Blastocystis SSU rRNA alignment

<p><i>Blastocystis</i> is a cosmopolitan protist inhabiting the human intestine; which prevalence varies between non-industrial and industrialized countries. Its role in the human gut ecosystem remains unclear due to persisting gaps in knowledge of epidemiology and factors affecting gut colonization. The aim of this study was therefore to expand the knowledge of the epidemiology of <i>Blastocystis</i> in the gut-healthy humans in one of the industrialized European countries, including the distribution of its subtypes, the correlation between its occurrence and several factors such as lifestyle, contact with animals, age and sex. A total of 288 stool samples were obtained from non-symptomatic individuals over the entire age-range and 136 samples from animals with which the volunteers were in frequent contact. All samples were examined in parallel by PCR and xenic culture. <i>Blastocystis</i> was detected in samples from both human and non-human hosts. In humans, the overall prevalence was 24% and eight subtypes were found, whereas in animals the prevalence was 10% and only five subtypes were detected. For factors, there was a higher incidence of <i>Blastocystis</i> in individuals traveling outside Europe who were in frequent contact with livestock and over 50 years of age. We found no effect on gender.</p>