I recently had a positive blood test for toxoplasmosis. I was told by my doctor that it was not necessary to take any medication, and that the disease was almost over. I am to have another blood test in a couple of months to see if the IgG has stabilized. I thought that once you got toxoplasmosis you had to take medication for life? The doctor also said I could eat all the raw meat I wanted to now since I would be immune to toxo. Is that accurate?

Carmen

Toxoplasmosis is an infection in cats and other animals, including humans, caused by a parasite called Toxoplasma gondii. People can be infected when they eat undercooked meat (usually pork) from an infected animal or consume food or water contaminated with cat feces containing the parasite's eggs. In most cases, infected adults have minimal or no symptoms. When the infection does cause illness, the symptoms resemble those of infectious mononucleosis (mono): fever, sore throat and enlarged lymph nodes in the neck. Even without treatment, this syndrome resolves on its own and is almost always benign.

In most people, however, the parasite persists indefinitely in a dormant state. Toxoplasmosis rarely becomes a problem again in individuals with normal immune systems, although in some people -- particularly those infected before birth -- the organism may reactivate and infect the retina of the eye, sometimes resulting in serious eye disease, even blindness. In people with weakened immune systems, such as AIDS patients or individuals who have received an organ transplant, a new toxoplasmosis infection -- or more often, reactivation of a latent infection -- can cause serious illness. In AIDS patients, toxoplasmosis most commonly results in encephalitis, a serious brain infection. In transplant patients, especially those receiving a heart, the parasite typically invades the transplanted organ. Without treatment, the infection is usually fatal in patients with impaired immunity.

If a pregnant woman becomes newly infected with toxoplasmosis -- which can occur without her being aware of the infection -- the disease may affect her unborn baby. Routine screening tests pick up most of these cases, and doctors follow standard procedures designed to prevent, detect and treat infection in the fetus. If not treated, severe infections of the fetus during early pregnancy can result in stillbirth and birth defects. Babies infected late in pregnancy usually show no signs of illness at birth but can still have subtle abnormalities, especially in neurologic development. Also, these babies are at risk of developing toxoplasmosis-related eye problems later in life.

You say you have a positive test for toxoplasmosis. I wonder why you had the test done. If you are planning to become pregnant, perhaps your obstetrician was screening to see if you were at risk of becoming newly infected with the parasite during pregnancy or whether you had acquired the infection in the past. If you had the test as a routine part of pre-pregnancy care, then the most likely scenario is that you had been infected in the past. (Some studies have found that about 25 percent of people tested are infected.) This would mean that you have very little risk of infecting your future babies, because only a newly acquired toxoplasmosis infection poses risk to the fetus. Repeat testing would confirm whether you were infected recently or not. Most experts would recommend avoiding pregnancy for a few months after a new infection.

On the other hand, if you were ill and had the test done to diagnose whether the cause of your illness was toxoplasmosis, repeat testing after a positive result would help confirm the diagnosis. You almost certainly need no therapy because treatment is unnecessary in patients who are not pregnant and who have no known immune impairment or toxoplasmosis-related eye problems.

With regard to your question about eating raw meat, although you need not be concerned about getting toxo again, you could get E. coli and a host of other infections. Raw meat can be contaminated (and usually is) with all kinds of bacteria, including the microbes found in the bowel of the animal the meat came from. Ground meat (such as that used to make hamburgers) can be especially dangerous because the act of grinding can spread surface contamination throughout the meat. Ground meat should be cooked through until it is no longer pink.