ABSTRACT
A total of 1500 people, including 1273 children with various gastrointestinal tract diseases and 327 patients with chronic viral hepatitis C, were examined. Microscopy and polymerase chain reaction (PCR) were used to determine Blastocystis in the feces. Blastocysts were detected in 33% of the patients with chronic viral hepatitis C and in 4.9% of the children. Genotyping established that Blastocystis species subtype 3 (antroponous) was encountered relatively rarely (25%) in these patients; there were most common Blastocystis species subtypes 5 (36.1%) and 6 (36.1%). Significant intestinal dyspepsia was noted in all the patients with chronic hepatitis C and Blastocystis invasion. Blastocystis species subtype 3 was prevalent (62.3%) among the examined children. The other subtypes were less frequently detected. These were subtype 1 (29.5%), subtype 2 (24.3%), subtype 4 (1.3%), and subtype 7 (3.8%) whereas subtype 5 and subtype 6 were not found in any case. The comparison of clinical symptoms in children could reveal the following tendency: there were digestive disorders and skin allergic reactions with Blastocystis species subtype 1 and subtype 2, respectively.