Prenatal diagnosis of congenital toxoplasmosis in 261 pregnancies

Abstract

Two hundred and sixty‐one pregnant women underwent prenatal screening by cordocentesis and/or amniocentesis between 1987 and 1994. The following tests were used: (i) detection of anti‐Toxoplasma gondii IgM, IgA, and IgE antibodies by immunocapture and the comparative immunological profile method based on enzyme‐linked immunofiltration assay of fetal blood and (ii) direct detection of the parasite in cell culture and by mouse inoculation with fetal blood (FB) and/or amniotic fluid (AF). Of the 31 cases of congenital toxoplasmosis, 24 (77 per cent) were detected prenatally. Overall, the FB and AF inoculation methods were the most effective (50 per cent sensitivity with FB inoculation to mice and/or cell culture and 74 per cent with AF). However, antibody detection in FB was the only positive test in three cases. Of 18 surviving children diagnosed prenatally, only one developed chorioretinitis (9 months of age). Seven newborns (23 per cent) with negative prenatal tests were diagnosed by postnatal laboratory monitoring, but none of these children developed clinical toxoplasmosis. There may have been more false negatives, as only 48 per cent of unaffected children were followed up for at least 12 months. All the tests had a specificity of 100 per cent. Fetal blood sampling has considerable value but also carries some risks and is currently being abandoned in favour of amniocentesis alone with gene amplification and mouse inoculation. © 1997 John Wiley & Sons, Ltd.

Toxoplasmosis

“…Although PCR assay in amniotic fluid is now the method of choice, cordocentesis [735][736][737] may still be used when PCR methods are unavailable or in the rare instances in which the PCR assay result is negative and the ultrasonographic findings suggest fetal infection. For this reason, findings on clinical studies using this method are described here along with those for PCR analysis.…”

Strategy for Diagnosis of Congenital Toxoplasmosis: Evaluation of Methods Comparing Mothers and Newborns and Standard Methods for Postnatal Detection of Immunoglobulin G, M, and A Antibodies

“…However, CT is generally subclinical, es-pecially in countries with effective screening programs where treatment in utero reduces the risk of major complications (5,12,20,29).…”

Prenatal diagnosis of congenital toxoplasmosis by duplex real-time PCR using fluorescence resonance energy transfer hybridization probes

“…Currently, the search for parasitic DNA with PCR has overtaken direct inoculation into mice. This search for DNA is mainly performed in amniotic¯uid which is more ef®cient than cord blood (Hohlfeld et al, 1994;Pratlong et al, 1996;Fricker-Hidalgo et al, 1997;Hezard et al, 1997;Gratzl et al, 1998;Foulon et al, 1999). Therefore, the reliability of the PCR technique is of utmost importance since DNA ampli®cation may be the only positive test for diagnosing congenital toxoplasmosis.…”