Scanning electron microscopy of Eimeria tenella infection and subsequent repair in chicken caeca

Abstract

The progressive tissue damage during an Eimeria tenella infection and the subsequent repair processes of the caecal mucosa were observed with the scanning electron microscope (SEM). Distinct ridges began to form around the collars about the third day post-infection (PI) in the mid caecal pouch and the distal tip of the caeca. These ridges persisted until the 6th day PI in the tip of the caeca. Damaged tissue had sloughed by the 8th day PI and there was some indication of early repair. Initially, new epithelial cells emerged from the crypts to cover the damaged tissue and simultaneously epithelial cells migrated from the undamaged tissue across the injured area. Repair of the damaged tissue was usually completed by the 21st day for the distal tip and later for the mid caecal pouch. The process of repair in the caeca was similar to healing in the mammalian small intestine and surface epithelial wounds.