Contribution of the real time PCR in antenatal diagnosis of congenital toxoplasmosis

ABSTRACT

The antenatal diagnosis of congenital toxoplasmo-sis rests in Tunisia on ultrasonography coupled with biological explorations. Among these explorations the search of Toxoplasma gondii by means of real time PCR in amniotic fluid is the examination of choice. We report the results of 33 parturients for which the biological examinations allowed to retain the notion of perigravidic or per-gravidic toxoplasmic infection. They were 13 patients having a seroconversion during the pregnancy, 19 having anti-toxoplasmic IgM with a low or intermediate index of avidity and a patient having presented a symptomatic anteconceptional primary infection. The ADN was extracted by means of the Kit [Qiagen]. Genie amplification by PCR TaqMan targeted a portion of 71 pairs of bases of the Bl gene. The PCR was positive among 9 patients [27,3%]. They were a patient having presented a symptomatic toxoplasmosis during the pregnancy, 4 patients having consulted only in the 2nd quarter and for which the index of avidity was intermediate and 4 patients having presented seroconversions of 1st [n=l] of 2nd [n=2] or 3rd trimester. Among these patients, 2 had a medical interruption of pregnancy. The 7 others were put under pyrimethamine sulfadiazine. The neonatal assessment practised at 5 new-born babies was negative in all the cases. The PCR was negative for 24 patients. 18 pregnancies were followed. The neonatal serology was negative. The follow-up of 13 newborn child showed the disappearance of the anti-toxoplasmic IgG between the 6th and 12th month