Molecular detection and genotyping of Toxooplasma gondiistrains isolated in Serbia

Toxoplasmosis, infection caused by the parasite Toxoplasma gondii, is one of the most widespread zoonoses in the world and it has been estimated that up to one third of the global human population is infected with this parasite. Although serological tests are the primary method in the routine diagnosis of toxoplasmosis, interpretation of the results can be not only difficult and time-consuming, but they can be inconclusive. Therefore, the introduction of highly sensitive molecular methods, by which results can be obtained within a day, into the diagnosis of toxoplasmosis is of great importance. The aim of this research was the introduction of molecular methods into the diagnosis of toxoplasmosis for the first time in Serbia, as well as genotypization of the isolated T. gondii strains. This study included 160 human biological samples from 127 patients serologically suspected of toxoplasmosis in which the presence of T. gondii was analyzed by PCR and by bioassay in mice. It was found that the detection of T. gondii DNA in human biological materials depends on the type of sample as well as on the initial volume. Real-time PCR was positive in 30.8% of peripheral blood samples, 33.3% of cord blood samples, 35.7% of amniotic fluid samples, 57.1% of CSF samples and 60% of humor aqueous samples. The detection rate of T. gondii by molecular methods was higher than by bioassay, in both blood samples from adults suspected of acute toxoplasmosis and samples from fetuses and newborns suspected of congenital toxoplasmosis. The results of this study emphasize the huge practical importance and potential of molecular diagnostics and show the benefit of introducing this method as part of the standard protocol for the diagnosis of toxoplasmosis. T. gondii has a wide range of host organisms, including all warm-blooded animals, so that in the second part of this research molecular methods for the detection of this parasite were applied in animal material, rodents specifically. Rodents were chosen because of their potentially important role as a link in the transmission chain of T. gondii infection. A total of 156 brain samples from 144 brown rats (Rattus norvegicus) and 12 house mice (Mus musculus) were analyzed. T. gondii DNA was vi detected in 10.4% of rats and in as many as 83.3% of house mice. The rate of positive findings in rats and mice collected in Belgrade is an indicator of the degree of contamination of the urban environment with T. gondii, reflecting a considerable