Diagnosis of Centrocestus formosanus Infection in Zebrafish (Danio rerio): A Window on a New Globalization-Derived Invasive Parasite

Abstract

AbstractCentrocestus formosanusis a digenetic trematode with a complex life cycle, involving invertebrate and vertebrate hosts, humans included. In particular, it causes gill lesions and mortality in freshwater fish species, and gastrointestinal symptoms in infected humans. Here,we describe the occurrence of C. formosanus infection in zebrafish imported in Italy. Gill arches of 30 zebrafish were examined for the presence of encysted metacercariae under a stereomicroscope, and processed through molecular analyses targeting the ribosomal Internal Transcribed Sequence 2 (ITS2) using species-specific primers of C. formosanus. Encysted metacercariae were found on the gills of 20/30 zebrafish and all were identified as C. formosanus.Despite C. formosanus distribution was originally restricted to Asia, it has been subsequently reported in new countries, revealing itself as an invasive species, and raising important concerns for biodiversity, economy, animal and public health. Given the crucial role likely played by the ornamental fish industry in the spreading of this parasite, there is an urgent need for control measures to prevent the introduction and establishment of C. formosanus in non-endemic areas, Europe included. An adequate surveillance and health-monitoring program should be conducted in the development of microbiological and epidemiological approaches to diagnose and face these new globalization-derived invasive species.