O desenvolvimento larval de Paratanaisia bragai foi estudado através de infecções experimentais em Subulina octona e se completou aos 40 dias pós-infecção, com o encistamento da metacercária. A localização e morfologia dos estágios larvais foram documentadas através de fotomicrografias.
SummaryThe morphology of the eggs and miracidia of Eurytrema coelomaticum was analyzed. The eggshell presented different composition according to the maturation stage of the egg, as seen by distinct birefringence after polarized light microscopic analysis. Detailed morphology of the brownish eggs, measuring 44.97±3.83 (38.67 -51.40) μm in length and 30. 71±2.54 (25.79 -34.47) μm in width, and the different electrondensities of the inner, middle and outer layers of the eggs were determined using light (bright fi eld and DIC) and electronic microscopy (scanning and transmission). The morphometry of the eggs is in accordance to those measures presented in previous studies. The miracidia were observed using light microscopy, inside and outside the egg. It was possible to observe the terebratorium at the anterior end of the body, the ciliated epidermal plates, placed according the formula E=2E 1 + 2E 2 , and the interepidermal ridge, but eyespots were not observed. The excretory vesicle was laterally placed in the posterior middle of the body and the germ balls were observed. The miracidium inside the egg was observed by routine techniques, but the miracidium was not well preserved. Thus, the eggs were processed using high pressure-freeze substitution technique and reasonable preservation was achieved. The cilia covering the larval body, with a typical ciliary organization, the terebratorium with folds and the junction of the epidermal ciliated cell with the larval body were seen. For the fi rst time detailed information on the eggs and miracidia of E. coelomaticum is given, which can be the basis for new studies.
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.Keywords: Paratanaisia bragai, Columba livia, kidney, histopathology.
ResumoParatanaisia 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.Palavras-chave: Paratanaisia bragai, Columba livia, rim, histopatologia.
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.
ABSTRACT. Development of ElIrylrellla coel omaliclIlII (Giard & Billet) (Digenea, Dicrococliidac) in Brat/ybaella silllilaris (Férussac) (Gastropoda, Xanthonychidae). To follow the larval development of Ewytrema coelomaliclIm (Giard & Billel, 1892) in 8radybaena similaris (Férussac, 1821) snails were separaled in three classes llsing lhe shell diameter: Class A (14.5-10 .2 mm), Class B (10.1-6.9 mm) and Class C (6.8-2.6 mm). Only snails belonging to classes A and B acquired the inteclion.Specimens of E. coelomalicum removed from lhe pancrealic ducts were exposed to lhree physiological solutions: Earle, Locke and saline 0.85%, to obtain eggs for the experimental infections. The Locke solution induced the best egg release. The route ofmigration lhe intramolluscan development oI' E. coelomalicum was stlldied with the aid 01" histology. The minimal period of intramolluscan development, ending aI lhe expelling of daughler sporocysts, was 107 days for the snails intecled in March, and 79 days for lhe snails infecled in November. The Sludenl "t" test and the Chi-square lest showed a significant difterence (u = 5%) between the two periods, although the mean lemperalure regislered during the experiments did not signiticanlly diftered (u = 5%). The eliminalion of daughter sporocysls occurred lhrough lhe snail's pneumostome, and always aI night. Most sporocysts were eliminated aI intervals thal varied between one to three days, without reglllarity. The time ofelimination ofthe dallghter sporocysts was ditlerenl for the two intection period studied: 12 weeks for the snails infecled in March, and llu'ee weeks for lhos e infecled in November. Posilive correlalion between the number of sporocysts expelled by the snail hOSI and higher lemperatures registered in lhe laboralOlY was observed. This correlation was more evident in November infeclion. KEY WORDS.
Urban agriculture is very common in the cities, as Rio de Janeiro and adjacencies, being important as economic activity. However, this practice can create appropriate conditions for establishment and maintenance of life cycle of many parasites. Lymneid snails can act as intermediate hosts of many trematodes species, including those that infect humans and wild and domestic. In the present study, the snail Lymnaea columella was collected from an urban watercress plantations and the morphology of cercariae released by them was analyzed by light and scanning electron microscopy. The specimens were identified as xiphidiocercariae, belonging to the Cercariae Ornatae group, of the order Plagiorchiiformes. Histological examination of the digestive gland of the infected snails revealed the presence of developing sporocysts, with hemocitary infiltration and metaplasia in the epithelial tissue.
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