T. gondii infections have the ability to change the behavior of rats and mice, making them drawn to rather than fearful of the scent of cats. This effect is advantageous to the parasite, which will be able to sexually reproduce if its host is eaten by a cat. The infection is highly precise, as it does not affect a rat’s other fears such as the fear of open spaces or of unfamiliar smelling food.
Studies have also shown behavioral changes in humans, including slower reaction times and a sixfold increased risk of traffic accidents among infected males, as well as links to schizophrenia including hallucinations and reckless behavior. Additionally, studies of students and conscript soldiers in the Czech Republic in the mid-1990s highlighted the fact that infected people showed different personality traits to uninfected people—and that the differences depended on sex. Infected women were more likely to become more outgoing and showed signs of higher intelligence, while men became aggressive, jealous and suspicious.
Most people I have tested have this parasite. It is so common you probably need these frequencies. Most cases of the swine flu include this parasite.