Crazy cat ladies have been confirmed to be a real thing. Well, sort of.
We’ve all met a human who seems more fascinated with their feline friends than their loved ones. Even people shopping for a new home consider how well their cats will like their new habitat and if there are enough cabinets and countertops for them to jump on.
Have you ever wondered what makes humans so “crazy” about cats?
It turns out that cats have a mischievous and interesting reputation in neuroscience. There is research to suggest that a single-cell organism can infect most animals and birds, but cats – wild and domestic – are its favorite host because the infectious parasites are excreted exclusively in cat feces.
Today, about a third of the world’s population is infected with the parasite called Toxoplasma gondii (or Toxo for short) and most of them don’t even know it.
In healthy people, symptoms often don’t show up at all, and if they do, they’re mild and flu-like, but these are just the physical symptoms; it’s also been proven it affects the brain.
The parasite can slow reactions and decrease concentration, which may explain why people who get in traffic accidents are three times more likely to have been infected with Toxo. Cats aren’t the only ones that can infect humans with oocysts (cysts formed by a parasite). Contaminated water, unwashed produce, playing in sandboxes, or cleaning out litter boxes can increase exposure.
Researchers showed that Toxo can travel into a rat’s brain and cause the rat to no longer avoid areas where cats live (why wouldn’t a rat run away from a cat?). The rats, in fact, become very attracted to the smell of cat urine. Previously repulsed by the smell, these brain-infected rodents run joyously through urine-laden environments.
These same protozoans can affect the brains of humans. Immuno-compromised patients, like those with AIDS, can contract the infection from a litter box and develop dangerous brain abscesses. Several studies have found connections between Toxo and schizophrenia, bipolar disorder, OCD, and aggression. In several cases, patients are treated with powerful antibiotics, and frequently recommended that they give away their cats.
According to Jaroslav Flegr, a scientist infected with the tiny organism has conducted numerous studies and researched his theories for years; mostly getting his ideas rejected ….until recently.
So far, he’s found that infected men were more likely to wear rumpled old clothes; infected women tended to be more meticulously attired, many showing up for studies in expensive, designer-brand clothing. Infected men tended to have fewer friends, while infected women tended to have more.
With up to one-third of the world infected with the parasite, Flegr now calculates that Toxo is a likely factor in several hundred thousand road deaths yearly. In addition, analysis of recent data revealed that, just like him, many other people who have the latent infection feel intrepid in dangerous situations. “Maybe,” he says, “that’s another reason they get into traffic accidents. They don’t have a normal fear response.”
Neuroscientists have shown that Toxo may have more subtle effects than brain abscesses and blindness. 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 how one’s body reacts to Toxo.
Theoretically, a strange Toxo-induced immune response in the brain could cause psychosis.
In the most extensive and best-controlled study to date, the researchers showed that those exposed to cats were at no increased risk of psychosis after controlling for a number of other variables (including ethnicity, social class, and dog ownership – to control for exposure to animal stool).
As lead author Francesca Solmi put it, “previous studies reporting links between cat ownership and psychosis simply failed to adequately control for other possible explanations.”
So, is Toxo the reason many people love cats (a whole lot)?
Right now, there’s an ongoing debate among the science community. It’s hard to say either way, but at least we know that Toxo is something real, can infect men and women alike, is linked to subtle behavioral changes, and can even contribute to schizophrenia.
As far as the reason for the bonafide crazy cat ladies, well, it’s probably just a cat-crazy obsession more than an infection.