RESUMO
Species in the genus Gorgoderina Looss, 1902 are parasites of the urinary bladder of amphibians and include around 50 species described globally. Molecular data on species of the genus are scarce, as is the information of their life-cycle patterns. During a survey on the genetic characterization of the frog trematodes in the tropical rain forest of Los Tuxtlas, in the Gulf of Mexico slope of Mexico, specimens of two morphotypes of Gorgoderina were sampled from the Rio Grande leopard frog, Rana berlandieri. One of them represented an undescribed species which is described herein as Gorgoderina rosamondae n. sp., whereas the other one was morphologically very similar to an apparently widely distributed North American species, G. attenuata, which has been previously reported in the same geographical area. Specimens of both morphotypes were sequenced for two nuclear and one mitochondrial genes. Phylogenetic trees corroborated the distinction of the new species, and data on the internal transcribed spacer 2 revealed genetic differences between G. attenuata sequenced from frogs in USA and specimens of Gorgoderina sp. from Los Tuxtlas, indicating the possibility that they also represent an undescribed species. COI sequences showed high genetic divergence values between the new species and Gorgoderina sp. from Los Tuxtlas (8.63-9.99%). Additionally, COI sequences of the larval forms (sporocyst, cercariae and metacercariae) sampled in the same locality from their first and second intermediate hosts (Pisidium sp. and Agriogomphus tumens, respectively) showed conspecificity, and the 3 host life-cycle of the new species was elucidated.
Assuntos
Ranidae , Trematódeos/classificação , Infecções por Trematódeos/veterinária , Animais , Cercárias/anatomia & histologia , Cercárias/classificação , Cercárias/crescimento & desenvolvimento , Cercárias/ultraestrutura , Metacercárias/anatomia & histologia , Metacercárias/classificação , Metacercárias/crescimento & desenvolvimento , Metacercárias/ultraestrutura , México/epidemiologia , Microscopia Eletrônica de Varredura , Oocistos/classificação , Oocistos/citologia , Oocistos/crescimento & desenvolvimento , Oocistos/ultraestrutura , Filogenia , Prevalência , Trematódeos/anatomia & histologia , Trematódeos/crescimento & desenvolvimento , Trematódeos/ultraestrutura , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologiaRESUMO
Trematodes are one of the largest taxa of mollusk parasites. The clam Leukoma thaca is an economically exploited bivalve found along the south-eastern Pacific coast of Peru and Chile. This bivalve is parasitized by various unidentified larval stages of digeneans in the mantle, gonads and digestive gland. The aims of this study were to determine and describe the different larval stages of the digeneans based on morphological characteristics, to identify them at the species level by performing molecular analyses, and to evaluate pathologies associated with the parasites of this clam. Individuals of L. thaca were collected in San Jorge Bay (23°S), Chile, between November 2018 and February 2019. Morphological description was carried out using in vivo and fixed specimens, and analyses including histological and scanning electron microscopy were performed. Individuals were also isolated for molecular analysis using nuclear ribosomal internal transcribed spacer 1 (ITS1), including partial subunit 18S rDNA (18S) and small subunit 5.8S gene (5.8S). Morphological characteristics indicated that the metacercaria larval stage belongs to the family Gymnophallidae, genus Parvatrema, which was supported by molecular analysis. Molecular results revealed that metacercaria, sporocysts and cercaria stages found in this clam belong to the same species of Parvatrema (genetic distance 0%), evidencing that this species uses L. thaca as the first and second intermediate host. Pathologies examined in the host were similar in nature to those reported in other gymnophallids in bivalves, but high prevalence of cercariae (20%) in gonads suggested an important castrator effect on the host.
Assuntos
Bivalves/parasitologia , Trematódeos/isolamento & purificação , Animais , Cercárias/anatomia & histologia , Cercárias/genética , Cercárias/crescimento & desenvolvimento , Cercárias/ultraestrutura , Chile , DNA de Helmintos/análise , DNA Ribossômico/análise , Metacercárias/anatomia & histologia , Metacercárias/genética , Metacercárias/crescimento & desenvolvimento , Metacercárias/ultraestrutura , Microscopia Eletrônica de Varredura , Trematódeos/anatomia & histologia , Trematódeos/genética , Trematódeos/ultraestruturaRESUMO
Abstract 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.
Resumo Agricultura urbana é muito comum nas cidades, como Rio de Janeiro e adjacências, sendo uma importante atividade econômica de subsistência. No entanto, esta prática pode criar condições adequadas para o estabelecimento e manutenção do ciclo de vida de muitos parasitos. Os moluscos limneídeos podem atuar como hospedeiros intermédios de muitas espécies de trematódeos, incluindo aqueles que infectam humanos e animais selvagens e domésticos. No presente estudo, o molusco Lymnaea columella foi coletado de plantações urbanas de agrião e a morfologia das cercárias liberadas por eles foi analisada por microscopia eletrônica de varredura leve e de varredura. As larvas foram identificadas como xifidiocercárias, pertencentes ao grupo das Cercariae Ornatae, Ordem Plagiorchiiformes. Análises histológicas da glândula digestiva dos moluscos infectados evidenciaram esporocistos, com formação de granuloma e metaplasia do tecido epitelial.
Assuntos
Animais , Trematódeos/fisiologia , Lymnaea/parasitologia , Trematódeos/crescimento & desenvolvimento , Trematódeos/ultraestrutura , Brasil , Microscopia Eletrônica de Varredura , Cidades , Nasturtium/crescimento & desenvolvimento , Agricultura , Cercárias/crescimento & desenvolvimento , Cercárias/fisiologia , Cercárias/ultraestruturaRESUMO
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.
Assuntos
Lymnaea/parasitologia , Trematódeos/fisiologia , Agricultura , Animais , Brasil , Cercárias/crescimento & desenvolvimento , Cercárias/fisiologia , Cercárias/ultraestrutura , Cidades , Microscopia Eletrônica de Varredura , Nasturtium/crescimento & desenvolvimento , Trematódeos/crescimento & desenvolvimento , Trematódeos/ultraestruturaRESUMO
We elucidate the life cycle of Maritrema orensense for the first time and experimentally confirm that of the sympatric Maritrema bonaerense. In Argentinean estuaries, both species parasitize the cochliopid snail Heleobia australis as first intermediate host, the grapsid crabs Neohelice granulata and Cyrtograpsus angulatus as second intermediate hosts, and gulls as definitive hosts. Here, we describe the daughter sporocysts and cercariae of M. orensense and redescribe these stages for M. bonaerense. Sporocysts of M. orensense are shorter, with fewer developed cercariae than M. bonaerense. The cercariae of M. orensense have longer, larger, and more undulating cephalic glands than M. bonaerense. We redescribe metacercariae and adults of both species and compare them with the previous descriptions. Intestinal ceca length, vitellaria shape and extension, and egg size are the most relevant characteristics in metacercariae and adults for differentiating the species. Hence, the detailed morphological description and comparative analyses of morphometrics obtained from natural and experimental infections permit clear differentiation of M. orensense and M. bonaerense at each life stage.
Assuntos
Doenças das Aves/parasitologia , Braquiúros/parasitologia , Estágios do Ciclo de Vida , Caramujos/parasitologia , Trematódeos/crescimento & desenvolvimento , Infecções por Trematódeos/veterinária , Animais , Cercárias/crescimento & desenvolvimento , Cercárias/ultraestrutura , Charadriiformes/parasitologia , Galinhas , Análise Discriminante , Brânquias/parasitologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/veterinária , Intestinos/parasitologia , Larva/crescimento & desenvolvimento , Larva/ultraestrutura , Metacercárias/crescimento & desenvolvimento , Metacercárias/isolamento & purificação , Metacercárias/ultraestrutura , Microscopia Eletrônica de Varredura , Oocistos/crescimento & desenvolvimento , Oocistos/ultraestrutura , Trematódeos/anatomia & histologia , Trematódeos/classificação , Infecções por Trematódeos/parasitologiaRESUMO
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.