Toxo: the not-so-secret feline plan for world domination

If you live with cats you know that a litter box is a biological weapon. If you deal with it personally, you may have considered buying a gas mask because sarin has nothing on the stench of a full litter box.

Well the stench is the most innocuous part of it. Cats have a weapon that not only ensures their food supply but changes the behavior of their prey. The way this change happens is so clever, so insidious, that the prey — rats and mice — actually become attracted to the stink of the litter box. “Attracted” as in “sexually aroused.”

“Yucch!” you may cry, but this weapon is so brilliant it even rewires our brains. Its potential uses for world domination are such that the US military has taken an interest ... in cat poop. Cat poop contains a parasite called Toxoplasmosis.

My own interest in Toxoplasmosis, Toxo for short, started ten years ago when my cat Koosi moved in. I noticed that the bags of kitty litter all had a strongly-worded warning about Toxoplasmosis and the dangers it posed to pregnant women. Oddly, the warnings never said exactly what Toxo is or what these terrible dangers are.

According to my longtime reference, Think Like A Cat by Pam Johnson-Bennett, Toxo is “acquired by cats ingesting infected prey or coming in contact with contaminated soil.” It “can cause birth defects.”

Years later, a hypochondriac friend (He once interpreted his own blood tests and for 15 minutes was convinced he was terminally-ill) pointed me to a disturbing article on Toxo. Apparently Toxo has a fascinating effect on mice: it makes them behave aggressively towards cats. They become so fearless that they basically jump in front of cats and cry, “Hey Kitty, come and get it!” In short, Toxo makes the prey behave in a way that guarantees it will be eaten.

My friend was convinced that I had been infected with Toxo from living with cats, and it had affected my behavior the way it does rats.’ I am too large and useful to end up in my cats’ stomachs, but I  do ensure that said stomachs are always full. Also I am rather ... forceful.

“See? This accounts for your whole world domination thing.”

Last week he sent me an article from edge.org by Robert Sapolsky, a professor of biological sciences and neurology at Stanford. Sapolsky talks about their astounding research into Toxo. “Toxo preferentially knows how to home in on the part of the brain that is all about fear and anxiety, a brain region called the amygdala. The amygdala is where you do your fear conditioning ... the amygdala is all about pathways of predator aversion, and Toxo knows how to get in there.

“Next, we then saw that Toxo would take the dendrites, the branch and cables that neurons have to connect to each other, and shriveled them up in the amygdala. It was disconnecting circuits. You wind up with fewer cells there. This is a parasite that is unwiring this stuff in the critical part of the brain for fear and anxiety ... It knows how to find that particular circuitry.”

It gets more amazing. Toxo not only destroys the rats’ fear response, it rewires their brains so that the smell of cat urine activates the sexual arousal pathway. The rat smells cat pee but instead of running away, it has to go and check it out.

The Toxo genome has two versions of the mammalian gene tyrosine hydroxylase — the enzyme for making dopamine. Dopamine controls pleasure, attraction, and anticipation.

“On a certain level, this is a protozoan parasite that knows more about the neurobiology of anxiety and fear than 25,000 neuroscientists standing on each other’s shoulders,” Sapolsky marvels.

Then it gets even more interesting. There is evidence that people infected with Toxo — and it is more prevalent here in the tropics — become less inhibited and more likely to do reckless things. A surgeon notes that people who die in motorcycle accidents seem to have higher rates of Toxo.

Two groups have reported that Toxo-infected people have three to four times the likelihood of being killed in accidents involving reckless speeding.

“Here’s something terrifying and not surprising,” Sapolsky writes. “Folks who know about Toxo and its affect on behavior are in the US military. They’re officially intrigued. And I would think they would be intrigued, studying a parasite that makes mammals perhaps do things that everything in their fiber normally tells them not to because it’s dangerous and ridiculous and stupid and don’t do it.”

So now I’m thinking: Did Genghis Khan have cats? Alexander of Macedonia? Napoleon Bonaparte? For sure the Egyptians loved cats, worshipped them, even carried them into battle. At the height of the Venetian empire there was this general whose cat sat on the prow of his warship.

Could we rewrite the history of the world according to Toxo? My cats refused to comment, but it’s probably a good thing that I don’t drive.