Immunohistological demonstration of antigenicity of the various endogenous stages ofEimeria apsheronica in goats

Ten naive goat kids obtained soon after birth were reared coccidia-free in cages indoors. At one month of age they were each infected with 25 000 oocysts ofE. apsheronica. Infection was monitored by examining the faeces for oocysts for two and a half weeks after patency. They were then euthanized and sections of their small intestines showing gross coccidial lesions were fixed for histology. Intestinal sections were incubated in pre-infection and post-infection sera to detect any antigen-antibody reactions using diaminobenzidine (DAB) as the stain. The sections treated with pre-infection sera stained very poorly in comparison to those treated with post-infection sera. The conclusion is drawn that serum antibodies which developed after infection reacted with the endogenous stages of the parasite and were histologically demonstrable.