Differentiating betweenBesnoitia besnoiti from cattle andSarcocystis hoarensis from rodents

To provide a biological basis for studies designed to establish the mode of transmission of the veterinary pathogenBesnoitia besnoiti, we compared salient features of this pathogen in cattle with those ofSarcocystis hoarensis in rodents. The cysts and cystozoites of these organisms can readily be distinguished morphologically. In contrast toS. hoarensis which is well adapted to rodents,B. besnoiti fails to mature in jirds or mice and generally is lethal in jirds. Serological reagents discriminately detect these pathogens.B. besnoiti, therefore, can unambiguously be differentiated fromS. hoarensis either by morphological or serological methods or on the basis of experimental comparisons of virulence in laboratory rodents.