Why Some Parasites Are Actually GOOD (And Which Can Kill You)

When we think parasites, we often think of illness, disease, and discomfort. But did you know some of them can actually be helpful? Join Stefan Chin and learn all about them in a fun SciShow compilation all about the world of parasites!

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Original Episodes:

[listennui]

No sir, this tapeworm is my antihistamine support animal

[stkygrnz]

Just seeing 2012 Hank shows that the man was made for being a presenter. He is so natural at it. His little tics and speaking style haven't changed at all over the years.

[SerunaXI]

Worst part of dealing with bedbugs is you are paranoid even years after you are free of them. Lord, there are days I still wanna prepare the vacuum and flip the mattress up just to do a sweep.

[joshuasalem]

1:24 The “You are mostly bacteria” fact has since been corrected. You actually have about the same number of human cells and bacteria cells, but you get rid of most of that bacteria every time you defecate.

[pentalarclikesit]

58, 484 fears. . . "Good news is very unlikely a fish will swim up your urethra!" . . . 58, 483 fears.

[baranorak]

2012 Hank... wow that's quite the throwback

[yamushu]

Hank's little laugh as he goes, "We're our little biome!"
that was rlly adorable

( 1:54 )

[renkio]

Since toxoplasma gondii infection correlates with an increase risk of depression and self-harm in humans, might it not cause the same in rats? So maybe infected rats become suicidal. It's not that they're suddenly cat-loving; they're probably like "just take me I don't care anymore".

[mistingwolf]

Oh, the worms part made me remember something very sad. I was watching a veterinarian show and owners came in with a very lethargic bearded dragon. Owners of any animal, be sure to get your pet checked regularly for parasites! (something gross follows)
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The poor thing had so many worms in it that when the animal was sedated for examination, they started crawling out of its windpipe. Yeah, that animal did not make it.

[ehjones]

It's worth pointing out about toxoplasmosis that the eggs shed in the faeces don't become infective for 1-5 days so fresh faeces isn't infective. It's microscopic faecal residue that might get on your cats paws and then gets shed wherever the cat goes that's infective.

Clean out the litter tray promptly, and wash your hands regularly, especially after gardening or playing outside.

[thescholarsjourney]

This may not be the episode for me to watch while I'm eating....

[stevie-ray]

Just accept that you're the host, & you have one helluva party inside!

[prapanthebachelorette]

Hank: Worms, don’t google it. It’s gross 🤢
Me: Well…. Studying healthcare in tropical zone makes that inevitable for me 🤣🤣🤣🤣

[alphatonic]

When i hear about helpful worms i have to think about that one Futurama episode where Fry got worms by eating a black tomato slice thinking he ate a chocolate cookie. The worms he got from it made him 100% healthy and even helped him grow some muscles. Back then i wanted those worms too.

[SuLokify]

Parasites are evolutionary wizards. Their relationship with their hosts create a beautifully elliptical fitness back-and-forth.

[robertabarnhart]

Interesting tidbit I learned in bio class: in areas where botflies are common, cuckoo eggs don't have to be so similar to the host bird eggs. The reason is that cuckoo chicks really love botfly larvae, so they keep their stepsiblings from getting blinded by botflies. So the host parents have an incentive to keep them around. Of course, it's not a conscious choice, just instinct.

[hannah]

At my last job my boss started getting colonics and was convinced she had parasites that would need multiple colonics… could you do an episode talking about the pseudoscience that goes into colonics and misdiagnosing normal changes in our poop as parasites?

[conlon]

Is anyone else really bothered by Hank keep calling bacteria animals? They're not even eukaryotes.

[Archronis]

Surprised Hank didn't mention the Rat Lungworm. Probably the scariest parasite out there.

[pabrown]

I contracted toxoplasmosis when I was 11. It nearly blinded me in one eye — my vision in that eye is 20/200. I’ve sometimes wondered if I was left with any other behavioral changes.