Seasonality of nematode larvae in Iguanodectes spilurus (Characidae) an ornamental fish from northeastern Para, Brazil

The current study presents a parasitological survey of larval nematodes from freshwater ornamental fish Iguanodectes spilurus caught in the watercourse of the Caete River, in the northeast region of the State of Para, Brazil. A total of 176 specimens, 1.36+ or -0.75 g weight and 5.53+ or -0.98 cm total length, were analyzed. Nematode larvae were identified as Capillaria sp., Procamallanus sp. and Anisakidae, with prevalence of 70.45% and infection intensity ranging from 1.81 to 4.70 larvae. The highest prevalence 57.38% occurred in the liver, but no seasonality was observed, indicating high infection throughout the year. Seasonality was observed in fish parasitized in the stomach, intestine and caecum, with prevalence and mean intensity of 17.61% and 2.32 parasites, 12.5% and 1.81 parasites, 10.79% and 2.21 parasites, respectively. The highest degree of infection was observed in the rainy season, probably due to increased availability of intermediate hosts or food.Original Abstract: O presente estudo apresenta um levantamento parasitologico de larvas de nematoides de Iguanodectes spilurus capturados no fluxo do Rio Caete, nordeste do Para, Brasil. Um total de 176 especimes com medias de 1,36 + or - 0,75 g de peso e 5,53 + or - 0,98 cm de comprimento total foram analisados. Foram identificados em 124 peixes os nematoides Capillaria sp., Procamallanus sp. e da familia Anisakidae, apresentaram uma prevalencia de 70,45% e intensidade de infeccao de 1,81 a 4,70 larvas. A maior prevalencia foi de 57,38% no figado, mas nao foi observada sazonalidade, indicando alta potencia de infeccao ao longo do ano. A sazonalidade foi observada em peixes parasitados no intestino, estomago e ceco com prevalencia e intensidade media de 17,61% e 2,32 parasitas, 12,5% e 1,81 parasitas, 10,79% e 2,21 parasitas, respectivamente. A maior infeccao foi encontrada na estacao chuvosa, provavelmente devido ao aumento da disponibilidade de hospedeiros intermediarios ou de alimentos.