Gross and histopathological alterations associated with cystic echinococcosis in small ruminants

Hydatidosis, an important parasitic zoonoses is a major public health as well as economic concern throughout the world. A total of 2100, sheep (2052) and goats (48), slaughtered or spontaneously dead, from various areas of Kashmir valley were screened for the presence of hydatidosis. Out of 2100 cases, 85 were positive for hydatidosis. The frequently infected organs were lungs and liver. The liver was observed to be the most frequently infected organ with relative prevalence of 61.17% followed by lungs (38.82%). The pulmonary cysts were more fertile (55%) compared to hepatic cysts (45%). Histopathologicallly, the cyst wall consisted of the inner germinal, middle lamellated/laminated, and outer fibrous layer. Inflammatory reaction around the cyst was variable and was characterized by an inner zone of loosely arranged fibroblasts infiltrated with mononuclear cells, followed by densely arranged fibroblasts along with mononuclear cells; and an outer layer of fibrous connective tissue. Fibroplasia and calcification were noted at places. In liver besides the cellular reaction against the expanding cyst, hepatocellular degeneration and cirrhosis were observed, the severity of which was inversely related to the distance from the cyst. The structural details of the protoscolices were clearly discernable.