MONDAY, Dec. 10 (HealthDay News) -- New research reveals how toxoplasma -- a parasite commonly found in cat litter boxes -- might affect behavior and mental health in humans.

Between 30 and 50 percent of the world's population is believed to be infected with the Toxoplasma gondii parasite, but very few people have symptoms because the immune system usually keeps the parasite from causing illness. T. gondii is also found in animals, particularly domestic cats.

[link to health.usnews.com]