EIMERIA ZUERNII INFECTION IN THAI NATIVE CALVES

Abstract

A 3-month-old, female calf in the Dontan district of Mukdaharn province, showed clinical signs of bloody diarrhoea over a period of 3 days and finally died on April 4, 2001. After necropsy, severe, diffuse, haemorrhagic caeco-colitis and proctitis were markedly evident. Histopathologically, various stages of coccidial development, including schizogony and gametogony, were found in the villous epithelium and the epithelial crypts. Infiltration
of lymphocytes, plasma cells, neutrophils and macrophages into the lamina propria, as well as into the submucosa was observed. Another 6-month-old, female calf from a nearby area also showed bloody diarrhoea with mild anorexia and numerous oocysts of coccidia were detected in the faeces. The oocysts of both native calves were examined microscopically and were seen to be morphologically similar to oocysts of Eimeria zuernii.