frequency of intestinal parasitic infections among individuals referred to the medical center laboratories in nahavand city, hamadan province, western iran

background: intestinal parasitic infections (ipis) cause serious public health problem in the world, especially those located in tropical and subtropical areas. this study was conducted with the aim of obtaining frequency of intestinal parasites in referred people to the nahavand city laboratories, hamadan province, western iran. m aterials and methods: a comparative cross-sectional study was conducted among checkup individuals and patients referred to laboratories of nahavand county. a total of 371 stool samples (150 from checkup individuals and 221 from patients) were selected by using systematic random sampling during summer 2014.  the stool specimens were examined macroscopically, and microscopically by using direct slide smear (saline wet mount and lugol staining), formaldehyde - diethyl ether concentration, trichrome staining and modified ziehl-neelsen staining techniques. the results were analyzed using spss version 16 and chi-square test. r es ults: ninety two patients (24.8%) were infected with single or multiple intestinal parasites. the overall prevalence of ipis in checkup individuals and patients was 21.3% and 27.1%, respectively. the frequency of the observed intestinal parasites was: blastocystis spp. 72 (19.4%), entamoeba coli 7 (1/9%), endolimax nana 7 (1/9%), giardia lamblia 5 (1/3%), cryptosporidium spp. 3 (0.8%), entamoeba hartmanni 3 (0.8%), entamoeba histolitica/e. dispar 1 (0.3%), trichomonas hominies 1 (0.3%), chilomastix mesnili 1 (0.3%), iodamoeba butschlii 1 (0.3% ) and enterobius vermicularis egg l (0.3%). c onclusion: the proportion of observed protozoan parasites 91 (24.5%) is higher than helminthes infection 1 (0.3%). the worm infections in nahavand city was dramatically decreased over the past decades, induced increases in public health at the community level.  blastocystis spp. was the predominant intestinal parasite in people referred to the nahavand city laboratories.  proportion of pathogenic ipis among patients 4.07% (9 of 221) was higher in compare to the checkup individuals in which only one out of 150 (0.66%) giardia lamblia was observed.