Helminth parasites of characiform fishes from farming systems in the states of Acre and Maranhão, Western Amazonia and Northeastern regions, Brazil.

Aquaculture has been recognized as one of the main solutions to the growing global food demand, as well as a significant resource for addressing the limitations imposed on wild fisheries. The most important fish species for Brazilian fish farming is Colossoma macropomum due to its zootechnical characteristics, economic and cultural importances. In cultivated systems, the presence of parasites can represent a major problem. Under these conditions, parasites of the phyla Acanthocephala and Platyhelminthes are commonly found parasitizing farmed fishes. This study aimed to investigate the helminth fauna and their parasitological indices in cultivated fish farms located in the municipalities of Imperatriz, state of Maranhão and in Rio Branco, state of Acre, Brazil. A total of 1,617 specimens of Monopisthocotyla were collected, and, among the endoparasites, 325 specimens belong to the phylum Acanthocephala and 10 specimens belonging to the class Trematoda were identified. The present study expands the known biodiversity and distribution of helminth parasites in South American aquaculture, providing new records for host-parasite associations and geographic locations in the states of Acre and Maranhão, Brazil.