Pathological studies on coccidiosis in broiler and layer chicken

Coccidiosis is one of the most economically important diseases of domestic poultry caused by intracellular protozoan parasites belonging to the genus Eimeria. The present work was conducted to study the pathological alterations associated with coccidiosis in broiler and layer birds. A total of 45 outbreaks of coccidiosis in chicken were recorded from three different districts (Srinagar, Ganderbal and Budgam) of Kashmir Valley, fifteen from each district. Out of a total number of 3057 carcasses necropsied, 325 cases were found affected with coccidiosis. A total of seven different species of Eimeria were identified; Eimeria tenella, E. acervulina, E. maxima, E. necatrix, E. mitis, E. praecox and E. brunetti. Grossly the carcasses of the birds were anaemic, pale, emaciated and dehydrated. In most severe cases of ceacal coccidiosis, liver, breast muscles, eyes and bursa also appeared pale due to anaemia. Histopathology of intestines revealed destruction of large number of epithelial cells due to the development of the asexual stages. Organisms in various stages of schizogony caused erosive and haemorrhagic lesions in whole intestine. Mucosa appeared denuded and disrupted with intense inflammation of lamina propria and further up to sub-mucosa. Thickening of muscularis mucosa was common with broken tips or fused tips of villi.