Molecular prevalence of Blastocystis sp. and subtype diversity in fecal samples collected from cattle in dairy farms in Turkey.

Close contact with infected animals is one of the main risk factors for zoonotic transmission of enteric protozoan parasite Blastocystis and thus, several animal species are being screened for the detection of the zoonotic subtypes. For this purpose, 22 fecal samples were collected from healthy cattle aged > 2 months and 39 fecal samples were also collected from cattle (aged <2 months) which are treated with TMP-SMX due to diarrhea. Later, Blastocystis sp. and subtypes were investigated by a PCR targeting the SSU rRNA gene and subsequently by sequencing. Among the 22 fecal samples collected from healthy cattle, Blastocystis was detected in 12 of them with a prevalence rate of 54.5 %. Among Blastocystis-positive samples, five different subtypes (ST3, ST5, ST10, ST12, and ST13) were detected. The predominant subtype was ST10 (allele 152) with a prevalence rate of 50 % (6/12). In the other group treated with TMP-SMX due to diarrhea, Blastocystis was detected in only one (2.56 %;1/39) fecal sample and its subtype was ST1 (allele 2). High prevalence of Blastocystis as well as predominance of ST10 (allele 152) were detected in healthy cattle. The identification of zoonotic ST1, ST3, ST5 and ST12 subtypes among the detected subtypes with a high prevalence (46.1 %; 6/13) showed the importance of cattle as a source for transmission of Blastocystis to humans. It was observed that the efficiency of TMP-SMX on the clearance of Blastocystis in cattle was very strong. Moreover, to our knowledge, this is the first study detecting Blastocystis ST13 subtype in the cattle.