Zoonotic parasites in common freshwater fish species in Serbia

Abstract

The Sava and Danube rivers are the source of freshwater fish species sold at the markets in Serbia. As only a few reports from Serbia on zoonotic parasites transmitted by fish have been published, the risk to consumers and the role of fish in the transmission of parasites to terrestrial hosts is not well established. For this study, fish fillets were cut for examination for plerocercoids of diphyllobothriids and Spirometra spp. The coelom, internal organs and musculature were inspected for Eustrongylides spp. larvae. Fillets were pooled by species and location and artificial digestion using trypsin was performed. The digested sediment was examined by microscopy prior to DNA extraction and detection of Metagonimus spp., Apophallus spp., Methorchis spp. and Opistorchis spp. by PCR. A total of 85 (48 from the Danube, 37 from the Sava River) specimens of European perch (Perca fluviatilis, n=14), common roach (Rutilus rutilus, n=30), common bream (Abramis brama, n=27), vimba bream (Vimba vimba, n=9), and white-eyed bream (Ballerus sapa, n=5) were examined. Eustrongylides spp. larvae were detected in 10/14 European perch (8/12 from the Danube, 2/2 from the Sava), and in 1/10 common bream from the Sava. Metacercariae were visually detected in pools of the common roach and vimba bream from the Sava. PCR confirmed the presence of Metagonimus spp. in the common bream from the Sava and Danube as well as the common roach from the Danube. The results suggest that European perch are heavily parasitized by Eustrogylides spp., as evident in some fish from the Danube. DNA of Metagonimus spp. with confirmed zoonotic potential was detected in common bream and roach. These findings indicate that fish caught for human consumption in the two largest rivers in Serbia may be a source of zoonotic parasites.