Three Creative Ways to Eradicate Diseases

Three Creative Ways to Eradicate Diseases

♪ Smallpox was a terrible disease. It was often fatal, and even if you survived,
you were left with scars where the painful blisters used to be. But thanks to an aggressive eradication campaign,
it became the first human disease we totally wiped out, save a few deadly samples kept
in labs around the world. So far, it remains the only one we’ve gotten
rid of entirely, but we’re getting close on a few more, like polio. And to do that, doctors have had to get creative,
and come up with different strategies tailored to each disease. Many diseases that are on the edge of elimination
are there thanks to the same kind of preventative measures that knocked out smallpox: vaccines. But the smallpox vaccine wasn’t ideal because
it involved getting people actually sick with a different but related virus to protect them. Most modern vaccines are different, and that’s
in part thanks to the creativity that led to the vaccine for the bacterial infection
diphtheria. Globally, we’ve gone from hundreds of thousands
of cases of diphtheria per year to less than 7,000 in 2016. Which is really awesome, because this thing
is pretty nasty. The diphtheria bacteria produces a toxin which
can break down tissues in the lungs and throat, forming a slimy grey mess called a pseudomembrane. People—usually kids—were often suffocated
because of it, which is why the disease became known as ‘the strangling angel’. But in the late 19th century, researchers
took the toxin and injected it into healthy animals, using their immune systems to create
toxin-neutralizing antibodies, which could then be injected into someone with the infection
to combat it. This serum therapy proved to be pretty effective,
and by 1895 companies were cranking out the antitoxin in bulk. But this method was still a treatment, not
a way to prevent new cases. So scientists attempted something pretty revolutionary. Since they could create anti-toxins, they
knew that the bacterial toxin could stimulate the immune system enough that a person could
theoretically create their own anti-toxins—if they survived the dose. So they tried to find a way to inactivate
the toxic effects while still retaining the toxin’s immune-stimulating abilities. And after getting the perfect mixture of formaldehyde,
toxin, and heat, they did it! This deactivated toxin became known as a toxoid,
and it’s the concept behind many vaccines today. And that includes the modern version of the
diphtheria vaccine. Unfortunately a few countries still lack affordable
access to it. So while we’ve made lots of progress, we
can’t say exactly when we’ll reach true eradication. For a disease to be completely eradicated,
there have to be literally zero cases of it in the entire world. And while smallpox is the only one to earn
that title so far, arguably the next closest contender is dracunculiasis or Guinea worm
disease. It’s caused by a parasitic worm that grows
inside a human host—and by grows, I mean an adult female can be about a meter long. INSIDE YOU. And back in 1986, about three and a half million
people were infected with these worms. But that number dropped to only 30 cases in
2017. Some of the last endemic countries like South
Sudan are aiming to be completely guinea worm free by 2020. And that’s largely thanks to education efforts
which teach people how to protect themselves. The disease gets started when the worm larvae
and the tiny water fleas they develop in are ingested, usually through drinking water from
still, stagnant ponds. The young worms bust out of the stomach, find
one another, and mate. Then the male dies while the female grows
under the skin for 10-14 months before she very slowly starts to push towards the surface. As she does, the person usually develops a
fever and painful swelling at the site of her eventual emergence. And while it’s not quite a scene from Alien,
the blister she creates as she works to break out is painful enough that people often try
to soothe their wound in water—which is the exact worst thing they could do. The worm takes the opportunity to release
her larvae into the water source, which starts the cycle over again. Usually these wounds occur on the legs or
feet, so it can be tough to get around while they heal. And if that’s not bad enough, they’re
also prone to secondary infections, so people can be incapacitated for months if they don’t
have access to good medical care. The bad news is there’s no medication to
kill the worms once they’re in you. Most commonly, people wait until one starts
to poke out, then grab it and twist it slowly around a stick a centimeter at a time over
weeks to eventually yank the thing out. So instead, the focus has been on educating
communities how to best prevent infection and helping them get and maintain access to
clean water. Surprisingly simple steps like filtering drinking
water and keeping people with infections away from waters people use have gotten us to the
point where the guinea worm is nearing extinction. We’ve also gotten a lot closer to getting
rid of the worms behind lymphatic filariasis—but with these worms, medication is the answer. In 2000, about 120 million people had the
disease, which is a lot. But between 2000 and 2016, nearly seven billion
treatments were given out, which have likely prevented or cured almost 100 million cases. About 500 million people who were once at
risk aren’t anymore because more than 40 countries have made serious headway towards
elimination. And a new treatment plan received the World
Health Organization’s stamp of approval in late 2017, which hopefully will help doctors
stay on track to eradicate lymphatic filariasis as a public health problem by 2020. The disease gets its name from the filarial
worms which cause it—little roundworms that clog the body’s lymphatic vessels. These vessels are big players in the balance
and distribution of bodily fluids. So when these worms gum up the pipes, they
can cause elephantiasis, severe swelling and hardening of the limbs and genitals. An adult female worm is only about 55 millimeters
long, but that’s big enough to cause blockage, and they can live for anywhere from 4 to 6
years inside you. But eradication of lymphatic filariasis really
doesn’t have anything to do with destroying the adult worms. Instead, doctors go after the babies. Antifilarials like ivermectin literally paralyze
the larvae and keep them from growing up and making more baby worms. These larvae get inside people through mosquito
bites. So combine larvae-killing drugs with anti-mosquito
efforts like nets and you can stop the disease in its tracks. At least, that’s the plan. There’s still plenty of work to do before
these and other diseases are totally gone. But thanks to the creative efforts of scientists
and doctors throughout the years, we’re a little bit closer to thinking of them like
smallpox — things of the past. Thanks for watching this episode of SciShow! If you liked learning about the history of
diphtheria, you might like our episode on how sled dogs delivering anti-toxin inspired
the Iditarod race. ♪

100 thoughts on “Three Creative Ways to Eradicate Diseases”

  1. At what point does the anti-vaxxer movement become a national security threat?
    There is a point. There is a level of permeance. The question's just when it is.

  2. Filarea are literally heartworms (or they're a version of them). Are you saying dogs and cats arent the only one that can get heartworms? Can humans get heartworm?!?!

    Veterinary professional

  3. It's 4:30am so I might be wrong but Michael doesn't blink at all in at least the first 30 seconds of this video possibly more than that and I am flabbergasted

  4. The word "toxin" has been so ruined by pseudoscience and quacks, that even when properly used for actual science education (like in this video), it trips my B.S. detector. It shouldn't, but that's where we are now. Jeez.

  5. ever wondered how mosquitoes carries so many diseases? what if we eradicated these arthropods or genetically modify them so that they are carriers of treatment instead?

  6. Betting we're going to see a return of diphtheria in the US (like we have with measles and mumps) thanks to the antivax dipshits.

  7. Yup, vaccines work, anti vaccinators have developed their own form of dementia, there is no vaccine for that.

  8. I think the guinea worm was targeted by ex-president Carter and his efforts are largely to thank for the near extinction. But maybe I am mis-remembering.

  9. In countries like India… Still many cases of diphtheria and filariasis can be seen
    Although the govt is trying its best to control and essentially eradicate them , there is still a long way to go

  10. You want to eradicate diseases solve the energy poverty issue by providing the third world with cheap and reliable energy like oil, coal, natural gas, nuclear, hydro. We all need to thank fossil fuels for giving us the ability to create vaccinations, proper sanitation, and clean water and air!

  11. but don't they have a vault or something where they store small pox & other stuff for future research in a high security area.

  12. Have fun with autism. I dont mind small pox atleast ill die being fully functional. Polio? Who tf needs legs ill become a professional gamer, blow me bruh.

    Cue austic screeching in 3….2..

  13. There’s now 2 eradicated diseases: smallpox and rinderpest. However, some of the diseases mentioned here are close

  14. Purposefully cause the extinction of an animal that just so happens to have humans in its food chain

  15. if u become vegan and fast u can get rid of any virus or disease don't always think the doctors are ur friends only if they created the disease themselves

  16. It's alarming how all this anti-vaxx bs is spreading quickly and risking to put everyone in danger.
    Here in Brazil we have 312 cities under alert due to low index of people getting immunization against Polio, which is considered ERRADICATED from Brazil since the mid 1990s.
    Cases of measles (WITH TWO DEATHS CONFIRMED) have been popping all around the country, after it being considered erradicated in 2016. And then there's rubella.

    ARGH. It's enfuriating.

  17. Do a video or a series of videos about dentistry. Like, the history of dental practice, current dental practices and what you think the future of dental medicine will be. I would love to see your opinion about this subject. Love you guys 😀

  18. I was waiting to see the poliovirus on this video, we almost got rid of it too. Thank God.
    Also ** anti vaxxers, they don't know how hard we worked to eliminate this diseases.

  19. DDT needs to make a Giant and well deserved return in Triumph as the eradicator of Malaria and many other diseases that it can be.
    Millions of HUMANS have died horrible deaths because it was banned
    Forgiveness is for God, I will never forgive the idiots that straight out ban DDT

  20. The elimination of the Guinea Worm owes a lot to Former President Jimmy Carter who has made it his latest project to make sure the parasite is eradicated.

  21. Caution! NB: You cannot actually get rid of a disease worldwide. We humans are like giants fighting pesky bugs. that elude us. There will always be a few. Preventative Mesures are the only answer in many cases.

  22. 30 cases in where? at a certain country, or the world? if it's the world, i'd say a lie, my relative was recently infected with one of em bursting from her ankle. Seems pretty common to me.

  23. Gasp!! We almost caused the guinea worms to go extinct? It's not to late to save this majestic species, guys.


  24. Oh so I shouldn't get medical advice from people who didn't study medicine?
    You mean celebrities shouldn't be making claims they don't understand?
    …things like vaccines (how and why they work), and about diseases (which they don't understand how and why they work).
    But hey? If you trust Jenny McCarthy or Jim Carrey to do surgery on your kid go right ahead!

  25. My dad still has the scar from the smallpox vaccine from when he was a kid. It's a circle on his shoulder about the size of a half dollar coin. I would hear stories from my maternal grandma, who's native, about how smallpox killed so many people. It used to scare me when I was little thinking I would need one when I went for my boosters before school, but then my dad would tell me this creative story about how he & his generation took care of it so I would never have to. I think about that every time someone whines about the MMR poisoning kids.

  26. I uh… I wouldn’t characterize a bunch of parasites as diseases… they’re just parasites.. now they may cause a disease but the parasite itself is not a disease

  27. I understand with the several million people that have come across our southern border, we are now exposed to an unknown number of disease including eboli. At least three Africans have tested positive for eboli after crossing the border. There are literally hundreds of the Africans that have moved across the border. The number of nationalities that have invaded us is not known at this time. At least we're not being told. You can thank the Democratic Socialist Party and media for this. I think we should use these people to test for exposure. It's the least they can do for their responsibilitie of maiming and killing Americans and the drug deaths need to be tallied against them. Someone needs to gag Nancy Pelosi and the rest of them. Am I angry. Yes and its long-term.

  28. I am not against any vaccines other than flu it changes rapidly and has so many strains the chance you still wont get another strain is so low to actually have true effectiveness you would need tons of shots at once and may need new ones every few weeks to make sure you wont get any strain of the flu

  29. Thank you SciShow for not bowing to the anti vaccination elected officials and internet characters, who both disavow the benefits of vaccines and attribute every ailment of the week to their existence.

  30. The vaccine makes people live longer and population is increasing, thanks to the anti vac parents, they keep it down by sacrifice their children to the disease

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