Genetic characterization of cryptosporidium spp. among children with diarrhea in Tehran and Qazvin Provinces, Iran

Cryptosporidium is an intracellular apicomplexan parasite that infects a wide range of vertebrates including humans. Cryptosporidiosis is a major cause of diarrhea in children with and without human immunodeficiency virus [HIV] infection in developing countries. More recently, the molecular methods for identification of morphologically indistinguishable species have been developed. The aim of this study was to determine the characterization of various species of this coccidian among children with diarrhea by using molecular methods. Fecal samples were collected from 1263 children with diarrhea who referred to Pediatrics Medical Centers in Qazvin and Tehran, two central provinces of Iran. Initial identification of Cryptosporidium was carried out by Zeihl-Neel-sen acid-fast staining method of stool samples. DNA was extracted from positive microscopically samples and were subjected to a two step nested PCR-RFLP based on SSU-rRNA gene. Out of 1263 collected samples, 31 [2.5%] were found to be contained Cryptosporidium oocysts. RFLP analysis showed that 80.6% of the positive isolates were Cryptosporidium parvum, 16.1% C. hominis and 3.2% had mix infection pattern of both C. parvum and C hominis. Our results showed that the zoonotic pattern of transmission is predominant and has considerable significance in epidemiology of Cryptosporidiosis in the study areas

Prevalence of Entamoeba histolytica and Entamoeba dispar in gonbad city, 2006, Iran

Differential diagnosis of two protozoan parasites Entamoeba histolytica and E. dispar is of great clinical and epidemiological importance, but except in the case of haematophagous trophozoites in acute dysentery, it is not possible to differentiate them by microscopy. The present study was carried out from February 2005 to July 2006 in order to determine the prevalence of E. histolytica and E. dispar in Gonbad City, by using a PCR method. Five hundred and sixty four fecal samples were collected from primary health care centers of Gonbad both urban and rural areas. The stool specimens were examined by light microscopy [Direct slide smear, Iodine wet mount, Formal-ether concentration and Trichrome staining] to distinguish E. histolytica/E. dispar complex and differentiate them from other non-pathogenic intestinal amoebae. The microscopy results of stool exams showed a frequency rate of 23 positive samples [4.07%] for cyst of E. histolytica/E. dispar complex. All the microscopy positive isolates appeared to be infected with cyst of E. histolytica/E. dispar complex were cultivated and maintained successfully in HSr + s medium for DNA extraction and identification by the PCR method. The PCR study showed that 16 isolates [69.56%] of the Entamoeba samples were E. dispar while 7 samples [30.43%] of those microscopy positive samples were not amplified and none of them showed E. histolytica pattern. High frequency rate of E. dispar in this study were in high agreement with the estimation rate of these entamoebas worldwide