[Differential diagnosis of Entamoeba histolytica from Entamoeba dispar and study on the intestinal parasites in rural areas of Ahwaz and Hamidieh]

ABSTRACT

Differential diagnosis of Entamoeba histolytica and Entamoeba dispar is important in clinical and epidemiological studies. The two organisms are morphologically identical but they differ in their genetics, biochemistry, and pathogenicity. The present study was carried out with the aim of distinguishing the two species and determining the prevalence of each organism in the rural areas of Ahwaz and Hamidieh. A total of 782 stool specimens were randomly collected and examined by formalin-ether concentration and direct methods. Twenty-one isolates of E. histolytica/ E. dispar were successfully cultured on Robinson's medium. DNA was extracted by the phenol/chloroform method and identified by PCR-RFLP after digestion with HinfI. Over 75% of the individuals were infected with at least one of the intestinal parasites. Entamoeba coli infection rates were very high [51.9%] among the population, while only 0.76% of individuals were positive for Dientamoeba fragilis. Sixty-five individual [8/3%] were infected with E. histolytica /E. dispar. The PCR-RFLP showed that 19 samples [90.48%] were positive for E. dispar; one sample [4.76%] was positive for E. histolytica and another sample [4.76%] showed mixed infection. Conclusion These findings show that the nonpathogenic E. dispar is predominant in Ahwaz and Hamidieh rural area