Isolation and Molecular Characterization of Toxoplasma Gondii Strains From Rats in Tehran

Abstract

Implication for health policy/practice/research/medical education: Based on the relatively high occurrence of this parasite in rats in Tehran, we have to consider it as a major risk factor for transmission of T. gondii in this area. Manceaux in 1908, from a type of rodent called a Cteno-dactylus gundi in the Pasteur Institute, Tunisia (4, 5). Simultaneously , Splendor, an English researcher, isolated the parasite from a laboratory rabbit (6). The parasite infects humans, as well as mammalians and different species of birds, and it can be propagated in a wide range 1. Background Toxoplasma gondii is a unicellular apicomplex organism, belonging to the Toxoplasma genus. Contamination with the parasite has been reported all over the world (1-3). This unicellular parasite was first isolated by Nicole and Background: Toxoplasma gondii is a unicellular apicomplex organism, belonging to the Toxoplasma genus. The parasite infects humans, as well as mammalians and different species of birds, and it can be propagated in a wide range of host cells. There have been no appropriate molecular or serological studies carried out previously in Iran on the prevalence of Toxoplasma gondii in rodents. Objectives: Therefore, the present study has been carried out to provide genetic identification and determination of wild rats in Tehran, Iran. Materials and Methods: Forty rats in Tehran were caught with traps. Subsequently, their brains were removed under sterile conditions, DNA extraction was performed with a phenol and chloroform method. In the current study, a repetitive sequence in the genome T. gondii was used for identification with a specific primer. By sequencing the purified Polymerase Chain Reaction product, seven strains were determined out of the positive samples. Results: Of the forty samples, 20 samples (50%) were positive for the 529-bp band. Samples No. 21 and No. 28 had 95% and 92% similarity with the RH strain sequence, respectively , which had the highest identity rate. The identity rate for samples No. 16 and No. 28 was 82% and 81%, respectively, which had the lowest rate of identification. Conclusions: The contamination rate was determined to be 50% using the PCR method. It can be stated that rats play an important role in the preservation of the Toxoplasma life cycle in Tehran. According to the alignment of results obtained from the seven se-quenced samples, the highest similarity was observed with the RH strain (81-95%).