Your Cat's Parasite Is Making You Poorer: Toxoplasmosis Linked to Unemployment and Income Loss
A 2025 study out of the University of Zurich has put hard numbers on what Toxoplasma gondii does to your bank account. People infected with the cat-borne brain parasite earn approximately 2,500 pounds less per year than those who are not infected, and they are 11 percent more likely to be unemployed.
These are not small effects. They are population-level economic damage caused by a single-celled organism that can only complete its reproductive cycle inside a cat's gut.
What the Study Found
Researcher Carlos Alos-Ferrer and his team developed a novel detection method based on cognitive task response times that achieved 97 percent agreement with blood tests among Rhesus-negative individuals. This allowed them to screen a large UK population sample without expensive blood draws.
The results confirmed what smaller studies had hinted at for years. Toxoplasma gondii disrupts dopamine, serotonin, and testosterone levels in infected individuals. The downstream behavioral effects include increased impulsivity, reduced self-control, and higher rates of smoking, drinking, and substance abuse.
The Entrepreneur Paradox
Here is where it gets strange. A separate study from the University of Colorado found that T. gondii-positive students were 1.4 times more likely to major in business and 1.7 times more likely to focus on management and entrepreneurship. Infected business professionals were 1.8 times more likely to have started their own company.
The parasite makes you take more risks. Sometimes that means launching a startup. More often, according to the economic data, it means gambling with your career, your savings, and your stability in ways that leave you worse off.
Country-level data tells the same story. Nations with higher T. gondii infection rates show more entrepreneurial activity but also greater economic insecurity and weaker institutional trust. The risk-taking the parasite induces is not the calculated, strategic kind. It is the impulsive, dopamine-chasing kind.
The Scale of Infection
Between 10 and 30 percent of the American population carries Toxoplasma gondii. In France, it is closer to 50 percent. Brazil, upwards of 60 percent. Globally, roughly a third of all humans are infected.
Cats are the only definitive host. The parasite can only sexually reproduce inside the feline intestine. A single infected cat sheds millions of oocysts in its feces over a two-week period. Those oocysts survive in soil and water for over a year.
There is no cure. Once you are infected, the parasite forms cysts in your brain tissue that persist for life. Your immune system walls them off but cannot eliminate them. The behavioral effects -- the impulsivity, the risk-taking, the income loss -- continue as long as you live.
Watch: SciShow Psych -- How Parasites in Your Cat Can Infect Your Brain