Background. Toxoplasma infection during pregnancy exposes the fetus to risks of congenital infection and sequelae that depend heavily on gestational age (GA) at time of infection. Accurate risk estimates by GA are necessary to counsel parents and improve clinical decisions. Methods. We analyzed data from pregnant women diagnosed with acute Toxoplasma infection in Lyon (France) from 1987 to 2008 and assessed how the risks of congenital toxoplasmosis and of clinical signs at age 3 years vary depending on GA at the time of maternal infection. Results. Among 2048 mother-infant pairs, 93.2% of mothers received prenatal treatment and 513 (24.7%) fetuses were infected. Because of a significant reduction in risk since 1992 when monthly screening was introduced (59.4% vs 46.6% at 26 GA weeks; P = .038), probabilities of infection were estimated on the basis of maternal infections diagnosed after mid-1992 (n = 1624). Probabilities of congenital infection were <10% for maternal infections before 12 weeks of gestation, rose to 20.0% at 19 weeks, and then continued increasing to 52.3% and almost 70% at 28 and 39 GA weeks, respectively. Because of a significant reduction in risk of clinical signs of congenital toxoplasmosis in infected children born from mothers diagnosed after 1995 when polymerase chain reaction testing on amniotic fluid was initiated (87/794 vs 46/1150; P = .012), probabilities of clinical signs at 3 years were estimated based on 1015 maternal infections diagnosed after 1995 including 207 infected children, with symptoms in 46 (22.2%). Conclusions. These analyses demonstrated that introduction of monthly prenatal screening and improvement in antenatal diagnosis were associated with a significant reduction in the rate of congenital infection and a better outcome at 3 years of age in infected children. Our updated estimates will improve individual management and counseling in areas where genotype II Toxoplasma is predominant.

Objective. Retinochoroiditis is the most frequent consequence of congenital toxoplasmosis. Early diagnosis and treatment are believed to reduce the risk of visual impairment. We report on the clinical evolution of ocular lesions and final visual function in a prospective cohort of congenitally infected children who were identified during monthly maternal prenatal screening. Methods. The study included 327 congenitally infected children who were monitored for up to 14 years at the Croix Rousse Hospital in Lyon, France. Data on date of maternal infection; time and type of therapy; antenatal, neonatal, and postnatal work-ups; and ocular status were analyzed. Results. All mothers but 52 had been treated. Pyrimethamine and sulfadiazine was given in utero to 38% of children and after birth to 72% of newborns. Fansidar was given for an average duration of 337 days in all but 2 children. After a median follow-up of 6 years, 79 (24%) children had at least 1 retinochoroidal lesion. In 23 (29%) of them, at least 1 new event had been diagnosed up to 10 years after detection of the first lesions: reactivation of an existing lesion (1 case), new lesion in a previously healthy location (19 cases), or both (3 cases). Fifty-five children had lesions in 1 eye; of the 45 children for whom final visual acuity data were available, 31 (69%) had normal vision. Twenty-four children had lesions in both eyes; of the 21 for whom final visual acuity data were available, 11 had normal vision in both eyes. None had bilateral visual impairment. Conclusions. Clinicians, parents, and elder children with congenital infection should be informed that late-onset retinal lesions and relapse can occur many years after birth but that the overall ocular prognosis of congenital toxoplasmosis is satisfactory when infection is identified early and treated accordingly.

Women infected with toxoplasmosis during pregnancy do not present symptoms in most cases, but the consequences of the congenital infection may be severe for the unborn child. Fetal damage can range from asymptomatic to severe neurological alterations to retinal lesions prone to potential flare up and relapses lifelong. Despite the possible severity of outcome, congenital toxoplasmosis (CT) is a neglected disease. There is no consensus regarding screening during pregnancy, prenatal/postnatal treatment or short or medium term follow-up. Since 1992, France has offered systematic serological testing to non-immune pregnant women, monthly until delivery. Any maternal infection is thus detected; moreover, diagnosis of congenital infection can be made at birth and follow-up can be provided. “Guidelines” drawn up by a multidisciplinary group are presented here, concerning treatment, before and after birth. The recommendations are based on the regular analysis of the literature and the results of the working group. The evaluation of the recommendations takes into account the robustness of the recommendation and the quality of the evidence.

OBJECTIVE: To provide clinicians with information about the accuracy of real-time polymerase chain reaction (PCR) analysis of amniotic fluid for the prenatal diagnosis of congenital Toxoplasma infection. METHODS: This was a prospective cohort study of women with Toxoplasma infection identified by prenatal screening in three centers routinely carrying out real-time PCR for the detection of Toxoplasma gondii in amniotic fluid. The data available were gestational age at maternal infection, types and dates of maternal treatment, results of amniocentesis and neonatal work-up and definitive infectious status of the child. We estimated sensitivity, specificity and positive and negative predictive values both overall and per trimester of pregnancy at the time of maternal infection. RESULTS: Polymerase chain reaction analysis was carried out on amniotic fluid for 261 of the 377 patients included (69%). It was accurate with the exception of four negative results in children who were infected. Overall sensitivity and negative predictive value were 92.2% (95% confidence interval [CI] 81–98%) and 98.1% (95% CI 95–99.5%), respectively. There was no significant association with the trimester of pregnancy during which maternal infection occurred. Specificity and positive predictive values of 100% were obtained for all trimesters. CONCLUSION: Real-time PCR analysis significantly improves the detection of T. gondii on amniotic fluid. It provides an accurate tool to predict fetal infection and to decide on appropriate treatment and surveillance. However, postnatal follow-up remains necessary in the first year of life to fully exclude infection in children for whom PCR results were negative. LEVEL OF EVIDENCE: III

Maternal infection by Toxoplasma gondii during pregnancy may have serious consequences for the fetus, ranging from miscarriage, central nervous system involvement, retinochoroiditis, or subclinical infection at birth with a risk of late onset of ocular diseases. As infection in pregnant women is usually symptomless, the diagnosis relies only on serological tests. Some countries like France and Austria have organized a regular serological testing of pregnant women, some others have no prenatal program of surveillance. Reasons for these discrepant attitudes are many and debatable. Among them are the efficacy of antenatal treatment and cost-effectiveness of such a program. A significant body of data demonstrated that rapid onset of treatment after maternal infection reduces the risk and severity of fetal infection. Recent cost-effectiveness studies support regular screening. This lack of consensus put both pregnant women and care providers in a difficult situation. Another reason why congenital toxoplasmosis is disregarded in some countries is the lack of precise information about its impact on the population. Precise estimations on the burden of the disease can be achieved by systematic screening that will avoid bias or underreporting of cases and provide a clear view of its outcome.

Even in the absence of manifestations at birth, children with congenital toxoplasmosis (CT) may develop serious long-term sequelae later in life. This systematic review aims to present the current state of knowledge to base an informed decision on how to optimally manage these pregnancies and children. For this, a systematic literature search was performed on 28 July 2022 in PubMed, CENTRAL, ClinicalTrials.gov, Google Scholar and Scopus to identify all prospective and retrospective studies on congenital toxoplasmosis and its long-term outcomes that were evaluated by the authors. We included 31 research papers from several countries. Virulent parasite strains, low socioeconomic status and any delay of treatment seem to contribute to a worse outcome, whereas an early diagnosis of CT as a consequence of prenatal screening may be beneficial. The rate of ocular lesions in treated children increases over time to 30% in European and over 70% in South American children and can be considerably reduced by early treatment in the first year of life. After treatment, new neurological manifestations are not reported, while ocular recurrences are observed in more than 50% of patients, with a mild to moderate impact on quality of life in European cohorts when compared to a significantly reduced quality of life in the more severely affected South American children. Though CT is rare and less severe in Europe when compared with South America, antenatal screening is the only effective way to diagnose and treat affected individuals at the earliest possible time in order to reduce the burden of disease and achieve satisfying outcomes.