Kudoa spp. (Myxozoa, Multivalvulida) parasitizing fish caught in Aracaju, Sergipe, Brazil / Kudoa spp. (Myxozoa, Multivalvulida) parasitando peixes capturados em Aracaju, Sergipe, Brasil

Abstract This study reports on Kudoa spp. (Myxozoa, Multivalvulida) from the fish species Lutjanus analis, Bagre marinus, Aspistor luniscutis and Lutjanus jocu, which were caught in Aracaju, state of Sergipe, Brazil. The parasites formed oval plasmodia around the esophagus of L. analis, and elongated plasmodia inside the skeletal muscle of B. marinus, A. luniscutis and L. jocu. Host myoliquefaction was not observed in all the cases studied. The current study provides a morphological and morphometric description of each parasite as well as a comparison with all the species described worldwide. Lack of molecular data impaired specific identification of the parasites. The importance of these parasites is discussed and the need for further studies on infections in Brazilian fish is emphasized because of the high economic impact of some Kudoa species which cause liquefaction in hosts’ muscles and render these fish unsuitable for consumption.

Resumo Este estudo relata Kudoa spp. (Myxozoa, Multivalvulida) de espécies de peixes Lutjanus analis, Bagre marinus, Aspistor luniscutis e Lutjanus jocu que foram capturados na costa litorânea de Aracaju, Estado de Sergipe, Brasil. Os parasitas formavam plasmódios ovais rodeando o esófago em L. analis, enquanto que nas espécies B. marinus, A. luniscutis e L. jocu formavam plasmódios alongados no interior das fibras musculares. Fenômenos de liquefação do músculo do hospedeiro não foram observados. O presente estudo proporciona uma descrição morfológica e morfométrica de cada parasita, sendo feita uma comparação com todas as espécies conhecidas em todo mundo. A inexistência de dados moleculares prejudica a identificação específica dos parasitas. A importância destes parasitas é discutida e a necessidade de mais estudos relacionados a infecções em peixes brasileiros é enfatizada por causa do alto impacto econômico de algumas espécies de Kudoa que causam liquefação nos músculos dos hospedeiros e tornam estes peixes impróprios para consumo.

Histopathological evaluation of seven Amazon species of freshwater ornamental armored catfish / Avaliação histopatológica em sete especies de cascudos ornamentais amazônicos

Fish commonly known as acaris or plecos are freshwater armored catfish economically important as a food resource and as ornamental fish. Most of these species are captured in the Amazon region. However, despite its economic importance, there is a lack of knowledge about their biological aspects. Thus, this study aimed to characterize and evaluate the histopathological aspects of important organs as gills, liver, integument and kidney of seven species of armored freshwater ornamental catfish from Guamá River, Pará State, Brazil. All organs showed typical characteristics of organs of other teleosts. In some species, gills and liver showed slight histopathological changes: telangiectasis, edema and morphological changes related to the presence of parasites (Monogenea and Digenea) in the gills, and changes in the arrangement of hepatocytes rows, and vacuolation of hepatocytes in the liver. Thus, the knowledge of the normal structure of organs and changes found can be used as tools for environmental and health monitoring of animals.

Os peixes conhecidos como Acaris ou Cascudos são siluriformes de água doce com o corpo revestido por placas ósseas, economicamente importantes como fonte de alimento e peixes ornamentais. A maioria destas espécies é capturada na região amazônica. Contudo, apesar de sua importância econômica, há desconhecimento sobre os aspectos biológicos desses peixes. Assim, o objetivo deste trabalho foi caracterizar e avaliar histologicamente órgãos importantes (brânquias, fígado, rim e tegumento) de sete espécies de peixes ornamentais de água doce do rio Guamá, Pará, Brasil. Todos os órgãos observados apresentaram as características típicas dos órgãos de teleósteos. Em algumas espécies, as brânquias e o fígado mostraram pequenas alterações histopatológicas: edema, telangiectasias e alterações morfológicas relacionadas com a presença de parasitas (Monogenea e Digenea) nas brânquias, e modificações no arranjo de linhas de cordões de hepatócitos e vacuolização destas células foram também observadas. Assim, o conhecimento da estrutura dos órgãos e as alterações encontradas podem ser utilizados como ferramentas para o monitoramento ambiental e sanitário dos animais.

First occurrence of Quadrigyrus nickoli (Acanthocephala) in the ornamental fish Hyphessobrycon eques / Primeira ocorrência de Quadrigyrus nickoli (Acanthocephala) no peixe ornamental Hyphessobrycon eques

The objective of this work was to report the first seasonal occurrence of the acanthocephalan Quadrigyrus nickoli Schmidt & Hugghins, 1973 (Quadrigyridae), in the "Mato Grosso" Hyphessobrycon eques (Characidae) (Steindachner, 1882), collected from the Chumucuí River, state of Pará, Brazil. The fish were collected between July 2006 (rainy season) and June 2007 (dry season) and were examined for parasites using pattern techniques. A total of 75 parasites were found in the stomach and intestine. Among 83 fish examined (50 in the dry season and 33 in the rainy season), 22 were parasitized by cystacanths of Q. nickoli. The importance of H. eques as a paratenic host for Q. nickoli is discussed. This is the first study on the biology of and infection by Q. nickoli occurring in the eastern Amazon region.

O objetivo desse trabalho foi registrar a primeira ocorrência sazonal do acantocefala Quadrigyrus nickoli Schmidt & Hugghins, 1973 (Quadrigyridae) no peixe "Mato Grosso", Hyphessobrycon eques Steindachner, 1882 (Characidae), capturados no Rio Chumucuí, região Bragantina, Pará, Brasil. Os peixes foram coletados no período de julho∕2006 a junho∕2007 e examinados com técnica padrão para detecção de parasitas. Um total de 75 parasitas foram encontrados no estômago e intestino. Dos 83 peixes capturados (50 na estação seca e 33 na chuvosa), 22 estavam parasitados por cistacantos de Quadrigyrus nickoli. No presente trabalho discute-se a importância do H. eques como hospedeiro paratênico para Quadrigyrus nickoli. Os presentes dados constituem o primeiro estudo sobre a biologia e a infecção de Q. nickoli na Amazônia oriental.

Parasites of four ornamental fish from the Chumucuí River (Bragança, Pará, Brazil) / Parasitas de quatro peixes ornamentais do Rio Chumucuí (Bragança-Pará, Brasil)

The objective of the present study was to evaluate the parasite fauna of four species of ornamental fish collected in the Chumucuí River, municipality of Bragança, Pará, Brazil. From June 2006 to December 2007. Fishes (n=307) belonging to four species were collected, including 23 specimens of Moenkhausia sanctaefilomenae (redeye tetra), 37 Carnegiella strigata (marbled hatchetfish), 7 Chilodus punctatus (spotted headstander), and 240 Astyanax bimaculatus (twospot astyanax). The parasites found belonged to three taxa: monogeneans in the gills, nematodes (larvae of Capillaria sp. and Contracaecum sp.) in the digestive tract and liver and acanthocephalans (Quadrigyrus torquatus, Q. brasiliensis and Q. nickoli) in the stomach and intestine. Astyanax bimaculatus presented higher prevalence of acanthocephalans in the wet season, and lower prevalence of nematodes in the dry season. The possible importance of these parasites in the exportation of ornamental fish is discussed.

O objetivo do presente trabalho foi avaliar a fauna parasitária de quatro espécies de peixes ornamentais capturados no rio Chumucuí, no município de Bragança-PA. Foram coletados um total de 307 peixes pertencentes a 4 espécies, sendo elas: Moenkhausia sanctaefilomenae (olho de fogo, n = 23), Carnegiella strigata (borboleta, n = 37), Chilodus punctatus (cabeça-para-baixo, n = 7) e Astyanax bimaculatus (lambari, n = 240) coletados de junho de 2006 a dezembro de 2007. Foram observados 3 taxa parasitando os peixes: monogenéticos nas brânquias, nematóides (larvas de Capillaria sp. e Contracaecum sp.) no trato digestório e fígado e acantocéfalos (Quadrigyrus torquatus, Q. brasiliensis e Q. nickoli) no estômago e intestino. Astyanax bimaculatus apresentou maior prevalência de acantocéfalos na estação chuvosa, menor prevalência de nematóides na estação seca. Discute-se a eventual importância destes parasitas na exportação de peixes ornamentais.

Nematode parasites of Pescada Gó, Macrodon ancylodon Bloch and Schneider, 1801 (Osteichthyes, Sciaenidae), from Vila dos Pescadores, Bragança-PA, Brazil

The objective of this work was to evaluate the host/parasite relationship of nematodes in Macrodon ancylodon. Ninety seven fishes (50 in wet season and 47 in dry season) were weighed (167.1 ± 109.9g) and measured (28.3 ± 5.2cm). Only twelve specimens were not infected by any parasites and the prevalence of infection was 87.6%. The highest prevalence values were observed in August and September (dry season, 100%). The stomach was the most infected organ during the whole months (prevalence of 64.2%, and mean intensity of 4.6±7.8 parasites/fish), and the medium intestine showed the lowest infection (prevalence 27.3% and mean intensity 2.5±2.1 parasites/fish). The nematodes were identified as Raphidascaris sp., Goezia sp. and Cucullanus sp. Only the male and juvenile fishes could be presented different values of infection according to rainfall, being more infected in August to October. The female hosts presented higher values of abundance and mean intensity of infection (p<0.01) throughout the year.

Environmental influences on antibody-enhanced dengue disease outcomes

Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.0025), no significant differences were detected between the SS experimental groups (Kaplan-Meyer log-rank test, p = 0.089). Survival curves from EE and IE animals infected with the AED regimen were extended after corticoid injection and this effect was greater in the EE than in the IE group (Kaplan-Meyer log-rank test, p = 0.0162). Under the AED regimen the EE group showed more intense clinical signs than the IE group. Dyspnoea, tremor, hunched posture, ruffled fur, immobility, pre-terminal paralysis, shock and death were associated with dominant T-lymphocytic hyperplasia and presence of viral antigens in the liver and lungs. We propose that the increased expansion of these memory T-cells and serotype cross-reactive antibodies facilitates the infection of these cells by DENV and that these events correlate with disease severity in an EE.

Effects of chromium supplementation on the infrapopulations of Anacanthorus penilabiatus (Monogenoidea) and Piscinoodinium pillulare (Dinoflagellida) parasites of Piaractus mesopotamicus (Characidae)

This study evaluated the parasitism by Anacanthorus penilabiatus (Monogenoidea) and Piscinoodinium pillulare (Dinoflagellida) in the gills of "pacu", Piaractus mesopotamicus supplemented with chromium in the diet. Randomised delineation by using factorial scheme (4x2x2) for Monogenoidea and 4x2x3 for Dinoflagellate with four levels of chromium (0, 6, 12, 18mg/kg diet), two stocking densities (4kg/m³ and 20kg/m ³), two classes of length (higher and lower than 17 cm) for a period of 7, 60 and 90 days, and four replicates was used. The fishes in low density which received 12 and 18mg/kg showed decreased monogeneoidea values, seven days after the experiment begin. Six, 12 and 18 mg/kg caused reduction in the dinoflagellate number in the fishes maintained at 20kg/m³. It was possible that chromium supplementation (12 e 18mg/kg) favoured the fishes health by reducing Monogenoidea and Dinoflagellida number in lower and higher densities, respectively.

O objetivo do trabalho foi avaliar a intensidade de parasitismo por monogenóide Anacanthorus penilabiatus e pelo dinoflagelado Piscinoodinium pillulare em pacus Piaractus mesopotamicus, cuja dieta foi suplementada com cromo. Foram utilizados dois delineamentos em esquema fatorial, consistindo de 4 níveis de cromo (0, 6, 12, 18 mgCQC/kg), duas densidades de estocagem (4 kg/m³ e 20 kg/m³) e duas classes de tamanho para monogenóide (maiores e menores de 17cm) e/ou 3 períodos de coleta (7, 60 e 90 dias), com quatro repetições. Os peixes que receberam 12 e 18mg CQC/kg apresentaram diminuição de monogenóides após 7 dias de alimentação na menor densidade. Nos peixes na maior densidade, os níveis de 6, 12 e 18 mgCQC/kg ocasionou redução de dinoflagelados. Os resultados demonstraram que a suplementação com cromo (12 e 18 mgCQC/kg) promoveu uma melhora na saúde dos peixes na menor e na maior densidade, respectivamente.