sensitive and specific PCR based method for identification of cryptosporidium sp. using new primers from 18S ribosomal RNA

The main goal of the present study was to develop a new sensitive and specific PCR based method for Identification of Cryptosporidium sp. using novel primers from 18S ribosomal RNA. Cryptosporidiosis in high-risk host groups particularly in neonates and immuno-compromised individuals may result in death. To the best of our knowledge this is the first study regarding develop a new PCR based method to diagnose the cryptosporidiosis in Iran. A total of 850 human fecal samples from patients clinically suspected to cryptosporidiosis and 100 healthy and diarrheic cattle stool specimens were collected. The simplified formol-ether concentration method was carried out for all samples. They were then examined microscopically by modified Ziehl-Neelsen staining method. Total DNA was extracted by QIA amp DNA stool mini kit. PCR and nested-PCR was carried out by using designed primers. Twenty nine cases of cryptosporidiosis infection in human and 30 samples from cattle microscopically were positive. The described primary and nested PCR method could detect all Cryptosporidium positive samples from human and cattle. Regards to suspected negative samples in primary PCR examination, the Nested PCR could approve two more positive results. Furthermore, Nested PCR analysis was able to detect one more case which was negative in both microscopically examination and primary PCR. Specificity of the test was 100%. Sensitivity of Nested PCR in comparison to our gold standard; microscopy after Ridley concentration modified ziehl-Neelsen, was 100%. Our developed PCR based method by using new primers devised from 18S ribosomal RNA revealed the ability for identification of the Cryptosporidium species such as C. parvum and C. huminis with high specificity and sensitivity

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

[Giardiasis and other parasitic infections in stool specimens, duodenal biopsy and duodenal aspiration in children]

Background: Infestation of the gastrointestinal tract with parasites is one of the commonest causes of the digestive tract syndromes especially in developing countries. The aim of the present study was to determine the incidence of parasitic infestation in the stool specimens in pediatric age group

Methods: Stool specimens of all the children referred to Children's Medical Center in Tehran, regardless of their clinical complaint, in the last 13 years, are examined microscopically

Findings: 14.27% of 64196 specimens were positive regarding parasites, isolated Giardia being 7.54%. Positive stool specimens of boys related to girls were more frequent

Conclusion: The incidence of infestation with Giardia is remarkable and regarding the possible complications of infestation, more intensive hygienic teaching of the public is recommended to prevent the expansion of the infestation