Name: Toxoplasma gondii.

Location: All over the place.

Appearance: Very small. A single cell, in fact. You’d need a microscope to see it.

Aw, how cute! Um, yeah. Kind of. Toxoplasma gondii is a parasite that spreads in cat faeces to other mammals, including humans.

Less cute. What does it do? Usually nothing. Indeed, it is extremely common. Worldwide, about two billion people have picked up toxoplasmosis, the disease that toxoplasma gondii causes, but in most cases they never feel anything at all, and are immune afterwards.

That sounds like my kind of disease. Yes, although it can make babies and people with weakened immune systems very ill. You may remember that Tommy in Trainspotting died from toxoplasmosis contracted from his kitten.

Yeesh. Plus it might secretly rule the world.

Eh? Research just published in the Proceedings of the Royal Society biological sciences journal found that students who had been infected with toxoplasmosis were 40% more likely to major in business at university, and 70% more likely to emphasise “management and entrepreneurship” in their business studies.

Wowzer. What’s more, at an entrepreneurship event for professionals, infected people were 80% more likely to have started a business.

Are you serious about this? I am. The effect could even be measured at a national level. “Nations with higher infection also had a lower fraction of respondents citing ‘fear of failure’ in inhibiting new business ventures,” the researchers say.

So capitalism is a disease! I knew it! Sort of. These people, and humanity in general, might actually have benefited from toxoplasmosis.

Because eating cat poo makes you more of a go-getter? Maybe.

That sounds slightly … far-fetched. I know, but it isn’t. Toxoplasmosis gondii is already much loved by evolutionary biologists because of how cleverly it spreads.

What’s clever about being pooed out by a cat? Not much. The clever part comes next. Mice that pick up the parasite from the soil develop one of the world’s weirdest symptoms.

Which is? They lose their fear of cats.

No way! Yes way. As a result, they wander blithely around these giant predators – and get eaten, thereby returning toxoplasma gondii to the gut of a cat, where it can breed.

That’s amazing. The theory is that toxoplasmosis might affect human behaviour, too.

Well, I suppose we do love hanging out with cats. That’s true. But there may be other things.

Like what? Past research suggests a link with schizophrenia and bipolar disorder. Toxoplasmosis might also make men less sociable, and women more so. For some pregnant women, the effects can also be serious.

So it is responsible for gender stereotypes, too? Could be.

Do say: “Welcome to Dragons’ Den. Or as we now know it, Toxoplasmosis Clinic.”

Don’t say: “Should we call it catipalism now?”