Majallah-i Dānishgāh-i ’Ulūm-i Pizishkī-i Shahīd Ṣadūqī Yazd (Apr 2005)
Comparative Study of Chronic Congenital Toxoplasmosis and Re-Infection In
Abstract
Introduction: Toxoplasma gondii is a coccidian parasite and has, as intermediate hosts, many warm-blooded animals, including mammals and birds. Congenital toxoplasmosis is one of the most important infectious diseases seen in fetuses and infants born from mothers infected with Tox.gondii during pregnancy. Congenital infection, which may occur if a mother is infected for the first time during pregnancy, is often serious, resulting in abortion or severe neurological and ophthalmological disorders. Information on human cases of neonatal toxoplasmosis makes it unquestionable that Toxoplasma crosses the placenta and invades the fetus in utero in each of the two cases. . Methods: Tox. gondii infection in newborn rat litters was detected by a bioassay and parasitological method. Rat litters were billed and where possible, separated from their mothers in order to prevent feeding. Their tissues were separately homogenized in normal saline or PBS and inoculated intraperitoneally in 3 mice. The tissues used for bioassays were brain, hearts, lungs, livers, and spleen of pups, which were killed on the day of birth. In addition, control infected rat were sacrificed and their different tissues were evaluated for parasite burden at each time point of reinfection and chronic infection. Results: Data in the occurrence of congenital transmission from chronically infected mother rats given similarly graded inoculums of the RH strains (1(106 to 5(106) presented that none of the 36 pups was infected with Tox.gondii. The occurrence of congenital transmission in rats reinfected with Toxoplasma shows that none of the 14 pups was infected with Tox.gondii. Rats were reinfected intra- peritoneally with 1(106 parasite at 1,2 and 4 months after primary infection, respectively. Conclusion: Thus, this study demonstrated that Rats chronically infected with Tox.gondii, have immunity capable of protecting their embryos from congenital infection, even if they are reinfected during pregnancy and the immunity systems of these mothers can fully protect the fetus from such infections
