Parasite Found in Cat Feces May Make You More Entrepreneurial

People infected with a common parasite found in cat feces are more likely to display entrepreneurial behaviors and have a reduced "fear of failure" when starting a new business, according to an international study published in the journal Proceedings of the Royal Society B.

The parasite—known as Toxoplasma gondii—infects a staggering 30-50% of the world's population, although it rarely causes illness in healthy adults. Despite this, "Toxo" has increasingly been associated with a number of intriguing behaviors in humans and other vertebrates.

For the study, a team of researchers led by Stefanie Johnson from the University of Colorado Boulder (UCB), sampled more than 1,500 students by testing their saliva for antibodies which would indicate whether they had been infected with the parasite at some point.

They found that the students who tested positive were more likely to major in business and have an emphasis on "management and entrepreneurship" over other business-related focuses. They also sampled people who attended entrepreneurship events, finding that those who had been infected were more likely to have started their own business than those who hadn't.

Finally, the team looked at global data on both the parasite and entrepreneurship using existing databases, finding that people from nations with higher infection rates were less likely to cite "fear of failure" as an inhibiting factor when thinking about starting a new business.

It is important to note that these links between the parasite and entrepreneurship are only correlational, meaning the researchers have not established that Toxo is the cause of the entrepreneurial behavior. However, scientists know that the parasite can have a significant effect on the brains of rats, which could provide insights into its effects on humans.

"The parasite reproduces sexually in cats—and only cats—and infects other animals, such as rodents, who eat its feces," Johnson told Newsweek. "The rodents show behavioral changes that cause them to be more risky—being attracted to cat urine for example—that might increase their chance of being eaten by a new cat."

The tiny parasite can enter the human body through contaminated food, water or other routes, after which it spreads to the brain and other parts of the body. Strangely, various studies have shown that infected individuals have a higher risk of suicide, being neurotic or dying as a result of risky behaviors—for example having a bike accident while not wearing a helmet.

While these associations are also correlational, Johnson suggests there may be biological mechanisms by which Toxo could be could be driving personality changes in humans.

"There have been quite a few studies showing effects of Toxo on hormones (like increased testosterone) and neurotransmitters (increased dopamine and serotonin)," she said. "The findings have really been mixed on the neurotransmitters. But the idea is that the increase in testosterone or dopamine causes people to be more aggressive and risky. If you have a large parasite mass in your brain, you can imagine it would alter some chemicals."

It will be difficult to prove definitively that Toxo is affecting behavior, Johnson said. This would require studies where people are randomly assigned to two groups—one in which individuals are given a placebo and another where they are infected with the parasite to see if differences in behavior will arise.

For ethical reasons alone this is likely not going to happen. However, brain scans or neurological data could help to better explain the relationships between the parasite and behavior.

"It is so wild to imagine that a small microorganism can affect individuals' behavior and maybe even societal outcomes, but I imagine that this is only the tip of the iceberg," Johnson concluded. "As we learn more about the complex ecosystem that our bodies house, I think we will find other microorganisms that shape human behavior."

How is Toxo so succesful at infecting humans?

It's likely that most people reading this do not regularly come into contact with cat feces. So, how do billions of people around the world become infected with Toxo?

Pieter Johnson, another author of the study from UCB, says that the parasite's success can be explained by its "low-host specificity"—which means it isn't picky—as well as its diverse modes of transmission.

"Because it can infect hundreds of different vertebrate species, it can persist almost anywhere, he told Newsweek. "This is true even when cats aren't around, and it's pretty fascinating that this infection shows up frequently in marine mammals—and has even been linked to a greater risk of white shark attacks on otters."

"Second, you can get infected through many routes," he said. "Not via inhalation per se, but its one of the most common food-borne illnesses because it can contaminate meat and water. Unborn babies can even acquire the infection from their mothers. Hypothetically, even in areas without cats, the parasite can still spread quite effectively through predation, scavenging, etc. (through the food web). Probably at least half of human infections are through diet, not cat feces exposure."