Trypanosoma; blood parasites; mixed infections; phylogeny; 18S rRNA; teleosts

One thousand three hundred seventy three fish specimens of eight different species from the vicinity of Kyiv, Ukraine, were examined for the presence of trypanosomes and 921 individuals were found to be infected. The prevalence of infection ranged from 24% in freshwater bream, Abramis brama (Linnaeus), to 100 % in spined loach, Cobitis taenia' Linnaeus. The level of parasitaemia also varied significantly between generally mild infections in pikeperch, Sander lucioperca (Linnaeus), and heavy ones in C. taenia'. In most cases the infections with trypanosomes were asymptomatic. Cases of co-infection with species of Trypanoplasma Laveran et Mesnil, 1901 were documented for five out of eight examined host species.