Prenatal testing urged for 'cat box' infection

/ Source: The Associated Press

Janet Morel doesn’t know whether it was the undercooked eggs she ate while she was pregnant or parasites from the pet cat that caused her daughter Dana’s blindness and brain damage.

Morel and her husband face a lifetime of caring for Dana, who is now 17. Doctors blame Dana’s problems on toxoplasmosis, which is why Morel supports a call for routine testing of pregnant women and infants for the parasitic infection.

“If you could see my daughter, you would understand why it is I feel so strongly about this,” said Morel, of Scottsdale, Ariz.

Few pregnant women or infants are routinely tested for toxoplasmosis, which can cause blindness and brain damage in babies. The infection can be contracted during pregnancy if a woman cleans a cat litter box, gardens or eats raw eggs or meat.

The infection is caused by the parasite Toxoplasma gondii, which can infect all animals and can be found in the ground. Cats spread the parasite in their feces.

A group of doctors who treat children born with the infection are calling for routine screening of pregnant women and infants.

It is not clear how big a risk toxoplasmosis is. Some studies suggest about 1 out of 1,000 babies is born with it; but in Massachusetts, which has routinely tested newborns for it for almost 20 years, only about 1 in 15,000 has turned up with toxoplasmosis.

New Hampshire is the only other state that tests all babies for the infection.

“What it takes is a little push to get this going,” said Dr. Kenneth Boyer, pediatrics chairman at Rush University Medical Center, who led a study on the infection’s risk factors with Dr. Rima McLeod of University of Chicago’s Toxoplasmosis Center. “I believe our paper ought to be a push in that direction.”

False positives worry parents
The research, published in the February issue of the American Journal of Obstetrics and Gynecology, found that even if doctors ask all the right questions to find known risk factors, they miss about half the women who give birth to babies with toxoplasmosis.

Some infected babies are born with no obvious symptoms and damage becomes apparent later. Others, like Dana Morel, have severe symptoms at birth.

Daily treatment during an infected baby’s first year of life can prevent some serious symptoms, Boyer said, but even that is not 100 percent effective.

Another problem with universal screening is that the test isn’t always accurate and can worry parents needlessly by turning up positive when there is no infection.

Universal testing also adds to health care costs, said Roger B. Eaton, director of the New England Newborn Screening Program at the University of Massachusetts Medical School.

But Eaton considers the testing cost-effective. In Massachusetts, it’s one of several newborn screening tests that together cost $55.

The study looked at 131 babies with toxoplasmosis who were referred to the Chicago Collaborative Treatment Trial, a project funded by the National Institutes of Health.

Researchers interviewed the children’s mothers, asking whether they owned cats, cleaned litter boxes, gardened or ate uncooked meat while pregnant.

The researchers also asked the women if they had flu-like symptoms or swollen lymph nodes during pregnancy.

Half the women recalled no symptoms or risk factors, the researchers found. Boyer said that shows that normal prenatal care, which involves such interview questions but no blood test, potentially misses about half the cases of toxoplasmosis during pregnancy.

The American College of Obstetrics and Gynecology does not recommend routine prenatal testing for toxoplasmosis.

Standard advice for pregnant women includes a warning not to clean cat litter boxes. Pregnant women also should wear gloves while gardening and avoid eating raw or undercooked food. Shellfish and untreated water are new suspected culprits, according to the study.