Search

Background: The protozoan parasite Toxoplasma gondii can infect any warm blooded nucleated cells. One of the ways for human infection is ingestion of oocysts directly from soil or via infected fruits or vegetables. To survey the potential role of T. gondii oocyst in soil samples, the present study was conducted in Tehran City, Iran.Methods: A total of 150 soil samples were collected around rubbish dumps, children's play ground, parks and public places. Oocysts recovery was performed by sodium nitrate flotation method on soil samples. For molecular detection, PCR reaction targeting B1 gene was performed and then, the posi­tive results were confirmed using repetitive 529 bp DNA fragment in other PCR reaction. Finally, the positive samples were genotyped at the SAG2 locus.Results: Toxoplasma DNA was found in 13 soil samples. After genotyping and RFLP analysis in SAG2 locus, nine positive samples were revealed type III, one positive sample was type I whereas three samples revealed mixed infection (type, I & III).Conclusion: The predominant genotype in Tehran soil samples is type III.

Background: This study was conducted to determine of molecular epidemiology of the Giardia lamblia by PCR-RFLP method in Tehran, capital of Iran. Methods: Thirty eight stool samples were randomly selected from 125 patients diagnosed with giardiasis using microscopy in Tehran. DNA extraction of some samples were performed by phenol/chloroform/isoamyl alcohol method and to raise the sensitivity of the PCR assay, the genomic DNA of the others were extracted using glass beads and the QIAamp Stool Mini Kit in order to effectively remove the PCR inhibitors. A single step PCR-RFLP assay, targeting the glutamate dehydrogenase (gdh) locus, was used to differentiate within and between assemblages A and B that have been found in humans. Results: Of the 38 isolates, 33 samples (87%) were found as G. lamblia (genotype AII), 3 (7.8%) belonged to assemblage B, genotype BIII, the mixed of genotype AII and B were detected only in two samples (5.2%). Conclusions: PCR-RFLP is a sensitive and powerful analytical tool that allows effective genotype discrimination within and between assemblages at targeting gdh gene, and makes it possible to identify the presence of mixed genotypes. Our data suggest that there is an anthroponotic origin of the infection route, assemblage A group II, in Tehran so it seems that the main reservoir of Giardia infection is humans in the area studies.

Background: The protozoan parasite Toxoplasma gondii can infect any warm blooded nucleated cells. One of the ways for human infection is ingestion of oocysts directly from soil or via infected fruits or vegetables. To survey the potential role of T. gondii oocyst in soil samples, the present study was conducted in Tehran City, Iran. Methods: A total of 150 soil samples were collected around rubbish dumps, children's play ground, parks and public places. Oocysts recovery was performed by sodium nitrate flotation method on soil samples. For molecular detection, PCR reaction targeting B1 gene was performed and then, the posi-tive results were confirmed using repetitive 529 bp DNA fragment in other PCR reaction. Finally, the positive samples were genotyped at the SAG2 locus. Results: Toxoplasma DNA was found in 13 soil samples. After genotyping and RFLP analysis in SAG2 locus, nine positive samples were revealed type III, one positive sample was type I whereas three samples revealed mixed infection (type, I & III). Conclusion: The predominant genotype in Tehran soil samples is type III.

Background: This study was conducted to determine of molecular epidemiology of the Giardia lamblia by PCR-RFLP method in Tehran, capital of Iran. Methods: Thirty eight stool samples were randomly selected from 125 patients diagnosed with giardiasis using microscopy in Tehran. DNA extraction of some samples were performed by phenol/chloroform/isoamyl alcohol method and to raise the sen­sitivity of the PCR assay, the genomic DNA of the others were extracted using glass beads and the QIAamp Stool Mini Kit in order to effectively remove the PCR inhibitors. A single step PCR-RFLP assay, targeting the glutamate dehydro­genase (gdh) locus, was used to differentiate within and between assemblages A and B that have been found in humans. Results: Of the 38 isolates, 33 samples (87%) were found as G. lamblia (genotype AII), 3 (7.8%) belonged to assemblage B, genotype BIII, the mixed of genotype AII and B were detected only in two samples (5.2%). Conclusions: PCR-RFLP is a sensitive and powerful analytical tool that allows effective genotype discrimination within and between assemblages at targeting gdh gene, and makes it possible to identify the presence of mixed genotypes. Our data sug­gest that there is an anthroponotic origin of the infection route, assemblage A group II, in Tehran so it seems that the main reservoir of Giardia infection is humans in the area studies.