Molecular identification and genotyping of Toxoplsma gondii isolated from sheep and cattle in northern Iran

Toxoplasmosis, a foodborn disease, in human occurs commenly after the ingestion of tissue cysts via the raw and/or undercooked meat of different infected intermediate hosts such as sheep and cattle.The current study aimed to detect the genetic structure of Toxoplasma gondii isolated from various organs of sheep and cattle in the north of Iran. Convetional PCR was carried out by B۱ and REP-۵۲۹ genes of T. gondii. Nested and RFLP-PCR were performed for all positive samples using SAG۲ and GRA۶ genetic markers. Amplicons from second round of nested-PCR were sequenced and analyzed with NCBI database. Among of ۱۷۹ examined samples, ۳۸(۲۱.۲۰%) were positive. The highest of positive cases were found in kidney (۲۸.۶۰%). PCR-RFLP of SAG۲ and GRA۶ genes demonstrated the alleles of clonal type III in the all of isolates. Sequence analysis of the amplicons revealed the alleles of clonal type III and atypical isolates (Tg-۶۷, Tg-۱۰۰ and Tg-۱۰۶). Phylogenetic analyses showed separate clade for the atypical isolates from others in the present study and the reference strains clades. In conclusion, the genetic characterization of T. gondii isolates from sheep and cattle showed high genetic diversity compared with standard type I, II and III genotypes. These results support the hypothesis of the existence of polymorphic and overlapping strains within livestock in Iran. It also suggested the necessity of increased genotyping and sampling efforts to accurately estimate T. gondii intra specific genetic diversity

کلیدواژه ها:

Atypical ، Cattle ، Genotype ، Sheep ، Toxoplsma gondii