Fine structure and development of schizonts, merozoites and macrogamonts of Eimeria acervulina in the goblet cells of the duodenal epithelium of experimentally infected birds.

The fine structure of trophozoites, schizonts, merozoites and macrogamonts of Eimeria acervulina found in goblet cells of the duodenal epithelium of chicks is described and compared with the corresponding stages formed in other epithelial cells. Complete schizogony, with the formation of mature merozoites, occurred freely in goblet cells. Developing macrogamonts (but no microgamonts) were rarely found in goblet cells. The stages observed were confined to the cytoplasm of the host cell above the Golgi apparatus and were usually seen between the mucous granules. The stages seen appeared normal, and contained similar structures to corresponding stages developing in other cells. The finding of developing stages of E. acervulina in goblet cells provides further evidence that site specificity of Eimeria at the cellular level is not as strict as previously thought.