Scratching the surface on cat-caused craziness
Or: How the 2010s podcasting era made us all into gentleman scientists
Some time in the middle 2000s / early 2010s, I feel like a lot of us got what I call “Podcast Smart.” During that blissful period wherein all of the headphones were still connected to our devices (which might have been wholly separate from our phones!) and at least once a day, they’d get snagged on something and yank out of your ear in a distinctive and absolutely mind-shattering moment, we were all cradled in the same cocoon of collective media consumption focused on the very specific category of Learning About The Minutiae of Life and History.
This period was driven largely by eggheaded podcasts (think: Freakonomics, Stuff You Missed in History Class, and of course, 💕RadioLab💕) that everyone recommended to one another back and forth forever. In this time, you could be sitting on the bus or train in any major city and look at some bookish individual sitting across from you and comfortably assume that they, too, were currently being pumped full of the same odd details of science, nature, crime, and the economy.
Among those details was the idea that cats - cat ownership and proximity to cat turds, specifically - could make you crazy.
Right? Like, most of us learned about this subject during The Golden Age of Podcasting? And now we’ve just been carrying around this understanding of cats as silent agent of mental illness?
If you did - if you have no idea what I’m talking about - that’s ok. Let’s go on this journey together.
Honestly, Less Toxic Than Ted Nugent
Like everyone else, I have a broad understanding that ~ cat scratch fever ~ is both a disease and a song written by a Hall of Fame-level piece of shit. But honestly, I don’t know much about it other than you’re really not supposed to let your cat get its gritty little tongue near an open wound. So let’s go to the experts.
The first thing you need to know is that there are a couple of different diseases that you can get from cat claws. One is cat scratch disease/cat scratch fever. Here’s the basics, according to the CDC:
Cat scratch disease (CSD) is a bacterial infection spread by cats. The disease spreads when an infected cat licks a person’s open wound, or bites or scratches a person hard enough to break the surface of the skin.
CSD is caused by a bacteria called B. henselae, which causes “fever, headache, poor appetite, and exhaustion,” as well as swollen lymph nodes. CSD isn’t typically serious, but it is very sneaky.
“Up to 30% of cats carry B. henselaei n their blood, although most cats with this infection show NO signs of illness,” according to the buzzkills at the CDC.
It’s fairly easily prevented, though; CSD is passed through flea bites, so if you’re worried, just get some Frontline from your vet. Even if your cat never goes outside, because fleas are really good about finding a way into your house. You should really do that anyway, cat scratch disease or not!
B. henselae can make you feel rotten, but it does not, you must know, make you crazy.
That’s a job for toxoplasmosis.
ToxoplasMOSTEST!
As a childfree individual, I know better than most just how devastating the idea of being a “crazy cat lady” is to some people. Not to me, mind you. I actually think it sounds dope but my partner doesn’t want a cat because “it poops in a box.”
Anyway, calling an Old Maid like me a “crazy cat lady” is supposed to be a 87th degree burn and one that is almost always saved for women who have had the unmitigated audacity to allow their uteruses to remain vacant.
But like, why? Why is it always cats, when there are objectively way more crazy bird ladies in the media (three words: TUPPENCE A BAG)?
The answer to this lies in, well, the aforementioned box poops. Or at least, that’s part of it. The main reason that it’s been attached to childfree women as an insult is because a.) a long history of childfree women being viewed as untrustworthy witches and thus, keeping the company of cats, and b.) misogynists aren’t super creative.
Sidebar: This is not a new thing. Cats have been linked to witches for millennia - in part because of Egyptian royalty, in part because women invented beer and the cats were helpful to keep the mice away from the grain, and in part because cats and humans have evolved together and are generally pretty intimately linked. But there are, of course, obvious undertones of marginalization. Cats were viewed as the companions of spinsters - single women who were to be both feared and pitied.
As Rae Alexander wrote for KQED:
In the early 20th century, as women inched ever closer to gaining the right to vote, cats became a standard feature of anti-suffrage propaganda. This served two purposes. First, depicting suffragettes as cats acted as a means to reduce women to the status of inconsequential, trifling animals. Second, associating women’s rights activists with this particular pet acted as a wink and a nod to the public about what kind of woman wanted the vote: lonely, bitter man-haters.
Anyway!
Toxoplasmosis is an infection caused by a single-celled parasite called Toxoplasma gondii. Most people who ingest the parasite never even know. Yes, I regret to inform you that you may have it right now. But for people who are symptomatic, parasitic infections can cause flu-like symptoms and, in rare cases, can infiltrate the brain, which is where the “crazy” idea comes from.
Toxoplasmosis in the brain can cause encephalitis, or brain inflammation. The Mayo Clinic states that the symptoms of encephalitis may include:
Confusion.
Poor coordination.
Muscle weakness.
Seizures.
Changes in alertness.
Critically, indoor-only cats rarely ever actually pick up T. gondii. They just don’t get exposed to it. Instead, it’s the purrrrrrview of indoor/outdoor and outdoor-only cats.
But if your cat is exposed, this parasite can live in cat turds and, as a result, can cause an infection if, say, you clean your cat’s litter box and then don’t wash your hands and then you eat something.
Or if your cat does a sloppy mudpie in its litter box, kicks it around, picks up toxo on its claws, and then swipes at you.
Or if a cat shits in your garden bed and you eat the beets or whatever you grew. Seriously, the CDC says that “accidentally ingesting contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits or vegetables from a garden)” can be a source. GROSS.
However, per the CDC, you can get from loads of sources, not just cats. Here’s the methods of infection that they list other than cats:
Eating undercooked, contaminated meat (especially pork, lamb, and venison) or shellfish (for example, oysters, clams or mussels).
Accidental ingestion of undercooked, contaminated meat or shellfish after handling them and not washing hands thoroughly (Toxoplasma cannot be absorbed through intact skin).
Eating food that was contaminated by knives, utensils, cutting boards and other foods that have had contact with raw, contaminated meat or shellfish.
Drinking water contaminated with Toxoplasma gondii.
So, you know, lots of people can get it, not just cat ladies.
But here’s the super-interesting part about Toxoplasma gondii, the crafty little minx of a parasite: It needs to live inside of a host to flourish and, as a result, has created a biological weapon to ensure that it’s always getting picked up again and again.
Toxo, you see, is “known to remove rodents’ innate fear of cats.” One paper noted that “even months after infection, when parasites are no longer detectable, the effect remains. This raises the possibility that the microbe causes a permanent structural change in the brain.”
And this is where we get the real (potential? probable? possible?) craziness that comes with cat scratches.
Batshit over cat shit
It seems more than plausible that Toxoplasma gondii is at least part of the crazy cat lady image, because, clever as it is, it literally makes its hosts love its other hosts more.
Here’s how clever. A story from Scientific American summarizes the way toxo works in the brain. And it’s…real wild.
The bug contains an enzyme that creates dopamine, a neurotransmitter. Humans given dopamine pills are at an increased risk of impulsive and risky behavior. Excess dopamine activity is also involved in schizophrenia. Immunologists point out that the known genetic risk factors for schizophrenia include many immune-related genes that could affect the way one's body reacts to Toxo.
So toxo makes your brain create more dopamine, which makes you feel good, ostensibly in the company of your beloved familiar. And while it’s possible that toxo can create a case of the brain scramblies, it may also be the case that it’s drawn to and exacerbates existing cases of mental illness like schizophrenia.
Again, from Scientific American:
Theoretically, a strange Toxo-induced immune response in the brain could cause psychosis. Even more alarming was a summary of thirty-eight studies, published in 2012, that found that individuals with schizophrenia were three times more likely than those without schizophrenia to have antibodies in their blood to the Toxoplasma protozoan, meaning their bodies developed an immune response to Toxo at some point.
So, then, we have a few questions:
Do people who already find themselves drawn to cats for other reasons also possess biological markers that make them more susceptible to toxo?
Or do some people just have more hospitable bodies than others?
And is it possible that some psychiatric diseases - which are often linked to dopamine production, use, and inhibition - might impact the outcome of a toxo invasion?
Or is it possible that there’s actually no link between behavior, mental health, and cat turds? Maybe T. gondii has just become a convenient scapegoat for a long list of human issues?
And the answer is…who knows! Science is weird and bodies are weird. And, in spite of what a lot of us learned (or thought we learned) from our 2012-era pods, there’s still a lot of disagreement over whether or not toxo is to blame for any of this.
So why did we all learn this at the same time?
About a decade ago, author Kathleen McAuliffe wrote a book about the role of parasites in our daily life and made the PR rounds. Grounded in her own concerns that toxo might have made her into a raving extrovert (the horror!) the book was one of about a zillion pop science books that media orgs salivated over during Obama’s second term.
And, unsurprisingly, most people wanted to talk to her about toxo. Specifically, about her conversations with a semi-reclusive oddball Czech scientist named Jaroslav Flegr who was specifically studying this bug.
Also unsurprisingly, this meant she got a lot of podcast and press time because the Age of Thinky Podcasts was also the Age of the Thinkpiece That Is Designed To Get People Chattering Around The Donut Box at Work.
In a story for The Atlantic, she quoted Flegr as saying that “Toxoplasma might even kill as many people as malaria, or at least a million people a year,” citing its impact on people with weakened immune systems.
Did you hear that sound? That was the sound of millions of people putting on rubber gloves to scoop the litter box!
McAuliffe’s book and her platforming of Flegr’s work is, I believe the primary source for most of our collective understanding of CSD and toxo and the general idea that cats can make you crazy.
But in the last 10ish years, there’s been significant pushback to the oversimplification of the role of T. gondii in mental health and illness. Because, as you might guess, there lot of other potential causes for bizarre behavior, aggression, or whatever else people might blame on toxo - and drawing a causal link is very hard to do.
Clinical researchers in 2016 conducted a relatively small overview of existing research into toxo and its relationship to patients with extreme anger. They found that “toxoplasmosis-positive individuals scored significantly higher on scores of anger and aggression.”
In their conclusion, they wrote that “these data are consistent with previous studies suggesting a relationship between T. gondii and self-directed aggression (ie, suicidal behavior) and further add to the biological complexity of impulsive aggression both from a categorical and a dimensional perspective.”
However, in an interview about the study, they stated that “we do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues.” They went on to explain that:
We don't understand the mechanisms involved — it could be an increased inflammatory response, direct brain modulation by the parasite, or even reverse causation where aggressive individuals tend to have more cats or eat more undercooked meat. Our study signals the need for more research and more evidence in humans
Another 2016 study was more forceful, calling into question the previous methodology.
“Infected individuals are commonly asymptomatic, though recent reports have suggested that infection might influence aspects of the host’s behavior,” wrote the study’s authors. “In particular, Toxoplasma infection has been linked to schizophrenia, suicide attempt, differences in aspects of personality and poorer neurocognitive performance. However, these studies are often conducted in clinical samples or convenience samples.”
Those researchers concluded that “there was little evidence that T. gondii was related to increased risk of psychiatric disorder, poor impulse control, personality aberrations or neurocognitive impairment.”
In conclusion: Your cat is fine and most of what we learned in the 2010s was oversimplified for our consumption
The more I go back and revisit things I learned - or think I learned - from the halcyon days before TikTok, back when Mitt Romney was the biggest threat to democracy (ah, we were so naive) and the national minimum wage was the same as it is now, the more I realize that there’s more to it.
Which isn’t a huge surprise - a pop science book about parasites by a lady who genuinely thought her own supposed T. gondii infection made her talk too much was never going to deliver a comprehensive picture. And this was back when every writer for the internet (myself included) was instructed to write for clicks, and when single online news site had their ChartBeat or whatever ticker they used displayed prominently in the news room to make sure you didn’t forget the goal.
If we take away nothing else, though, let’s remember that:
You can get toxo from shellfish, improperly cooked meats, and bad water.
Things we learned from podcasts in the 2010s might not be super accurate/you may have been made afraid of things during this time and it’s probably good to double-check that stuff
T. gondii probably doesn’t make you crazy (listen, babe, there’s tons of other things in your life that might be the source before you go straight to cat shits)
And if the neighbor’s cat uses your raised beds as an al fresco litter box, WASH YOUR DAMN CARROTS.
Ok, give your cat a pat for me. xoxo HBO