Pathological and histochemical studies of the effects of cystic echinococcosis in sheep

A total of 2100 sheep, 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. Histopathologicallly, the cyst wall consisted of the inner germinal, middle lamellated, 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 and densely packed fibroblasts mixed with mononuclear cells; and an outer layer of concentrically packed fibrous connective tissue. Mast cell reaction was observed mainly in the bronchiolar, peribronchiolar, and inflammatory zones in the lungs; while in the liver, mast cells were noted in portal triads and bile ducts and were least evident in the vicinity of the cysts. Qualitative increase was observed for acid mucopolysaccharides in fibroblasts, inflammatory cells, and bronchial epithelium, especially hyperplastic epithelial cells. Masson’s trichrome revealed intense formation of collagen fibers in the pericystic connective tissue. The calcareous corpuscles of the protoscolices were distinct when stained with combined Alcian blue PAS and toluidine stains but were not visible when stained with H & E and Masson’s trichrome stains.