Blastocystis spp. subtypes and other enteroparasites in vulnerable urban and rural communities: a prevalence study

Blastocystis spp. is the most common protist found in the global population, with an estimated prevalence of one billion infected individuals, primarily in developing countries. However, its role as a pathogen has been a subject of significant debate. Some studies have shown a high prevalence of this parasite among people living in socioeconomic vulnerability in certain regions of Brazil. Methodology: 96 fecal samples were collected from participants in two low-income communities in the State of Rio de Janeiro to determine the prevalence of Blastocystis spp. and its subtype distribution. Fecal samples were processed using the Hoffman Pons & Janer and Rugai techniques. Aliquots of unpreserved samples were used to identify Blastocystis spp. subtypes through PCR. Results: Gastrointestinal parasites were detected in 70% (67/96) of the samples. Blastocystis spp. was the most prevalent with a higher prevalence in urban areas (64.3%; 36/56) compared to rural areas (50%; 20/40). Endolimax nana was the second most common, with prevalence of 21.4% (12/56) in urban areas and 30% (12/40) in rural areas. Ascaris lumbricoides and Trichuris trichiura infections were exclusively found in rural areas, while Urbanorum spp. infections were detected in urban areas. Subtype analysis revealed ST1 was the most frequent in urban areas while in rural areas, ST1 and ST3 predominate. The study suggests that Blastocystis spp. was the most prevalent with a lower frequency of other intestinal parasites. Conclusions: This research highlights a possible link with socioeconomic factors, underscoring the need for improved sanitation infrastructure in these communities.