Dietary effect of multi-strain prebiotics and probiotics on growth, hemato-biochemical parameters, intestinal histomorphometry, and resistance to hypoxia in juvenile tambaqui (Colossoma macropomum).

This study evaluated the effects of a multi-strain prebiotics and probiotics on the diet of tambaqui Colossoma macropomum. One hundred and fifty juvenile tambaqui (20.2 ± 3.6 g and 10.32 ± 5.78 cm) were randomly distributed in 15 experimental units with a volume of 80 L and fed for 45 days with a diet containing the symbiotic additive at five inclusion levels (0, 2, 4, 6 and 8 g kg feed- 1). At the end of the period, growth performance, survival, hemato-biochemical and intestinal parameters, as well as the fish's resistance to stress were evaluated. The additive did not alter the growth performance, hemato-biochemical and intestinal parameters of the tambaqui. However, the hemato-biochemical parameters of aspartate aminotransferase (AST), plasma protein, hematocrit, glucose, triglycerides and cholesterol showed differences between treatments after the stress challenge. AST increased significantly during challenge and post-challenge. Plasma protein increased significantly during and after the challenge. The hematocrit was highest at 48 h after the challenge and lowest in the 2 g, 6 g and 8 g groups. Glucose was significantly reduced 24 h after the challenge, while triglycerides were lower 24 h and 48 h after the challenge. Cholesterol increased significantly in the challenge. There was an interaction between the factors sampling time and symbiotic concentration for hematocrit and glucose. In hypoxic stress situations, the 2 g concentration was more favorable for the fish. We recommend further studies with 2 g kg feed- 1 in trials lasting more than 45 days.

Artificial blood-feeding of phlebotomines (Diptera: Psychodidae: Phlebotominae): is it time to repurpose biological membranes in light of ethical concerns?

BACKGROUND: The aims of the present study were to evaluate and compare the efficacy of blood-feeding in phlebotomines through industrially processed membranes from the small intestine of pigs (used for the production of commercial sausages) and the skin of euthanized chicks. METHODS: Laboratory-bred Lutzomyia longipalpis and different field-caught phlebotomine species were subjected to the artificial feeding systems under similar conditions. Paired tests were performed using the control (skin from euthanized chicks) and test membranes (pig small intestine). The feeding rates were compared by paired t-test, and Pearson correlation was used to examine the relationship between the thickness of the membranes and feeding rate. RESULTS: The feeding rate was greater with the test membrane than with the control membrane for L. longipalpis (t-test, t = -3.3860, P = 0.0054) but not for the most frequent field-caught species, Nyssomyia antunesi (t-test, t = 0.7746, P = 0.4535). The average thicknesses of the control and test membranes were 184 ± 83 µm and 34 ± 12 µm, respectively (Mann-Whitney U-test, U = 0.00, Z = 2.8823, P = 0.0039); however, there was no correlation between feeding rate and membrane thickness. A moderate positive correlation was observed between the number of phlebotomines that fed and the total number of phlebotomines in the cage for each type of membrane and for each species. CONCLUSIONS: The test membrane is a viable alternative for the artificial blood-feeding of phlebotomines, and is thus a potential substitute for the skin of animals that are euthanized for this purpose. Feeding rate was independent of membrane thickness.

New species of Myxidiidae Thélohan, 1892 (Myxosporea: Bivalvulida) found in characiform fish from the basin of Tocantins River in eastern Brazilian Amazonia.

Coelozoic parasites of the family Myxidiidae were observed in fish of the order Characiformes captured in the middle Tocantins River, Maranhão, Brazil, within the transition between the Cerrado savanna biome and the eastern extreme of the Brazilian Amazon Forest. The analysis of the morphological characteristics of the parasites, complemented with a Bayesian phylogenetic analysis, supported the description of new specie Myxidium imperatrizensis n. sp., found parasitising the gallbladder of specimens of the fish Triportheus angulatus. The study is also only the second report of the occurrence of Myxidium parasites in fish of the family Triportheidae in Brazilian rivers. The results of the present study expand the known distribution of the genera Myxidium the basin of the Tocantins River, the largest hydrographic basin located entirely within Brazil, which encompasses parts of both the Cerrado and Amazon biomes.

Morphological and molecular analysis of Henneguya lagunensis n. sp. (Cnidaria, Myxosporea) parasitizing the gills of Eugerres brasilianus from Brazil.

Plasmodia containing myxospores belonging to the genus Henneguya Thélohan, 1892 were found in the gills of Eugerres brasilianus (Cuvier, 1830). Despite the economic importance, few parasitological studies have been done with this species. We describe Henneguya lagunensis n. sp. using morphological and molecular data. The mature myxospores were rounded, measuring 29.1 ± 2.2 µm in total length, 8.2 ± 1.0 µm in body length, 7.9 ± 0.2 µm in body width, 20.7 ± 2.4 µm in tail length and 4.8 ± 1.0 µm in thickness. The polar capsules measured 3.3 ± 0.4 in length and 1.7 ± 0.3 µm in width. Polar filaments had 4-5 turns, helical. Phylogenetic analysis showed Henneguya lagunensis n. sp. as a sister species of Henneguya cynoscioni Dyková, Buron, Roumillat and Fiala, 2011, within a clade that contained mostly Henneguya species that parasitize marine fish of the order Perciformes. This is the first report of a species of Henneguya parasitizing Eugerres brasilianus.

Morphological and phylogenetic characterisation of Unicauda tavaresii n. sp. (Myxosporea: Myxobolidae): a parasite of the circumorbital tissue of the eye of two characiform fishes from the Amazon region of Brazil.

Myxozoans of the family Myxobolidae are common parasites in fish. The diversity and ecology of the species of the genus Unicauda are poorly known, which hampers the understanding of the distribution and prevalence of this group of parasites. In the present study, cysts containing parasites whose morphology was consistent with the genus Unicauda were found in the circumorbital region of the ocular conjunctiva of the freshwater fish Moenkhausia grandisquamis Müller & Troschel, 1845 (Characiformes: Characidae) and Triportheus angulatus Spix & Agassiz, 1829 (Characiformes: Triportheidae). The spores have an oval body and long caudal appendage, with a mean total length of 65.2 ± 5.9 µm and width of 5.2 ± 0.7 µm, with two oval and symmetrical polar capsules of 4.9 ± 0.5 µm in length and 1.4 ± 0.2 µm in width, containing polar filaments with five or six coils. An integrated comparative analysis of the morphological characteristics of this parasite and partial sequences of the SSU rDNA gene supported the identification of a new species of histozoic parasite of the genus Unicauda found in fish from the Tocantins River basin, in the eastern Brazilian Amazon region. The new species was denominated by Unicauda tavaresii n. sp.

Infection of Henneguya sp. on the gills of Metynnis lippincottianus from Curiaú River, in eastern Amazon region (Brazil).

Infection of fish gills by Henneguya causes greater contact between the secondary gill lamellae, thereby giving rise to decreased absorption surface area at the end of the filaments. This ectoparasite can cause damages on the gills infected fish. In the present study, fresh gills of Metynnis lippincottianus were analyzed using optical microscopy techniques. The myxoporean Henneguya sp. was found to be infecting 80% of the gills of this host fish. Presence of this parasite caused hyperplasia and fusion of the gill lamellae, but without inflammation in the parasitized organ.

Myxobolus sp. (Myxozoa; Myxosporea) causing asymptomatic parasitic gill disease in Astyanax aff. bimaculatus (Characiformes; Characidae) in the Tocantins river basin, amazon region, Brazil / Myxobolus sp. (Myxozoa; Myxosporea) causando doença parasitária assintomática nas brânquias em Astyanax aff. bimaculatus (Characiformes; Characidae) na bacia do rio Tocantins, região amazônica, Brasil

Abstract The middle course of the Tocantins river is located in the eastern portion of the "Legal Amazon" region of Brazil and the Dantas river is one of its tributaries. Among the components of the aquatic biota, eukaryote microparasites establish direct relationships with several species of fish and have zoonotic potential that is still little known. Myxozoans stand out among these parasites: they cause myxosporidiosis, a disease that gives rise to high mortality rates worldwide. The genus Myxobolus accounts for the largest number of species that have been described. Thirty specimens of Astyanax aff. bimaculatus that had been caught in the Dantas river were examined. The prevalence of cysts with spores morphologically compatible with myxozoans of the genus Myxobolus in the arcuate and gill filaments of these specimens was 20%.

Resumo O curso médio do rio Tocantins está localizado na porção leste da região da "Amazônia Legal" do Brasil, e o rio Dantas é um dos seus afluentes. Dentre os componentes da biota aquática, os microparasitos eucarióticos estabelecem relações diretas com várias espécies de peixes e possuem potencial zoonótico ainda pouco conhecido. Os mixozoários destacam-se entre esses parasitos causando mixosporidiose, doença que dá origem a altas taxas de mortalidade em todo o mundo. O gênero Myxobolus é responsável pelo maior número de espécies descritas de mixozoários. Trinta espécimes de Astyanax aff. bimaculatus capturados no rio Dantas foram examinados. A prevalência de cistos com esporos morfologicamente compatíveis com mixozoários do gênero Myxobolus nos filamentos arqueados e branquiais desses espécimes foi de 20%.

Myxobolus sp. (Myxozoa; Myxosporea) causing asymptomatic parasitic gill disease in Astyanax aff. bimaculatus (Characiformes; Characidae) in the Tocantins river basin, amazon region, Brazil.

The middle course of the Tocantins river is located in the eastern portion of the "Legal Amazon" region of Brazil and the Dantas river is one of its tributaries. Among the components of the aquatic biota, eukaryote microparasites establish direct relationships with several species of fish and have zoonotic potential that is still little known. Myxozoans stand out among these parasites: they cause myxosporidiosis, a disease that gives rise to high mortality rates worldwide. The genus Myxobolus accounts for the largest number of species that have been described. Thirty specimens of Astyanax aff. bimaculatus that had been caught in the Dantas river were examined. The prevalence of cysts with spores morphologically compatible with myxozoans of the genus Myxobolus in the arcuate and gill filaments of these specimens was 20%.

New occurrence of Kudoa orbicularis parasitizing the freshwater catfish Trachelyopterus galeatus (Siluriformes: Auchenipteridae) in the Brazlian Amazon region.

The aim of this was describe an infection by Kudoa orbicularis in freshwater catfish Trachelyopterus galeatus. A sample of 80 specimens of T. galeatus was collected in the municipality of Cachoeira do Arari, Marajó Island, in the state of Pará, Brazil. Pseudocysts were found in the muscle fibers of the epaxial and hypaxial regions of 85.0% of the specimens analyzed, reflecting a high infection rate. The pseudocysts contained spores that were pseudo-square in shape, with a mean length of 4.65 µm (range: 4.04-5.54) and mean width of 1.53 µm (1.56-1.74). Analyses on the morphology of the spores and a partial 934-bp sequence of the SSU rDNA gene confirmed that the microparasite was Kudoa orbicularis. This is the second record of this microparasite in a siluriform host in the Brazilian Amazon region.

New occurrence of Kudoa orbicularis parasitizing the freshwater catfish Trachelyopterus galeatus (Siluriformes: Auchenipteridae) in the Brazlian Amazon region / Nova ocorrência de Kudoa orbicularis parasitando peixe de água doce Trachelyopterus galeatus (Siluriformes: Auchenipteridae) na região Amazônica brasileira

Abstract The aim of this was describe an infection by Kudoa orbicularis in freshwater catfish Trachelyopterus galeatus. A sample of 80 specimens of T. galeatus was collected in the municipality of Cachoeira do Arari, Marajó Island, in the state of Pará, Brazil. Pseudocysts were found in the muscle fibers of the epaxial and hypaxial regions of 85.0% of the specimens analyzed, reflecting a high infection rate. The pseudocysts contained spores that were pseudo-square in shape, with a mean length of 4.65 µm (range: 4.04-5.54) and mean width of 1.53 µm (1.56-1.74). Analyses on the morphology of the spores and a partial 934-bp sequence of the SSU rDNA gene confirmed that the microparasite was Kudoa orbicularis. This is the second record of this microparasite in a siluriform host in the Brazilian Amazon region.

Resumo O objetivo deste estudo foi descrever a infecção por Kudoa orbicularis em Trachelyopterus galeatus. Foram analisados 80 espécimes de T. galeatus capturados no município de Cachoeira do Arari, ilha de Marajó, estado do Pará, Brasil. A presença de pseudocistos nas fibras musculares das regiões epiaxial e hipoaxial em 85,0% dos exemplares analisados, mostra alto grau de infecção. Os pseudocistos continham esporos de formato pseudoquadrado, medindo 4,65 (4,04-5,54) µm de comprimento e 5,25 (4,78-5,98) µm de largura, com quatro cápsulas polares de tamanho iguais medindo 2,22 (2,05-2,32) µm de comprimento e 1,53 (1,56-1,74) µm de largura. Através das análises morfológicas dos esporos e molecular de uma sequência parcial de 934bps do gene SSU rDNA, confirma que o microparasito é Kudoa orbicularis, sendo este o segundo registro desse microparasito em hospedeiro da ordem Siluriformes da Amazônia brasileira.

Ellipsomyxa arariensis n. sp. (Myxozoa: Ceratomyxidae), a new myxozoan parasite of Pygocentrus nattereri Kner, 1858 (Teleostei: Characidae) and Pimelodus ornatus Kner, 1858 (Teleostei: Pimelodidae) from Marajó Island, in the Brazilian Amazon region.

Ellipsomyxa arariensis n. sp. was found in the gallbladder of Pygocentrus nattereri Kner, 1858 and Pimelodus ornatus Kner, 1858 from the Arari River on Marajó Island in Pará, Brazil. The new species has disporous plasmodium that varies in size and shape, with ellipsoidal mature spores in the sutural view that have a curved suture line. The spores are 12.6 (12.0-13.4) µm in length and 7.3 (6.7-8.0) µm in width. The two polar capsules present in the spore are pyriform and of equal size, with subterminal openings that project in opposite directions. The polar capsules are 3.5 (3.4-4.0) µm long and 2.6 (2.5-3.2) µm wide. Based on the partial sequences of the SSU rRNA gene of the Ellipsomyxa arariensis n. sp. spores found in Pygocentrus nattereri Kner, 1858 (1325 bps) and Pimelodus ornatus Kner, 1858 (1240 bps), the new species is clearly distinct from all the other myxozoan sequences deposited in GenBank. Based on Bayesian inference and p distances, the new species belongs to the "Ellipsomyxa clade", together with all the other Ellipsomxa species, reinforcing the monophyletic status of this genus. Overall, the morphological data and the partial sequences of the SSU rRNA gene provide a conclusive diagnosis of Ellipsomyxa arariensis n. sp. as a species distinct from all the other Ellipsomyxa species described previously.

Anisakid larva parasitizing Plagioscion squamosissimus in Marajó Bay and Tapajós River, state of Pará, Brazil.

In November 2014 and May 2015, a total of 44 specimens of the South American silver croaker Plagioscion squamosissimus were collected: 30 in Marajó Bay and 14 in the Tapajós River, state of Pará, Brazil. The aim was to investigate the presence of anisakid nematodes and determine their parasitism indices and sites of infection, because of their importance regarding health inspection. Sixty-nine Anisakis sp. larvae were found; among them, 16 larvae in seven fish collected in Marajó Bay and 53 larvae in four fish in the Tapajós River. The parasitism indices of the nematodes collected from the fish in Marajó Bay comprised prevalence (P) of 23%, mean infection intensity (MI) of 2.28, mean abundance (MA) of 0.53, range of infection (RI) of 1-4, and infection site (IS) in the mesentery. The fish from the Tapajós River showed P = 28%, MI = 13.2, MA = 3.8, RI = 1-22, and IS = mesentery and intestine. To assist in taxonomic identification, images of the specimens obtained through optical microscopy with Nomarski's interferential contrast system and scanning electron microscopy were used. This is the first record of Anisakis sp. parasitizing P. squamosissimus.

Anisakid larva parasitizing Plagioscion squamosissimus in Marajó Bay and Tapajós River, state of Pará, Brazil / Larva de anisaquídeo parasitando Plagioscion squamosissimus na Baía de Marajó e no Rio Tapajós, estado do Pará, Brasil

Abstract In November 2014 and May 2015, a total of 44 specimens of the South American silver croaker Plagioscion squamosissimus were collected: 30 in Marajó Bay and 14 in the Tapajós River, state of Pará, Brazil. The aim was to investigate the presence of anisakid nematodes and determine their parasitism indices and sites of infection, because of their importance regarding health inspection. Sixty-nine Anisakis sp. larvae were found; among them, 16 larvae in seven fish collected in Marajó Bay and 53 larvae in four fish in the Tapajós River. The parasitism indices of the nematodes collected from the fish in Marajó Bay comprised prevalence (P) of 23%, mean infection intensity (MI) of 2.28, mean abundance (MA) of 0.53, range of infection (RI) of 1-4, and infection site (IS) in the mesentery. The fish from the Tapajós River showed P = 28%, MI = 13.2, MA = 3.8, RI = 1-22, and IS = mesentery and intestine. To assist in taxonomic identification, images of the specimens obtained through optical microscopy with Nomarski's interferential contrast system and scanning electron microscopy were used. This is the first record of Anisakis sp. parasitizing P. squamosissimus.

Resumo Em novembro de 2014 e maio de 2015, foi coletado um total de 44 espécimes de pescada branca, Plagioscion squamosissimus, sendo 30 na Baía de Marajó e 14 no Rio Tapajós, Estado do Pará, Brasil, com o objetivo de pesquisar a presença de nematoides anisaquideos e fornecer os índices parasitários, assim como os sítios de infecção, devido a sua importância na inspeção sanitária. Encontrou-se um total de 69 larvas de Anisakis sp., sendo 16 em 7 peixes coletados da Baía de Marajó e 53 larvas em 4 peixes do Rio Tapajós. Os índices parasitários desses nematoides coletados dos peixes da Baía de Marajó apresentaram prevalência (P) de 23%, intensidade média (IM) de 2,28, abundância média (AM) de 0,53, amplitude de variação da intensidade de infecção (AI) de 1-4 e sítio de infecção (SI) o mesentério; e os do Rio Tapajós P = 28%, IM = 13,2, AM = 3,8, AI = 1-22 e SI = mesentério e intestino. Para auxiliar na identificação taxonômica foram utilizadas imagens obtidas dos espécimes por microscopia ótica com sistema de contraste interferencial de Nomarski e microscopia eletrônica de varredura. Esse é o primeiro registro de Anisakis sp. parasitando P. squamosissimus.

Myxozoan infection in the muscle layer of the intestine of Rhamdia quelen from the Amazon River Basin, Brazil / Infecção por Myxozoa na camada muscular intestinal do Rhamdia quelen da Bacia do Rio Amazonas, Brasil

ABSTRACT: The present study investigated the morphology and pathology associated with the occurrence of cysts caused by Myxobolus sp. in the intestine of the silver catfish Rhamdia quelen . Comparisons with the other Myxobolus species that infect the intestines of cyprinids and siluriforms revealed that the pyriform spores of Myxobolus sp. are similar in shape to those described previously in M. miyairii, M. duodenalis and M. cunhai, but different in size. Morphometric analyses revealed that mature spores of Myxobolus sp. (10.9 x 5.1μm) are smaller than those of most species except M. cunhai (10.0 x 5.0μm), which has been described infecting the Brazilian catfish Pimelodus clarias , although the spores differ morphologically in relation to the shape of the polar capsules. Further research is necessary in order to clarify the taxonomic and phylogenetic relationships among these congeneric species.

RESUMO: O presente estudo investigou a morfologia e patologia associada com a ocorrência de cistos de Myxobolus sp. no intestino do peixe siluriforme Rhamdia quelen . Comparações com outras espécies de Myxobolus que têm infectado intestinos de carpas e bagres de água doce demonstraram que os esporos piriformes de Myxobolus sp. são similares no formato dos anteriormente descritos para M. miyairii, M. duodenalis e M. cunhai , diferindo, no entanto, quanto ao tamanho. As análises morfométricas revelaram que os esporos maduros de Myxobolus sp. (10,9 x 5,1μm) são menores do que os da maioria das espécies, exceto para M. cunhai (10,0 x 5,0μm), que foi descrito infectando o bagre brasileiro Clarias pimelodus , embora os esporos sejam diferentes morfologicamente em relação à forma das cápsulas polares. Futuras pesquisas são necessárias para esclarecer as relações taxonômicas e filogenéticas entre espécies congêneres.

Potaspora aequidens n. sp. (Microsporidia, Tetramicridae), a parasite infecting the freshwater fish Aequidens plagiozonatus (Teleostei, Cichlidae) from Brazil.

Morphological and molecular procedures were used to describe a new species of microsporidian that infects the muscles of the sub-opercular region and the caudal fins of the freshwater Aequidens plagiozonatus in Brazil. This microsporidian forms whitish xenomas containing variable number of spores, reaching up to ~0.4 mm in diameter. The mature spores, pyriformin shape, with slightly round ends, measured 3.4 ± 0.5 µm long and 1.9 ± 0.3 µm wide (n = 50) and showed characteristics typical of Microsporidia. The average thickness of the spore wall was 100 (96-108) nm (n = 50), and the spore wall was composed of two layers, a thin, electron-dense exospore and a thick electron-transparent endospore. The exospore was surrounded by a thin, irregular layer of granular material. The anchoring disc was mushroom-like, located in the apical region of the spore in an eccentric position relative to the spore axis, rendering bilateral asymmetry to the spore. The anterior part of the polar filament (PF) (manubrium) measured approximately 125 (122-128) nm thick (n = 30), and the angle of tilt between the anterior PF and the spore axis was ~45°; the posterior part was packed in 8-9 coils. Phylogenetic analysis showed a strongly supported clade containing family Spragueidae Weissenberg, 1976, family Tetramicridae Matthews and Matthews, 1980, Microsporidium sp. RBS1, and Kabatana spp. In conclusion, the available morphological, ultrastructural, and molecular data shows that this microsporidian is a new species belonging to group 4, classified as Potaspora aequidens n. sp. This is the second species described in the genus Potaspora.

Anatomopathological study of parrot pufferfish Colomesus psittacus parasitized by the aspidogastrean Rohdella sp.

Aspidogastrea are globally-distributed parasites of the class Trematoda, which have been described as pathogens of a range of aquatic organisms, in marine and freshwater environments. The principal morphological characteristic of the group is an adhesive ventral disc, which is responsible for fixing the parasite to the host organism. In this study, 112 specimens of Colomesus psittacus from the municipality of Cametá, in the state of Pará (Brazil), were necropsied. Platyhelminthes of the genus Rohdella attached to the mucous membrane of the fish's intestine by the adhesive disc were observed. Fragments of parasitized tissue were fixed in Davidson solution and then processed and stained with hematoxylin-eosin. Other fragments were fixed in glutaraldehyde, processed and observed under a scanning electron microscope. The prevalence of the parasite was 76.4%, mean intensity of infection was 8.0 and mean abundance was 6.2. The parasitism provoked chronic enteritis with diffused inflammatory infiltration. The adherence of the parasite to the mucous membrane of the intestine resulted in strangulation and hyperplasia of the region, as well as causing hypertrophy of the muscle of the mucous membrane. The present study describes the anatomopathological and ultrastructural aspects of the parasitism of the intestine of C. psittacus by Rohdella sp.

Anatomopathological study of parrot pufferfish Colomesus psittacus parasitized by the aspidogastrean Rohdella sp / Estudo anatomopatológico do peixe baiacu papagaio Colomesus psittacus parasitado pelo aspidogastrea Rohdella sp

Aspidogastrea are globally-distributed parasites of the class Trematoda, which have been described as pathogens of a range of aquatic organisms, in marine and freshwater environments. The principal morphological characteristic of the group is an adhesive ventral disc, which is responsible for fixing the parasite to the host organism. In this study, 112 specimens of Colomesus psittacus from the municipality of Cametá, in the state of Pará (Brazil), were necropsied. Platyhelminthes of the genus Rohdella attached to the mucous membrane of the fish's intestine by the adhesive disc were observed. Fragments of parasitized tissue were fixed in Davidson solution and then processed and stained with hematoxylin-eosin. Other fragments were fixed in glutaraldehyde, processed and observed under a scanning electron microscope. The prevalence of the parasite was 76.4%, mean intensity of infection was 8.0 and mean abundance was 6.2. The parasitism provoked chronic enteritis with diffused inflammatory infiltration. The adherence of the parasite to the mucous membrane of the intestine resulted in strangulation and hyperplasia of the region, as well as causing hypertrophy of the muscle of the mucous membrane. The present study describes the anatomopathological and ultrastructural aspects of the parasitism of the intestine of C. psittacus by Rohdella sp.

Os Aspidogastreas são parasitos da classe Trematoda, distribuídos globalmente e têm sido descritos como patógenos em uma gama de organismos aquáticos de ambientes marinhos e de água doce. A principal característica morfológica do grupo é um disco adesivo na região ventral responsável pela fixação do parasito no organismo hospedeiro. Neste estudo, 112 espécimes de Colomesus psittacus provenientes do município de Cametá, no estado do Pará (Brasil), foram necropsiados. Foram observados platelmintos do gênero Rohdella aderidos à mucosa intestinal através do disco adesivo. Fragmentos de tecido com parasito foram fixados em solução de Davidson e processados e corados em Hematoxilina-Eosina. Outros fragmentos foram fixados em glutaraldeído, processados e observados em microscopia eletrônica de varredura. A prevalência parasitária foi de 76, 4%, intensidade média de infecção de 8,0 e abundância média de 6,2. O parasitismo ocasionou uma enterite crônica com difuso infiltrado inflamatório. A fixação do parasito na mucosa intestinal provocou estrangulamento e hiperplasia da região, bem como hipertrofia da muscular da mucosa. O presente trabalho descreve os aspectos anatomopatológicos e ultra-estruturais da ação parasitária por Rohdella sp. no trato intestinal de C. psittacus.

Nematodes in Hoplerytrinus unitaeniatus, Hoplias malabaricus and Pygocentrus nattereri (pisces characiformes) in Marajó Island, Brazil.

The aim of this study was to evaluate the tegument, musculature and mesentery of 102 specimens of Hoplerytrinus unitaeniatus, 104 of Hoplias malabaricus and 101 of Pygocentrus nattereri, from Arari Lake, Marajó Island, State of Pará, Brazil. Were identified the nematodes Contracaecum sp., Eustrongylides sp. and Procamallanus sp. Contracaecum sp. was the most prevalent, with rates of 84.31% (H. unitaeniatus), 95.19% (H. malabaricus), and 89.11% (P. nattereri). The highest prevalences of Eustrongylides sp. occurred in H. unitaeniatus (56.86%) and H. malabaricus (53.84%). Procamallanus sp. was only collected in the mesentery. Specimens of Eustrongylides sp. collected from the musculature were 91.9% of its population. Among the nematodes found in the mesentery, 98.34% were Contracaecum sp. with a mean intensity (MI) of 7.92 ± 8.11 (H. unitaeniatus), 8.49 ± 8.34 (H. malabaricus) and 7 ± 6.40 (P. nattereri). Contracaecum sp. presented the highest MI (8.49 ± 8.34) and mean abundance (8.09 ± 8.34). The highest MI values were observed in the mesentery. Eustrongylides sp. presented MI of 2.65 ± 3.21 (H. unitaeniatus), 3.41 ± 3.27 (H. malabaricus) and 2.17 ± 1.18 (P. nattereri). Nematodes with zoonotic potential that were found with high prevalence, shows the importance of actions by the health authorities.

Nematodes in Hoplerytrinus unitaeniatus, Hoplias malabaricus and Pygocentrus nattereri (pisces characiformes) in Marajó Island, Brazil / Nematóides em Hoplerytrinus unitaeniatus, Hoplias malabaricus e Pygocentrus nattereri (pisces characiformes) na Ilha de Marajó, Brasil

The aim of this study was to evaluate the tegument, musculature and mesentery of 102 specimens of Hoplerytrinus unitaeniatus, 104 of Hoplias malabaricus and 101 of Pygocentrus nattereri, from Arari Lake, Marajó Island, State of Pará, Brazil. Were identified the nematodes Contracaecum sp., Eustrongylides sp. and Procamallanus sp. Contracaecum sp. was the most prevalent, with rates of 84.31% (H. unitaeniatus), 95.19% (H. malabaricus), and 89.11% (P. nattereri). The highest prevalences of Eustrongylides sp. occurred in H. unitaeniatus (56.86%) and H. malabaricus (53.84%). Procamallanus sp. was only collected in the mesentery. Specimens of Eustrongylides sp. collected from the musculature were 91.9% of its population. Among the nematodes found in the mesentery, 98.34% were Contracaecum sp. with a mean intensity (MI) of 7.92 ± 8.11 (H. unitaeniatus), 8.49 ± 8.34 (H. malabaricus) and 7 ± 6.40 (P. nattereri). Contracaecum sp. presented the highest MI (8.49 ± 8.34) and mean abundance (8.09 ± 8.34). The highest MI values were observed in the mesentery. Eustrongylides sp. presented MI of 2.65 ± 3.21 (H. unitaeniatus), 3.41 ± 3.27 (H. malabaricus) and 2.17 ± 1.18 (P. nattereri). Nematodes with zoonotic potential that were found with high prevalence, shows the importance of actions by the health authorities.

Examinou-se o tegumento, mesentério e musculatura de 102 espécimes de Hoplerytrinus unitaeniatus, 104 de Hoplias malabaricus e 101 de Pygocentrus nattereri, do Lago Arari, Ilha do Marajó, Estado do Pará, Brasil. Foram identificados os nematóides Contracaecum sp., Eustrongylides sp. e Procamallanus sp. nas três espécies de peixes. Contracaecum sp. foi o mais prevalente, com índices de 84,31% (H. unitaeniatus), 95,19% (H. malabaricus) e 89,11% (P. nattereri). As maiores prevalências de Eustrongylides sp. foram observadas em H. unitaeniatus (56,86%) e H. malabaricus (53,84%). Procamallanus sp. só foi coletado no mesentério, sendo o sítio de infecção mais parasitado. Na musculatura, foram coletados espécimes de Eustrongylides sp., representando 91,9% de sua população. Dos nematóides coletados no mesentério, 98,34% foram Contracaecum sp. com intensidade média (IM) de 7,92 ± 8,11 (H. unitaeniatus), 8,49 ± 8,34 (H. malabaricus) e 7,0 ± 6,40 (P. nattereri). Contracaecum sp. apresentou maior IM (8,49 ± 8,34) e abundância média (8,09 ± 8,34). Os maiores valores de IM foram obtidos no mesentério. Eustrongylides sp. apresentou IM de 2,65 ± 3,21 (H. unitaeniatus), 3,41 ± 3,27 (H. malabaricus) e 2,17 ± 1,18 (P. nattereri). Nematóides com potencial zoonótico, encontrados com alta prevalência, demonstram a importância para ações das autoridades sanitárias.

Calyptospora sp. in Brachyplatystoma vaillantii trapped at the Vigia, state of Pará, Brazil / Calyptospora sp. em Brachyplatystoma vaillantii capturadas no município de Vigia, estado do Pará, Brasil

The article describes the first occurrence of hepatic coccidiosis in catfish of the species Brachyplatystoma vaillantii, captured in the coastal region of the Vigia city , state of Pará, Brazil, caused by species of the genus Calyptospora, family Calyptosporidae. Thirty specimens of piramutabas were examined where 60% were infected with liver location, featuring numerous mature and immature oocysts, grouped or isolated, with four sporocysts in pyriform shape. They were described on their morphology and dimensions of the oocysts and sporocysts, obtained from light microscopy and differential interference contrast.

O artigo descreve a primeira ocorrência de coccidiose hepática em bagres da espécie Brachyplatystoma vaillantii, capturados na região costeira do Município de Vigia, Estado do Pará, Brasil, causada por espécies do gênero Calyptospora, família Calyptosporidae. Foram examinados trinta exemplares de piramutabas, dos quais 60% encontravam-se parasitados com localização hepática, apresentando vários oocistos maduros e imaturos, agrupados ou isolados, com quatro esporocistos de formato piriforme. São descritas as características morfológicas e dimensões dos oocistos e esporocistos, obtidas a partir de microscopia de luz em campo claro e em contraste interferencial de fases.