prevalence of intestinal parasites in patients with gastrointestinal symptoms by focus on soil-transmitted helminthes infection

aim : the aim of this study was to determine the prevalence of soil-transmitted helminth infections (sths) infection and other intestinal parasites in patients with gastrointestinal (gi) symptoms in tehran province, iran. background : the world health organization (who) suggests that many people in the world are chronically affected by sths and intestinal parasites. furthermore infection is closely correlated with poverty, poor environmental hygiene and impoverished health services. patients and methods : in this cross-sectional study, random stool samples from 912 patients with gi symptoms were collected and examined using light microscopy and the formalin-ether concentration method for detection of protozoa and of sth eggs. also modified acid-fast staining was used to identify cryptosporidium parvum .  agar plate cultures were used for the recovery of strongyloides stercoralis larvae. results : sth infections found in these patients were ascaris lumbricoides 5(0.5%), hookworm 3(0.3%), hymenolepis nana 14(1.5%), enterobius vermicularis 3(0.3%). the prevalence of protozoan parasites were 46 (5.1%), for entamoeba coli, 31 (3.4%) for blastosystis hominis, 27 (3%) for giardia lamblia, 25 (2.74%) for endolimax nana, 20 (2.2%) for entamoeba histolytica/entamoeba dispar complex, 12 (1.31%) for iodomoeba butchelii 9, (1%) for chilomastix mesenelli, and 7 (0.8%) cryptosporidium parvum . conclusion : a significant relationship was found between age group, location and educational achievement with sth infection but no statistical correlation was seen between demographic parameters and gi symptoms with intestinal protozoan parasites.  the result of this study showed that, even in tehran province with a relatively high level of social hygiene, it is possible to find a high level of sth and intestinal protozoan infections.