Distribution of Blastocystis subtypes isolated from humans from an urban community in Rio de Janeiro, Brazil.

Background: Blastocystis is a cosmopolitan protist parasite found in the human gastrointestinal tract and is highly prevalent in developing countries. Recent molecular studies have revealed extensive genetic diversity, which has been classified into different subtypes (STs) based on sequence analysis of small subunit ribosomal RNA gene. Blastocystis is one of the most common fecal parasites in Brazil, but the diversity of subtypes remains unknown in the country.