[Identification of Fasciola species by PCR-RFLP assay in northern Iran]

Background and Objective: Identification ofFasciola species is important. Fascioliasis is one of the important diseases in animals and humans caused by genus Fasciola. This study was done to determine the identification of Fasciola species with RFLP-PCR in animal liver in Gorgan City, northern Iran

Methods: In this descriptive study, worms were obtained from the livers of infected sheep and cattle in Gorgan slaughterhouse in northern Iran. DNA of worms was extracted with phenol- chloroform method. Fragment of ITS-1 genome was amplified and TasI enzyme was utilized for amplified fragments then 8 samples were sequenced

Results: A total of 49 Fasciola worms were isolated from infected cattle and sheep. The PCR products of all specimens were affected by the TasI enzyme, and F.hepatica species showed two fragments and F.gigantica species indicated three fragments. The enzyme in F.hepatica species showed a fragment of 151 bp and a fragment of 312, but in the F.gigantica, three fragments were 151, 93 and 219 bp. 36 [73.46%] worms were identified as Fasciola gigantica and 13 [26.53%] worms were identified as Fasciola hepatica. Out of the six infected sheep liver, 22 were isolated from the Fasciola worms, 13 [59.1%] of which were F.hepatica and 9 [40.9%] of them were F.gigantica. Out of the six infected cattle liver, 27 Fasciola worms were identified, all of which were identified as Fasciola gigantica [100%]

Conclusion: This study showed that Fasciola gigantica is the dominant species in infected livers of the cattle in Gorgan city

Chemical stability of Bioglass in simulated oral environment

Statement of Problem: bioglasses are a series of biocompatible dental materials, which are considered as light conducting inserts in resin composite restorations. Consequently, their chemical stability is more essential when they are used in conjunction with resin composite

Objectives: the aim of this study was to evaluate and compare the chemical stability of Bioglass with dental porcelain and resin composite by determining the amount of released K[+], Na[+], Ca[2+] ions and silicone elements from these materials as a result of exposure to tested solutions with different pH levels including: Sodium Bicarbonate [SB, [pH=9.2]], Sodium Buffer Lactate [SBL, [pH=2.4]], Acetic Acid [AA, [pH=2.4]], and Distilled Water [DW, [pH=6.2]]

Materials and Methods: in this experimental study, forty 2.0 × 4.0 cylindrical rods for each tested material group [Dental porcelain, Resin composite and Bioglass] were prepared. They were divided into four subgroups of 10 rods each, which immersed in one of the four testing solutions in a designated container. The containers were stored at 50 [degree]C and 100% humidity for one week. The released ions were measured by using a spectrophotometer [[micro]g/cm[2]/ml]. The data were statistically analyzed by nonparametric Kruskal-Wallis H test

Results: it was observed that the tested materials released ions at different levels of concentration. The significant amounts of Sodium, Calcium, and Silicon ions release were measured in Bioglass subgroups in all the tested solutions [p < 0.001]. Potassium ion release from dental porcelain was the largest in all solutions except for AA in which Bioglass had the greatest potassium ion release [p < 0.001]

Conclusions: a greater structural instability was observed for Biogalss group than dental porcelain and resin composite in testing solutions with different pH levels

Effect of self-etch adhesives on self-sealing ability of high-copper amalgams

Statement of the Problem: Similar to conventional amalgam, high-copper amalgam alloy may also undergo corrosion, but it takes longer time for the resulting products to reduce microleakage by sealing the micro-gap at the tooth/amalgam interface

Purpose: The aim of this study was to evaluate the effect of self-etch adhesives with different pH levels on the interfacial corrosion behavior of high-copper amalgam restoration and its induction potential for self-sealing ability of the micro-gap in the early hours after setting by means of Electro-Chemical Tests [ECTs]

Materials and Method: Thirty cylindrical cavities of 4.5mm x 4.7mm were prepared on intact bicuspids. The samples were divided into five main groups of application of Adhesive Resin [AR]/ liner/ None [No], on the cavity floor. The first main group was left without an AR/ liner [No]. In the other main groups, the types of AR/liner used were I-Bond [IB], Clearfil S[3] [S[3]], Single Bond [SB] and Varnish [V]. Each main group [n=6] was divided into two subgroups [n=3] according to the types of the amalgams used, either admixed ANA 2000 [ANA] or spherical Tytin [Tyt]. The ECTs, Open Circuit Potential [OCP], and the Linear Polarization Resistance [LPR] for each sample were performed and measured 48 hours after the completion of the samples

Results: The Tyt-No and Tyt-IB samples showed the highest and lowest OCP values respectively. In LPR tests, the R[p] values of ANA-V and Tyt-V were the highest [lowest corrosion rate] and contrarily, the ANA-IB and Tyt-IB samples, with the lowest pH levels, represented the lowest R[p] values [highest corrosion rates]

Conclusion: Some self-etch adhesives may increase interfacial corrosion potential and self-sealing ability of high-copper amalgams

study of hematological changes in sheep naturally infected with Anaplasma spp. and Theileria ovis: Molecular diagnosis

Ovine anaplasmosis and theileriosis are important tick-borne diseases of sheep and goats which are dis-tributed in the tropical and subtropical areas of the world. This study was performed to assess hematological status in sheep naturally infected with Anaplasma and Theileria spp. to clarify the pathogenic aspects of various species involved in ovine anaplasmosis and theileriosis in Ahvaz region. 109 sheep were sampled, and blood parasite infections were diagnosed by microscopic examination and PCR. The blood samples were also subjected to hematologic assessment. PCR analysis revealed A. ovis infection in 86.2% of sheep, while mixed infections with A. marginale were also detected in 53.2% of them. However, Anaplasma inclusion bodies were only observed in 32.1% of the tested animals. T. ovis were found in 88% of the inspected sheep by PCR, and 67.8% of them were detected microscopically, as well. Hematologic assessment showed that mean RBC, PCV, Hb, and MCHC were significantly lower, whereas MCV and RDW were higher in the animals with mixed infections of'Anaplasma with parasitemia and Theileria, compared to the uninfected sheep and groups with single infection or without parasitemia. In brief, it seems that Anaplasma can be activated and induce its pathogenesis in the presence of other infective agents in the carrier or asympthomatic animals. It can also be concluded that mixed infections of Anaplasma with parasitemia and Theileria may induce a regenerative anemia which is most likely attributable to a combined effect of the two

Double-stranded RNA viral infection in Tehran trichomonas vaginalis isolates

Trichomonas vaginalis is a pathogenic protozoon and may be contaminated with dsRNA virus called Trichomonas vaginalis virus [TVV]. The viral infection is an important factor for its pathogenesis and sensitivity to metronidazole. The presence of TVV is associated with qualitative and quantitative expression of cysteine proteinases and surface immunogenic; P270. The purpose of this study was to determine TVV frequency in T. vaginalis clinical isolates in Tehran, Iran. The 46 T. vaginalis isolates were collected from Tehran Province and cultured in TYI-S-33 culture medium. Viral RNA was extracted and RT-PCR was done. Of 46 T. vaginalis isolates, 8 isolates [17.39%] were infected with TVV-1. There was not any association between patient age and TVV- infected T. vaginalis. There were 17.39% viral infection in T. vaginalis isolates which was lower than that reported by other researchers. This is the first report on T. vaginalis isolates infection by TVV-1 in Iran

Molecular detection and identification of Anaplasma species in sheep from Ahvaz, Iran

Ovine anaplasmosis is a tick-borne rickettsial disease, widespread in tropical and subtropical areas. In the present study, a PCR-RFLP method based on major surface protein 4 [MSP4] gene, was utilized for the detection of Anaplasma infection in 119 sheep blood samples collected from different parts of Ahvaz in the southwest of Iran. PCR identified Anaplasma infections in 87.4% [104/119] of the samples in contrast to the routine blood smear examination, which revealed inclusion bodies in only 33.6% [40/119] of samples. RFLP assessment revealed that all PCR positive samples were A. ovis, while for the first time in Iran, a mixed infection with A. marginale was seen in 50% [52/104] of Anaplasma infected samples. These results suggest higher sensitivity of PCR method over the conventional microscopic technique for diagnosis of anaplasmosis, particularly in carrier animals. It also revealed that ovine anaplasmosis caused by A. ovis and A. marginale is present and highly prevalent in Ahvaz and appears to be the first report from this region

Gene regulation of pteridine reductase 1 in leishmania promasti-gotes and amastigotes using a full-length antisense construct

Pteridine metabolic pathway is unusual features of Leishmania, which is necessary for the growth of parasite. Leishmania has evolved a complex and versatile pteridine salvage network which has the ability of scavenging a wide area of the conjugated and unconjugated pteridines especially folate and biopterin. In this study, we focus on the inhibition of ptr1 gene expression. L. major ptr1 gene was cloned into pcDNA3 and digested using KpnI and BamHI. The gene was subcloned so that antisense will transcribe and called pcDNA-rPTR. Leishmania major was cultured and late logarithmic-phase promastigotes were harvested. The promastigotes were divided into two groups. One group was transfected with 50 micro g of pcDNA-rPTR, whereas the other group was transfected with pcDNA3. Transfected cells were cultured and plated onto semi-solid media. Mouse pritonean macrophages were transfected using pcDNA-rPTR-tansfected promastigotes. Western blotting was performed on mouse transfected pritonean macrophages and extracts from transfected promastigotes of L. major using a L. major ptr1 antibody raised in rabbits. The PTR1 protein was not expressed in pcDNA-rPTR- tansfected promastigotes and mouse macrophage transfected with pcDNA-rPTR- tansfected promastigotes. This approach might be used to study the pteridine salvage pathway in Leishmania or to assess the possibility of using gene expression inhibition in the treatment of leishmaniasis.

Expression and purification of P43 Toxoplasma gondii surface antigen

Toxoplasma gondii is an obligate intracellular protozoan parasite, capable of infecting all species of mammals including man. Congenital toxoplasmosis is more important during pregnancy for the first time. In this study we expressed and purified P43 Toxoplasma gondii tachyzoite and bradyzoite specific surface antigen. The recombinant pGEMEX-1 contained Toxoplasma P43 coding sequence was transformed into E. coli and mass cultured in LB medium contained 100 micro g/ml ampicillin at 37 [degree sign]C over night .The T7 promoter was induced by 1mM isopropyl-1-thio-beta-D-galactopyranoside [IPTG. Recombinant protein was purified by affinity chromatography and confirmed by gel diffusion dot blot and western blot,-using specific anti Toxoplasma antibodies. Recombinant plasmid was induced by IPTG and analyzed by SDS-PAGE. Recombinant protein was confirmed by Western-blot and dot blot using anti human Toxoplasma antibody. Recombinant Toxoplasma P43 was produced successfully

[Identification of mutation for drug resistance gene in cutaneous leishmaniasis]

Cutaneous leishmaniasis is a common parasitic disease and one of the health problems world wide. The pentavalent antimonial drugs [e.g. pentostam and Glucantime] are the first line treatment for leishmaniasis, and resistance to these drugs is a serious problem. Using PCR method, this study was carried out to identify the mutation for sodium stibogluconate resistance gene in cutaneous leishmaniasis cases referred to different health centers during 2006-8. This descriptive study was conducted on 150 isolates of leishmania major and leishmania tropica to identify the mutation in drug resistance gene. Promastigote clones were cultured in enriched RPMI 1640 medium and then the genomic DNA was isolated and using a pair of primers, a 400 bp of the gene was amplified. Finally, the PCR products were screened by conformation sensitive gel electrophoresis [CSGE] method and then the mutation was confirmed using RFLP with Sdu1 enzyme. Screening using CSGE and RFLP methods showed that 6.3% of the samples carried a mutation for drug resistance gene. Results showed a resistance for cutaneous leishmania against sodium stibogluconate. Further studies are required to determine the biochemical mechanism of this resistance

Inhibition of leishmania major PTR1 gene expression by antisense in escherichia coli

Protozoa related to Trypanosome family including Leishmania, synthesize enzymes to escape from drug therapy. One of them is PTR1 that its enzymatic activity is similar to dihydrofolate reductase [DHFR]. Dihydrofolate reductase - thymidylate synthase has a major role in DNA synthesis, if it is inhibited, the result would be the death of parasite. Since PTR1 activity is similar to DHFR, causes the decrease of inhibition effect of drug. The aim of this study was inhibition of Iranian L. major PTR1 expression with mRNA antisense in prokaryotic system as an approach to appear of the drugs therapeutic effects more. PTR1 gene was ligated to pACYCDuet-1 and pcDNA3 plasmids as sense and antisense plasmids, respectively. Simultaneously transfer of sense and antisense plasmids was done in E. coli strain M15. SDS-PAGE and western blot analysis were carried out to analyze the expression. Sense and antisense plasmids were prepared and confirmed by restriction analysis and PCR then simultaneously transfer of them was done. SDS-PAGE and western blot analysis showed PTR1 gene was inhibited by mRNA antisense in bacterial cells. Expression of PTR1 gene in sense plasmid was inhibited successfully by antisense plasmid

[Epidemiological study of cutaneous leishmaniasis in Aran and Bidgol city from April to September 2009]

Leishmaniasis caused by leishmania protozoa can be considered as a zoonotic disease. This disease caused major health problems in some parts of Iran. Aran and Bidgol city [Isfahan province, Iran] is considered as one of the endemic foci of cutaneous leishmaniasis [Salak]. For success in controlling the disease and to provide the necessary training for high-risk groups, the epidemiological data of disease in the region is required. This cross-sectional study was carried out on 94 patients admitted to the health center of Aran and Bidgol from April to September 2009. The demographic and epidemiologic data were collected and analyzed. Thirty percent [30.8%] of patients were in the age group of 1-9 years. The number of patients in urban areas was more than that of rural areas and in men more than women. Most of these cases were seen in Aran and Bidgol city [52.1%] and then in Abuzeydabad city [22.3%], respectively. Moreover, most cases of disease were found in July [37.2%] and 54.3% and 45.7% of cases were dry and wet cutaneous sores, respectively. It seems that the high incidence of disease in age group of 1-9 years is due to the susceptibility of this age group to leishmaniasis. Therefore, regulating the control training programs in this group is suggested

Detection of drug resistance gene in cutaneous leishmaniasis by PCR in some endemic areas of Iran

Cutaneous leishmaniasis is still a health problem in many rural and urban regions of Iran and drug resistance has emerged as a major impediment in the treatment of leishmaniasis. This study aims to determine the drug resistance gene in cutaneous leishmaniasis by PCR in some endemic areas of Iran. Ninety seven samples were collected from ulcers of leishmaniasis patients from some endemic areas of Iran. The Giemsa stained samples were examined microscopically and cultured in NNN and RPMI 1640 mediums for parasite detection. After DNA extraction, PCR was done by a pair of specific primers. For detection of mutation in DNA, first PCR products were electrophoresed on CSGE gel. The suspected samples were compared by sequencing and RFLP results were demonstrated. Comparison of DNA derived from a wild type cell and mutant cell was undertaken by CSGE and sequencing methods. Among 90 isolates [92.8%] examined for detection of mutation in gene with CSGE and RFLP, 10 [11.1%] revealed a disorder in sequencing selection for unresponsive to drug. Drug resistance in cutaneous leishmaniasis to sodium stiboglocanat is probably due to a mutation in a genome. A field study is needed to determine the distribution of drug resistance and other gene mutations involved in unresponsiveness to drugs in leishmaniasis endemic areas of Iran

Genomic organization of leishmania species

Leishmania is a protozoan parasite belonging to the family Trypanosomatidae, which is found among 88 different countries. The parasite lives as a mastigote in vertebrate macrophages and as a promastigote in the digestive tract of sand fly. It can be cultured in the laboratory using appropriate culture media. Although the sexual cycle of Leishmania has not been observed during the promastigote and amastigote stages, it has been reported by some researchers. Leishmania has eukaryotic cell organization. Cell culture is convenient and cost effective, and because posttranslational modifications are common processes in the cultured cells, the cells are used as hosts for preparing eukaryotic recombinant proteins for research. Several transcripts of rDNA in the Leishmania genome are suitable regions for conducting gene transfer. Old World Leishmania spp. has 36 chromosomes, while New World Leishmania spp. has 34 or 35 chromosomes. The genomic organization and parasitic characteristics have been investigated. Leishmania chromosomes are smaller with larger numbers of genes confined to a smaller space within the nucleus. Leishmania spp. genes are organized on one or both DNA strands and are transcribed as polycistronic [prokaryotic-like] transcripts from undefined promoters. Regulation of gene expression in the members of Trypanosomatidae differs from that in other eukaryotes. The trans-splicing phenomenon is a necessary step for mRNA processing in lower eukaryotes and is observed in Leishmania spp. Another particular feature of RNA editing in Leishmania spp. is that mitochondrial genes encoding respiratory enzymes are edited and transcribed. This review will discuss the chromosomal and mitochondrial [kinetoplast] genomes of Leishmania spp. as well as the phenomenon of RNA editing in the kinetoplast genome

Development of sensitive detection of cryptosporidum and giardia from surface water in Iran

The protozoan parasites Cryptosporidium spp. and Giardia are known to occur widely in both raw and drinking waters. They are two of the causative agents of waterborne outbreaks of gastroenteritis throughout the world. In the present study, a PCR assay and FA were developed for detection of Cryptosporidium oocysts and Giardia cyst in environmental samples. We have detected Cryptosporidium spp. oocysts and Giardia cysts in seeded and unseeded environmental water samples by PCR method. Water samples were spiked with oocysts [50, 100, 300, 500] and filtrated with a 1.2- micro m pore size cellulos nitrate and follow by DNA extraction and purification by QIA amp DNA mini kit. Nested -PCR assay amplified an 850 bp fragment of 18s rDNA gene specific for Cryptosporidium and 453 bp fragment of glutamate dehydrogenase [GDH] target genre for Giardia. Also many river water from north of Iran, be checked by these methods. Cryptosporidium and Giardia DNAs were detected in seeded water sample and Giardia was detected in all 5 water samples from river in north of Iran by nested-PCR and FA. Also in one river water sample, Cryptosporidium was detected. This protocol if effective for detection of these waterborne parasites in treated and untreated water samples. This study can also serve as a platform for further investigations and research water source in Iran

[Identification of nonresponsive isolates to glucantime in patients with cutaneous leishmanaisis in bam]

Background and Aims: Cutaneous leishmaniasis [CL] is a prevalent disease worldwide including Iran. In Iran Leishmania tropica and Leishmania major are two causing factors of cutaneous leishmaniasis and Bam is one of the old and well-known focuses of CL. The objective of the present study was to identify the resistant isolates to meglumine antimoniate [MA] for implementation of future control measures in Bam

Methods: This work has been conducted during 2009-2010 in the city of Bam and Kerman School of Medicine. From a total of 2126 patients with CL, 235 patients [11.1%] were resistant against MA [Glucantime] of whom 51 ones were randomly selected. Skin scrapings were taken for direct smear preparations and culture media and Nested-polymerase chain reaction [PCR] were used for species identification

Findings: In this study, 122 males [51.9%] and 113 females [48.1%], resistant to MA were identified that shows no significant difference between the two sexes. With a significant difference most of the resistant patients were in the age group 11-21 years [29.4%], followed by 10 years [21.6%] and the lowest were in the age group 55 years [5.9%]. Most of the lesions were on face [55.5%], the majority had one lesion [64.5%] and 33.3% received MA intra -lesionally. According to the results of PCR, all 51 isolates were Leishmania tropica

Conclusion: To our knowledge this is the first study that is carried out on the resistant patients to MA in Bam. Since the incidence of this disease and drug resistance have been increased after the earth quake of 2003, further studies to identify genetic variants of resistant isolates in order to use new alternative drugs are required

Cloning and expression of human vascular endothelial growth factor gene and inhibition of its expression by antisense in prokaryotic system

Angiogenesis is an important process in physiology and disease pathogenesis and is controlled in a healthy body by a number of stimulatory and inhibitory factors. The aim of this study was to determine the effect of antisense transcript on the sense transcript of the endothelial growth factor [EGF] gene in bacterial system as an approach for the gene regulation in tumors. The hepatoma cell line [HepG2] was stimulated by PMA. VEGF mRNA was used for RT-PCR. VEGF cDNA was synthesised and cloned into T- vector pTZ57R, then sense fragment of VEGF subcloned into pACYC Duet-1 expression vector and antisense VEGF subcloned into pCDNAS expression vector. Recombinant plasmids were transforemed into BL2 1 bacterial cells. Expression of recombinant plasmid was analysed by western blot technique. The recombinant pCDNA3-VEGF [pYZantiVEGF] was successfully expressed in BL21 cells. Western blot analysis showed that the expression of VEGF decreased significantly in the cells transfected with VEGF antisense RNA compared with the pACYCDUET-1 - VEGF [pYZsenseVEGF] transfected and control. The expression of VEGF in BL21 cells was strong. In vitro, antisense of VEGF inhibited VEGF expression significantly in BL21 cells

Study on ITS1 gene of Iranian Trichomonas vaginalis by molecular methods

Trichomoniasis is a worldwide protozoan parasitic disease and metronidazole is a choice drug for its treatment. Because of disease importance in public health and its controversial ideas about the prevalence of drug resistance, this study was carried out. Fifty-two suspected vaginal samples were collected from 2006 to 2007 in Gynecology Maryam Hospital, Tehran, Iran. All isolates were examined by microscopic, culture and PCR techniques. The PCR products were analyzed by RFLP and CSGE methods and two suspected samples were sequenced. Trichomonas vaginalis was identified from all 52 samples. Of 52 isolates, 45 samples were successfully cultured and amplified by PCR except one. Seven were positive only by PCR. Finally, ITS1 fragment was successfully amplified in 51 of 52. CSGE analysis and PCR products digestion by MspI followed by sequencing showed nucleotide mutation at position 209 [C209T] of the ITS1 fragment in two [3.9% of them. The results showed mutation in ITS1 fragment of T. vaginalis in two [3.9%] of Iranian isolates which may be related to metronidazole resistance

Identification of theileria species in sheep in the eastern half of Iran using nested PCR-RFLP and microscopic techniques

Theileria species are common in tropical and subtropica regions and cause great economical losses in ruminants. Two species, T. lestoquardi and T. ovis, are suspected to cause ovine theileriosis in Iran. The epidemiological aspects of ovine theileriosis in Iran are poorly understood and further investigations by sensitive and precise techniques are required. In a previous study, a sensitive and specific PCR-RFLP method was used for the identification of Theileria spp. in sheep. In the present study, Theileria species involved in ovine theileriosis were determined in five different regions in eastern half of Iran [Zabol, Lar, Ferdows, Semnan and Gorgan]. Blood samples were collected in EDTa. Of 220 blood samples obtained from sheep in different regions, 60% [132.220] were positive for Theileria spp. by nested-PCR compared with 22.27% different regions, 60% [132.220] were positive for Theileria spp. by nested-PCR compare with 22.27% [49.220] by microscopic examination. Using RFLP of PCR products, out of 132 positive blood samples, 55.3% [73.132] were positive for T. lestoquardi and 44.7% [59.132] were positive for T.ovis. The infection with these two Theileria species in different areas is compared in the article. This is the first report in which ovine theileriosis has been studied in different regions in Iran using molecular identification techniques

Investigation of the relationship between osteoporosis and sexual satisfaction in women

As clinical observations have shown, osteoporotic women were complaining of lack of sexual satisfaction and are more prone to depression. Hence, we decided to find the statistical direct relationship between these two factors. The case group included 53 menopause women [21 with osteoporosis and 32 with osteopena] and 53 premenopausal women [37 osteoporotic, and 16 osteopenic]. In the control group, there were 53 menopause women, and 53 premenopausal women who had normal bone density. Sexual satisfaction in both groups of case and control was assessed by standard Larson's sexual satisfaction questionnaire and bone density was investigated by Dual-energy x-ray absorptiometry [DEXA], in Chamran Hospital bone mass densitometry center. The menopause women had significantly less sexual satisfaction in comparison with non-menopause ones. Osteoporotic women showed significantly less sexual satisfaction that means that the main effect of osteoporosis and menopause is significant. Osteoporotic women reported significantly less sexual satisfaction in comparison with the two groups of healthy women and osteopenic women [Scheffe test]. Osteopenic women also had less sexual satisfaction in comparison with healthy women. This study suggests that there is a relationship between bone loss and sexual satisfaction in both groups of women. Therefore, this correlation suggests the importance and necessity of quick diagnostic investigation and the management of osteoporosis in women with sexual dissatisfaction

[Cryptosporidium genetic diversity based on analysis of COWP, SSU-rRNA and TRAP-C2 polymorphic genes in children with diarrhea in Tehran and qazvin provinces: a survey from Iran]

Since Cryptosporidium is a worldwide distributed protozoan parasite and is considered as one of the most common causes of infection and diarrhea in humans with autoimmune deficiency, as well as in young live stock, molecular epidemiologic studies of cryptosporidiasis will be helpful for underlying transmission and molecular pathogenesis of Cryptosporidium in humans. The aim of the present study was to determine the species and genotypes of Cryptosporidium among children with diarrhea in Tehran and Qazvin provinces by PCRRFLP using the three polymorphic regions of SSU-rRNA, COWP and TRAP-C2 genes. 1263 stool samples were collected from the children less than 12 years with diarrhea who referred to Pediatrics Medical Centers in Gazvin and Tehran Provinces, Iran, during 2005-2007. After determination of the presence of Cryptosporidium oocytes by ZiehlNeelsen acid, fast staining genomic DNA was extracted. Nested PCR-RFLP was performed by -rRNA, COWP and TRAP-C2 genes. Results of microscopically positive samples showed that the overall prevalence of infection in children was 31 [2.5%]. Results of nested PCR amplification showed that of 31 isolates of children, all of three targeted gene were successfully amplified. Our results indicated that the zoonotic transmission is the main mode of infection in Iran and indicates that direct or indirect contact with animals, especially calf, is possibly the main route of human infection