Prevalência, distribuição geográfica e sazonal de protozoários e mixozoários parasitos de jaú (Zungaro jahu) no Pantanal Matogrossense / Prevalence, geographic and seasonal distribution of protozoan and myxozoan parasites of jaú (Zungaro jahu) in the Pantanal of Mato Grosso, Brazil

Estudo realizado no Pantanal Matogrossense, avaliou a prevalência, a distribuição geográfica e sazonal de protozoários e mixozoários parasitos de jaú (Zungaro jahu). Os peixes foram capturados no Sul do Pantanal, na região dos rios Aquidauana, Miranda e Paraguai, em 2001, 2002 e 2003, na região Central (Parque Nacional do Pantanal - PARNA Pantanal) em 2003, 2004, 2005 e 2008, e na região Norte (rios Cuiabá e Manso, no município de Nobres) em 2003, 2004 e 2005. Foi identificado Trichodina sp. parasitando pele e brânquias de jaú nas três regiões estudadas. Ocorrência de Epistylis sp. na pele e Cryptobia sp. nas brânquias foram restritas às coletas da região Central, enquanto Ichthyophthirius multifiliis foi identificado parasitando a pele nas três regiões estudadas. Também foi observada a ocorrência de mixozoários, Myxobolus cordeiroi parasitando vários órgãos e Henneguya sp. parasitando brânquias de jaú das três regiões estudadas.

In a study carried out in the Pantanal of Mato Grosso, Brazil, the prevalence, geographic and seasonal distribution of protozoan and myxozoan parasites of Zungaro jahu was evaluated. The fish were captured in the southern region of Pantanal Mato-grossense (Aquidauana, Miranda and Paraguay rivers) in 2001, 2002 and 2003, in the central region (Pantanal National Park - PARNA Pantanal) in 2003, 2004, 2005 and 2008, and in the northern region (Cuiabá and Manso rivers, in the municipality of Nobres) in 2003, 2004 and 2005. Trichodina sp. was identified parasitized skin and gills of jaú in the three regions studied. Epistylis sp. parasitized skin and Cryptobia sp. the gills and were restricted to the Central region, whilst Ichthyophthirius multiiiliis parasitized skin in the three regions studied. The occurrence of myxozoans was also observed: Myxobolus cordeiroi parasitized several organs and Henneguya sp. parasitized the gills of jaú in the three regions studied.

Phylogeny, ultrastructure, histopathology and prevalence of Myxobolus oliveirai sp. nov., a parasite of Brycon hilarii (Characidae) in the Pantanal wetland, Brazil

This paper presents the morphological, histological and ultrastructural characteristics of Myxobolus oliveirai sp. nov., a parasite of the gill filaments in Brycon hilarii from the Brazilian Pantanal. Out of 216 B. hilariispecimens examined (126 wild and 90 cultivated), 38.1 percent of wild specimens (n = 48) were infected. The parasites form elongated plasmodia primarily in the tip of gill filaments, reaching about 3 mm in length. A thorough comparison with all the Myxobolus species described from South American hosts, as well as nearly all the Myxobolus species described so far is provided. Partial sequencing of the 18S rDNA gene revealed a total of 1,527 bp. The Myxobolus species parasite of B. hilarii did not match any of the Myxozoa available in GenBank. In the phylogenetic analysis, M. oliveirai sp. nov. composed a monophyletic group with eight other species: five species of Myxobolus parasites of mugilid fishes, two parasites of pangasiid and one of centrarchid. Infection prevalence values of the parasite revealed no significant differences between wet and dry seasons or between males and females. The importance of the infection to the farming of the host species is emphasized.

Helmintos parasitos do pirarucu, Arapaima gigas (Schinz, 1822) (Osteoglossiformes: Arapaimidae), no rio Araguaia, estado de Mato Grosso, Brasil / Helminth parasites of pirarucu, Arapaima gigas (Schinz, 1822) (Osteoglossiformes: Arapaimidae) from Araguaia River, State of Mato Grosso, Brazil

Foram examinados 65 exemplares de pirarucu em agosto de 2004, provenientes do rio Araguaia, Estado de Mato Grosso, Brasil para o estudo dos seus helmintos parasitos. Cinco espécies foram registradas parasitando Arapaima gigas: Dawestrema cycloancistrium (Monogenea) nas brânquias, Nilonema senticosum e Goezia spinulosa (Nematoda) na vesícula gasosa e no estômago respectivamente; Caballerotrema brasiliense (Digenea) e Polyacanthorhynchus rhopalorhynchus (Acanthocephala) no intestino. Os valores mais altos de prevalência foram observados para D. cycloancistrium (100 por cento) and P. rhopalorhynchus (96,9 por cento). Os maiores valores de intensidade e abundância média foram calculados para C. brasiliense e N. senticosum (61 e 46,9, respectivamente). Todas estas espécies são registradas pela primeira vez na Bacia do Rio Araguaia.

Sixty-five specimens of pirarucu collected in August 2004 from Araguaia River, State of Mato Grosso, Brazil, were examined to study their helminth parasites. Five species were recorded parasitic Arapaima gigas: Dawestrema cycloancistrium (Monogenea) in gills, Nilonema senticosum and Goezia spinulosa (Nematoda) in the swimbladder and stomach, respectively; Caballerotrema brasiliense (Digenea) and Polyacanthorhynchus rhopalorhynchus (Acanthocephala) in the intestine. Highest prevalence values were detected for D. cycloancistrium (100 percent) and P. rhopalorhynchus (96.9 percent). Highest values of mean intensity and mean abundance were detected for C. brasiliense and N. senticosum (61 and 46.9, respectively). All these species are recorded by the first time in the Araguaia River basin.