Subtype distribution of Blastocystis sp. isolated from humans in Iran: a systematic review and meta-analysis

AIM: This systematic review and meta-analysis evaluated the subtyped Blastocystis sp. isolated from humans in Iran. BACKGROUND: Blastocystis sp. is an anaerobic intestinal protozoan that infects humans as well as domestic and wild animals, i.e. mammals, amphibians, reptiles, and arthropods. METHODS: A comprehensive search for papers published before April 2022 was undertaken utilizing English and Persian databases. The following MeSH keywords were used in the electronic search: (Blastocystis sp.) AND (molecular OR subtype) AND (prevalence OR epidemiology) AND Iran. The quality of the included studies was evaluated. Thereafter, a random-effects meta-analysis was conducted to estimate the pooled prevalence and odds ratios regarding the included studies. RESULTS: A total of 32 studies comprised of five case-control studies and 27 cross-sectional studies met the eligibility criteria. The overall pooled prevalence of subtyped Blastocystis sp. in Iran was estimated to be 10% (95% confidence interval: 6 to 15%). Eight subtypes of Blastocystis sp. (ST1- ST7 and ST9) were identified in our study, of which ST3 was the most common subtype (0.04); 0.02-0.07). The difference in subtypes between two case and control groups in reported studies was not significant, but the odds ratio of infection by ST3 (0.98; 95% CI, 0.30 to 3.20) was higher in cases. CONCLUSION: The current systematic review showed that with the exception of ST8 and ST12, all human Blastocystis sp. subtypes reported in the world are found in different parts of Iran.