Scientist developing vaccine

UW–Madison researchers are developing a vaccine against Toxoplasma gondii, a parasite that is the third-leading cause of foodborne deaths in the United States.

The parasite is found in warm-blooded animals as a dormant cyst in muscle or brain tissue, or as an actively dividing form. Meat animals, such as hogs and sheep, harbor the dormant cyst. In cats, the actively dividing form can develop into an oocyst that is shed in its feces. Humans contract toxoplasmosis when they eat undercooked meat, drink contaminated water or contact contaminated cat feces. Once an animal (or person) is exposed to the parasite, it remains a host for life.

Microbiologist Laura Knoll and her colleagues are developing a strain of Toxoplasma that can’t form cysts. Knoll believes this strain could be used in a meat-animal vaccine, which would greatly reduce human exposure.

Although most exposures produce mild, flu-like symptoms, some people are at risk for severe complications.