Â鶹´«Ã½É«ÇéƬ

News

This common parasite causes birth defects — but the US doesn’t screen for it during pregnancy

Bill Sullivan
Sept. 1, 2024

Imagine the shock of your baby being born with a swollen brain, blindness and debilitating seizures. Now imagine learning that these devastating conditions could have been prevented if you took a simple test for the common parasite .

Toxoplasma can be picked up anywhere an infected cat has defecated, such as the litter box, sandbox, garden or yard. Other routes of infection include consumption of contaminated water, undercooked meat or shellfish. Most people experience mild illness and can get the infection under control.

Toxoplasma gondii is a single-celled parasite.
Toxoplasma gondii is a single-celled parasite.

However, if contracted for the first time while pregnant, Toxoplasma can cross the placenta and cause spontaneous abortion or serious birth abnormalities. Such mother-to-child transmission during pregnancy is called . may be born with congenital toxoplasmosis in the U.S. each year.

As at the Indiana University School of Medicine, I study the biology of Toxoplasma in my lab. can monitor the amount of Toxoplasma antibodies in the parent. Increases indicate an acute infection is taking place, putting the fetus at risk of congenital toxoplasmosis. However, to pregnant people who develop toxoplasmosis can help protect the fetus from the worst outcomes of congenital toxoplasmosis.

Several nations, such as France and Austria, have been during pregnancy for decades. Brazil recently started a similar program.

However, Toxoplasma testing is not included in prenatal screening in the U.S.

Why screen for toxoplasmosis during pregnancy?

Toxoplasma is a widespread and stealthy infection. Over are infected with the parasite, underscoring how easy it is to catch. And since the infection usually doesn’t cause overt symptoms, many mothers of infected babies they became infected.

Studies conducted in multiple countries have demonstrated the benefits of detecting and treating toxoplasmosis during pregnancy.

Some countries, such as France, have implemented routine prenatal toxoplasmosis screening and treatment.
Some countries, such as France, have implemented routine prenatal toxoplasmosis screening and treatment.

The first randomized clinical trial assessing the efficacy and safety of a treatment to reduce toxoplasmosis transmission prenatally, , published its findings in 2018. Although the trial was halted due to lack of funding, results suggested that treatment not only reduced infection transmission, but also decreased disease severity for breakthrough infections.

A meta-analysis of 33 studies published from 2017 to 2021 also found that pregnant women given the antibiotic spiramycin also showed to their unborn child compared with untreated mothers.

For Jose Montoya, a toxoplasmosis researcher and clinician at the , the value of screening is clear. “In countries that perform prenatal screening for toxoplasmosis, the than what is routinely observed in the U.S.,” he said.

Congenital toxoplasmosis may be more common than believed

Some have argued that congenital toxoplasmosis is too rare to warrant prenatal testing. But the U.S. currently screens for conditions that are even rarer than toxoplasmosis, .

The incidence of congenital toxoplasmosis may also be underestimated. Currently, there are no national surveillance data on toxoplasmosis available, as it is not a in the U.S. Since most states do not monitor or report this infection during pregnancy, researchers don’t know how many miscarriages are caused by Toxoplasma or how many children suffer from the infection.

A 2021 report by the Centers for Disease Control and Prevention highlighted the , stating that routine, standardized testing during pregnancy would provide crucial data to evaluate the scope of this threat to babies. Additionally, it would inform researchers on the causes of the in the U.S., which .

A pregnant person can transmit toxoplasmosis to their developing baby.

Some researchers have warned that Toxoplasma prevalence may and climate change. Free-range animals are more prone to pick up infectious Toxoplasma oocysts in outdoor pastures and water sources, which have a higher likelihood of being contaminated with cat feces. Warmer temperatures and more powerful storms due to climate change in the environment – for example, through increased soil erosion polluting waterways.

Additionally, reports of migrating from South America may exacerbate the severity of congenital toxoplasmosis infections in the U.S.

Costs of toxoplasmosis during pregnancy

“This disease not only has a steep physical and emotional cost, but also an important economic one,” said , director of the Toxoplasmosis Center at the University of Chicago.

A study McLeod conducted in 2011 estimated that following France’s prenatal screening and treatment model could save U.S. taxpayers .

Researchers have also developed new technologies that reduce concerns about the testing costs.

McLeod’s team developed an that detects Toxoplasma within 30 minutes. Other researchers have also developed a .

How to avoid toxoplasmosis

Avoiding litter duty while pregnant can help protect you from toxoplasmosis.
Avoiding litter duty while pregnant can help protect you from toxoplasmosis.

Toxoplasma produces significant, lifelong neurological and vision impairments in hundreds of babies born in the U.S. each year. Congenital toxoplasmosis can be largely mitigated with that are safe and easy to perform.

“Those who conducted the Toxogest clinical trial did not incorporate a placebo control because it was deemed unethical not to monitor and treat congenital toxoplasmosis,” Montoya said. “But currently, pregnant people in the U.S. are being relegated into such a placebo group – denied simple, low-cost procedures that could save their children from birth defects.”

Without systematic prenatal testing for congenital toxoplasmosis, the best that pregnant people can do is become . Those who are pregnant should avoid cleaning the litter box and other areas where cats may have defecated. Fruits and vegetables should be washed before consuming. Meat products should be cooked to proper temperature.

This article is republished from under a Creative Commons license. Read the .

The Conversation

Enjoy reading ASBMB Today?

Become a member to receive the print edition four times a year and the digital edition weekly.

Learn more
Bill Sullivan

Bill Sullivan is a professor at Indiana University School of Medicine and the author of several books.

Related articles

From the journals: JLR
Swarnali Roy
Summertime can be germy
Bill Sullivan
From the journals: JBC
Ken Farabaugh
From the journals: JBC
Isabel Casas
The other malaria parasite
Rajendrani Mukhopadhyay

Get the latest from ASBMB Today

Enter your email address, and we’ll send you a weekly email with recent articles, interviews and more.

Latest in Science

Science highlights or most popular articles

Elucidating how chemotherapy induces neurotoxicity
Award

Elucidating how chemotherapy induces neurotoxicity

Dec. 2, 2024

Andre Nussenzweig will receive the Bert and Natalie Vallee Award at the 2025 ASBMB Annual Meeting, April 12–15 in Chicago.

Where do we search for the fundamental stuff of life?
Essay

Where do we search for the fundamental stuff of life?

Dec. 1, 2024

Recent books by Thomas Cech and Sara Imari Walker offer two perspectives on where to look for the basic properties that define living things.

UCLA researchers engineer experimental drug for preventing heart failure after heart attacks
News

UCLA researchers engineer experimental drug for preventing heart failure after heart attacks

Nov. 30, 2024

This new single-dose therapy blocks a protein that increases inflammation and shows promise in enhancing muscle repair in preclinical models.

The decision to eat may come down to these three neurons
News

The decision to eat may come down to these three neurons

Nov. 28, 2024

The circuit that connects a hunger-signaling hormone to the jaw to stimulate chewing movements is surprisingly simple, Rockefeller University researchers have found.

Curiosity turned a dietitian into a lipid scientist
Award

Curiosity turned a dietitian into a lipid scientist

Nov. 27, 2024

Judy Storch will receive the Avanti Award in Lipids at the 2025 ASBMB Annual Meeting, April 12–15 in Chicago.

From receptor research to cancer drug development: The impact of RTKs
Award

From receptor research to cancer drug development: The impact of RTKs

Nov. 26, 2024

Joseph Schlessinger will receive the ASBMB Herbert Tabor Research Award at the 2025 ASBMB Annual meeting, April 12–15 in Chicago.