An evolutionary biologist is making headlines for his claims that a parasite, most often found in cats, is controlling human brains.
Toxoplasma gondii is a common parasite that jumps from rats to cats to humans.
The parasite hijacks the rat’s brain, reducing its fear and slowing its reaction times, which make the rat easier prey for felines who, after digesting their kill, become infected themselves.
The leap from cat human happens mostly through contact with undercooked meat, contaminated water and cat litterboxes.
After being infected in 1990, presumably by one of his two cats, evolutionary biologist Jaroslav Flegr noticed changes in his behavior and wondered if the parasite could be controlling his brain.
“I thought it might explain some of my strange behaviours – ones that are non-adaptive for me but adaptive for a parasite that needs to get to a new host.”
Like the rats, Flegr seemed to be lacking in fear. “I would cross the street in traffic and not jump when the cars honked.”
Widely mocked at the time, Flegr dedicated the next 15 years to proving his hypothesis and discovered some startling patterns.
Those infected with the parasite were 2.6 times more likely to be in a car accident and had a higher risk of developing schizophrenia. Other researchers also found links between suicide and Toxoplasma gondii.
“Infected people also tend to be less conscientious. And our male subjects considered the scent of cat urine quite pleasurable,” Flegr told National Geographic.
Interestingly, the parasite appears to have perfectly opposite effects on men and women. Males become more suspicious, introverted and rule-breaking. Females become more outgoing, trusting and rule-abiding.