Isolation and Genotypic Characterization of Toxoplasma gondii Based on GRA6 Gene from Environmental Soil Samples in Mazandaran Province, North of Iran

Background: Soil is one of the environmental sources of Toxoplasma gondii oocysts. The other hand, genotype of the parasite is one of the important factors for its pathogenicity. Due to the importance of toxoplasmosis on public health, this study aimed to isolation and genotyping of T. gondii in environmental soil samples of Mazandaran Province, north of Iran. Methods: Overall, 192 soil samples were collected from different areas in Mazandaran Province from Apr to Sep 2014. The flotation method was used for recovering oocysts. Then, soil samples were investigated for DNA detection of T. gondii using nested PCR of RE gene, genotyping with Semi-nested PCR of GRA6 gene and restriction fragment length polymorphism (RFLP) analysis. Results were analyzed using Chi-squared test. A significant difference was considered with a P<0.05. Results: From 192 soil samples, T. gondii DNA was detected in 150 samples (78.1%). Then genotype of 23 samples was determined (91.3% type I and 8.7% type II). Conclusion: Prevalence of T. gondii in soil samples of Mazandaran province, north of Iran is high and T. gondii GRA6 type I is predominant. Soil can be the most important source of severe toxoplasmosis in this province.