The Asian fish tapeworm Schyzocotyle acheilognathi is widespread in baitfish retail stores\xa0in Michigan, USA

Seth J Herbst,Mohamed Faisal,Thomas P Loch,Gary E Whelan,Traimat Boonthai,Michelle Gunn Van Deuren

doi:10.1186/s13071-017-2541-6

Seth J Herbst, Mohamed Faisal + Show 4 more

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https://doi.org/10.1186/s13071-017-2541-6

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Abstract

BackgroundThe Asian fish tapeworm Schyzocotyle acheilognathi (Yamaguti, 1934) is an important fish pathogen because of its wide range of intermediate and definitive hosts and its pathological consequences. This study was designed to determine if baitfish are a likely vector contributing to the expansion of the invasive Asian fish tapeworm.ResultsWe collected live baitfish for examination from 78 retail stores in Michigan between September 2015 and June 2016. A total of 5400 baitfish (90 lots, 60 fish/lot) were examined, including 42 emerald shiners [Notropis atherinoides (Rafinesque, 1818)] lots, 30 fathead minnow [Pimephales promelas (Rafinesque, 1820)] lots, 11 golden shiners [Notemigonus crysoleucas (Mitchill, 1814)] lots, 3 sand shiners [Notropis stramineus (Cope, 1865)] lots, 1 lot each of spottail shiners [Notropis hudsonius (Clinton, 1824)], Northern redbelly dace [Phoxinus eos (Cope, 1861)], and blacknose dace [Rhinichthys atratulus (Hermann, 1804)] and 1 lot of mixed two species: weed shiners [Notropis texanus (Girard, 1856)] and sand shiners.ConclusionsBased on its scolex and strobilar morphology combined with gene sequence analysis, S. acheilognathi was only found in emerald shiners, golden shiners and sand shiners. The mean within lot prevalence and abundance of infection was highest in emerald shiners (20.3 ± 14.0 and 1.15 ± 1.34), followed by golden shiners (8.3 ± 10.7 and 0.89 ± 1.27) and sand shiners (1.3 ± 2.6 and 0.02 ± 0.05). However, the mean intensity of S. acheilognathi in emerald shiners was lower (4.3 ± 2.6) than that of golden shiners (6.6 ± 6.7). S. acheilognathi-infected fish exhibited enlargement of the abdomen, distension of the intestinal wall, and intestinal occlusion and hemorrhage. This finding suggests that live baitfish are a likely vector by which the invasive Asian tapeworm’s range is expanding.

Highlights

The Asian fish tapeworm Schyzocotyle acheilognathi (Yamaguti, 1934) is an important fish pathogen because of its wide range of intermediate and definitive hosts and its pathological consequences
Based on morphological identification combined with gene sequence analysis, S. acheilognathi was identified in emerald, golden and sand shiners, but not in any fathead minnow, spottail shiner, northern redbelly dace, blacknose dace, or weed shiner lots that were examined in this study (Table 1)
Asian fish tapeworm identification The anterior portion of intestine was the site where S. acheilognathi was attached to the intestinal walls, whereas their bodies extended throughout the entire length of the intestine

Summary

Introduction

The Asian fish tapeworm Schyzocotyle acheilognathi (Yamaguti, 1934) is an important fish pathogen because of its wide range of intermediate and definitive hosts and its pathological consequences. In the Great Lakes region, the spread of the invasive Asian fish tapeworm, Schyzocotyle acheilognathi (Yamaguti, 1934) Brabec, Waeschenbach, Scholz, Littlewood & Kuchta, 2015 (Cestoda: Bothriocephalidae) (formerly Bothriocephalus acheilognathi [7]) is a great concern among managers. Schyzocotyle acheilognathi is indigenous to East Asia and was reported in the USA for the first time in 1975 [10] This parasite has since spread to multiple states and watersheds [11, 12] where it threatens some endangered and threatened wild fish species [13, 14], as well as farmed fish [15]

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