Is there a disease that makes us love cats? – Jaap de Roode


Is there a disease
that makes us love cats, and do you have it? Maybe, and it’s more likely than you’d think. We’re talking about toxoplasmosis, a disease caused by toxoplasma gondii. Like all parasites, toxoplasma lives
at the expense of its host, and needs its host to produce offspring. To do that, toxo orchestrates a brain
manipulation scheme involving cats, their rodent prey, and virtually all other birds and mammals, including humans. Documented human infections go as far back
as ancient Egypt. We found samples in mummies. Today, about a third of the world’s
population is infected, and most of them never even know it. In healthy people, symptoms often
don’t show up at all. When they do, they’re mild and flu-like. But those are just the physical symptoms. Toxoplasma also nestles into our brains and meddles with our behavior
behind the scenes. To understand why, let’s take a look
at the parasite’s life cycle. While the parasite can multiply
in practically any host, it can only reproduce sexually
in the intestines of cats. The offspring, called oocysts,
are shed in the cat’s feces. A single cat can shed up to
a hundred million oocysts. If another animal, like a mouse,
accidentally ingests them, they’ll invade the mouse’s tissues
and mature to form tissue cysts. If the mouse gets eaten by a cat, the tissue cysts become active
and release offspring that mate to form new oocysts, completing the cycle. But there’s a problem. A mouse’s natural desire to avoid
a cat makes it tough to close this loop. Toxoplasma has a solution for that. The parasites invade white blood cells
to hitch a ride to the brain where they seem to override the innate
fear of predators. Infected rodents are more reckless
and have slower reaction times. Strangest of all, they’re actually
attracted to feline urine, which probably makes them more likely
to cross paths with a cat and help the parasite
complete its life cycle. How does the parasite pull this off? Although the exact mechanism isn’t known,
toxo appears to increase dopamine, a brain neurotransmitter that is involved
in novelty-seeking behavior. Thus, one idea is that toxo tinkers
with neurotransmitters, the chemical signals
that modulate emotions. The result? Fatal attraction. But mice aren’t the only animals
that end up with these parasites, and that’s where humans,
and all of toxo’s other hosts, come in. We can accidentally ingest oocysts
in contaminated water, or unwashed produce, or from playing in sandboxes, or cleaning out litter boxes. This is behind the common recommendation
that pregnant women not change cat litter. Toxo can cause serious birth defects. We can also get toxo
from eating undercooked meat from other animals that picked up
some oocysts. And it turns out that toxo can mess with
our brains, too. Studies have found connections between
toxo and schizophrenia, biopolar disorder, obsessive compulsive disorder, and aggression. It also slows reactions
and decreases concentration, which may be why one study found
that people involved in traffic accidents were almost three times more likely
to have toxoplasma. So is toxo manipulating our brains
as an evolutionary strategy to get predatory cats to eat us? Or are our brains just similar enough
to a rodent’s that the same neurological tricks that
lure them in catch us in the net, too? And is toxo the reason so many people
love cats and keep them as pets? Well, the jury’s still out on that one. Some recent studies
even contradict the idea. Regardless, toxoplasma has definitely
benefited from humans to become one of the world’s
most successful parasites. It’s not just our willingness to let
cats on our dining room tables or in our beds. Raising livestock
and building cities which attract rodents has provided billions of new hosts, and you and your cat may be two of them.

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100 thoughts on “Is there a disease that makes us love cats? – Jaap de Roode

  1. The comment section is full of cat lovers. But honestly I dont like cat that much bcz of its smell, I dont know how describe it. The cat's smell is weird n not good for my nose, I just dont like that smell..

  2. Louis Wain was a schizophrenic artist. Look his name up and see how his drawings have changed through years. He used to paint regular, simple cat art, but the worse his disorder got, the more complex the paintings were. It's truly terrifying.

  3. i still have fear of my dad but i love cats IT MUST BE MAGIC OR DIFFRENT DISEASE IF THIS IS TRUE

  4. Playlist: "Is there a disease that makes us love
    Me: Excuse me what
    Playlist: cats?"
    Me: Oh… That's what it meant.

  5. I don't like cats very much. But now I can understand why some people do! That and also because they're kind of cute.

  6. If you have toxoplasm when you were a kid , you won't have it when you are pregnant , and it is a good thing . Most toxoplasm infections come from eating badly washed raw vegetables , not well cooked meat, or even not washing properly your hands when gardening . Only young cats , who have been hounting rodents outside , and have an active infection can be contagious through their feeces , but after they have stayed in dirt for 12 or 24 hours . A lot of pregnat whomen give a positive toxoplasma test , that usually meams that they had it in the past , and it will keep them from getting it while pregnant .

  7. Question, will this disease kill you? Will it kill your cat? And is it true because I've never heard of it until now? Not saying Ted Talk is always wrong but some things have been proven wrong on a few of the videos.

  8. Research the effects of ammonia on the human brain too. Cat urine is rife with that. I think the toxoplasma is one of my least concerns but it would explain why so many cat keepers are so effed in the brain.

  9. My cat never went outside (she's perfectly fine)…. I never eat undercooked meat.. I never changed a litterbox… The list goes on.. And I am still fuckin addicted to cats…. Iam pretty sure this happens cause mind control from cats

  10. Everybody, it says you have to INGEST the cat's poop to catch this. That means (assuming you don't have coprophagia–the poop-eating mental illness) that you catch it by scooping the litter box and putting your hands on your food or in your mouth WITHOUT washing them. So just wash your hands after scooping the litter box.

  11. I love cats, clean their litter and have bipolar. I am a little bit freaked out, but my mother has schizophrenia and she got her first symptoms at 17 with no pet cats.
    We had a pet mouse that was best friends with our cat Baby. They loved each other, but maybe he had it. The first time he met Baby cat he bit her on the noise. She would move him about in her mouth, but totally unharmed. He died of cancer at two and a half years old.

  12. Ok what about me who has never ever met a cat nor even touched him.i started watching cat videos and now i am obsessed 😍😍😍

  13. actually, i just love cat because i thinks she is cute, Some cats i don't like though, so the boy cat i don't like because he is lazy and useless

  14. i have 2 cats and 2 dogs. I used to have a zoo, now my cats are my only surviver. My dogs we got last year.
    (hint: MY CATS ATE THE ZOO) I don't think the cats are going near those dogs LOL

  15. Is Toxoplasmosa really a parasite if it helps the cat find and catch prey? Doesn't that technically count more towards being a symbiotic relationship?

  16. Oocyte is a parasite first shape of its lifecycle ,it’s the primary figure , and it makes the parasite persist toward the last stages , and that of course if it gets the right nutrients and the appropriate environment . It’s similar to what’s known in the humans world the embryo .

  17. We cats are not amused!(We demand the owner of this video to eat lasagna,and cheesecake for his crimes against us cats by spreading lies about us cats!)

  18. Ха! Я тут одна наверно русская, но что ж, напишу га русском свой отзыв…. у мен, есть кошка, и я очень люблю ее. Я ем с ней, целуюсь и т.д. и я думаю, что этого заболевания у меня больше всех!😂🌸🙈

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