A large-scale study on the prevalence of intestinal parasites in patients referred to medical laboratories in Urmia, Northwest Iran

INTRODUCTION: Intestinal parasitic infections (IPIs), caused by helminths and protozoans, are among the most prevalent infections in humans in developing countries. This study aimed to determine the prevalence of IPIs in patients referred to three educational and medical centers affiliated with Urmia University of Medical Sciences in Urmia. MATERIALS AND METHODS: In this cross-sectional study, 2845 stool samples, including 2174 (76.4%) males and 671 (23.6%) females, were collected from patients referred to Imam Khomeini and Shahid Motahhari hospitals and Shahid Nikkhah Health Center in Urmia, Northwest Iran, from January 2020 to February 2022. The microscopic examination for IPIs was carried out using the wet mount method, and the hard-to-identify samples were stained by trichrome for accurate identification of protozoa. For diagnosis of infections by coccidian parasites modified Ziehl-Neelsen (mZN) staining was used. RESULTS: Based on the results, two hundred nine intestinal parasites were identified in 184 out of 2845 (6.5%) patients of which 136 out of 2174 males (6.3%) and 48 out of 671 females (7.2%) were positive. Some patients had tested positive for multiple protozoa. The observed intestinal protozoa are as follows: Blastocystis spp. 118 (4.1%), Endolimax Nana 42 (1.5%), Entamoeba coli 24 (0.8%), Giardia lamblia 13 (0.5%), Cryptosporidium spp. 6 (0.2%), Iodamoeba butschlii 3 (0.1%), Chilomastix mesnili 2 (0.1%), and an accidentally detected helminthic infection Enterobius vermicularis 1 (0.05%). CONCLUSION: According to the results, the most prevalent IPIs in West Azerbaijan Province are caused by Blastocystis spp., and Giardia lamblia. Most intestinal protozoa observed in the study were nonpathogenic and commensal, which shows water or food contamination in the area. Thus, medical technologists in the parasitology section must be trained and aware of IPIs in medical laboratories.