Molecular Epidemiology, Subtype Distribution, and Zoonotic Importance of Blastocystis sp. in Camelids (Camels and Alpacas): A Worldwide Systematic Review and Meta-Analysis

Focusing on the global epidemiology and subtype distribution of Blastocystis sp. in camelids (camels and alpacas), the present systematic review and meta-analysis was conducted. Utilizing relevant keywords, a thorough search was conducted on four electronic databases (PubMed, Scopus, Google Scholar, and Web of Science) with no time constraints up to April 1, 2024. Total estimates and 95% confidence intervals (CIs) were subsequently calculated using a random-effects model. Finally, 11 studies with 18 datasets provided the required data. The global prevalence of Blastocystis sp. in camelids was estimated at 22%, with a 95% CI of 17.2-27.6%. Among 1061 camels, the pooled prevalence of Blastocystis sp. was 21.6% (95% CI: 16.6-27.6%) across 5 countries, which was lower than the 23.5% (95% CI: 12.2-43.1%) found in 449 tested alpacas across 3 countries. Camels were found to carry 15 genetically diverse subtypes (STs) of Blastocystis sp. (ST1-ST7, ST10, ST14, ST15, ST21, ST24, ST25, ST26, and ST30). Among these, ST10 exhibited the highest pooled prevalence [five datasets, 38.3% (95% CI: 22.4-57.1%)], followed by ST1 [three datasets, 24% (95% CI: 6-61.2%)] and ST14 [four datasets, 15.2% (95% CI: 6.7-31%)]. Alpacas exhibited three distinct STs (ST5, ST10, and ST14). Among these, ST10 [four datasets, 50.3% (95% CI: 33.3-67.3%)] had the greatest weighted frequency, with ST14 [four datasets, 40.2% (95% CI: 23.8-59.1%)] following closely behind. Of note, 9 zoonotic STs (ST1-ST7, ST10, and ST14) have been identified in camels and 3 in alpacas (ST5, ST10, and ST14) out of the 16 zoonotic STs (ST1-ST10, ST12, ST14, ST16, ST23, ST35, and ST41) of Blastocystis sp. reported to date. Overall, camelids (camels and alpacas) can serve as a diverse reservoir for various Blastocystis sp. STs, potentially contributing to infections in humans, animals, and water sources. Nevertheless, research in this area is somewhat restricted, necessitating careful interpretation of the findings.