Frequency of Sarcocystis spp in Detroit, metropolitan area, Michigan.

A survey of Sarcocystis spp in feral animals and in domesticated animals slaughtered in Detroit, MI, was undertaken during a 6-month period, April to September, 1973, using histologic and digestion diagnostic techniques. Results indicated 75.3% of 789 sheep and 10.8% of 306 lambs were infected. Infection in young and adult sheep was low in April (0% of 78 lambs and 6.7% of 62 adult sheep), but increased in July (24% of 90 lambs and 94.1% of 201 adult sheep). High frequency of Sarcocystis in summer seems to be an epizootiologic feature of this parasite in sheep. Frequency of macroscopic cysts in sheep increased from 0 in April to 14.5% in September. During July and August, infection rates for 100 cattle and 55 pigs older than 1 year were 62 and 12.7%, respectively, but none of 55 calves and 48 pigs less than 1 year were infected. Sheep were more heavily infected than other animals examimpned. Sarcocystis spp were also found in opossum (Didelphis virginiana), raccoon (Procyon lotor), and grackle (Quiscalus quiscula). This is believed to be the first record of a Sarcocystis sp in the raccoon.