Genotyping of toxoplasma gondii isolates from soil samples in Tehran, Iran

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. 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. 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 and III]. The predominant genotype in Tehran soil samples is type III

SSU-rRNA gene analysis of cryptosporidium spp. in HIV positive and negative patients

Cryptosporidium is an apicomplexan parasite of humans and a wild range of domestic as well as wild animals. An 833-bp fragment of the 18S-rRNA gene was used to identify Cryptosporidium spp. recovered from children and adult patients, in human immunodeficiency virus [HIV] positive and negative patients in Iran. Initial identification of cryptosporidiosis was carried out by Ziehl-Neelsen acid-fast staining method of stool samples. The samples, then, were identified specifically by nested PCR, targeting the most polymorphic region of the 18S-rRNA gene. The genotype encountered was detected by re-striction endonuclease digestion of the nested-PCR product. Among 17 analyzed isolates, two different genotypes of Cryptosporidium were identified; 24% of the isolates belonged to C. parvum human genotype, and 76% to the potentially zoonotic species of C. parvum bovine genotype. The results of the present study showed that in contrast to HIV negative individuals, HIV positive individuals were more likely to be infected with zoonotic genotypes of the parasite; it was also confirmed the fact that zoonotic transmission of the parasite in Iran was as frequent as the transmission of anthroponotic origin. These outcomes are helpful for researchers to establish the corresponding prevention and treatment measures