Toxoplasmosis is an infection that is caused by contact with a microscopic parasitic organism called Toxoplasma gondii. When contracted by a pregnant woman, it can pose a serious risk to her unborn baby.
Most cases of toxoplasmosis go undiagnosed, because symptoms, if any, resemble those of the flu. Infection is often picked up by eating raw or undercooked meat that is contaminated with the parasite or through exposure to cat feces.
Maternal infection during pregnancy can be transmitted to the fetus causing lesions of the fetal central nervous system.
People can get infected with toxoplasmosis by eating undercooked meat or meat products (lamb, beef, or game, including salami), having contact with soil, or by inhaling or swallowing infected cat litter. When cats (and only cats) become infected with toxoplasmosis, they harbor the toxoplasma "oocytes" in their intestines. These oocytes are excreted through their feces into the cat litter. This is the so-called 'intestinal phase' of the toxoplasma life cycle and it occurs in cats only (wild as well as domesticated cats). The oocytes can be inhaled or swallowed and infect others, or if the cat feces goes into the earth, people and other animals can get it when the soil gets into their mouths. The extraintestinal phase occurs in all infected animals (including cats) who come in contact with the oocytes. Infected animals (including humans) produce "tachyzoites" and, eventually, "bradyzoites" or "zoitocysts." These tacgyzoites, bradyzoites, and zoitocysts reside in muscle, and when you (or other animals) eat undercooked meat, you can get infected.
You can also get infected with toxoplasma by putting infected soil into your mouth (always wash your hands!) or by eating undercooked meat (including salami and other similar foods) from an animal who has become infected. Cats are the only animals excreting the oocytes in their feces.
Should I get tested?
There is no recommendation to routinely test all pregnant women for toxoplasmosis.
The problem with getting tested for the first time in pregnancy is that if you test positive sometimes it's difficult to find out exactly when the infection happened.
A good time to be tested is therefore before pregnancy. If you test positive, then you know you have partial immunity. If you test negative, then becoming infected for the first time during pregnancy may pose a risk to the fetus.
In areas where infections are high (eg in France or Germany), women who initially test negative are often tested again early in the third trimester (around 288 weeks of the pregnancy) to confirm that they have not become infected since the last examination.
If you test positive for the IgM immunoglobulin then a more recent infection is possible and additional testing in specialized laboratories are need to find out more about when the initial infection happened.