Abstract

Purpose The present review was done to evaluate the prevalence and subtype distribution of Blastocystis infection among small ruminants, at a global perspective. Methods Systematic search was performed in PubMed, Scopus, Google Scholar, and Web of Science until 30th January 2022 and total estimates along with 95 confidence intervals (CIs) were computed using a random-effects model. Results Ultimately, the required data were extracted from 25 papers including 19 datasets for each animal. Among 3125 sheep, the Blastocystis prevalence was 25.3 (95 CI 16.1-37.4) (10 countries), being lower in comparison to that in 2869 examined goats 20.5% (95% CI 11-35.1%) (12 countries). Regarding STs distribution, fourteen genetically diverse STs of Blastocystis (ST1-ST5, ST7, ST10, ST12, ST14, ST15, ST21, ST23, ST24, ST26) have been reported in sheep, and the highest pooled prevalence was related to ST10 11 datasets, 57.8% (95% CI 43.7-70.8%), followed by ST14 8 datasets, 28.4% (95% CI 20.2-38.4%), and ST7 2 datasets, 21.1% (95% CI 4.5-60.3%). Compared to sheep, more STs (ST1, ST3-ST7, ST10, ST12, ST14, ST21, ST23-ST26, and ST32) were reported from goats, and the highest weighted frequency was related to ST10 6 datasets, 45.1% (95% CI: 25.6-66.2%), followed by ST7 2 datasets, 40.4% (95% CI 30-51.7%), and ST14 4 datasets, 29% (95% CI 15.5-47.7%). Out of ten known zoonotic STs reported for Blastocystis (ST1-ST9, and ST12), 7 were isolated from sheep (ST1-ST5, ST7, and ST12) and 7 were reported from goats (ST1, ST3-ST7, ST12). Conclusions Overall, Blastocystis epidemiology in sheep and goats is yet to be elucidated and demands more comprehensive studies.