Akbar Keshavarz

Shahid Beheshti University, Teheran, Tehrān, Iran

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Publications (7)4.76 Total impact

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    Journal of Paramedical Sciences. 06/2014; 5(3):17-20.
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    ABSTRACT: Cryptosporidium is a worldwide protozoan parasite and one of the most common causes of infection and diarrhea in humans and cattle. The aim of the present study was determination of subtypes of Cryptosporidium among children with diarrhea in Tehran by sequence analysis of the highly polymorphic 60-kDa glycoprotein (GP60) gene. Fecal samples were collected from 794 diarrheic children. Initial identification of Cryptosporidium was carried out on stool samples by Ziehl-Neelsen acid-fast staining method. DNA was extracted from positive microscopically samples and Cryptosporidium genotypes and subtypes were determined, accordingly. Out of 794 collected samples, 19 (2.40%) were positive for Cryptosporidium oocysts. Sequences analysis of GP60 gene showed that 17 (89.47%) of the positive isolates were Cryptosporidium parvum and 2 (10.52%) were C. hominis. All subtypes of C. parvum isolates belonged to allele families IIa (6/17) and IId (11/17). The most common allele in all 17 isolates belonged to IId A20G1a (41.18%). A22G1 (IF) subtype was detected in two C. hominis isolates of the children. The predominancy of C. parvum species (specially, IId A20G1a subtype) in current study underlines the importance of zoonotic Cryptosporidium transmission in Iran.
    Iranian journal of parasitology. 12/2011; 6(4):41-5.
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    ABSTRACT: Cryptosporidium is an intestinal parasite associated with severe acute diarrhea in humans and animals. To investigate subtypes of Cryptosporidium spp. isolated from humans and cattle in Iran, 47 Cryptosporidium parvum (22 from children and 25 from cattle) and three Cryptosporidium hominis from children were characterized by sequence analysis of the 60 kDa glycoprotein (gp60) gene. Nine subtypes (two of C. hominis and seven of C. parvum) in four subtype families were identified. Cattle were mainly infected with C. parvum IIa subtypes and humans mostly with the C. parvum IIa and IId subtypes. Consequently, cattle could be a source of human infection with C. parvum IIa in Iran. However, the occurrence of subtype IId families in Iranian children, suggests that other infection sources might also be involved in C. parvum transmission. To our knowledge, this is the first published record and description of Cryptosporidium subtypes in Iran.
    Veterinary Parasitology 02/2011; 179(1-3):250-2. · 2.38 Impact Factor
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    ABSTRACT: Aim: The aim of the present study was to determine the species and genotypes of Cryptosporidium spp. among children with diarrhea by PCR-RFLP using the TRAP-C2 gene. Background: Cryptosporidium is a globally distributed protozoan parasite and one of the most common causes of infection and diarrhea in humans. Patients and methods: Four hundred and sixty nine stool samples were collected from children less than 12 years with diarrhea who had been referred to Pediatrics Medical Centers in Gazvin provinces. The presence of Cryptosporidium oocysts was determined by Ziehl-Neelsen acid fast staining, then, genomic DNA was extracted from positive samples and nested PCR-RFLP was performed to amplify the TRAP-C2 gene. Results: The overall prevalence of Cryptosporidium infection in children was 2.5 %. Results of nested PCR amplification showed that of 12 positive children samples, 10 (83.3%) were belonged to C. parvum, followed by C. hominis in 1 (8.3%) and mixed infection in 1 isolate (8.3%). Conclusion: This study showed that Cryptosporidium parvum (the zoonotic genotypes) is more prevalent than other Cryptosporidium species in children from this area. This suggests that zoonotic transmission is the main mode of transmission of Cryptosporidium infection in Iran.
    Gastroenterology and Hepatology From Bed to Bench Gastroenterology and Hepatology From Bed to Bench.Gastroenterology and Hepatology From Bed to Bench. 01/2011; 4(4):29-33.
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    ABSTRACT: The aim of this study was to determine the prevalence, variability with host age, and the genotypes of species of Cryptosporidium in cattle from 15 dairy farms in Qazvin province, Iran. Fecal samples, collected from 272 cattle during May 2006 to December 2007, were characterized microscopically. Oocysts from 51 positive samples were analyzed using PCR assay of 18S SSU rRNA, restriction fragment length polymorphism (RFLP) and sequencing. We identified 72.6% of the positive samples as Cryptosporidium parvum, 17.7% as Cryptosporidium andersoni, 7.8% as Cryptosporidium bovis and 1.9% as a novel genotype of C. parvum possessing a single mutation on MboII restriction. An infection rate of 19.5% of C. parvum among 174 pre-weaned calves was significantly higher than the 3.1% among 98 post-weaned calves (P<0.0006). This is the first report of C. bovis and the new subgenotype of C. parvum in Iranian cattle.
    Veterinary Parasitology 11/2008; 160(3-4):316-8. · 2.38 Impact Factor
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    ABSTRACT: Background: 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 indistin-guishable 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. 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 sub-jected to a two step nested PCR-RFLP based on SSU-rRNA gene. Results: 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. Conclusion: Our results showed that the zoonotic pattern of transmission is predominant and has considerable significance in epidemiology of cryptosporidiosis in the study areas.
    01/2008; 3:30-36.