Silent Invader: Study assesses Importance of Toxoplasma Antibody Screening in Pregnancy

Toxoplasma gondii is a widespread parasite responsible for toxoplasmosis, an infection that often lacks clear symptoms but can have severe consequences, particularly in pregnant women. Accurate detection is crucial for managing this disease during pregnancy, where cases of congenital toxoplasmosis can lead to serious fetal complications, particularly in the first and second trimesters. Recently published study evaluates various serological tests that measure Toxoplasma antibodies, specifically IgM, IgG avidity, and IgA, focusing on their diagnostic effectiveness for acute toxoplasmosis.

Prevalence of Toxoplasma Infections

A systematic review and meta-analysis reinforced that Toxoplasma infections are prevalent among pregnant women, with a reported nine infections per 10,000 pregnancies. The study highlights that the stage of infection greatly affects fetal health. A noteworthy finding is the prevalence of IgG antibodies in 39% of pregnant women studied, while only 2.3% showed IgM positivity and 43% had IgA antibodies, underlining the complexity in interpreting serological tests. Notably, the detection of IgM can produce false positives due to various factors, which complicates diagnosis and may lead to unnecessary anxiety and medical interventions.

Effectiveness of IgG Avidity Testing

The effectiveness of IgG avidity testing in distinguishing between acute and chronic infections is emphasized, as acute infections are associated with low avidity antibodies that transition to high avidity over time. By employing IgG avidity alongside IgM and IgA tests, healthcare providers can achieve more accurate assessments of acute infections. IgA testing shows promise as an additional marker for recent infection, although its reliability has been debated. Despite the evident benefits of these serological tests, the study notes significant variability in testing and diagnostic guidelines across different countries, suggesting that improved screening practices are necessary. Mandatory testing protocols exist in some regions, while others, such as the U.S. and Canada, do not recommend it, potentially leaving gaps in early detection.

Conclusion and Recommendations

In conclusion, the findings advocate for integrating multiple serological methodologies, particularly IgG avidity and IgA tests, for more reliable differentiation between recent and past infections. The study calls for ongoing advancements in diagnostic techniques to enhance care management for pregnant women, aligning with global health initiatives aimed at reducing preventable maternal and child health issues related to toxoplasmosis.

Key Points

- Toxoplasma gondii is a common parasite linked to toxoplasmosis, which can have severe consequences for pregnant women, especially leading to congenital complications in fetuses during the early stages of pregnancy. The importance of accurate detection methods for managing this risk is emphasized.

- A systematic review reveals the prevalence of Toxoplasma infections in pregnant women at approximately nine infections per 10,000 pregnancies. The analysis highlights IgG antibodies present in 39% of subjects, with a low IgM positivity rate of 2.3%. Additionally, 43% of participants tested positive for IgA, indicating complexities in interpreting serological results.

- The study underscores the significance of IgG avidity testing, which aids in differentiating acute infections from chronic ones, as the latter is characterized by an increase in antibody avidity over time. Combining IgG avidity with IgM and IgA tests enhances diagnostic accuracy for acute infections.

- While IgA has potential as a marker for recent infection, concerns regarding its reliability persist. The findings stress the necessity for more standardized testing procedures to improve outcomes, noting existing disparities in testing guidelines by geographic region.

- Variability in diagnostic protocols across countries is mentioned, with some regions enforcing mandatory testing while others (like the U.S. and Canada) do not, potentially hindering timely detection and intervention for toxoplasmosis.

- The study advocates for a multi-faceted approach in serological testing, particularly suggesting the integration of IgG avidity and IgA tests to better distinguish between recent and historical infections, alongside recommending ongoing advancements in diagnostic approaches to support global health efforts aimed at minimizing maternal and child health risks associated with toxoplasmosis.

Reference –

M. Tork et al. (2025). Assessment Of Simultaneous IgM, IgG Avidity, And IgA Testing In Diagnosis Of Acute Toxoplasmosis In Pregnant Women: A Systematic Review And Meta-Analysis Study. *BMC Pregnancy And Childbirth*, 25. https://doi.org/10.1186/s12884-025-07580-6.