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

Results of the REIV-TOXO national survey on prenatal screening for toxoplasmosis in Spain

INTRODUCTION

Currently, the status of serological screening for toxoplasmosis in pregnant women in Spain is unknown, and there is no official recommendation. The objective of this study is to show the current practice of gestational screening for toxoplasmosis in hospitals belonging to the Spanish Network for Research on Congenital Toxoplasmosis (REIV-TOXO).

METHODS

An electronic survey was sent between April 2021 and September 2021 to investigators from 118 hospitals of REIV-TOXO, representing all Spanish regions. Nine items related to gestational screening for toxoplasmosis were collected. This information was compared with cases of congenital toxoplasmosis (CT) identified in REIV-TOXO to determine if these were diagnosed in the presence of gestational screening.

RESULTS

During the study period, serological screening was performed in 53.3% (63/118) hospitals, with variations between regions and even among hospitals within the same region. Testing performed in each trimester was the most common practice (57.7%), followed by a single determination (24.4%). 89.4% of CT cases between January 2015 and September 2021 were diagnosed due to gestational screening.

CONCLUSION

The decision to perform gestational screening for toxoplasmosis in Spain is highly heterogeneous, with significant local and regional differences. Despite this, screening still allows the diagnosis of most CT cases. It is urgent to have current epidemiological data to inform decision-making in public health.

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

Background

Toxoplasma gondii is one of the world’s most common parasites. Primary infection of the mother during pregnancy can lead to transmission to the fetus with risks of brain and eye lesions, which may cause lifelong disabilities. France instituted a national program based on monthly retesting of susceptible pregnant women to reduce the number of severe cases through prompt antenatal and postnatal treatment and follow-up.

Objective

To evaluate the ability of the French prenatal retesting program to reduce the lifetime costs of congenital toxoplasmosis.

Methods

We measured and then compared the costs and benefits of screening vs. not screening using decision-tree modelling. It included direct and indirect costs to society of treatment and care, and the lifetime lost earnings of children and caregivers. A probabilistic sensitivity analysis was carried out.

Findings

Total lifetime costs per live born child identified as congenitally infected were estimated to be €444 for those identified through prenatal screening vs €656 for those who were not screened. Estimates were robust to changes in all costs of diagnosis, treatment, and sequelae.

Interpretation

Screening for the prevention of the congenital T. gondii infection in France is cost saving at €212 per birth. Compared with no screening, screening every pregnant woman in France for toxoplasmosis in 2020 would have saved the country €148 million in addition to reducing or eliminating the devastating physical and emotional suffering caused by T. gondii. Our findings reinforce the conclusions of other decision-analytic modelling of prenatal toxoplasmosis screening.

Congenital toxoplasmosis: Should we still care about screening?

Prenatal systematic screening for congenital toxoplasmosis has been performed in Austria and France since 1975 and neonatal screening for congenital toxoplasmosis has been part of the New England Newborn screening program since 1986.

In this narrative review we review the data leading up to the systematic screening programs in Austria and France, highlighting the main finding of the European Union funded research in the 1990s and early 2000s. Different descriptive studies of the effect of pre- or postnatal treatment are discussed. Toxoplasma gondii has different genetic lineages with different pathogenicity in humans. This means that results in areas with a low pathogenic lineage cannot be extrapolated to an area with highly pathogenic lineages. The importance of meat as a source of infection is discussed in the light of an increased prevalence of T.gondii in organic livestock production .

MODERN ASPECTS OF INTRAUTERINE INFECTION

OBJECTIVE

The aim: To analyze the main types of intrauterine infections(IUI), their routes of transmission and features of the clinical picture, as well as the influence of pathogens on the course of pregnancy.

PATIENTS AND METHODS

Materials and methods: Data review of native and foreign literature published over the past 5 years.

CONCLUSION

Conclusions: Summing up, it should be noted the role of infections in the pathogenesis of pathological conditions that form in the perinatal period. This is evidenced by numerous works on the problem of CBS. The most significant perinatal risk factors for fetal infection have been identified. It is proved that in the development of infectious lesions of the fetus, the severity of the disease, the localization of the pathological process, the rate of implementation, and manifestations of the pathology are an important type of pathogen, the path of penetration of microorganisms from mother to fetus to the immune response. Unfortunately, today the problem of preventing CBS is still far from being solved. However, knowledge of the pathogenesis, quality diagnostic methods, effective prevention, and treatment measures can significantly reduce the frequency of VUI and the severity of their consequences for the child.

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

BACKGROUND

Infection with the parasite Toxoplasma gondii is a common infection in animals and humans worldwide. This infection can occur after ingestion of water or food contaminated with cat oocytes, ingestion of tissue cysts in mammalian and avian meat and congenitally. The prenatal infection can lead to Congenital Toxoplasmosis with miscarriage or stillbirth. After infection, laboratory tests are positive within 2-3 weeks and remain positive throughout life. However, testing for Toxoplasma infection during pregnancy is necessary in some countries, while in others it is not a mandatory "screening" test.

OBJECTIVE

The aim of this study was to review systematically the screening of toxoplasmosis in pregnancy in different countries worldwide.

METHODS

Cohorts, retrospective and cross-sectional studies were incorporated in our review, finally including 11 articles from an initial pool of 1532 related papers.

RESULTS

The seroprevalence of pregnant women varies from countries with low prevalence to regions with high prevalence and screening policies also differ. Most countries worldwide have control policies, while Germany and Mexico that do not have systematic screening for Toxoplasma during the prenatal period.

CONCLUSION

Our results show that Congenital Toxoplasmosis is very rare in some countries and it is very difficult to find a balance between potential risk and benefit of a screening program. For this reason, some countries are limited to prenatal counseling to reduce CT. In addition, the reduction of major sources of contamination especially in developing countries is the most important prevention measure.

[Toxoplasmosis in pregnancy: Practical Management]

The burden of congenital toxoplasmosis has become small in France today, in particular as a result of timely therapy for pregnant women, fetuses and newborns. Thus, the French screening and prevention program has been evaluated and recently confirmed despite a decline over time in the incidence of toxoplasmosis. Serological diagnosis of maternal seroconversion is usually simple but can be difficult when the first trimester test shows the presence of IgM, requiring referral to an expert laboratory. Woman with confirmed seroconversion should be referred quickly to an expert center, which will decide with her on treatment and antenatal diagnosis. Although the level of proof is moderate, there is a body of evidence in favor of active prophylactic prenatal treatment started as early as possible (ideally within 3 weeks of seroconversion) to reduce the risk of maternal-fetal transmission, as well as symptoms in children. The recommended therapies to prevent maternal-fetal transmission are: (1) spiramycin in case of maternal infection before 14 gestational weeks; (2) pyrimethamine and sulfadiazine (P-S) with folinic acid in case of maternal infection at 14 WG or more. Amniocentesis is recommended to guide prenatal and neonatal care. If fetal infection is diagnosed by PCR on amniotic fluid, therapy with P-S should be initiated as early as possible or continued in order reduce the risk of damage to the brain or eyes. Further research is required to validate new approaches to preventing congenital toxoplasmosis.