isolation and molecular characterization of toxoplasma gondii strains from rats in tehran

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 sequenced samples, the highest similarity was observed with the rh strain (81-95%).