Survey on GRA6 gene in differentiating Toxoplasma gondii genotypes, using PCRRFLP method, in sheep aborted fetuses in Ardabil area, Iran

Toxoplasma gondii, is an isosporean intracellular protozoa in warm blooded animals. Its importance relies on public health hazards and significant economical losses in man and some domestic and wild animals. Its life cycle develops in two hosts: Cat and other felids are definitive hosts which produce oocyts and man and many domestic and wild animals are the accidental intermediate hosts which harbor tissue cysts in their bodies. This parasite causes abortion in man and some herbivorous animals, too. Because the infection rate of toxoplasmosis in sheep aborted fetuses of Ardabil was over 75 %, by PCR method, we decided to use GRA6 gene of Toxoplasma in order to reveal the strains and their pathogenicity in this area. All 75 fetuses were tested by PCR-RFLP method. However, this gene was not amplified in none of the fetuses. Meanwhile, results of bioassay, following intraperitoneal injection of fetal brains to albino mice, revealed that no tissue cyst developed in mice brains. In conclusion, it is probable that the amount of Toxoplasma organisms was not sufficient for the gene amplification. In addition, it seems that the low number of the parasite as well as the presence of non virulent murine strain of Toxoplasma, may not be the cause of sheep abortion in Ardabil area.