The influence of environmental factors on Clinostomum sp. (Digenea) infection in the fish Cichlasoma paranaense (Kullander, 1983) in central Brazil

Abstract

This study analyzed the parasitism by Clinostomum sp. metacercariae of the neotropical fi sh Cichlasoma paranaense (Kullander 1983) and environmental variables’ infl uence on their host-parasite relationship in Central Brazil. Fish were collected in fi ve impoundments (I) from three towns: Itauçú (n = 2), Inhumas (n = 1), and Goiânia (n = 2), Goiás State, Brazil. Ninety-fi ve fi sh were analyzed, weighted and length measured. Afterward, the presence of metacercariae in the gills, muscles, fi ns, and body cavities was investigated. The metacercariae were fi xed in AFA solution, kept in 70% alcohol, and stained with carmine. The infection prevalence revealed that 0.64, 0.56 and 0.91% of fi sh was infected. The abundance was 4.14, 3.22 and 5.88, with a mean intensity of 6.44, 5.80 and 6.42 per impoundment (I 13, I 15 and I 16), respectively. The frequency of metacercariae was higher in fi sh collected in Goiânia. High frequency of parasites was observed in the gills, muscles, and fi ns. The limnological variables did not present direct interference in the parasitism. The fi sh’ standard length infl uenced the number of metacercariae positively but did not differ to the relative condition coeffi cient.