Larvae of the genus Contracaecum can be found in several species of fish. This study aims to analyze the prevalence, incidence and average abundance of Contracaecum sp. in fish, and to relate host species richness to parasite abundance. A total of 2888 specimens of host fish were collected, and only 217 specimens showed Contracaecum sp. infections. A total of 64 species of fish were collected, in which the greatest richness of hosts was evidenced during the dry season. During the dry season, the highest prevalence values ​​of Contracaecum sp. were found in Erythrinus erythrinus (P=43.18%) and Acestrorhynchus sp. (P=17.39%).  The values ​​of high abundance (AM= 0.73) and average intensity (IM= 9.77) were evidenced in Sorubim lima. During this period, the relationship between host richness and occurrence of Contracaecum sp. was also significant. In conclusion, the study showed the...

The family Raphidascarididae is composed of nematodes that carry out their life cycle in environments using diverse intermediate or paratenic hosts including invertebrates, fish, waterfowl, and mammals. The genera of this family include Raphidascaris Railliet & Henry, 1915, Ichthyascaris Wu, 1949 and Sprentascaris Petter & Cassone, 1984; all can act as fish parasites. The objective of this work was to analyze host fish of the family Loricariidae including two species of zoonoticnematodes. The study was carried out in the municipality of Cruzeiro do Sul, Acre, Brazil. A total of 42 Sprentascaris mahnerti Petter & Cassone, 1984 was collected from three hosts of the family Loricariidae, 27 from Limatulichthys griseus Eigenmann, 1909, 10 from Spatuloricaria sp. Schultz, 1944 and 5 in Hypoptopoma steindachneri Boulenger, 1895. For Raphidascaris sp. Railliet & Henry, 1915 a tot...