RESUMO
The morphometric characteristics and the ultramicroscopic findings of Cryptosporidium spp. at various stages of their life cycle in the intestinal and bursal epithelial cells of naturally infected 30-day-old commercial turkeys are reported. Small, sporulated oocysts, observed in the small intestinal content after flotation, were identified as Cryptosporidium meleagridis on the basis of morphometric characteristics (round in shape and 4.5-5.0 microm in size) and the small intestinal localization. Light section examinations revealed the presence of the protozoon in multiple organs, but its prevalence was highest in the intestinal and bursal epithelial cells. Ultramicroscopic studies on ileum and bursal samples showed the presence of all the life cycle stages in the microvillar brush epithelial cells in both the organs examined. On the basis of the comparison of the morphology and the sizes of the microorganisms parasitizing the ileum and the bursa, hypotheses are considered on the possible species involved.