Sazonalidade da infecção por Procamallanus (Spirocamallanus) inopinatus (Nematoda: Camallanidae) em Bryconops melanurus (Characiformes: Iguanodectidae).

This study evaluates the host-parasite-environment relationship between the parasitic nematode Procamallanus (Spirocamallanus) inopinatus and the fish host Bryconops melanurus, as well as reports the seasonal occurrence of the parasite in the host. The study was performed in a total of 78 fish collected from a tributary of Caeté River, Bragança, PA, Northern Brazil. The nematode was present in several organs (stomach, pyloric caecum, anterior intestine, posterior intestine) from 76 out of 78 fish specimens. For each location the prevalence and mean intensity of the infection are provided. The level of parasitism was not influenced by the month of capture, but higher parasitic loads were observed in pyloric caecum and posterior intestine during the rainy season (March to June 2007). Seasonal fish host-nematode relationship can be influenced by fish feeding behaviour patterns associated with flood period variations. Key words: Amazon; fish; camallanid; parasitology; flooding; host-parasite relationship