Friday, May 9, 2008

Is there a reason why we become “cat people”?

I know I creeped out a few people last week with my post about corpse brides.

If it makes you feel any better, this week it’s my turn to freak out. That’s because I've learned that a strange parasite is trying to get cozy with our cats. And the bug might be capable of affecting human behavior.

I discovered this odd bit of news when I spoke to my daughter, who is doing some research into the Toxoplasma parasite. Toxoplasma is excreted by cats. The parasite can be found in cat litter. (It’s the reason why women shouldn’t clean the cat box while they’re pregnant.)

It turns out that in most infected people, the Toxoplasma parasite is fairly benign. Which is a good thing, because up to half the people on the planet carry the parasite’s tiny cysts in their brain (ugh). But Toxoplasma causes birth defects in fetuses, and I’ve also heard that it can cause blindness if the parasite migrates to your eye (so much for being benign).

Cats are the natural hosts for the parasite, which gets very crafty in its attempts to reach a feline. Research has shown that when a rat is infected with Toxoplasma, the rat’s brain is altered so that the rodent loses its fear of cats. The infected rat becomes much more likely to get eaten by a cat, and then—voila!—the parasite has reached its target host.

Some research I read about suggests that even human behavior can be affected by the Toxoplasma parasite.

A parasitologist (who knew such a field existed?) once reported that women who are infected with Toxoplasma tend to be more extroverted and caring—to what end, is not known. My personal theory is that perhaps the parasite is trying to make us take better care of its feline hosts.

I’m freaking out about the possibility that the bug might affect human behavior, because everyone in my family loves cats.

As a clan, we like dogs just fine. But we’re nuts about cats. For example, I have an aunt who has nine indoor kitties. She also feeds and takes care of dozens of feral cats.

My sister is another fierce protector of all things feline. She has appointed me executor of her estate on behalf of her two cats. I have precise instructions for where and how they’ll be cared for if they outlive her (her will even includes funding for a long-term kitty haven).

Then there’s me. My husband calls me a “cat whisperer.” When I see or hear a cat on the street, I’m magnetically drawn to it. I’m strangely drawn to it, I’m thinking now.

Our familial tendency to adore cats and care for them makes me wonder—could it be that we’re all infected with the Toxoplasma parasite, and we’ve been passing the bug down through the generations? Maybe the parasite has altered our brains to make sure that we take excellent care of its host, Mr. Cat.

Bottom line: Is a bug pulling our strings?

Technically speaking, I’m not even sure that a parasite is a bug (science teachers, help me out here). But I’m sure it looks like one under a microscope. I’ll bet it looks really disgusting, too.

The whole thing makes me think about some signs my relatives have hanging all around their houses. The signs say things like:

“The cat owns the house. We just work here.”

Things may be worse than they know.

We might all be working for a damned bug.
Update on treatment
I had a question from Sheila about treatment for toxoplasma. There are treatments available for the parasite (primarily with antibiotics), but--and this news won't reassure too many people--the treatments may not cure "latent" cases, where the brain cysts are just hanging out, biding their time. Also, some species are evidently exhibiting immunity to the treatments. Here's more from Wikipedia:


Sheila Connolly said...

That Toxoplasm parasite got me out of cleaning the cat litter while I was pregnant--and my husband's been doing it ever since (our daughter is now 23). Who am I to argue?

And I'm a cat whisperer too (is there a club?). Once I was in Dublin, sitting on a bench outside the cathedral, and the resident cat came up to me, climbed under my coat (while I was wearing it, mind you), and went to sleep. I have pictures.

What you don't tell us here is how (or if) we can prevent this nasty parasite, and what we should do about it.

Joanna Campbell Slan said...


I absolutely adore cats. I am also incredibly allergic to them. So much so that it's almost dangerous for me. And that's just awful because I long for a kitty. There's nothing more wonderful. Yes, I love my dogs, but cats? Cats rule!

Kathryn Lilley said...

There is a treatment I've heard, Sheila (per my daughter). I'll do a search and see if I can turn it up--and leave her a message. Every time I call her she's in the science lab, lol! My sympathies on the cat allergy, Joanna. I once had a friend visit who was allergic, and my Persian cat entered the room while we weren't looking. The first clue was that his face turned tomato-red, and all puffy! Poor guy never came back, lol.

ellen said...

There have been science fiction stories where cats were the True Rulers of Earth. There have also been stories where dogs were. And as I recall, a movie where the two species were contending for rule.

Now we have to worry about it being toxoplasma instead? Which will bump humans down yet another step on the pyramid?


Linda O. Johnston said...

Okay, I can understand loving cats, but because of a parasite??? That's really scary. Especially if the cats somehow control the parasite. Ugh. Maybe it's just as well that not all cats deign to be cuddled. We have one who rules our street, and we call him the mayor.

Kathryn Lilley said...

I updated the post, Sheila, with a brief discussion of treatments, and a link to wikipedia, which has much more good information. I think the bottom line is that it's good to avoid cleaning cat litters when you're pregnant, or if you have other major health issues, such as AIDS.

Kathryn Lilley said...

There are other parasites--flukes--that can control an animal's behavior in strange ways. One of them makes an ant freeze at the top of a blade of grass, so that it is more likely to be eaten by a grazing animal. Another causes fish to jump and shimmy out of the water so that they're more likely to be caught by predatory birds. Fascinating, huh? About the cuddling, Linda, there seems to be no evidence that the parasite lives on a cat's fur. But I guess few countries screen for the disease because of cost concerns, and the fact that it's usually benign, so there may be a lot we don't know yet!

Kathryn Lilley said...

Oh, and like I said in the blog, the idea of us loving cats due to the parasite is only my own, nonscientific theory. I didn't find any research to suggest that--it's probably just my morbid mystery writer's imagination running amok again, lol.

stupid123 said...

I do not think i CAUGHT THE

Kathryn Lilley said...

...caught the cat? LOL

Craig said...

I'm a bit freaked out by this toxoplasmosis business as well...the parasite isn't trying to make you look after your cats so much as be eaten by them - leopards live on monkeys in some places, the parasites in those areas benefit from pushing the monkeys to take actions that get them eaten. Our trouble with the parasites probably stems from that sort of an environment.

The effects are just so interesting, it's not just that it may make you love cats - though I'd love to see a study on how many 'cat people' are infected compared with 'dog people' - it makes men more reckless and jealous and women both more caring and more promiscuous. And the effects get stronger the longer you are infected.

What about crazy old ladies who live with dozens of cats? Toxomoplasmosis is linked to schitzophrenia...

Is it too crazy to wonder about the cat worship in ancient egypt? Was that parasite-related?