The present study forms the first report of Nematopsis sp. infection in the edible oyster, Crassostrea madrasensis from India. The study was carried out as part of a detailed pathological investigation of C. madrasensis along the southwest coast of India. Sporozoites of Nematopsis sp. were found in samples collected from two locations. Light microscopic observation revealed ellipsoidal oocysts measuring 16.63±2.40 µm in length and 11.11± 2.49 µm in width (n=30) in the connective tissues of gills, mantle, visceral mass and gonads. Prevalence of infection ranged from 11 to 27%. Apparent pathological changes included compression of adjacent digestive diverticulae in visceral connective tissue infections and presence of phagocytosed oocysts in water channels in the case of gill infections. With relevance to the expanding culture of C. madrasensis, monitoring potential pathogens of this species in its natural habitat is important for developing suitable health management packages.

Background: Fasciolosis is a crucial helminthes disease caused by two trematodes of the genus Fasciola: Fasciola hepatica (temperate liver fluke) and Fasciola gigantica (tropical liver fluke). Methods: A cross-sectional study was conducted on cattle and sheep in a slaughterhouse to detect animals infected with Fasciolosis. Liver samples were collected from infected animals and transferred to the laboratory for histopathological and immunohistochemical examinations. Result: Microscopically, the liver sections were showed extensive fibrous connective tissue surrounding the central vein and portal area with extensive thickening of bile ducts wall and fibrosis. Marked infiltration of inflammatory cells was also seen.