Toxoplasmosis test explained

Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. MedlinePlus states that this parasite is found in people all over the world and in many species of animals and birds, and that it also lives in cats. A person can become infected through a blood transfusion or an organ transplant, when handling cat litter, by eating food that has come into contact with contaminated soil, or by eating raw or undercooked meat (lamb, pork, beef). The infection can also pass from an infected mother to the fetus through the placenta — this is called congenital toxoplasmosis.

There are often no symptoms at all; if they do appear, this usually happens about 1–2 weeks after exposure to the parasite. The disease can affect the brain, lungs, heart, eyes or liver, and in people with weakened immunity symptoms appear more often and can be more severe. A blood test for toxoplasmosis is one of the tests a doctor may order together with a physical examination in order to assess whether there is an infection.

• During pregnancy — MedlinePlus states that pregnant women should be tested for toxoplasmosis (MedlinePlus)
• With HIV/AIDS — these people should also be tested for toxoplasmosis (MedlinePlus)
• When immunity is weakened and symptoms appear, for example confusion or seizures (MedlinePlus)
• When an infection is suspected because of symptoms — enlarged lymph nodes, headache, fever, a mononucleosis-like illness, muscle pain or vision disturbances (MedlinePlus)
• As part of the tests when a doctor carries out a physical examination and assesses possible exposure to the parasite (MedlinePlus)

The result of a toxoplasmosis blood test is positive or negative. The cause and the next steps are assessed by a doctor — MedlinePlus describes this blood test as one of the tests a doctor may order together with a physical examination in order to assess whether there is an infection.

A positive result

A positive toxoplasmosis blood test result shows infection with the parasite Toxoplasma gondii. MedlinePlus states that people without symptoms usually do not need treatment, but that when symptoms are present medicines are prescribed (antiparasitic preparations, antibiotics); for pregnant women, infants and people with weakened immunity the result is assessed more cautiously, because the infection can be more severe for them.

What can lie behind a positive result

• Contact with a cat litter box, or with soil contaminated with cat faeces
• Eating raw or undercooked meat (lamb, pork, beef)
• A blood transfusion or an organ transplant
• Infection from the mother through the placenta (congenital toxoplasmosis)
• An earlier exposure to the parasite that has already passed

Symptoms that can occur

• Enlarged lymph nodes in the head and neck area
• Headache and fever
• A mononucleosis-like illness, muscle pain, sore throat
• Vision disturbances
• When immunity is weakened — confusion, seizures, blurred vision due to inflammation of the retina

What a doctor usually assesses alongside a positive result

• Whether there are symptoms and how long they have been going on
• Whether the immune system is weakened by an illness or by medicines
• Whether further tests are needed — a head CT scan, a brain MRI scan, an eye examination with a slit lamp
• In pregnancy — which further tests are ordered to assess the fetus
• When to seek help urgently — if symptoms appear in a baby or in someone with a weakened immune system, and also if confusion or seizures appear (MedlinePlus)

Related pages

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