Acanthocephalans parasites in farmed fish in Brazil: A review

Abstract

Studies of acanthocephalans have increased due to outbreaks in Brazilian fish farms. This review aimed to compile results of studies carried out in Brazil, which have reported occurrences of acanthocephalans in fish from fish farms, discuss histopathological and haematological implications, and describe the different treatments in use to combat these parasites. Scientific articles, short communications, monographs, dissertations and theses are included. Eight species of acanthocephalans have been recorded: Neoechinorhynchus buttnerae, Neoechinorhynchus sp. and Echinorhynchus jucundus, Echinorhynchus gomesi, Polyacanthorhynchus macrorhynchus, Polyacanthorhynchus sp., Pomphorhynchus sp., and Quadrigyrus sp. Studies of histopathology and haematology have reported perforations, inflammation and changes in host intestines and immune cells, due to infection with acanthocephalans. Early‐stage testing, both in vitro and in vivo, has shown essential oils, oleoresins and plant extracts to be highly efficacious in combating acanthocephalans. However, there are no national records regulating the use of these anthelmintics in commercial fish farms. In view of this, we are recommending good management practices, including (a) cleaning tanks after fish removal (drying the soil and adding hydrated lime); (b) crop cycles with time intervals, (c) acquisition of healthy fry followed by quarantine; and (d) controlled feeding.