[Evaluation of the toxoplasmosis seroprevalence in pregnant women and creating a diagnostic algorithm]

Toxoplasma gondii, an obligatory intracellular protozoon is widely distributed around the world and can infect all mammals and birds. While acquired toxoplasmosis is usually asymptomatic in healthy subjects, acute infection during pregnancy may lead to abortion, stillbirth, fetal neurological and ocular damages. For the prevention of congenital toxoplasmosis it is recommended that a screening programme and a diagnostic algorithm in pregnant women should be implemented while considering the cost effectiveness. Thus, it is necessary to determine the seroprevalence of toxoplasmosis in pregnant women and the actual risk of T.gondii transmission during pregnancy in a certain area. The aims of this study were to detect the T.gondii seropositivity in the pregnant women admitted to our hospital and to create a diagnostic algorithm in order to solve the problems arising from interpretation of the serological test results. A total of 6140 women aged 15-49 years who were admitted to our hospital between April 1st, 2010 to July 31st, 2013, were evaluated retrospectively. In the serum samples, T.gondii IgM, IgG and IgG avidity tests were performed by VIDAS automated analyzer using TOXO IgM, TOXO IgG II and TOXO IgG avidity kits (bioMerieux, France). It was noted that, both T.gondii IgM and IgG tests were requested from 4758 (77.5%) of the pregnant women, while only IgM test from 1382 (22.5%) cases. Sole IgM positivity was found as 0.2% (11/6140), IgG as 26.4% (1278/4758) and both IgM + IgG as 0.9% (44/4758). T.gondii IgG avidity tests were requested from 12 of 44 women who were found both IgM and IgG positive and eight of them revealed high avidity and four low avidity. Avidity test was ordered for the 91 (7.1%) of 1278 sole IgG positive cases and four of them were found to have low avidity. IgG avidity test was ordered for 554 (16.2%) of IgM and/or IgG negative subjects, however, the test was not performed according to rejection criteria of the laboratory. It was noticed that no re-testing was requested for none of the seronegative cases (3428/4758; 72%) during their follow-up. In our study, total Toxoplasma seropositivity rate among pregnant women was detected as 28% (1330/4758), showing statistically significant increase (p< 0.05) with age. There was no significant difference (p> 0.05) in the seropositivity rate between the years (2010-2013). Following the evaluation of the test orders, the problems related to test orders and interpretation of the test results were determined and a diagnostic algorithm to be used in our hospital, was established to minimize such problems in toxoplasma serology. It was concluded that a diagnostic algorithm related to toxoplasmosis serology should be implemented for the appropriate evaluation of the risk of acute toxoplasmosis during pregnancy. Such an approach is necessary to support the clinical diagnosis and to minimize the anxiety in pregnant women about congenital toxoplasmosis.