Frequency of enteric protozoan parasites among patients with gastrointestinal complaints in medical centers of Zahedan, Iran.

We investigated the prevalence of intestinal protozoan parasites in patients with gastrointestinal complaints in medical centers in Zahedan, Iran. A total of 1562 stool samples was examined from July 2004 to January 2006 using microscopy (direct smear, formalin-ether concentration), xenic culture and PCR techniques. Four hundred and twenty-seven (27.3%) of the patients were infected with one or more intestinal parasites. Giardia lamblia (10.1%), Entamoeba coli (10%), E. hartmanni (1.7%), Blastocystis hominis (2.2%), Chilomastix mesnili (1.7%), Trichomonas hominis (0.7%), E. histolytica/E. dispar (0.51%) and Iodamoeba butschlii (0.45%) were the most prevalent protozoa detected with microscopy. Of the eight microscopy-positive E. histolytica/E. dispar samples, six were identified as E. dispar by PCR/gel electrophoresis, whereas E. histolytica was not detected at all. Although Zahedan is an area with poor hygiene located in a tropical area near the border of Pakistan and Afghanistan, the prevalence of E. histolytica and E. dispar here compared with other parasites and infectious diseases is unexpectedly low.