Leprosy brings to mind images of biblical
beggars, lonely leper colonies, and seems, for some, to have all but disappeared into
the history books. But leprosy stills haunts many parts of the
world and there’s an absurd amount that we don’t know about the disease. Leprosy has been around since at least 2000
B.C. but, after all this time, we still don’t really know how the disease is transmitted. We don’t know where it starts in the body. Oh, and we can’t grow leprosy bacteria in
a culture. But… maybe we should start with what we
do know. My name is Cressida Madigan. I’m an assistant professor at UC San Diego
in the molecular biology section. And I work on leprosy and other neurological
infections to try to understand how these infectious agents are damaging our nervous
system during infection. I love micro-bacteria which is the kind of
bacteria that causes leprosy. They’re very unusual organisms. And part of what makes leprosy bacteria, or
mycobacterium leprae, so unusual is that it is thought to only be able to replicate inside
a living cell. These bacteria can’t be grown in the lab the
way that we grow other bacteria. We don’t know why. We don’t know if maybe we’re just missing
a key component of the recipe that it needs to grow. Could also be that leprosy simply can not
grow outside of an animal. So, scientists like Dr. Madigan study leprosy
inside living animals like mice, armadillos, and zebrafish. But this still makes the bacteria difficult
to observe and run tests on, especially since it occupies a unique part of the body – the
nerves. It’s the bacteria invading the nerves and
the immune system’s response that eventually causes the major symptoms of the disease. So, while we aren’t really sure how the
disease gets into the body or how it travels to the nerve cells, we know it infects what
are called Schwann cells, which produce the protective myelin sheath that covers neuronal
axons, helping to conduct electrical impulses along the nerves. So there’s some evidence that when leprosy
infects Schwann cells, it stops those cells from being able to make myelin which is this
sort of insulating wrapping that surrounds the axons of our nerves. Something about the infection causes the protective
myelin to die. And this is because the bacteria is destroying
the small, but mighty mitochondria in the nerve cells. So mitochondria are sort of like the batteries
within cells. They produce the energy for the cell so that
it can function. So, as a cell, if you don’t have mitochondria
you will essentially die at some point, right? Over time, the nerve axons also become damaged
by the immune system’s response to the bacteria, which is why people with leprosy can lose
feeling in their skin. But the immune system isn’t activated immediately
and that’s because leprosy bacteria is notorious for moving at a snail’s pace. While other bacteria like e. Coli can replicate
in as short of a time as 20 minutes and disseminate quickly, leprosy bacteria replicates only
once every two weeks or so. So someone could be infected for years and
not experience any symptoms because the bacteria isn’t setting off any alarms. This also makes the bacteria difficult to
treat. Many antibiotics work by targeting bacteria
that are replicating. So if you’re a bacterium and you’re not replicating,
then you will be naturally resistant to several classes of antibiotics. To treat the disease, you’d have to take
a cocktail of various antibiotics daily for up to two years to make sure the drugs hit
the bacteria at the exact moment it’s trying to replicate. And you would need to take multiple antibiotics
at one time to ensure that the bacteria doesn’t become resistant to the treatment. Which is not ideal. But the good news is, leprosy really isn’t
that contagious compared to other diseases. So part of the stigma of leprosy is that this
disease is very contagious. But that’s actually not true. In fact, you need to be around someone with
leprosy for a long time to catch the disease. It also helps that 95% of people are naturally
immune to leprosy. So in order to contract leprosy you have to
be living with a family member who has the disease who is infectious and you have to
have close intimate contact with that person for a period of years. And while the symptoms are undesirable, leprosy
doesn’t directly cause death. In some patients, the symptoms take decades
to manifest. So… like we said earlier about the leprosy
bacteria. They’re very unusual organisms. The Byzantines knew about leprosy. They knew that it was infectious. And so to try to stop the spread of leprosy
throughout the Byzantine Empire, the Byzantines would assign leprosy patients to leprosaria
which were like very posh leper colonies essentially and the leprosarias were actually really nice
places for patients to live. They got free medical care, free food, housing
and so life was so good within the leprosaria that people started trying to fake the symptoms
of leprosy in order to be admitted. Oh, to be a leper in the Byzantine era…
am I right?

100 thoughts on “How Does Leprosy Damage the Human Body?”

  1. I thought Schwann cells was where they stored the ice cream sandwiches before people put them in the fridge

  2. Here at Pepperridge Farms we remember that mitochondria is the powerhouse of the cell. Do you remember? Pepperidge Farms remembers

  3. Hmm but couldn't this slow replication be its very downfall? Like, if you had a single bacterium in your body, couldn't you just like, push a needle in there and burst it to death or something like that?

  4. 𝓜𝓲𝓽𝓸𝓬𝓱𝓸𝓷𝓭𝓻𝓲𝓪 𝓲𝓼 𝓽𝓱𝓮 𝓹𝓸𝔀𝓮𝓻𝓱𝓸𝓾𝓼𝓮 𝓸𝓯 𝓽𝓱𝓮 𝓬𝓮𝓵𝓵

  5. I have MS. No known cause. No cure.

    It's a disease that's essentially a myelin stripper…

    And the thing i wonder about as i watch this is the relationship between MS and leprosy.

    I can tell you, for sure, that an American with MS isn't treated as well as the leproscitc Byzantines.

    Thanks for making and posting this video. Really good. Your choice of "explaining researcher" was excellent.

  6. This and STDs like syphilis tells me that western medicine needs to reconsider air-germ theory if it wants to be taken seriously.

  7. I was a little upset when she said mitochondria are like The batteries of the cell and not "mitochondria is the powerhouse of the cell"

  8. If this bullshit runs on electricity then disrupt this and see how it likes it. Many Armadilos may have to be sacrificed intially.

  9. Interesting bit at the end. I often think that if California or Oregon set about curing addiction and/or homelessness en massé, then homeless people from around the country would move there. Thus big problems need to be tackled comprehensively and widely.

  10. What a powerful meme. They tried to make a cool sciencie presentation but the only thing the comments notice is m i t o c h o n d r i a

  11. Was going to comment about the mitochondria but it seems that 90% of the comments beat me to it thanks guys

  12. Cruel "research" bastards infecting innocent beasties for their sadistic impulses. All life is precious unto itself. If someone infected a research bastard, I'd like to see what conclusions they would present while writhing in agony. F you, torture monger.

  13. First time i saw this it was in a junji ito manga. It was the one where this lady was trying to get into a teen boys bed room.

  14. Is it too hard to use macrophages to treat leprosy? Its a bacterium according to this video, we just need a bateria predator to kill the bacterium.

  15. If it seemingly cannot reproduce or survive outside of a host, it's quite obvious…. It's spread through the consumption of improperly cooked meat, and a lack of hygiene.

  16. So it's her job to try and cultivate diseases in a petri dish? Great! Now let's sing together:
    "The USA loves to threaten countries with their bioweapons… nanana.. in a hundred years or so in word war three her studies will kill millions of people in some country where there is oil.. nanana"

    Yeah, just keep researching, lady. 🙁

  17. Someone mentions mitochondria
    Retards: Mitochondria are the powerhouse of the cell hahahaha hahaha haha.

  18. Yooo I came to the comments as soon as I heard the mitochondria thing, I was like cmon lady we all know what the mf mitochondria is

  19. mitochondria will always be the powerhouse of the cell. it’s literally the only thing i took away from bio besides shape=function

  20. Some lady scientist :Mitochondria are the batteries of the cells

    Mitochondria are the powerhouse of the cell : Hold my ATP

  21. This was a shitty covering of the disease I will not watch another one of your videos being so brief and uninformative

  22. I should've know a sexually confused hipsters with a bull lesbian nose ring would disappoint me in a educational video

  23. It's so good to see that we all have studied in the different part of the world, but Mitochondria is still the *powerhouse*… and not battery of a cell as per our science syllabus.

  24. Well maybe the reason it can't grow outside the body is due to the difference between atmospheric pressure and blood pressure, or there are elements/molecules in the air that effect its growth that aren't in the blood or visa versa.

  25. Hi, how’s everyone doing? Allow me to introduce myself……only guy here who has no idea what this “batteries/powerhouse” reference is all about.

  26. leprosy is coming back, CDC states that new strains are coming from South America through unchecked medical exams when folks from the south come into the USA illegally. The main stream media will not mention this because they and a lot of left leaning liberal politicians welcome illegal entry to this country. Please note, these illegal folks are the folks who are preparing your burger or taco or cleaning your hotel room- have fun when you contract leprosy.

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