Toxoplasmosis

Toxoplasmosis is a human parasitic disease caused by the parasite Toxoplasma gondii. People can get infected by eating raw meat or by contact with cat faeces. Congenital toxoplasmosis is a special form in which an unborn child is infected via the placenta. The danger of congenital toxoplasmosis is the reason that pregnant women should avoid contact with cats.

At least one third of the world population may have had a toxoplasmosis infection in their lifetime, but the parasite rarely causes any symptoms in otherwise healthy adults. People with a weakened immune system are susceptible, such as people infected with HIV. The parasite can cause encephalitis (infection of the brain) and neurologic diseases and can affect the heart, liver, and eyes (chorioretinitis).

Treatment is very important for infected pregnant women, to prevent infection of the foetus. But even with antibiotics the parasite cannot be killed completely and the infection can come back later.

Table of contents

1 How can I get toxoplasmosis? 2 What are the symptoms of toxoplasmosis? 3 Who is at risk for severe toxoplasmosis? 4 Human prevalence 5 References

How can I get toxoplasmosis?

• Through accidental ingestion of contaminated cat feces. This can occur if you accidentally touch your hands to your mouth after gardening, cleaning a cat’s litter box, or touching anything that has come into contact with cat feces.
• Through ingestion of raw or partly cooked meat, especially pork, lamb, or venison, or by touching your hands to your mouth after handling undercooked meat.
• Through contamination of knives, utensils, cutting boards and other foods that have had contact with raw meat.
• Through drinking water contaminated with Toxoplasma.
• Although extremely rare, by receiving an infected organ transplant or blood transfusion.

What are the symptoms of toxoplasmosis?

You may feel like you have the "flu," swollen lymph glands, or muscle aches and pains that last for a month or more. Rarely, a person with a "normal" immune system may develop eye damage from toxoplasmosis. However, most people who become infected with toxoplasmosis do not know it. Persons with weak immune systems, such as infants, those with HIV/AIDS, those taking certain types of chemotherapy, or persons who have recently received an organ transplant, may develop severe toxoplasmosis. This can cause damage to the brain or the eyes. Most infants who are infected while in the womb have no symptoms at birth but may develop symptoms later in life. Only a small percentage of infected newborns have serious eye or brain damage at birth.

Who is at risk for severe toxoplasmosis?

• Infants born to mothers who became infected with Toxoplasma for the first time DURING or JUST BEFORE pregnancy.
• Persons with severely weakened immune systems, such as persons with AIDS. This results from an acute Toxoplasma infection or an infection that occurred earlier in life that reactivates and causes damage to the brain, eyes, or other organs.

Human prevalence

In the U.S. NHANES III national probability sample, 22.5% of 17,658 persons >12 years of age had Toxoplasma-specific IgG antibodies, indicating that they had been infected with the organism.

References

• CDC factsheet: Toxoplasmosis
• CDC document: Toxoplasma gondii Infection in the United States, 1999–2000

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Note: parts of this article are taken from the public domain CDC document CDC factsheet: Toxoplasmosis.