Cryptosporidium Meleagridis

Host: Domestic turkey.

Location: All stages occur on the villus epithelium of the terminal third of the small intestine.

Geographic Distribution: Scotland.

Prevalence: Unknown; found in 1 flock.

Morphology: This species was described by Slavin (1955). The oocysts are oval, 4.5 by 4.0 u, with very foamy cytoplasm and an eccentric, faint, poorly defined wisp of nucleus. No sporulated oocysts were seen.

Life Cycle: The young schizonts (trophozoites) are attached to the epithelium of the villi, often in enormous numbers. They have an attachment organ which penetrates the striated border of the epithelial cells. Slavin also saw these forms in the goblet cells, between cells as far down as the basement membrane, and in surface depressions between the epithelial cells. The mature schizonts measure 5 by 4 u and contain 8 merozoites. These are falciform, 5 by 1 u, and taper toward the ends, with one end blunter than the other. The nucleus is subterminal. The microgametocytes are rounded or oval, 4 u in their greatest diameter, and contain 16 intensely staining rod-like microgametes. These measure 1 by 0.3 u and have no flagella. The macrogametes are roughly oval, 4.5 to 5.0 by 3.5 to 4.0 u.

Pathogenesis: According to Slavin (1955), C. meleagridis may cause illness with diarrhea and a low death rate in 10- to 14-day-old turkey poults.