USDA’s AgResearch Magazine reports that Toxoplasma gondii is a parasite that has infected an estimated one-fourth of the world’s population—potentially more than 1 billion people—including about 50 million in the United States. This makes T. gondii the most widespread parasite in the world. This one-celled parasite, invisible to the naked eye, causes a human disease called “toxoplasmosis.” It can lead to serious health complications in people with weakened immune systems and in infants born to infected mothers. Prevention is key.

