Morphology and surface ultrastructure of Dadaytrema oxycephala (Digenea: Cladorchiidae) with a new host record from Peruvian Amazon floodplain

In this study, a new host record for Dadaytrema oxycephala (Digenea: Cladorchiidae) is described from an important Amazonian ornamental fish. The parasite was identified based in the general morphology and surface ultrastructure of the young and mature trematodes using scanning electron microscopy. The digenetic trematodes were found in the intestine of 15 of 80 specimens (18.7%) of Brochis multiradiatus captured from two floodplain lakes of the Amazonas River, Department of Loreto, Peru and no clinical signs were observed in the parasitized organ. This is the first report of D. oxycephala parasitizing fish of the genus Brochis in the Amazon basin and the first to report this parasite infection in an ornamental fish from Peru. Given that international trade of ornamental fish is a major factor for transboundary spreading of fish parasites and taking account that Peru is the second largest exporter of the Amazonian countries, there is a fundamental need of constant monitoring for diagnosis and timely control of infections by digeneans in order to better prevent introduction in new environments, dissemination and future disease outbreaks.