Pathology caused by three species of Eimeria that infect the turkey with a description of a scoring system for intestinal lesions

Three-week-old turkey poults were infected with pure lines of three species of Eimeria (E. adenoeides, E. gallopavonis, and E. meleagrimitis) recently isolated from commercial turkey farms. The lines had been propagated from a single oocyst and identified by species-specific PCR amplification of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Five to six days after infection their intestines were removed and examined for the presence of intestinal lesions. A description and review of the pathology caused by these parasites is provided, and a scoring system developed by which the severity of the lesions can be evaluated. The system is similar to that described by Johnson, J. and Reid, W. M. [1970. Anticoccidial drugs: lesion scoring techniques in battery and floor-pen experiments with chickens. Experimental Parasitology, 28, 30-36] for chickens in which a score of zero to four is assigned to lesions of increasing severity. The intestinal lesions observed here, and their assigned scores, are supported by representative illustrations. It is hoped that they may prove a useful tool for evaluating the pathology caused by E. adenoeides, E. gallopavonis, and E. meleagrimitis in the turkey.RESEARCH HIGHLIGHTSA scoring system has been developed for intestinal lesions caused by three species of Eimeria that infect the turkey.The lesions attributable to these species are illustrated.