[Comparative studies of the virulent and immunogenic properties of the Toxoplasma strains isolated from domestic animals].

Comparative investigations were carried out on the virulent and immunogenic properties of 5 cytogenic Toxoplasma strains (3 isolated from rabbits and 2--from fetuses of ewes that had miscarried). It was found that at shortening the interval of passage to 7--10 days and increasing the amount of the inoculate the virulence of the strains rose. Particularly virulent for albino mice proved the oocysts of T. gondii obtained after the feeding of kittens with cysts. The role was confirmed of Toxoplasma organisms in the etiology of abortions observed in experimentally infected guinea pigs and sheep. There were in the placenta and the brain of aborted fetuses characteristic histopathologic changes. Immunologic studies revealed that the isolated strains were immunologically identical.