lacking. Primarily from the analysis of diagnostic records of hen flocks Wilson (1944), Hess (1963) and Vindel (1964) concluded that an increase in coccidiosis resulted in an increase in leukosis. In reports based .