Parasitic infections of two invasive fish species, the Caucasian dwarf goby and the Amur sleeper, in Hungary

Parasitic infection of Cobitis elongatoides Băcescu & Mayer, 1969 by zoonotic metacercariae Clinostomum complanatum (Rudolphi, 1814)

An infection of zoonotic Clinostomum complanatum metacercariae with potential human transmission was recorded close to fish farms in the Tisa River Basin of Slovakia and Ukraine. The prevalence varied from 19.4% to 81.3%, and the intensity of infection varied from 7 to 41. The results of a generalized linear model predicted a positive trend for the Cobitis elongatoides host and a standard length and intensity of infection, with females having a higher number of parasites. However, no significant impact was found of the intensity of infection on Clark's condition of the host. The metacercariae were primarily located in the anterior part of the host's body. Our study also showed significant evidence that water velocity affects the number of C. complanatum metacercariae, regardless of the host's (Cobitis) microhabitat.

The Phylogenetic Position of Spironucleus sp. (Diplomonadida: Hexamitidae) from the Intestine of Chinese Sleeper Perccottus glenii Dybowski, 1877 (Actinopterygii: Odontobutidae)

INTRODUCTION

The Chinese (Amur) sleeper (Perccottus glenii Dybowski, 1877) (Actinopterygii: Odontobutidae) is a freshwater fish species with high invasive potential. Diplomonads have been detected in the intestines of Chinese sleepers using light microscopy.

AIM

The aim of this study was to identify the diplomonads in Chinese sleepers using molecular-genetic methods.

MATERIALS AND METHODS

The fish used in this analysis were caught in the following bodies of water in Russia between 2014 and 2016: Lake Dolgoe, the floodplain of the Ingoda River (Amur River basin), the Tsna River (the Oka River basin), and the littoral of the Kotlin Island (Gulf of Finland). Partial sequences of small subunit rRNA genes were obtained for the intestinal diplomonads of Chinese sleeper.

RESULTS

The analysis of all sequenced samples revealed the presence of Spironucleus salmonis Moore, 1922; other Spironucleus species were not found in the sampled fish. With 82% probability, the sampled sequences of diplomonads from Chinese sleeper formed a separate cluster in the clade of S. salmonis on the phylogenetic tree.

CONCLUSION

This is the first record of S. salmonis in fish in the family Odontobutidae.

Parasite communities and infection levels of the invasive Chinese sleeper Perccottus glenii (Actinopterygii: Odontobutidae) from the Naab river basin, Germany

The Chinese sleeper (Perccottus glenii), an invasive Asian fish, was first registered in Germany in 2009 (westernmost extent of its invasive range). We sampled Chinese sleepers from two localities on the Bücherlgraben creek (a tributary of the River Naab) in south-eastern Germany in November 2015 and examined them for parasite infection. Twelve taxa were registered, including ciliates (unidentified Trichodina), a monogenean, three cestode species, two digenean taxa, two acanthocephalan species, two nematode species and one mollusc glochidia. Infracommunities consisted of 1-5 species, with 10% of fish uninfected. Three parasite species (Acanthocephalus anguillae, Gyrodactylus luciopercae and Pseudocapillaria tomentosa) were recorded on Chinese sleepers for the first time. The results highlight the important role of the Chinese sleeper as a second intermediate host in the life cycle of heron and grebe parasites. The Chinese sleeper parasite community displayed low homogeneity at both localities sampled, with allogenic parasites (metacercariae and mesocercoids) mostly shared. Differences between localities were mainly caused by autogenic parasites. No invasive parasites associated with the Chinese sleeper were observed in the study area, all parasites being representatives of European fauna. This supports the hypothesis of introduction via the aquarium trade or through transport with commercial fish.