Asian Fish Tapeworm (Schyzocotyle acheilognathi) Found in New York State for the First Time After a Long-Term Fish-Parasite Survey

The first report of Asian fish tapeworm (AFT), Schyzocotyle acheilognathi (Yamaguti, 1934) Brabec, Waeschenbach, Scholz, Littlewood and Kuchta, 2015, is provided for New York State. This finding resulted from a long-term fish parasite survey in various water bodies in Otsego County in central-east New York that took place during 2008–2018. In total, 1,637 individual fish representing 44 species were examined for AFT, with 4 (9%) of the 44 species of fish infected with S. acheilognathi. These 4 species were all cyprinids: Notemigonus crysoleucas (golden shiner), Notropis heterodon (blackchin shiner), Pimephales promelas (fathead minnow), and Semotilus atromaculatus (creek chub). Among these host species, the prevalence of Schyzocotyle acheilognathi was highest in Notemigonus crysoleucas, with 19 (15.7%) of 121 fishes infected. The infection in Notropis heterodon constitutes a new host record for S. acheilognathi. The observed occurrence of S. acheilognathi only in cyprinid species was generally consistent with previously reported infection patterns for this cestode, but we note that AFT was absent from multiple fish species in our survey that had elsewhere been reported as hosts. The source of AFT for water bodies in Otsego County, New York is unknown, but bait-bucket introduction of infected Notemigonus crysoleucas is considered a possible explanation. This study contributes to a growing body of molecular data for this highly invasive tapeworm by providing sequence data for 2 markers (large ribosomal subunit, 28S, and cytochrome c oxidase I) for 6 specimens.