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Prenatal diagnosis of congenital toxoplasmosis by duplex real‐time PCR using fluorescence resonance energy transfer hybridization probes
Author(s) -
Costa JeanMarc,
Ernault Pauline,
Gautier Evelyne,
Bretagne Stéphane
Publication year - 2001
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/1097-0223(200102)21:2<85::aid-pd18>3.0.co;2-1
Subject(s) - toxoplasmosis , duplex (building) , parasite load , real time polymerase chain reaction , parasite hosting , biology , amniotic fluid , pathology , polymerase chain reaction , pregnancy , medicine , fetus , immunology , dna , genetics , immune system , world wide web , gene , computer science
The diagnosis of congenital toxoplasmosis frequently relies on PCR tests of amniotic fluid (AF). A duplex real‐time quantitative PCR test based on fluorescence resonance energy transfer was developed to quantify the parasite load and to decrease the risk of contamination. An internal control based on the detection of 10 pg mouse DNA added to the AF was included to check for PCR efficiency. The relationship between the parasite load and the occurrence of ultrasonographic abnormalities in 87 samples of AF was analyzed. Seven AF (8%) had a parasitic load >10 3 ; 14 (16%) had >10 2 –≤10 3 ; 26 (30%) had >10–≤10 2 ; and 40 (46%) had ≤10 parasites/ml. Four of the six AF with cerebral ventriculomegaly had >10 3 parasites/ml. The other two had 130 and 24 parasites/ml, respectively. No parasitic loads of >10 3 parasites/ml and no ultrasonographic abnormalities were observed in the 11 AF with maternal toxoplasmosis in the third trimester. Therefore, there is a trend to associate high parasite count with ultrasonographic abnormality, but the main concern remains early maternal infection. The importance of quantification should be better evaluated with postnatal studies. The duplex LightCycler PCR test currently provides rapid and safe results. Copyright © 2001 John Wiley & Sons, Ltd.