What is toxoplasmosis?

Toxoplasmosis is an infection caused by a single-celled parasite called Toxoplasma gondii. While the parasite is found throughout the world, more than 40 million people in the United States may be infected with the Toxoplasma parasite. The Toxoplasma parasite can persist for long periods of time in the bodies of humans (and other animals), possibly even for a lifetime. Of those who are infected however, very few have symptoms because a healthy person’s immune system usually keeps the parasite from causing illness. However, pregnant women and individuals who have compromised immune systems should be cautious; for them, a Toxoplasma infection could cause serious health problems.

How do people get toxoplasmosis?

A Toxoplasma infection occurs by one of the following:

- Eating undercooked, contaminated meat (especially pork, lamb, and venison) or shellfish (for example, oysters, clams or mussels).

- Accidental ingestion of undercooked, contaminated meat or shellfish after handling them and not washing hands thoroughly (Toxoplasma cannot be absorbed through intact skin).

- Eating food that was contaminated by knives, utensils, cutting boards and other foods that have had contact with raw, contaminated meat or shellfish.

- Drinking water contaminated with Toxoplasma gondii.

Accidentally swallowing the parasite through contact with cat feces that contain Toxoplasma. This might happen by:

- Cleaning a cat’s litter box when the cat has shed Toxoplasma in its feces;

           - Touching or ingesting anything that has come into contact with cat feces that contain Toxoplasma; or

           - Accidentally ingesting contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits or vegetables from a garden).

           - Mother-to-child (congenital) transmission.

           - Receiving an infected organ transplant or infected blood via transfusion, though this is rare.