Subtype Distribution of Blastocystis in Türkiye.

Blastocystis is an anaerobic protozoan with global importance because of infecting a variety of hosts and having high prevalence in many countries. Blastocystis isolates display remarkable genetic differences, and many subtypes (STs) have currently been defined based on polymorphism in SSU rRNA coding gene. Each 25 subtype may have different characteristics such as pathogenicity, host specificity, and structural variations. Most current research on Blastocystis has focused on these differences and molecular epidemiology. This review aimed to provide a summary of Blastocystis subtype distribution in Türkiye. Regarding human samples, 16 manuscripts were found in the literature, which presented 783 Blastocystis isolates from 9 cities in Türkiye. The most common subtype was ST3 (47.9%), the others were ST1 30 (17.5%), ST2 (14.7%), ST4 (4%), and ST5-ST7 (15.9%). There were few studies on animal hosts and environmental samples. The faecal samples from rats, farm, and pet animals were examined for Blastocystis subtypes and ST1, ST3, ST4-ST7, ST10, and ST12-ST14 were reported. In addition, two studies reported Blastocystis ST1 and ST3 subtypes in environmental water samples. In conclusion, the review of available literature showed that a systematic understanding of the subtype distribution of 35 Blastocystis in Türkiye is still lacking. Most of the studies were performed in a limited number of cities, animal hosts, and environmental samples, therefore, more studies from different provinces are needed in forthcoming research. The majority studies were performed in a limited number of provinces, animal species and very few environmental samples, so in the future; there is a need of novel studies that evaluate more samples from different provinces.