Studies on the presence of Blastocystis subtypes in water samples are far less numerous compared with stool samples. The main aim of this study was to examine the occurrence of Blastocystis subtypes in 36 natural water bodies in north-western Poland in the period from winter 2009 to autumn 2010. Single PCR with the use of Blast 505-532/Blast 998-1017 set of primers was used to detect Blastocystis DNA in the obtained water samples. Sequencing of the obtained amplicons revealed the presence of ST1 and ST3 subtypes in five of the 36 (13.9%) examined water bodies within 1 year period. Further examinations with the use of new samples are needed in order to check if Blastocystis occurs in the examined water bodies at the present time, however, the risk of infection should be taken into consideration.
Keywords: Blastocystis; SSU rRNA gene; monitoring; subtypes; water.