CONGENITAL TOXOPLASMOSIS - VALUE OF POSTN ATAL BIOLOGICAL FOLLOW-UP

Objectives: The diagnosis of congenital toxoplasmosis includes a postn atal follow-up, often preceded by a prenatal diagnosis. The aim of our study nas to assess the performances of the different techniques used and the value of the samples in the postnatal biological diagnosis. M ethods: The methods available between 1985 and 1993 consisted in the d etection of: i) Toxoplasma gondii in the placenta; ii) anti-T. gondii IgM in infant's blood by enzyme-linked immuno-sorbent assay (ELISA), i mmuno-sorbent agglutination assay (ISAGA) and indirect immune-fluoresc ence (IFI), and anti-T. gondii IgG by ELISA and IFI; and iii) neo-synt hetized anti-T. gondii IgG and IgM by enzyme-linked immuno-filtration assay (ELIFA). Results: Among 100 cases of seroconversion diagnosed du ring pregnancy, a sure diagnosis with complete follow-up could be esta blished for 104 infants; 37 of them had proven congenital toxoplasmosi s (CT+) while 75 had no congenital toxoplasmosis (CT-). Biological arg uments supporting congenital toxoplasmosis had been observed as early as birth in 78.4% of CT+ cases and before two months in 94.6%. The ser ologic tests were positive in 88.2% of CT+ cases by ELIFA, in 73.0% by ISAGA, in 43.3% by ELISA M and in 14.0% by IFI M. ELIFA was the less specific method (91.3%). Conclusion: The sensitive techniques (ELIFA a nd ISAGA), were essential for the instant follow-up to detect toxoplas mic infection as early as birth.