What Is Toxoplasma?
What Is Toxoplasmosis? Symptoms, Tests and Precautions During Pregnancy
Toxoplasmosis is an infection caused by a parasite called Toxoplasma gondii. In many people with a healthy immune system, it causes no symptoms or only mild, flu-like symptoms. An infection acquired for the first time during pregnancy can be transmitted to the baby; in people with a weakened immune system, it can cause more serious illness.
How is toxoplasmosis transmitted?
The infection can be acquired through:
- Eating undercooked or raw meat
- Contact with soil, water, vegetables or fruit contaminated with the parasite
- Touching cat litter or soil contaminated with infected cat faeces and then touching the mouth without washing the hands
Owning a cat does not in itself mean you have an infection. The risk of transmission is particularly associated with ingesting material contaminated with faeces. Toxoplasmosis is not transmitted directly by stroking a cat, holding it on your lap or living in the same home.
What are the symptoms of toxoplasmosis?
The infection may cause no symptoms in most people. When symptoms occur, they may include a mild fever, fatigue, muscle pain or swollen lymph nodes. Eye involvement or serious illness affecting the brain and other organs can develop, particularly in people with a weakened immune system. During pregnancy, the absence of symptoms does not in itself indicate that there is no infection.
How is testing for toxoplasmosis performed?
As part of the initial assessment, Toxoplasma IgG and IgM antibodies may be measured in the blood. Results are assessed alongside the person's symptoms, pregnancy status, previous tests and the timing of the test.
- IgG positive, IgM negative: Usually suggests a past infection; this alone does not indicate the exact timing of the infection.
- Both IgG and IgM positive: In addition to the possibility of a recent infection, IgM may remain positive for a long time or the result may be falsely positive. Further assessment may be needed, particularly during pregnancy.
- IgG negative, IgM positive: This may indicate a very early infection or a false-positive result; the doctor may request repeat testing or confirmatory testing.
A positive IgM result alone does not prove a recent infection. Additional tests, such as IgG avidity testing, comparison of serial blood samples or testing by a specialist laboratory, may be needed to confirm uncertain results during pregnancy. Low avidity alone does not definitively determine the timing of the infection; the result should be interpreted in conjunction with the test used and the gestational age.
If transmission of the infection to the baby is suspected during pregnancy, an obstetrician may arrange investigations such as ultrasound and, where appropriate, PCR testing of amniotic fluid, in addition to maternal blood tests. These assessments should be carried out by a specialist physician.
A blood sample can be provided at Wellcare Laboratories for Toxoplasma IgG and IgM tests. It is important that the results are assessed by a doctor, particularly during pregnancy.
How can you prevent toxoplasmosis during pregnancy?
- Cook meat thoroughly; do not eat raw or undercooked meat.
- Wash vegetables and fruit thoroughly.
- Wear gloves when gardening or handling soil, and wash your hands afterwards.
- If possible, have someone else change the cat litter. If this is not possible, wear gloves, clean the litter daily and wash your hands afterwards.
- Do not feed cats raw or undercooked meat.
Toxoplasmosis screening and the timing of tests may vary by country and clinical circumstances; discuss the need for testing during pregnancy with your doctor.
Can toxoplasmosis be treated?
The need for treatment depends on the person's symptoms, immune status and whether they are pregnant. Many people who have no symptoms and a healthy immune system may not need treatment. In cases of a possible recent infection during pregnancy or in people with a weakened immune system, the decision to treat should be made by the relevant specialist physician.
Frequently asked questions
Does a positive Toxoplasma IgM result mean I have had a recent infection?
Not on its own. IgM can remain positive for a long time or may be falsely positive. Additional tests and a doctor's assessment may be needed, particularly during pregnancy.
Should I be tested for toxoplasmosis if I have a cat?
Owning a cat does not in itself mean you have an infection. The need for testing is assessed by a doctor based on exposure history, symptoms, pregnancy and other clinical findings.
Is toxoplasmosis transmitted only through cat faeces?
No. Undercooked meat and contaminated soil, water, vegetables or fruit can also be sources of infection.