Sarcocystosis in neonatal bison fed Sarcocystis cruzi sporocysts derived from cattle.

A 6-day-old female (Bison bison) was inoculated with 10 million sporocysts of the B1 isolate of Sarcocystis cruzi originally obtained by feeding heart of a naturally infected cow (Bos taurus) to a laboratory-raised coyote. The bison became febrile, lethargic, and anorectic at about 25 days after inoculation of the sporocysts, and was euthanatized 3 days later. There were widespread hemorrhages, hepatitis, myocarditis, nephritis, and enteritis; intravascular meronts were found in the adrenal cortex and lamina propria of the small intestine. Another 7-day-old male bison was inoculated with 100,000 sporocysts of the same B1 isolate of S cruzi. Except for mild fever and transient diarrhea, the bison remained clinically normal. Sarcocysts were found at necropsy on day 76 after inoculation. It was concluded that S cruzi of cattle is transmissible to bison.