Geospatial analysis and epidemiological aspects of human infections with Blastocystis hominis in Mazandaran Province, northern Iran

OBJECTIVES: Blastocystis hominis is a very common large intestinal protozoan with global prevalence in humans and non-human hosts. No precise statistics exist regarding the geographical distribution of Blastocystis that would enable the identification of high-risk communities. Therefore, the current research aimed to characterize the spatial patterns and demographic factors associated with B. hominis occurrence in northern Iran. METHODS: The current study was performed among 4,788 individuals referred to health centers in Mazandaran Province, from whom stool samples were obtained. Socio-demographic data were gathered using a questionnaire. Samples were examined by a direct wet mount, the formalin-ethyl acetate concentration technique, and trichrome staining. Moran local indicators of spatial association and a geographically weighted regression model were utilized to analyze the results. RESULTS: Generally, the infection rate of Blastocystis parasites was 5.2%, and was considerably higher in the age group of 10-14 years (10.6%) than in other age groups (p=0.005). Our data showed important associations between the occurrence of B. hominis and age, residence, job, contact with domestic animals, anti-parasitic drug consumption, and elevation above sea level (p<0.001). CONCLUSIONS: The current study characterized for the first time the infection rate and risk of B. hominis in the north of Iran, and produced a prediction map. It is expected that this map will help policymakers to plan and implement preventive measures in high-risk areas and to manage already-infected patients.