• S L Choubisa

      Articles written in Proceedings – Animal Sciences

    • Histochemical demonstration of esterase in certain freshwater larval trematodes with a note on neuroanatomy

      S L Choubisa

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      Histochemical method for non-specific esterases has been applied to cercariae belonging to 4 different trematode groups viz Monostome, Amphistome, Xiphidio and Echinostome. Various structures containing esterases revealed positive reactions to the standard method and are visualized in simple whole mount preparation. Different degrees of non-specific esterase activities were observed in the nervous and the excretory systems, suckers and sub-tegumentary cells. In general, nervous systems of cercariae are composed of a pair of cerebral ganglia connected to each other by a transverse commissure to form a cerebral complex. These give off 3 pairs of anterior longitudinal and 3 pairs of posterior longitudinal nerve cords. Simultaneously nervous systems of redia of monostome cercaria have also been focused in the present study.

    • Histological and histochemical observations on the digestive gland ofMelanoides tuberculatus (Gastropoda) infected with certain larval trematodes and focus on their mode of nutrition

      S L Choubisa

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      Histological and histochemical observations were made on infected and uninfected digestive glands of snails,Melanoides tuberculatus. Infected gland either with sporocysts ofCercaria diglandulata (Xiphidio) or with rediae ofCercaria martini (Monostome) revealed basically two types of histopathological abnormalities (damages), mechanical (lesion 1) and physiological (lesion 2). Depletion of carbohydrates, lipids and proteins as well as increased activities of phosphatases, lipase, non-specific esterase and glucose-6-phosphatase were also reflected by infected digestive gland. Alterations either histological or histochemical in infected glands are associated with the type and size of trematode larvae and degree of parasitemea and these were greater in glands infected with rediae than in sporocysts. Besides pathogenesis, the present study also focusses on the mode of nutrition in certain trematode larvae.

    • Histopathological observations on the digestive gland ofLymnaea auricularia infected with larval trematodes

      S L Choubisa

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      Histological observations were made on the digestive gland of infected and uninfected freshwater snails,Lymnaea auricularia, and the varying degree of histopathogenesis of echinostome cercaria,Cercaria itoi, as well as strigeoid metacercaria,Tetracotyle lymnaei, along withCercaria itoi (double infection) in the digestive gland have been observed. Basically 3 types of lesions, L1, L2 and L3 were found and were associated with the types and size of trematode larvae as well as with the degree of parasitemia. In the early stage of larval development or in mild infection, type I lesions (L1) were commonly observed in which degenerative changes were confined to individual digestive gland tubules, and neighbouring tubules mostly remained healthy or unaffected. The type II lesions (L2) were associated with severe infection and were less common than L1 lesions and large areas of parasitised digestive gland tubules were revealed to be necrotic. Type III lesions (L3) were also associated with severe infection in which digestive gland tubules appeared as rudimentary tubules located between trematode rediae. In the present study, in addition to a description of the different types of lesions, the various alterations of cellular structures of the digestive gland ofLymnaea auricularia due to single or double infections (Cercaria itoi + Tetracotyle lymnaei) are also discussed.

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