The parasite load in amniotic fluid can help to identify a fetus who may be expected to have symptomatic infection with Toxoplasma gondii. The authors are from the University of Sao Paulo in Brazil.
Analysis of amniotic fluid: quantitative PCR on the amniotic fluid
Symptomatic infants had a parasite load > 57 parasites per mL (75th percentile).
Severe symptoms were associated with a parasite load > 200 parasites per mL (95th percentile).
The highest parasite load was 30,000 per mL.
Symptomatic infection also was correlated with earlier gestational age at maternal seroconversion. The risk was greatest for symptomatic infection during the first trimester but risk also extended into the second trimester.
Fetal ultrasonography could detect abnormal findings that may include:
(1) hepatosplenomegaly
(2) brain calcifications
(3) hydrocephalus
(4) growth retardation
Symptomatic neonates usually show positive IgM antibodies to Toxoplasma gondii.
If there is evidence of intrauterine infection then:
(1) therapy of the mother is started, especially for high parasite loads in the amniotic fluid
(2) there should be closer monitoring of the mother and fetus
(3) there should be a more careful evaluation at birth with closer monitoring during infancy
Performance:
• The use of both amniotic fluid parasite load and gestational age had an area under the ROC curve of 0.97.
