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.

New insight into the morphology of Eurytrema coelomaticum (Trematoda, Dicrocoeliidae) cercariae by light, scanning, and transmission electron microscopies.

Eurytrema coelomaticum is a digenetic trematode that parasitizes the pancreatic ducts of ruminants. In the present study, the morphology of the cercariae was analyzed using light, scanning, and transmission electron microscopies. The size of the larvae was larger than that reported in the literature. An oral sucker with many papillae and an oral aperture in its center and a ventral sucker with few discrete papillae on the edge were observed. No stylet at the anterior end of the larval body and spines on the tegument of the end of the tail were observed. The cercariae had lateral penetration glands and (central) pre-acetabular glands, from which ducts lead to the anterior region and open into a small anterior pocket. The flame cells were located laterally and communicated with fine branches, converging to two lateral excretory collecting ducts that opened into an excretory bladder, centrally located at the posterior end of the body. The tegument presented an external layer loosely attached to the larval body, below which an amorphous syncytial outer layer with many mitochondrial profiles was observed. This region exhibited many secretions and released secretory granules, indicating intense secretory activity. The circular and longitudinal muscle layers were arranged in sequence below the outer layer. The outer layer was connected by cytoplasmic bridges crossing the muscular layers to the internal region of the tegument, where the cell body with nucleus was located. In the cercarial body, it was possible to observe a typical flame cell with the barrel region, where cilia and the internal and external ribbed regions were found. The somatic cells seem to have an active metabolism, with a well-developed endoplasmic reticulum, secretory granules, and evident nuclei. The results are discussed in the light of the biology and taxonomy of this species.

Histopathological changes in the kidneys of vertebrate hosts infected naturally and experimentally with Paratanaisia 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.

Ultrastructure of the sporocysts of Eurytrema coelomaticum (Giard Et Billet, 1892) Looss, 1907.

The digenetic trematode Eurytrema coelomaticum is a parasite of pancreatic ducts of ruminants. The ultrastructure of the mother and daughter sporocysts of E. coelomaticum was analyzed. The mother sporocyst was attached to the coelome of the intestine wall of intermediate snail host Bradybaena similaris, intimately adhered in some regions. It presents a highly folded tegument with granules and the body wall was composed by an outer syncitial layer, basal lamina, and circular and longitudinal muscle layer. Below was the cell body (cyton) with the nucleus. The daughter sporocysts obtained by dissection exhibited many granules and secretory vesicle in the outer layer indicating an intense secretory activity. The body wall presented the same layers of the mother sporocysts, but the outer syncitial layer invaginated and an amorphous layer was present between the syncitial and circular muscle layers. The protonephridial excretory system was viewed. The anterior and posterior end of the expelled sporocyst exhibit a degenerated structure, but biological activity still occurred in these regions. The swollen middle of the body was filled by a lamellar structure formed by degenerating membranes, but the excretory system was preserved. The endocyst wall was fibrilar and filled by cercariae and amorphous, membranous and secretory material inside it. These results were discussed.

Light and scanning electron microscopy of sporocysts of Eurytrema coelomaticum (Giard et Billet, 1892) Looss, 1907.

Eurytrema coelomaticum is a fluke that infects ruminants in South America, Europe and Asia. The morphology of the mother and daughter sporocysts of E. coelomaticum obtained from Bradybaena similaris, the first intermediate host, is described for the first time by light and scanning electron microscopy. The intermediate host was exposed to E. coelomaticum eggs and after 30 days the mother sporocyst was found in the coelom adhered to the intestine wall. This sporocyst was a rounded or elongated mass (0.1078 mm), with numerous germinal balls in it, and a folded tegument with no specializations. The daughter sporocysts obtained following dissection of infected snails have varied shape, one hollow tapered region with many transversal and longitudinal striations, named anterior end. The expelled daughter sporocyst presented an oval sac-like central region with a small anterior and a posterior longer filament-like prolongation. The measures of the expelled sporocysts are presented and compared to previous descriptions.

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.