LAUSR

Background: Blastocystis sp., located in the large intestine, is one of the most common zoonotic parasites. Risk factors affect its prevalence and pathogenicity, and it causes gastrointestinal disorders. Thus, this study aimed to investigate the Blastocystis sp. prevalence and its relationship with gastrointestinal disorders, in patients referred to laboratories, and provide some prevention strategies. Methods: In this descriptive-analytical study, 1,000 stool specimens were collected from patients referred to Ilam, Iran laboratories from 2018–2019. Wet mount method was conducted on samples, and suspected specimens were confirmed using trichrome staining. The demographic and clinical information was recorded in a questionnaire. Finally, the results were analyzed using the SPSS. Results: Blastocystis infection was detected in 81 out of 1,000 patients (8.1%) including 61 (75.3%) males and 20 (24.7%) females. and illiterate people were more at risk. The prevalence in rural was more than urban areas, and it was more in the age group of 31–50 year. Conclusion: There was a significant relationship between Blastocystis sp. and risk factors (age, sex, level of education, and residence) and clinical symptoms (stomach ache and nausea) (P<0.05), but interestingly there was no significant relationship between bloating and diarrhea.