Name: How To Make Antivenom
Uploaded: 2018-07-24T12:42:25.000Z
Duration: 4 min 36 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Well, you probably shouldn't waste three precious minutes watching this video,

but if you're going to do it anyway, I can tell you

Some animals have a natural resistance to snake venom

which can be bitten in the face by a cobra and still not care

but for people, historically, you just had two choices:

you could either just hope you'd recover, or you could just die.

but all that changed with Albert Calmette,

French researcher, dedicated public health advocate, and co-creator of the tuberculosis vaccine

Calmette also developed the first snake antivenom in the late 1890s.

The story goes that Calmette was sent to Saigon, in what is now Vietnam

by his mentor Louis Pasteur, one of the fathers of microbiology,

to help inoculate people against smallpox and rabies.

One day, a major flood swept through his village, flushing up a bunch of monocled cobras that started biting everyone.

and, being an expert in the business of vaccine making, he whipped up an antivenom called "Calmette's serum"

His technique was so solid that it remains largely unchanged today.

Antivenom works by stimulating the production of antibodies

the highly specialised warrior proteins released by your immune system to neutralise dangerous antigens

like viruses, bacteria, or, in this case, venom.

Antivenom can't destroy a venom's toxins or reverse its ill effects

but the antibodies they create can smother them, preventing further spread and rendering them harmless.

To make antivenom, you need venom. And if you're wondering about the name, yes -

you can also call it "antivenin" if you want to; "venin" is actually the French word,

and since he was French, that's what it was originally called

But a while back, the World Health Organisation decided that, in English at least, "antivenom" made a lot more sense.

Anyway, to make an antidote for venom, you need a lot of it

so, once you've got your bag of deadly snakes, grab one, open its mouth over a vial, and gently squeeze its venom glands until they're empty.

You'll only get a little bit at a time, so multiple snakes must be "milked", as they call it, many times

For example, in 1965, the National Institute of Health told famed snake-wrangler Bill Haast

to collect about half a litre of Coral Snake venom.

It took him 69,000 milkings, over a three-year period, to reach that goal.

Once the snake is milked, the venom is freeze-dried to concentrate and preserve it.

Step 3: use some other animal to make antibodies.

Find a horse, sheep, or goat, and inject them with little doses of the venom again and again

This allows the animal to build antibodies and fight off the venom

The antibodies peak after a couple of months, at which point they can be harvested

by which, I mean that up to 6 litres of blood is typically drained from the animal's jugular.

But don't worry; the animal isn't bled to death. It will live on to enjoy the process all over again.

Step 4: Purify, concentrate, and deliver.

After the bloodletting is done, you filter out the antibodies, and then purify and concentrate them into dose vials

If you need it, like, RIGHT NOW, then good!

But if you're just going to store it up for the next snake-handling encounter, then stash it in the freezer.

The fact that antivenom must be kept cold poses a serious problem for developing countries with scarce electricity.

Unfortunately, those tend to be the same places that are inundated with killer snakes.

You've probably noticed by now that this whole process isn't easy.

Making antivenom is expensive and time-consuming, which is one reason why it suffers global supply shortages all the time.

A single vial may cost over $1500, and a victim may require 20 to 30 vials to fully recover

Remember Bill Haast, and his half-litre of snake spit?

He practiced a form of mithridatism, the process of making yourself immune to a toxin by gradually taking non-lethal amounts.

He milked 100 snakes a day with his bare hands

and made his own, decidedly lower-tech, antivenom

leaving the horses out of it and using his own body.

He pretty much single-handedly saved 21 snakebite victims by flying around the world,

He lived to be 100 years old, surviving 172 snake bites, and only losing one finger

Thank you for watching this episode of SciShow

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