FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

TOXOPLASMOSIS USUALLY NOT A WORRY, UNLESS YOU'RE PREGNANT

Question: I have two cousins who both tested positive for toxoplasmosis. They are suspicious that their mother passed it on to them. One of them thinks she later passed it on to her baby. Would you please explain toxoplasmosis. How does one contract it, and is it possible to pass it on to your baby?

Answer: Toxoplasmosis is a worldwide problem. In the United States about 50 percent of us have had this infection. This illness is caused by a microscopically small animal (protozoan) that invades and then sets up housekeeping inside our body's cells. It isn't particularly picky where it calls home as it can lodge in essentially every type of cell in the human body. The severity of the infection and the particular cells that are involved determine the significance of this illness.

Since 50 percent of us have had toxoplasmosis, yet it isn't a common topic of discussion, you can correctly assume that infection usually results in very few symptoms. Typically, infection results from swallowing or breathing in an immature form, technically a cyst or oocyst, of the microscopic protozoan (Toxoplasma gondii). The infection reaches the bloodstream, which then rapidly spreads it to any cell of the body. The body's immune system reacts to kill this invader. This happens so quickly that 80 percent of us never have any symptoms of this assault and our body's effective counterattack. The remaining 20 percent usually develop swollen lymph glands and just don't feel well.

In toxoplasmosis infection, the body kills most of the protozoans, but some survive by walling themselves off inside a cyst. These rarely cause a problem, unless they are within the eye or if the individual's immune system loses effectiveness, as can occur with AIDS and other illnesses.

While, as you can see, the course of toxoplasmosis is relatively benign for most people, it can be a real hazard to unborn babies. The expectant mother must become infected during her pregnancy in order to pass the infection on to the baby. A woman who has had toxoplasmosis before pregnancy cannot give the infection to her baby. So, if your aunt had toxoplasmosis during one of her pregnancies, she may have passed the illness on to one of your cousins, but your cousin couldn't then pass it on to her baby, because your cousin had the infection years before her pregnancy with that baby.

Between two and five out of every 1,000 pregnancies in the world are complicated by toxoplasmosis infection, but in only 40 percent of these pregnancies does the baby also become infected. Of these infected babies, about one half have no symptoms of illness. Their infection can only be identified by blood tests. In the remaining group, the baby may be stillborn or suffer neurological damage, including seizures, retardation and fluid on the brain. Fever, enlarged spleen and liver, and rash also occur. Infections acquired during the second month through the end of the sixth month of pregnancy are more likely to cause severe disease in the baby than are third-trimester infections.

Prevention of toxoplasmosis in pregnancy is of major importance for mom, baby, and society. Pregnant women should minimize contact with cats, especially strays or cats who eat raw meat, since they are major carriers of this disease. A woman who is trying to conceive and has a house cat that doesn't roam outdoors is at low risk. However, it is still wise for her to wash her hands after contact with the cat, and she should have another person empty the litter box daily. If the pet cat runs loose, the risks are significantly higher. Perhaps it would be wiser to send the cat to live with friends until after the baby is born. In addition, pregnant women should wash all fruits and vegetables before eating them, and they should not eat undercooked meat.

Fortunately there is effective treatment for toxoplasmosis, including for newborns, and early intervention can greatly reduce the risk of developing serious complications of this common disease.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.