Infecção por Austrodiplostomum sp. (Digenea: Diplostomidae) em tucunarés (Cichla sp.) do Açude Joana, Pedro II, Piauí

Abstract

Trematodes of the genus Austrodiplostomum (Digenea: Diplostomidae) are widely distributed parasites in freshwater fish, capable of causing physiological and behavioral impacts on their hosts, as well as influencing the ecological dynamics of aquatic ecosystems. The present study aimed to identify metacercariae found in fish from the Joana Reservoir, located in the municipality of Pedro II, Piauí, Brazil. To this end, 18 fish were collected and analyzed between September and October 2023, identified as Cichla sp. (n = 10), Oreochromis niloticus (n = 5), and Hoplias sp. (n = 3). The only parasitized species was Cichla sp., with a prevalence of 50%. The metacercariae were found in the vitreous chamber of the eyes and were morphologically identified as belonging to the genus Austrodiplostomum. The presence of this parasite may impair the vision of hosts, making them more susceptible to predation and altering their feeding behavior. The exclusive infection in Cichla sp. may be related to its ecology, feeding habits, and the fact that it is a widely introduced species in reservoirs in northeastern Brazil. The results contribute to the knowledge of the parasitic fauna in the region and highlight the importance of parasitological monitoring in predatory fish, especially in environments subject to species introduction and ecological changes.