EN
The aim of this study was the isolation of diplomonads from the digestive tract of infected rainbow trout (Oncorhynchus mykiss) and the molecular identification of Spironucleus species from samples. Samples were collected from a total of 40 fish (0.8 g ± 0.1) from a commercial farm in Pomorskie Voivodeship, Poland. Polymerase chain reaction (PCR) and a partial sequence analysis of the 18S ribosomal gene were used to identify Spironucleus species. The PCR of the 18S rDNA yielded a 705 bp DNA band on agarose gel, and a sequence analysis of the DNA confirmed the isolate as Spironucleus salmonis. This is the first molecular identification of an isolate of S. salmonis in Poland. Further studies are needed to determine the prevalence of the parasite in this species of fish in other locations and to investigate the impact of the parasite on the total fish population.