ohmidog!

An eccentric Czech scientist says a single-celled parasite that can be passed on through contact with cat feces can lead people to behave in strange and destructive ways.

And Jaroslav Flegr has more than studies to back up his theory. He has the parasite — Toxoplasma gondii (or Toxo for short).

Flegr and his work are profiled in a fascinating (and scary) article this month in The Atlantic, which describes the 63-year-old evolutionary biologist as a “sloppy dresser … with the contemplative air of someone habitually lost in thought” and “frizzy red hair that encircles his head like a ring of fire.”

Flegr, the article says, has pursued his theory for decades in relative obscurity — partly because he’s not much of a conversationalist and rarely goes to scientific conferences, partly, he says, because people just don’t want to hear it.

“There is strong psychological resistance to the possibility that human behavior can be influenced by some stupid parasite,” he says. “Nobody likes to feel like a puppet.”

His theory is gaining credence, though, The Atlantic reports.

That parasites can be passed on through cat feces is nothing new, as the article notes:

Since the 1920s, doctors have recognized that a woman who becomes infected during pregnancy can transmit the disease to the fetus, in some cases resulting in severe brain damage or death … (It’s) the reason pregnant women are told to avoid cats’ litter boxes. T. gondii is also a major threat to people with weakened immunity: in the early days of the AIDS epidemic, before good antiretroviral drugs were developed, it was to blame for the dementia that afflicted many patients at the disease’s end stage. Healthy children and adults, however, usually experience nothing worse than brief flu-like symptoms before quickly fighting off the protozoan, which thereafter lies dormant inside brain cells—or at least that’s the standard medical wisdom.

Flegr thinks that, even in its latent stage, the parasite may be messing with the connections between our neurons, affecting our response to frightening situations, our outgoingness, our trust of others and our preference for certain scents.

He thinks the organism is a factor in car crashes, suicides, and mental disorders such as schizophrenia. All tolled, he says, it might be, in an indirect kind of way, killing a million people a year.

Flegr had long wondered about his own behavior. Sometimes, he didn’t move out of the way of oncoming traffic, and exhibited other behaviors that might be described as self-destructive. He began to suspect that a single-celled parasite in the protozoan family was manipulating his personality.

In 1990, he joined the biology faculty of Charles University, which was a leader in documenting the health effects of T. gondii and in developing methods for detecting the parasite.

Colleagues searching for infected individuals on whom to test their improved diagnostic kits asked him to volunteer, and that’s when he confirmed he had the parasite.

Humans, the article notes, can be exposed to the parasite not only through litter boxes, but by drinking water contaminated with cat feces, eating unwashed vegetables, or by consuming raw or undercooked meat.

It’s believed to have worked its say into 10 to 20 percent of Americans.

Indoor cats pose no threat, Flegr says, and outdoor cats shed the parasite for only three weeks of their life, typically when they’re young. Flegr recommends taking extra care to keep kitchen counters and tables wiped clean during that period.

More important for preventing exposure, he says, is to clean vegetables thoroughly and avoid drinking water that has not been properly purified. He also advises eating meat well-done — or freezing it before cooking.

In experiments, subjects who tested positive for the parasite had significantly delayed reaction times. Males who had the parasite were more introverted, suspicious, and inclined to disregard rules. Infected women reacted the opposite way, becoming more outgoing, trusting and rule-abiding. Infected men were more likely to wear rumpled clothes and had fewer friends, while infected women dressed more meticulously and had more friends.

With up to one-third of the world infected with the parasite, Flegr calculates that T. gondii is a factor in hundreds of  thousands of road deaths each year.

The writer of the article, Kathleen McAuliffe, admits to wondering if she was infected after she began researching the parasite — whether it might explain some of her own behavior. She got herself tested before interviewing Flegr, and found out the results later.

We wouldn’t feel right sharing her medical information here — but for the results of her test, and the rest of the thought-provoking story, check out this month’s issue of The Atlantic.

(Photo by Michael Novotny / The Atlantic)