RESUMO

Herein, a detailed molecular phylogeny analysis was developed to determine the phylogenetic position of a new freshwater histozoic myxosporean cnidarian, Henneguya markiana sp. nov. from the world's largest tropical wetland area, Pantanal, Brazil. The new species is described using an integrative taxonomy approach including morphology, biological traits and molecular data. Phylogenetic analysis inferred by Maximum Likehood method showed the new Henneguya species in a well-supported clade of myxosporean gill parasites of South American characids fishes. In this same clade, the new Henneguya described appeared in a sub-clade clustering with H. lacustris and H. chydadea. Nevertheless, the sequences of the new species and H. lacustris and H. chydadea have a large genetic divergence of 10.4% (148 nucleotides-nt) and 10.5% (147 nt) respectively. To the best of our knowledge, this is the first report of a cnidarian myxosporean species parasitizing a fish from Stevardiinae from South America. In the light of the differences observed from the integrative taxonomy, we are confident that this isolate is a new species of Henneguya, increasing the knowledge of diversity of this enigmatic group of cnidarians.

RESUMO

We describe Myxobolus cataractae n. sp., found parasitizing Imparfinis mirini from Cachoeirinha stream, a tributary of Pardo River, Paraná River basin, municipality of Botucatu, São Paulo State, Brazil. We based the description on myxospore morphology, histology, and small subunit ribosomal DNA partial sequences. Whitish and elongated mass of myxospores were found in gill filaments, occupying an intrafilamental position. The myxospores were slightly ellipsoidal and the morphometric measurements revealed a myxospore body length of 7.8 ± 0.4 µm; myxospore width of 5.9 ± 0.4 µm; and thickness of 3.9 ± 0.3 µm. The polar capsules are equal in size and measured 3.5 ± 0.2 µm in length and 1.7 ± 0.2 µm in width. The polar tubules had 6-7 coils. Myxobolus cataractae n. sp. is classified as the intrafilamental type and chondreal subtype by the histological analysis of gills. Phylogenetic analysis showed a well-supported subclade formed by species that parasitize gills of Siluriformes, with M. imparfinis as a sister species of Myxobolus cataractae n. sp. Using molecular and morphological characterization, this cryptic species was identified as a new species of the genus Myxobolus.

Assuntos

RESUMO

This study increases the known biodiversity of cnidarian parasites in neotropical bryconid fishes. Two novel Myxobolus species are described based on morphology, ultrastructure and small subunit ribosomal DNA (ssrDNA) sequencing: Myxobolus vetuschicanus n. sp. infecting fins of Salminus franciscanus and Myxobolus mineirus n. sp. infecting the mesentery of Brycon orthotaenia from the São Francisco River basin, Minas Gerais State, Brazil. Ultrastructural analysis of the two species revealed an asynchronous sporogenesis process, with germinative cells and young developmental stages of myxospores in the periphery of the plasmodia. In M. vetuschicanus n. sp., the plasmodia were surrounded by a layer of fibroblasts and in M. mineirus n. sp., the plasmodial membrane had direct contact with the host tissue. The phylogenetic analysis based on the ssrDNA of Henneguya/Myxobolus species showed that the two novel Myxobolus species grouped in subclades together with other parasite species of bryconid fishes.

Assuntos

RESUMO

A new myxozoan species belonging to the genus Henneguya was isolated from the serous membrane of the visceral cavity of the hognosed catfish Brochis multiradiatus from Peruvian Amazon. Whitish plasmodia, macroscopically visible, were found in four of the thirty examined fishes. Mature myxospores were ellipsoidal in shape in frontal view and had a total length of 44.5 ± 0.6 µm (43.9-45.1), spore body measured 18.7 ± 0.9 µm (16.8-19.6) in length, 7.1 ± 0.2 µm (6.6-7.4) in width and 5.5 ± 0.3 µm (4.9-5.6) in thickness. The two polar capsules were elongated and equal in size, measuring 9.1 ± 0.1 µm (8.8-9.4) in length and 1.7 ± 0.1 µm (1.6-1.8) in width, occupying half of the myxospore body. Polar tubules coiled in 10-11 turns perpendicular to the long axis of the polar capsule. The caudal appendage was not bifurcated and measured 25.8 ± 0.6 µm (24.7-26.5) in length. The sequencing of the 18S rDNA gene resulted in 1400 bp and this sequence did not match any of the myxozoans available in GenBank. Phylogenetic analysis placed the new species in a well-supported subclade of Henneguya spp. infecting callichthyid fishes, with Henneguya loretoensis being the closest species. This study is the first description of a myxozoan species, Henneguya multiradiatus n. sp. from a fish of the genus Brochis.

Assuntos

RESUMO

Most species of Myxobolus (Cnidaria: Myxozoa) infect freshwater and marine fish, and cause sporozoosis. Passage of myxozoan parasites into human feces has been described occasionally. We examined fecal samples from 97 dwellers of a riverine community in Amazonas State (Brazil), which revealed Myxobolus sp. in 13 (13%) samples. The discovery probably does not represent true parasitism as the myxospores - most likely ingested through the consumption of infected fish - were eliminated unchanged after passing through the gastrointestinal tract. This discovery represents the first report of this myxosporean in human fecal samples in Brazil. (AU)

A maioria das espécies de Myxobolus (Cnidaria: Myxozoa) infecta principalmente peixes de água doce e marinhos, nos quais produz esporozoose. A passagem de parasitos mixozoários em fezes humanas tem sido ocasionalmente descrita. Nós examinamos amostras fecais de 97 moradores de uma comunidade ribeirinha no estado do Amazonas e identificamos Myxobolus sp. em 13 (13%) delas. O achado provavelmente não representa um parasitismo verdadeiro, uma vez que os mixosporos − mais provavelmente ingeridos ao consumir peixes infectados − foram eliminados inalterados após a passagem pelo trato gastrointestinal. O achado representa o primeiro relato deste mixosporídeo em amostras fecais humanas no Brasil.(AU)

Assuntos

RESUMO

Most species of Myxobolus (Cnidaria: Myxozoa) infect freshwater and marine fish, and cause sporozoosis. Passage of myxozoan parasites into human feces has been described occasionally. We examined fecal samples from 97 dwellers of a riverine community in Amazonas State (Brazil), which revealed Myxobolus sp. in 13 (13%) samples. The discovery probably does not represent true parasitism as the myxospores - most likely ingested through the consumption of infected fish - were eliminated unchanged after passing through the gastrointestinal tract. This discovery represents the first report of this myxosporean in human fecal samples in Brazil.(AU)

A maioria das espécies de Myxobolus (Cnidaria: Myxozoa) infecta principalmente peixes de água doce e marinhos, nos quais produz esporozoose. A passagem de parasitos mixozoários em fezes humanas tem sido ocasionalmente descrita. Nós examinamos amostras fecais de 97 moradores de uma comunidade ribeirinha no estado do Amazonas e identificamos Myxobolus sp. em 13 (13%) delas. O achado provavelmente não representa um parasitismo verdadeiro, uma vez que os mixosporos mais provavelmente ingeridos ao consumir peixes infectados foram eliminados inalterados após a passagem pelo trato gastrointestinal. O achado representa o primeiro relato deste mixosporídeo em amostras fecais humanas no Brasil.(AU)

RESUMO

Ultrastructural and phylogenetic description of a fish-infecting myxosporean found infecting the gallbladder wall of the teleostean Eugerres brasilianus Cuvier, 1830, collected from the Atlantic coast near the city of Maceió (Alagoas State), Brazil. Groups of mature pseudo-conical myxospores, agglutinated forming pseudocyst structures, occurring in the mucosa of gallbladder were 5.2 ± 0.8 µm (4.5-6.0) (n = 30) long, 4.3 ± 0.6 µm (3.8-4.7) (n = 25) thick, and 2.9 ± 0.2 µm (2.7-3.2) (n = 25) wide. The two ellipsoidal polar capsules, 1.8 ± 0.4 × 1.2 ± 0.4 µm (n = 25), opened close to the sutural line, each containing an isofilar polar tubule. The latter consisted of a single coil with five to six turns, arranged obliquely to the axis of the polar capsule. This myxosporean parasite, while being morphologically similar to Sphaerospora spp., displays tissue tropism and phylogenetic relationships distinct from the latter. Bayesian inference (BI) and maximum likelihood (ML) analyses showed the parasite and two other related species clustering within the marine clade, more specifically within a subclade of the larger Kudoa (Multivalvulida) clade. Consequently, this atypical new myxozoan species was classified as Kudoa eugerres n. sp. and two other histozoic Sphaerospora spp. sensu lato were transferred to the genus Kudoa.

Assuntos

RESUMO

Myxosporean are endoparasitic cnidarians of wide distribution and responsible for important economic losses in fisheries and aquaculture. A new myxosporean species, Henneguya peruviensis n. sp., is herein described as obtained from the gill filaments of Hyphessobrycon loretoensis caught in the Nanay River, Department of Loreto, Peru. The parasite was found in 37 of 45 (82.2%) examined H. loretoensis. The new species was characterized based on morphological features and 18S rDNA gene sequence data. The sequencing of the 18S rDNA gene from the spores of H. peruviensis n. sp. resulted in 1632 nucleotides and this sequence did not match any of the myxozoan available in the GenBank. Phylogenetic analysis showed that H. peruviensis n. sp. closed together with H. leporinicola. Nonetheless, the 18S rDNA sequences of H. peruviensis n. sp. and H. leporinicola have only 82% similarity. This is the first description and molecular study of a Myxozoa parasitizing fish of the genus Hyphessobrycon in the Amazon basin. Given the importance of the ornamental fish industry in translocation of aquatic organisms worldwide, the international movement of myxosporeans in infected fish is discussed in terms of disease outbreaks and the need for preventative action.

Assuntos

RESUMO

Myxosporean Myxobolus saladensis sp. nov. in the gills of Mugil liza Valenciennes, 1836 from Samborombón Bay was described by light and electron microscopy studies. Spores were pyriform and binucleated, measuring 10.63±0.36 µm (n=20) long, 9.24±0.50 µm (n=20) wide and 4.13±0.36 µm (n=20) thick, included in polysporic cyst-like plasmodia. Elongated pyriform polar capsules were of equal size (3.84±0.27 µm long and 2.30±0.12 µm wide). The sporoplasm contained some sporoplasmosomes. Each PC contained a polar filament with 4-5 coils obliquely arranged in relation to the polar capsules axis. The PC wall was composed of two layers of different electron densities. Based on the morphological and ultrastructure differences of the spore to those of previously described species of Myxobolus, we describe a new species, Myxobolus saladensis sp. nov.(AU)

Assuntos

RESUMO

Myxosporean Myxobolus saladensis sp. nov. in the gills of Mugil liza Valenciennes, 1836 from Samborombón Bay was described by light and electron microscopy studies. Spores were pyriform and binucleated, measuring 10.63±0.36 µm (n=20) long, 9.24±0.50 µm (n=20) wide and 4.13±0.36 µm (n=20) thick, included in polysporic cyst-like plasmodia. Elongated pyriform polar capsules were of equal size (3.84±0.27 µm long and 2.30±0.12 µm wide). The sporoplasm contained some sporoplasmosomes. Each PC contained a polar filament with 4-5 coils obliquely arranged in relation to the polar capsules axis. The PC wall was composed of two layers of different electron densities. Based on the morphological and ultrastructure differences of the spore to those of previously described species of Myxobolus, we describe a new species, Myxobolus saladensis sp. nov.

Assuntos

RESUMO

ABSTRACT Myxosporean Myxobolus saladensis sp. nov. in the gills of Mugil liza Valenciennes, 1836 from Samborombón Bay was described by light and electron microscopy studies. Spores were pyriform and binucleated, measuring 10.63±0.36 µm (n=20) long, 9.24±0.50 µm (n=20) wide and 4.13±0.36 µm (n=20) thick, included in polysporic cyst-like plasmodia. Elongated pyriform polar capsules were of equal size (3.84±0.27 µm long and 2.30±0.12 µm wide). The sporoplasm contained some sporoplasmosomes. Each PC contained a polar filament with 4-5 coils obliquely arranged in relation to the polar capsules axis. The PC wall was composed of two layers of different electron densities. Based on the morphological and ultrastructure differences of the spore to those of previously described species of Myxobolus, we describe a new species, Myxobolus saladensis sp. nov.

RESUMO

Abstract The genus Myxobolus, parasites that infect fishes, which cause myxobolosis, includes spore organisms belonging to the phylum Myxozoa and represents approximately 36% of all species described for the entire phylum. This study describes lymphocytic meningoencephalomyelitis associated with Myxobolus sp. infection in the brain and spinal cord (the central nervous system, CNS) of Eigenmannia sp., from the Amazon estuary region, in the Administrative District of Outeiro (DAOUT), Belém, Pará, Brazil. In May and June 2015, 40 Eigenmannia sp. specimens were captured from this region and examined. The fish were anesthetized, slaughtered and dissected for sexing (gonad evaluation) and studying parasites and cysts; after diagnosing the presence of the myxozoans using a light microscope, small fragments of the brain and spinal cord were removed for histological processing and Hematoxylin-Eosin and Ziehl-Neelsen staining. Histopathological analysis of the brain and spinal cord, based on histological sections stained with Hematoxylin-Eosin, pronounced and diffuse edema in these tissues, and congestion, degeneration, and focal necrosis of the cerebral cortex. The present study describes lymphocytic meningoencephalomyelitis associated with infection by Myxobolus sp. in the central nervous system of Eigenmannia sp.

Resumo O gênero Myxobolus é composto por parasitas esporais que podem infectar peixes e causar a “myxobolose”. São organismos pertencentes ao filo Myxozoa e representam cerca de 36% do total de espécies descritas para todo o Filo. Este estudo descreve meningoencefalomielite linfocitária, associada à infecção por Myxobolus sp. no cérebro e medula espinhal (SNC) de Eigenmannia sp, oriundo de região estuarina amazônica, no Distrito Administrativo de Outeiro (DAOUT), município de Belém, Pará, Brasil. Foram capturados e examinados 40 espécimes de Eigenmannia sp. entre os meses de maio e junho de 2015. Os peixes foram anestesiados, abatidos e dissecados para sexagem (avaliação das gônadas) e pesquisa de parasitos e cistos. Após o diagnóstico da presença dos mixosporidios, utilizando-se microscópio de luz, pequenos fragmentos do cérebro e da medula espinal foram removidos para processamento histológico e coloração por Hematoxilina-Eosina e coloração especial em Ziehl-Neelsen. A análise histopatológica do cérebro e da medula espinhal, com base em cortes histológicos corados com Hematoxilina-Eosina, mostrou edema difuso nesses tecidos, e congestão, degeneração e necrose focal do córtex cerebral. O presente estudo descreve meningoencefalomielite linfocítica, associada à infecção por Myxobolus sp., no sistema nervoso central de Eigenmannia sp.

Assuntos

RESUMO

The genus Myxobolus, parasites that infect fishes, which cause myxobolosis, includes spore organisms belonging to the phylum Myxozoa and represents approximately 36% of all species described for the entire phylum. This study describes lymphocytic meningoencephalomyelitis associated with Myxobolus sp. infection in the brain and spinal cord (the central nervous system, CNS) of Eigenmannia sp., from the Amazon estuary region, in the Administrative District of Outeiro (DAOUT), Belém, Pará, Brazil. In May and June 2015, 40 Eigenmannia sp. specimens were captured from this region and examined. The fish were anesthetized, slaughtered and dissected for sexing (gonad evaluation) and studying parasites and cysts; after diagnosing the presence of the myxozoans using a light microscope, small fragments of the brain and spinal cord were removed for histological processing and Hematoxylin-Eosin and Ziehl-Neelsen staining. Histopathological analysis of the brain and spinal cord, based on histological sections stained with Hematoxylin-Eosin, pronounced and diffuse edema in these tissues, and congestion, degeneration, and focal necrosis of the cerebral cortex. The present study describes lymphocytic meningoencephalomyelitis associated with infection by Myxobolus sp. in the central nervous system of Eigenmannia sp.(AU)

O gênero Myxobolus é composto por parasitas esporais que podem infectar peixes e causar a myxobolose. São organismos pertencentes ao filo Myxozoa e representam cerca de 36% do total de espécies descritas para todo o Filo. Este estudo descreve meningoencefalomielite linfocitária, associada à infecção por Myxobolus sp. no cérebro e medula espinhal (SNC) de Eigenmannia sp, oriundo de região estuarina amazônica, no Distrito Administrativo de Outeiro (DAOUT), município de Belém, Pará, Brasil. Foram capturados e examinados 40 espécimes de Eigenmannia sp. entre os meses de maio e junho de 2015. Os peixes foram anestesiados, abatidos e dissecados para sexagem (avaliação das gônadas) e pesquisa de parasitos e cistos. Após o diagnóstico da presença dos mixosporidios, utilizando-se microscópio de luz, pequenos fragmentos do cérebro e da medula espinal foram removidos para processamento histológico e coloração por Hematoxilina-Eosina e coloração especial em Ziehl-Neelsen. A análise histopatológica do cérebro e da medula espinhal, com base em cortes histológicos corados com Hematoxilina-Eosina, mostrou edema difuso nesses tecidos, e congestão, degeneração e necrose focal do córtex cerebral. O presente estudo descreve meningoencefalomielite linfocítica, associada à infecção por Myxobolus sp., no sistema nervoso central de Eigenmannia sp.(AU)

Assuntos

RESUMO

This study describes aspects of the infection caused by the myxosporean genus Henneguya, which forms cysts in the bony portion of the gill filaments of Hypophthalmusmarginatus. Specimens of this catfish were acquired dead from artisanal fishermen near the town of Cametá, state of Pará, northern Brazil, between July 2011 and May 2012. They were transported in refrigerated containers to the Carlos Azevedo Research Laboratory at the Federal Rural University of Amazonia, in Belém, where analyses were performed. After confirmation of parasitism by the genus Henneguya, observation were made using optical and differential interference contrast (DIC) microscopy. The histological technique of embedment in paraffin was used. Ziehl-Neelsen staining was applied to the histological sections. Necropsy analyses on specimens of H. marginatus showed that 80% of them (40/50) had cysts of whitish coloration inside the bony portion of the gill filaments, filled with Henneguya spores. The present study found inflammatory infiltrate in the vicinity of the cysts. Furthermore, the special Ziehl-Neelsen staining technique made it possible to mark the Henneguya sp. cysts in the bone tissue and in spore isolates in the gill tissue structure. The descriptions of these histopathological findings show that this parasite is very invasive and causes damage to its host tissues.(AU)

O presente estudo descreve os aspectos da infecção causada por mixosporídio do gênero Henneguya, formando cistos na porção óssea dos filamentos branquiais de Hypophthalmus marginatus. Espécimes desse bagre foram adquiridos mortos de pescadores artesanais perto da cidade de Cametá, Estado do Pará, Brasil, entre julho de 2011 e maio de 2012. Os animais foram transportados em contêineres refrigerados até o Laboratório de Pesquisa Carlos Azevedo, na Universidade Federal Rural da Amazônia, em Belém, onde se procederam as análises. Após a constatação do parasitismo pelo gênero Henneguya, foi realizada a observação em microscópio óptico e em microscópio de contraste de interferência diferencial (DIC). Foi realizada técnica histológica de impregnação em parafina e coloração dos cortes histológicos em Ziehl-Neelsen. As análises necroscópicas dos espécimes de H. marginatus revelaram que 80% (40/50) destes apresentavam cistos esbranquiçados na porção óssea dos filamentos branquiais, repletos de esporos do gênero Henneguya. O presente estudo revelou infiltrado inflamatório nas imediações dos cistos. Além disso, a técnica especial de coloração em Ziehl-Neelsen possibilitou marcar os cistos de Henneguya sp. no tecido ósseo e de esporos isolados na estrutura de tecido branquial. As descrições desses achados histopatológicos mostram que esse parasita é muito invasivo e produz danos aos seus tecidos do hospedeiro.(AU)

Assuntos

RESUMO

This study describes aspects of the infection caused by the myxosporean genus Henneguya, which forms cysts in the bony portion of the gill filaments of Hypophthalmusmarginatus. Specimens of this catfish were acquired dead from artisanal fishermen near the town of Cametá, state of Pará, northern Brazil, between July 2011 and May 2012. They were transported in refrigerated containers to the Carlos Azevedo Research Laboratory at the Federal Rural University of Amazonia, in Belém, where analyses were performed. After confirmation of parasitism by the genus Henneguya, observation were made using optical and differential interference contrast (DIC) microscopy. The histological technique of embedment in paraffin was used. Ziehl-Neelsen staining was applied to the histological sections. Necropsy analyses on specimens of H. marginatus showed that 80% of them (40/50) had cysts of whitish coloration inside the bony portion of the gill filaments, filled with Henneguya spores. The present study found inflammatory infiltrate in the vicinity of the cysts. Furthermore, the special Ziehl-Neelsen staining technique made it possible to mark the Henneguya sp. cysts in the bone tissue and in spore isolates in the gill tissue structure. The descriptions of these histopathological findings show that this parasite is very invasive and causes damage to its host tissues.

O presente estudo descreve os aspectos da infecção causada por mixosporídio do gênero Henneguya, formando cistos na porção óssea dos filamentos branquiais de Hypophthalmus marginatus. Espécimes desse bagre foram adquiridos mortos de pescadores artesanais perto da cidade de Cametá, Estado do Pará, Brasil, entre julho de 2011 e maio de 2012. Os animais foram transportados em contêineres refrigerados até o Laboratório de Pesquisa Carlos Azevedo, na Universidade Federal Rural da Amazônia, em Belém, onde se procederam as análises. Após a constatação do parasitismo pelo gênero Henneguya, foi realizada a observação em microscópio óptico e em microscópio de contraste de interferência diferencial (DIC). Foi realizada técnica histológica de impregnação em parafina e coloração dos cortes histológicos em Ziehl-Neelsen. As análises necroscópicas dos espécimes de H. marginatus revelaram que 80% (40/50) destes apresentavam cistos esbranquiçados na porção óssea dos filamentos branquiais, repletos de esporos do gênero Henneguya. O presente estudo revelou infiltrado inflamatório nas imediações dos cistos. Além disso, a técnica especial de coloração em Ziehl-Neelsen possibilitou marcar os cistos de Henneguya sp. no tecido ósseo e de esporos isolados na estrutura de tecido branquial. As descrições desses achados histopatológicos mostram que esse parasita é muito invasivo e produz danos aos seus tecidos do hospedeiro.

RESUMO

This study describes aspects of the infection caused by the myxosporean genus Henneguya, which forms cysts in the bony portion of the gill filaments of Hypophthalmusmarginatus. Specimens of this catfish were acquired dead from artisanal fishermen near the town of Cametá, state of Pará, northern Brazil, between July 2011 and May 2012. They were transported in refrigerated containers to the Carlos Azevedo Research Laboratory at the Federal Rural University of Amazonia, in Belém, where analyses were performed. After confirmation of parasitism by the genus Henneguya, observation were made using optical and differential interference contrast (DIC) microscopy. The histological technique of embedment in paraffin was used. Ziehl-Neelsen staining was applied to the histological sections. Necropsy analyses on specimens of H. marginatus showed that 80% of them (40/50) had cysts of whitish coloration inside the bony portion of the gill filaments, filled with Henneguya spores. The present study found inflammatory infiltrate in the vicinity of the cysts. Furthermore, the special Ziehl-Neelsen staining technique made it possible to mark the Henneguya sp. cysts in the bone tissue and in spore isolates in the gill tissue structure. The descriptions of these histopathological findings show that this parasite is very invasive and causes damage to its host tissues.

O presente estudo descreve os aspectos da infecção causada por mixosporídio do gênero Henneguya, formando cistos na porção óssea dos filamentos branquiais de Hypophthalmus marginatus. Espécimes desse bagre foram adquiridos mortos de pescadores artesanais perto da cidade de Cametá, Estado do Pará, Brasil, entre julho de 2011 e maio de 2012. Os animais foram transportados em contêineres refrigerados até o Laboratório de Pesquisa Carlos Azevedo, na Universidade Federal Rural da Amazônia, em Belém, onde se procederam as análises. Após a constatação do parasitismo pelo gênero Henneguya, foi realizada a observação em microscópio óptico e em microscópio de contraste de interferência diferencial (DIC). Foi realizada técnica histológica de impregnação em parafina e coloração dos cortes histológicos em Ziehl-Neelsen. As análises necroscópicas dos espécimes de H. marginatus revelaram que 80% (40/50) destes apresentavam cistos esbranquiçados na porção óssea dos filamentos branquiais, repletos de esporos do gênero Henneguya. O presente estudo revelou infiltrado inflamatório nas imediações dos cistos. Além disso, a técnica especial de coloração em Ziehl-Neelsen possibilitou marcar os cistos de Henneguya sp. no tecido ósseo e de esporos isolados na estrutura de tecido branquial. As descrições desses achados histopatológicos mostram que esse parasita é muito invasivo e produz danos aos seus tecidos do hospedeiro.

RESUMO

This study describes aspects of the infection caused by the myxosporean genus Henneguya, which forms cysts in the bony portion of the gill filaments of Hypophthalmusmarginatus. Specimens of this catfish were acquired dead from artisanal fishermen near the town of Cametá, state of Pará, northern Brazil, between July 2011 and May 2012. They were transported in refrigerated containers to the Carlos Azevedo Research Laboratory at the Federal Rural University of Amazonia, in Belém, where analyses were performed. After confirmation of parasitism by the genus Henneguya, observation were made using optical and differential interference contrast (DIC) microscopy. The histological technique of embedment in paraffin was used. Ziehl-Neelsen staining was applied to the histological sections. Necropsy analyses on specimens of H. marginatus showed that 80% of them (40/50) had cysts of whitish coloration inside the bony portion of the gill filaments, filled with Henneguya spores. The present study found inflammatory infiltrate in the vicinity of the cysts. Furthermore, the special Ziehl-Neelsen staining technique made it possible to mark the Henneguya sp. cysts in the bone tissue and in spore isolates in the gill tissue structure. The descriptions of these histopathological findings show that this parasite is very invasive and causes damage to its host tissues.

O presente estudo descreve os aspectos da infecção causada por mixosporídio do gênero Henneguya, formando cistos na porção óssea dos filamentos branquiais de Hypophthalmus marginatus. Espécimes desse bagre foram adquiridos mortos de pescadores artesanais perto da cidade de Cametá, Estado do Pará, Brasil, entre julho de 2011 e maio de 2012. Os animais foram transportados em contêineres refrigerados até o Laboratório de Pesquisa Carlos Azevedo, na Universidade Federal Rural da Amazônia, em Belém, onde se procederam as análises. Após a constatação do parasitismo pelo gênero Henneguya, foi realizada a observação em microscópio óptico e em microscópio de contraste de interferência diferencial (DIC). Foi realizada técnica histológica de impregnação em parafina e coloração dos cortes histológicos em Ziehl-Neelsen. As análises necroscópicas dos espécimes de H. marginatus revelaram que 80% (40/50) destes apresentavam cistos esbranquiçados na porção óssea dos filamentos branquiais, repletos de esporos do gênero Henneguya. O presente estudo revelou infiltrado inflamatório nas imediações dos cistos. Além disso, a técnica especial de coloração em Ziehl-Neelsen possibilitou marcar os cistos de Henneguya sp. no tecido ósseo e de esporos isolados na estrutura de tecido branquial. As descrições desses achados histopatológicos mostram que esse parasita é muito invasivo e produz danos aos seus tecidos do hospedeiro.

Assuntos