Surface changes in the intestinal mucosa of mice infected with Eimeria falciformis

Scanning electron microscopy (SEM) was used to study changes in the mucosa of the cecum and colon of mice infected with Eimeria falciformis. Pieces of the cecum and colon were removed from mice that had been inoculated 1–12 days earlier with 106 or 2 × 104 sporulated oocysts, and then processed for SEM. Alterations of the mucosal surface of infected mice were restricted to the cecum and upper half of the colon. At 2–8 days postinoculation (DPI), the apical area of absorptive enterocytes gradually increased to more than 4 times normal, and goblet cells initially increased in number, then declined and eventually disappeared. Lesions in the epithelium which exposed the basal lamina were most severe at 6–8 DPI. Repair of the epithelium occurred at 9–12 DPI.