- Not a substitute for professional veterinary help.
Reviewed by Dr. Sarah Nelson, DVM, on July 19, 2022
My father used to hate cats. When I was a kid, we weren’t allowed to have indoor cats, although a rotation of semi-feral outdoor cats roamed the courtyard and courtyard. As an adult, I’ve had three cats in my home for over 15 years, and my dad never bothered to learn their names. It’s safe to say, I never imagined he’d turn out to be a cat guy.
But a few months ago, my dad found a tiny jet-black kitten huddled under a diesel tank on his farm. Now that kitten (whose name is Diesel, of course) runs around the house, galloping down the hallway with my parents’ yellow lab, eating fine ceramics, lounging on a brand new cat tree, and even—gasp!– sleep in bed at night.
There can only be one explanation for this complete personality and lifestyle change: feline parasites are controlling my dad’s brain.
“The Cat Parasite?”
Toxoplasma gondii (T. gondii) is a protozoan (protozoan) parasite that infects most warm-blooded animals and causes toxoplasmosis. New York Times 2014 article called it “one of the most successful parasites on Earth.”
If any warm-blooded animal can contract it, how did T. gondii get the nickname “cat parasite?” As it turns out, the cat is the only species required for the life cycle of T. gondii: it can only reproduce sexually inside the cat’s intestines. As the New York Times explains, “the parasites that produce the cysts are removed from the cat with its feces; Once in the soil, the cysts infect new hosts.” From there, Toxoplasma gondii returns to cats through their prey.
This is where things get really interesting (and a bit horrifying, imo): studies show that T. gondii changes the behavior of the animals it infects. For example, rodents have evolved to avoid cat odors as much as possible so as not to be eaten, but once infected with Toxoplasma gondii, many species lose their natural fear of cat odors. Sometimes, they even seem to be drawn to it. “Cat parasites” directly affect their behavior and make them harmful – and convenient, to rodents-loving cats.
iStock via Firmafotografen
How Toxoplasma affects animals (including your cat)
Toxoplasma gondii doesn’t just help outdoor cats prepare dinner. In recent years, Studies have shown that toxoplasmosis can cause behavioral changes in hyena cubs, putting them at greater risk of lion attacks.
And in Hawaii, toxoplasmosis is the leading cause of death in Endangered monk seal.
As Rover resident cat expert Dr Mikel Delgado explains, “toxoplasmosis can be a problem for a number of species including marine mammals such as seals and otters.” One recent research showed that places with higher populations have higher numbers of T. gondii cases in wild animals. Why? Because more people means more cats roaming freely outside to defecate. Cat feces are filled with T. gondii eggs that are carried through soil and rainwater to vulnerable marine animals.
Unfortunately, if your cat is the one carrying them, you’ll probably never know. Although domestic cats are the main carriers of T. gondii, according to Cornell Veterinary College, “Parasites rarely cause clinical disease in them.” But you can protect nearby wildlife by keeping an indoor cat (there’s the added bonus of extending their lifespan!) and carefully dispose of their waste. Dr Delgado says: “Cat waste should be thrown in the trash, not flushed down the toilet. “Discharge of infected feces can lead to water contamination that spreads the parasite to other species.”
You should also get your cat to chase or capture your cat and support trap release programs in your area. While plucking and torturing doesn’t prevent cats from carrying Toxoplasma, it does prevent unwanted litters that are more likely to roam free and parasitize in the wild.
Can Toxoplasmosis Change Human Brains?
In today’s famous article “How your cat drives you crazypublished by The Atlantic in 2012, science writer Kathleen McAuliffe profiled Czech scientist Jaroslav Flegr, who hypothesized that the Toxoplasma parasite could change Mankind behavior. Another scientist cited in the story said, “the organism coils up circuits in parts of the brain that process initial emotions such as fear, anxiety, and sexual arousal.”
While this is true for rodents, the evidence is less conclusive for humans. According to the article in the Atlantic, there are some evidence shows that men carrying Toxoplasma gondii are “more introverted, suspicious, indifferent to other people’s opinions of them and tend to disregard the rules”. On the other hand, women carrying the parasite tended to be “more extroverted, trusting, image-conscious, and rule-abiding than uninfected women”. However, even Dr. Flegr admits, “the impact of parasites on personality is very subtle.”
Although changes in human behavior make for interesting headlines, over the past 5-10 years there hasn’t been much new evidence of conclusion demonstrate that Toxoplasma gondii alters the human brain the way it affects wildlife.
And there’s absolutely no data on whether feline parasites can turn formerly cat-hating dads into a soft-hearted kitten, regardless of how certain writers think that’s true. whatever.
iStock via CasarsaGuru
How To Know If You Have Toxoplasmosis (And What To Do About It)
Centers for Disease Control (CDC) estimate that in the United States, “11% of the population 6 years of age and older have been infected with Toxoplasma.” In developing countries, infection rates are up to 60%, especially in hot and humid climates. In other words, millions of people around the world are carrying T. gondii – but most of them never feel the effects.
As Dr. Delgado explains, the majority of people who carry Toxoplasma gondii “have an asymptomatic infection”. if you do develop symptoms, they are like a mild cold — sore muscles and tender lymph nodes — and may go away in a few weeks.
People who are pregnant or immunocompromised have the highest risk of developing symptoms and complications, but that doesn’t mean pregnant or immunocompromised people shouldn’t keep cats. Like anyone else, they should simply practice good trash hygiene. Delgado explains, “because it takes at least 24 hours for the Toxoplasma parasites in feces to become infectious, cat owners are not at risk if they scoop out the can twice daily, which I recommend. should do. If someone is in an at-risk group, they can wear gloves, or ask someone else in the household to clean the bins.”
iStock via Timbicus
Do cats control our brains?
The truth is, cats aren’t even the main cause of human toxoplasmosis. It is much more common to get toxoplasmosis through contaminated water, or from eating contaminated, undercooked meat or shellfish. As Dr. Delgado says, “People are still more at risk of toxoplasmosis from handling raw meat than from their cats.”
So maybe my dad wasn’t affected by a tiny protozoan that forced him to let the kitten lick his mustache. There might be a more obvious explanation for his seemingly sudden change in behavior: Kittens are so cuteAnd it’s impossible not to love them.
I suppose, that way, cats control our brains – but that’s not the parasite’s fault.
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