Carbohydrate metabolism evaluation of terrestrial snail Subulina octona (Gastropoda, Subulinidae) experimentally infected by the Paratanaisia bragai digenetic trematode (Digenea, Eucotylidae).

Among the effects of the larval development of digenetic trematodes on their intermediate hosts, changes in the carbohydrate metabolism in the snails stand out. The aim of this study was to analyze, every 10 days after infection (d.p.i.), the effects of Paratanaisia bragai infection on the glycogen content in the digestive gland and cephalopedal mass in Subulina octona snail, and also verify the glucose concentration and the enzyme D- and L-lactate dehydrogenase activity (EC1.1.1.27 and EC1.1.1.28) (LDH) and the concentration of some metabolites(oxalic, succinic, pyruvic and lactic acid) presents in the hemolymph. Histochemical analisys were also performed. We verified a total increase of 54.81% in glucose concentration in infected snails and an oscillating pattern in the glycogen content in the cephalopedal mass and in the digestive gland. LDH activity shows an increase of 10 d.p.i. (+ 74.32%) and 40 d.p.i. (+ 47.81%) and decrease at 20 d.p.i. and 30 d.p.i. The concentrations of oxalic, succinic and pyruvic acids showed significant and progressive reductions; however, lactic acid had a significant increase. Histological and histochemical analysis showed a tissue disorganization in the cephalopedal mass of infected snails and morphological changes in the digestive gland. These results confirm that infection causes metabolic pathway changes in the snails due to activation of an alternative anaerobic pathway for producing energy, indicated by the increased lactic acid content and LDH activity.

Histopathological changes in the kidneys of vertebrate hosts infected naturally and experimentally withParatanaisia bragai (Trematoda, Digenea)

Paratanaisia bragai is a trematode parasite that reaches sexual maturity in the kidney collecting ducts of domesticated and wild fowl and whose intermediate hosts are the snails Subulina octona and Leptinaria unilamellata. There are some discrepancies in descriptions of the pathology of this parasite in bird kidneys. Therefore, the purpose of this study was to analyze the kidneys of rock pigeons (Columba livia) naturally infected and of chickens (Gallus gallus) experimentally infected with Paratanaisia bragai, by means of macroscopic observation and by light and scanning electron microscopy. Both bird species showed significantly dilated collecting ducts. In addition, lymphocyte infiltration was observed in the kidneys of C. livia and metaplasia in the epithelial lining of the kidney collecting ducts of G. gallus.

Paratanaisia bragai é um trematódeo que atinge sua maturidade sexual nos ductos coletores de rins de aves domésticas e silvestres, tendo os moluscos Subulina octona e Leptinaria unilamellata como hospedeiros intermediários. A patologia descrita no rim das aves apresenta uma série de divergências. Dessa forma, o presente estudo teve como objetivo analisar rins de Columba livia, naturalmente infectada, e de Gallus gallus infectados experimentalmente por Paratanaisia bragai. Através das análises, verificaram-se alterações macroscópicas, por microscopia de luz e eletrônica de varredura, sendo caracterizada significativa dilatação dos túbulos coletores. Essas alterações foram observadas nas aves infectadas naturalmente e experimentalmente. Por outro lado, foi observada infiltração linfocitária nos rins de C. livia, naturalmente infectada, e ocorrência de metaplasia no revestimento epitelial dos túbulos coletores dos rins de G. gallus, experimentalmente infectados.