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European Research Network on Congenital Toxoplasmosis


- To determine the principal risk factors for toxoplasma infection among pregnant women in different European regions.
- To develop the clinical and epidemiological base required and to initiate a multicentre study to determine the risk of vertical transmission of toxoplasma infection and the short and long term clinical consequences for infected children.
- To determine the validity and clinical applicability of tests for the diagnosis of congenital infection in the fetus and young infant.

Objective 1. We propose to conduct a multicentre, case-control study on risk factors for acquisition infection during pregnancy. A multicentre case-control study is required to allow risk factors in different European regions to be identified and to determine the relative importance of risk factors. The 6 participating centres to date are: Brussels, Copenhagen, Lausanne, Milan, Naples and Oslo.

The study is a case control design with affected cases selected as women who seroconvert during pregnancy OR who are found to be toxoplasma IgM positive at the first prenatal test. The same questionnaire is used in all centres translated into the national language.

Objective 2. The aim is to establish a European cohort of children born to mothers infected during pregnancy which can be followed longitudinally to provide informative data on: the risk of vertical transmission of infection; the prevalence of short and long term clinical sequelae and associated impairment.

The variety of different approaches to congenital toxoplasmosis within Europe can be attributed to the lack of up to date, population-based data which is unbiased by referral patterns and is based on a sufficiently large study population. As a result, decisions about existing programmes are largely based on studies over 30 years ago.
The study will be developed through 3 phases:

Phase 1: Survey of policies and practices on prevention, diagnosis and treatment of congenital toxoplasmosis in different European centres. Phase 2: Develop a consensus protocol for a longitudinal cohort study of women and children born to women identified as infected during pregnancy. Phase 3: Establish a longitudinal cohort study of children born to women infected with Toxoplasma gondii during pregnancy.
A well-defined cohort of children with congenital toxoplasmosis will be followed for at least 5 years, but longer follow up will be feasible in some centres.
There is variation in the criteria of definition of ocular toxoplasmosis in different centres. The diagnosis of ocular toxoplasmosis is an important endpoint in the proposed study, and it is therefore necessary to establish a consensus on the classification of ocular toxoplasmosis.

Objective 3. i) Continue studies on quality control and quality assessment of serological tests: ii) determine the validity of tests based on PCR technology for the diagnosis of congenital toxoplasmosis especially in amniotic fluid: iii) determine the sensitivity and specificity of diagnostic and screening tests for congenital toxoplasmosis in early infancy: v) study new treatments of congenital toxoplasmosis.
A Network Resource will be needed for: i) the development of epidemiological study protocols for the network; ii) the day to day management of the epidemiological studies, including data collection, liaison with clinicians and monitoring data collection at study centres; iii) data analysis, and iv) preparations of study results for publication and presentation.

Funding Scheme

CON - Coordination of research actions


Statens Serum Institut
2300 København