Congenital toxoplasmosis: What is the evidence for chemoprophylaxis to prevent fetal infection?

Abstract

Although prenatal diagnosis and prenatal and neonatal therapy of congenital toxoplasmosis are available, there is controversy concerning the effectiveness of prophylaxis to prevent placental transmission. Experimental, parasitological, and clinical data suggest a "window of opportunity" following maternal infection. Among medications active against Toxoplasma gondii, mainly spiramycin (Spy) and pyrimethamine + sulfonamide combinations (P-S) have been evaluated. Results from observational studies suffered treatment bias, since prescriptions differed according to the gestational age at seroconversion, which is the major risk factor for transmission, and many lacked precise timing. Some large retrospective studies found no difference in transmission according to prophylactic treatment, but transmission was lower when treatment started promptly after maternal seroconversion. A few recent studies adjusting for timing of infection observed lower transmission in case of P-S than other or no prophylaxis. In the only randomized controlled trial, transmission was lower with P-S than S (18.5% vs 30%, P = .147); this association was strengthened when the treatment was started within 3 weeks of seroconversion, and the incidence of fetal cerebral ultrasound signs was significantly reduced in the P-S group. Rapid initiation of prophylactic therapy following maternal infection, which is usually asymptomatic, requires systematic screening for maternal seroconversion during pregnancy.

40 years of prenatal diagnosis in 2020

“…17 We also publish the latest on congenital toxoplasmosis, including a large case series gathered from 30 fetal medicine centers across France, 18 and a review of pharmacotherapy from Mandelbrot. 19 We conclude the issue with reviews on other important infections in pregnancy, including HIV, 20 syphilis, 21 and parvovirus B19. 22 Diana Bianchi, Editor-in-Chief 2007-2020. and clinical communities.…”

“…We asked experts to give us their approach to counseling couples at risk of cCMV, 15 and routine serological screening for CMV, 16 which become even more topical in light of new data on antiviral therapy 17 . We also publish the latest on congenital toxoplasmosis, including a large case series gathered from 30 fetal medicine centers across France, 18 and a review of pharmacotherapy from Mandelbrot 19 . We conclude the issue with reviews on other important infections in pregnancy, including HIV, 20 syphilis, 21 and parvovirus B19 22 …”

Prevention of congenital toxoplasmosis in France using prenatal screening: A decision-analytic economic model

“…Experimental, parasitological, and clinical data indicate that prompt initiation of anti-parasitic treatment following maternal infection reduces the risk of placental transmission. Several recent studies from Europe and South America that adjust for the gestational age at the time of maternal infection (the major risk factor for transmission) observed lower rates of transmission with pyrimethamine-sulfadiazine than other or no prophylaxis [38]. A single RCT found a trend towards less transmission with pyrimethamine-sulfadiazine than spiramycin (18.5% vs. 30%, p = 0.147).…”

The Importance of Use of the On-line Databases as a Source for Systematic Review of Toxoplasmosis Screening During Pregnancy

“…Of those who become infected initially during pregnancy, 40% will give birth to congenitally infected children. Only women with parasitemia (primary infection) are at risk of transmitting the infection to the fetus ( 9 , 10 ). In 2017, 194 confirmed cases of congenital toxoplasmosis were reported in the EU/EEA ( 8 ).…”

“…Indicatively, in the USA, this is referred to as “name” (Dr. Jack S. Remington Laboratory for Specialty Diagnostics) ( 22 ). If screening is carried out before 20 weeks of gestation, and especially during the first trimester, negative IgM and positive IgG antibodies show a previous infection, so no confirmation test is needed ( 23 ). Given that recent infection is particularly important for fetal infection, recent toxoplasmosis can be diagnosed when IgM and IgG seroconversion has been confirmed in sequential testing.…”