Morphology and morphometry of Paratanaisia bragai () Freitas, 1959 (Digenea, Eucotylidae) through light and scanning electron microscopy.

Paratanaisia bragai is a digenetic trematode that reaches sexual maturity in the kidney collecting ducts of domestic and wild birds, while the snails Subulina octona and Leptinaria unilamellata serve as its intermediate hosts in Brazil. The present study analyzed the morphology and morphometry of P. bragai. Adult specimens of the parasite were collected from naturally infected Columba livia kidneys, fixed and prepared for observation via bright field and differential interference contrast light microscopy and scanning electron microscopy. The parasite has an elongated and flattened body, with a subterminal oral sucker located at the anterior end of the body, as observed by all techniques used. Staining the parasite with hematoxylin-eosin enabled observation of the pharynx, located posteriorly to the oral sucker, the vitelline glands, which are extra-cecal and extend anteriorly to the pre-ovarian region and later to the median region of the body, and intestinal caeca parallel to the vitelline glands. The presence and functionality of the acetabulum are controversial points in the literature, but it was observed in all specimens analyzed by scanning electron microscopy, with a major diameter of 38.36 ± 6.96 (28.77 - 45.39) and minor diameter of 31.59 ± 7.04 (21.75 - 38.16). Close to the acetabulum, scales were observed in the integument of the parasite. Scales with (1 - 5) blade divisions were identified. In the genital pore, it was possible to see the everted cirrus with rosette shape. The excretory pore (first morphometric record) is dorsal and subterminal, with major diameter of 12.27 ± 9.16 (5.79 - 18.75) and minor diameter of 3.95 ± 1.49 (2.89 - 5.00).

Evaluation of the reproductive profile of Subulina octona (Gastropoda, Subulinidae) experimentally infected by Paratanaisia bragai (Digenea, Eucotylidae) / Avaliação do perfil reprodutivo de Subulina octona (Gastropoda, Subulinidae) infectada experimentalmente por Paratanaisia bragai (Digenea, Eucotylidae)

Abstract Snails infected by trematodes may increase or decrease their reproductive activity in response to the presence of infection. Our aim was to verify the reproductive alterations in Subulina octona after infection by Paratanaisia bragai. The infected snails were individually exposed for 24 hours to 20 parasite eggs and four groups were formed (10, 20, 30 and 40 d.p.i.- days after infection), along with control groups. Every 10 days, the number of eggs in the reproductive tract, number of eggs hatched, galactogen content and histopathological changes were evaluated. The reproductive in the control and infected snails presented an alternating pattern, where periods of high production of eggs and newly hatched were followed by periods of low production. However, in relation to the amount of galactogen, both control and infected groups followed the same pattern of variation. In the histology, we observed the presence of male and female gametes with marked reduction in the number of oocytes. The results indicate that the intra-snail development of the parasite affects the reproductive biology of the host.

Resumo Moluscos infectados por trematódeos podem aumentar ou diminuir sua atividade reprodutiva em resposta à presença da infecção. Nosso objetivo foi verificar as alterações reprodutivas de Subulina octona após a infecção por Paratanaisia bragai. Os moluscos infectados foram individualmente expostos durante 24 horas a 20 ovos do parasito e quatro grupos foram formados (10, 20, 30 e 40 d.p.i. - dias pós infecção), com respectivos grupos controle. A cada 10 dias, o número de ovos no trato reprodutivo, o número de ovos eclodidos, o conteúdo de galactogênio e alterações histopatológicas eram avaliadas. O padrão reprodutivo nos moluscos controle e infectados evidenciou um comportamento alternante, nos quais períodos de alta produção de ovos e filhotes foram seguidos por períodos de baixa produção. No entanto, em relação ao conteúdo de galactogênio, moluscos controle e infectados seguiram o mesmo padrão de variação. Na histologia, observamos a presença de gametas masculinos e femininos com acentuada redução no número de óocitos. Os resultados indicam que o desenvolvimento intramolusco do parasito afeta a biologia reprodutiva do hospedeiro.

Evaluation of the reproductive profile of Subulina octona (Gastropoda, Subulinidae) experimentally infected by Paratanaisia bragai (Digenea, Eucotylidae).

Snails infected by trematodes may increase or decrease their reproductive activity in response to the presence of infection. Our aim was to verify the reproductive alterations in Subulina octona after infection by Paratanaisia bragai. The infected snails were individually exposed for 24 hours to 20 parasite eggs and four groups were formed (10, 20, 30 and 40 d.p.i.- days after infection), along with control groups. Every 10 days, the number of eggs in the reproductive tract, number of eggs hatched, galactogen content and histopathological changes were evaluated. The reproductive in the control and infected snails presented an alternating pattern, where periods of high production of eggs and newly hatched were followed by periods of low production. However, in relation to the amount of galactogen, both control and infected groups followed the same pattern of variation. In the histology, we observed the presence of male and female gametes with marked reduction in the number of oocytes. The results indicate that the intra-snail development of the parasite affects the reproductive biology of the host.

Xiphidiocercariae from naturally infected Lymnaea columella (Mollusca, Gastropoda) in urban area: morphology and ultrastructure of the larvae and histological changes in the mollusc host / Xifidiocercárias obtidas em Lymnaea columella (Mollusca, Gastropoda) naturalmente infectadas em área urbana: morfologia e ultraestrutura da larva e alterações histológicas do molusco hospedeiro

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.

Xiphidiocercariae from naturally infected Lymnaea columella (Mollusca, Gastropoda) in urban area: morphology and ultrastructure of the larvae and histological changes in the mollusc host.

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.

Evaluation of the reproductive profile of Subulina octona (Gastropoda, Subulinidae) experimentally infected by Paratanaisia bragai (Digenea, Eucotylidae)

Abstract Snails infected by trematodes may increase or decrease their reproductive activity in response to the presence of infection. Our aim was to verify the reproductive alterations in Subulina octona after infection by Paratanaisia bragai. The infected snails were individually exposed for 24 hours to 20 parasite eggs and four groups were formed (10, 20, 30 and 40 d.p.i.- days after infection), along with control groups. Every 10 days, the number of eggs in the reproductive tract, number of eggs hatched, galactogen content and histopathological changes were evaluated. The reproductive in the control and infected snails presented an alternating pattern, where periods of high production of eggs and newly hatched were followed by periods of low production. However, in relation to the amount of galactogen, both control and infected groups followed the same pattern of variation. In the histology, we observed the presence of male and female gametes with marked reduction in the number of oocytes. The results indicate that the intra-snail development of the parasite affects the reproductive biology of the host.

Resumo Moluscos infectados por trematódeos podem aumentar ou diminuir sua atividade reprodutiva em resposta à presença da infecção. Nosso objetivo foi verificar as alterações reprodutivas de Subulina octona após a infecção por Paratanaisia bragai. Os moluscos infectados foram individualmente expostos durante 24 horas a 20 ovos do parasito e quatro grupos foram formados (10, 20, 30 e 40 d.p.i. dias pós infecção), com respectivos grupos controle. A cada 10 dias, o número de ovos no trato reprodutivo, o número de ovos eclodidos, o conteúdo de galactogênio e alterações histopatológicas eram avaliadas. O padrão reprodutivo nos moluscos controle e infectados evidenciou um comportamento alternante, nos quais períodos de alta produção de ovos e filhotes foram seguidos por períodos de baixa produção. No entanto, em relação ao conteúdo de galactogênio, moluscos controle e infectados seguiram o mesmo padrão de variação. Na histologia, observamos a presença de gametas masculinos e femininos com acentuada redução no número de óocitos. Os resultados indicam que o desenvolvimento intramolusco do parasito afeta a biologia reprodutiva do hospedeiro.

Molecular investigation of Neorickettsia risticii in trematodes and snails in a region with serological evidence of this agent in horses, state of Rio de Janeiro / Pesquisa molecular de Neorickettsia risticii em trematódeos e moluscos em região com evidência sorológica do agente em equinos, estado do Rio de Janeiro

In Brazil, some studies have indicated that Neorickettsia risticii circulates in horses, but it is unclear which are the possible intermediate vectors of this bacterium in the country. The aim of this study was to use molecular techniques in order to analyze the presence of N. risticii in snails and larval stages of trematodes in farms in a region with a history of seroreactive horses towards this bacterium, in Rio de Janeiro, Brazil. Convenience sampling was used in the studied region. The collected snails were exposed to incandescent light (60W) for 2-4 hours in order to investigate trematodes in larval forms. Deoxyribonucleic acid (DNA) was extracted from snail tissue and trematode. Real-time PCR (qPCR) technique was used to investigate the presence of a 16S rRNA gene fragment of N. risticii. Snail specimens (n=410) were collected from 11 horse-breeding farms, and the following species were identified: Melanoides tuberculata, Pomacea sp., Biomphalaria tenagophila, Physa acuta, Drepanotrema anatinum and Biomphalaria straminea. Only 3.17% (n=13/410) of the collected snails were infected by trematodes. The cercariae obtained from these snails were classified as Megalourous cercariae, Pleurolophocercus cercariae and Furcocercous cercariae. There was no amplification of the target DNA of N. risticii in the snail and trematode samples tested by qPCR. Based on these data, the transmission of N. risticii by trematodes using these snail species in this region does not appear to occur or occurs at very low rates. Thus, further studies are needed in order to clarify which species of invertebrate hosts are infected by this bacterium and potentially participate in the transmission chain of equine neorickettsiosis in the state of Rio de Janeiro, Brazil.(AU)

No Brasil, estudos apontam a circulação de Neorickettsia risticii em equinos, contudo não estão claros quais os possíveis vetores intermediários dessa bactéria no país. O objetivo do presente estudo foi analisar a presença de N. risticii, utilizando-se técnicas moleculares, em caramujos e estágios larvais de trematódeos em propriedades rurais de uma região com histórico de equinos sororreativos para essa bactéria, no Rio de Janeiro, Brasil. Uma amostragem por conveniência foi utilizada na região de estudo. Os caramujos coletados foram expostos à luz incandescente (60W) durante duas-quatro horas para a investigação de trematódeos nas formas larvais. A extração de ácido desoxirribonucleico (DNA) foi realizada em tecidos de caramujos e trematódeos. A técnica de PCR em tempo real (qPCR) foi utilizada para investigar a presença de um fragmento do gene 16S rRNA de N. risticii. Foram coletados 410 espécimes de caramujos de 11 propriedades com criações de equinos, sendo identificadas as seguintes espécies: Melanoides tuberculata, Pomacea sp., Biomphalaria tenagophila, Physa acuta, Drepanotrema anatinum e Biomphalaria straminea. Apenas 3,17% (n=13/410) dos caramujos identificados estavam infectados por trematódeos. As cercárias obtidas desses caramujos foram classificadas em Megalourous cercariae, Pleurolophocercus cercariae e Furcocercous cercariae. Não foi observada a amplificação do DNA-alvo de N. risticii, por meio da qPCR, em nenhuma das amostras de caramujos e trematódeos testadas. Com base nesses dados, a transmissão de N. risticii por trematódeos que utilizam as espécies de caramujos nessa região parece não ocorrer ou ocorre a taxas muito reduzidas. Portanto, novos estudos são necessários para elucidar quais espécies de hospedeiros invertebrados se infectam por essa bactéria e potencialmente participam da cadeia de transmissão da neorickettsiose equina no estado do Rio de Janeiro, Brasil.(AU)

Nematode cysts and larvae found in Achatina fulica Bowdich, 1822.

This study describes the morphology of the nematode cysts and larvae found in Achatina fulica (giant African snail) in Brazil. Sixty snails were collected in Mesquita, Rio de Janeiro State. Fourteen of the snails were naturally infected. The cysts were spherical, pink colored and measured 0.97 to 1.57 mm in diameter. In the majority of cases they had a single larvae involved in amorphous material. A total of 222 encysted larvae were recovered. Of these, 30 were utilized in the morphological study. The length of the larvae varied from 2.57 to 5.8 mm and they were classified as small--up to 3.5 mm; medium--from 3.53 to 4.5 mm; and large--greater than 4.52 mm. The average length of the larvae in the three groups was 2.85, 3.87 and 5.23 mm, respectively. The larval cuticle was white, shiny and transversally striated until the posterior end of the body. At the anterior end there is a mouth with three lips, with amphids and papillae, followed by a muscular esophagus with average length of 0.61 mm, terminating in an esophageal bulb and having a nerve ring in the middle third of the esophagus, and an intestine with an opening near the posterior end. The tail begins from this opening and has two types of ends: short and abrupt or long and gradually tapering. The difference in the tail end can suggest sexual dimorphism, although no primordial reproductive structures were observed. These characteristics were not sufficient to identify the larvae, so there is a need for further study.