5 Infectious Facts About Leprosy | What the Stuff?!

5 Infectious Facts About Leprosy | What the Stuff?!


“Try this one…” Leprosy gets a bad rap. Sure, it’s preferable to not have leprosy,
but people who have it are neither victims of their own sins – as was
believed in the past – nor highly contagious and doomed. DOOMED! Leprosy is still a serious health
concern in a few populations around the world, but it’s actually very treatable
these days, especially if it’s caught early, and it has a low transmission rate.
But the true facts about leprosy are still fascinating – some morbidly so. Here are five of them. Armadillos are the only known carrier of
leprosy other than humans in the entirety of the
animal kingdom. The disease is caused by infection with
the bacteria mycobacterium leprae and it’s been genetically proven that
armadillos carry the exact same strain that we do. But digging deeper than that it’s humanities fault that armadillos
have leprosy to begin with! This is surprising, because many zoonotic
diseases – that is, diseases that can be passed between humans and other animals –
originated in other animals and only started infecting us when we encroached on
their natural habitats – like the flu or Ebola but not so with leprosy. Researchers think that the disease
wasn’t present at all in the western hemisphere before Christopher Columbus
spearheaded Europe’s lasting contact with the Americas in the late 1400s and armadillos are only indigenous to
the Western Hemisphere. So it looks like they got it from us. Susceptibility to infection with M. leprae
is genetic and rare. Science hasn’t identified exactly what genes or more
specifically what variants of genes allow the bacteria to take hold but at least a dozen have been
implicated. All of them are responsible for some
aspect of immune system function on a cellular level, meaning they affect how
your immune system cells target and respond to bodily invaders. Most of our immune systems can identify
and destroy leprosy bacteria without a problem. One of the premier questions in genetics
is how we can encourage specialized cells to act like generalized stem cells. Mycobacterium leprae do exactly that –
they target your nervous system’s Schwann cells. These cells are part of the
support system that insulates your peripheral nerves – the ones that aren’t
in your brain and spine. Schwann cells help those nerves grow, regenerate, and
function. Leprosy reprograms the Schwann cells.
No one is entirely sure how, but M. leprae bacteria take those cells and make them
revert to a stem cell-esque state. That is, they allow the cells
to convert into other types of cells. The converted cells then migrate through the
body to join up with tissue of their new type. The hijacked Schwann cells bring
the M. leprae bacteria along with them spreading the infection. If we could
figure out how leprosy bacteria do that we could potentially cure the disease
and use the mechanism to create treatments for degenerative diseases
like Alzheimer’s. Written records of leprosy
stretch back to 1500 BCE. That’s when it’s first mentioned in the
Egyptian Ebers papyrus it’s also mentioned in other ancient
writings including asian area texts dating back to 600 BCE. But researchers have found even older
evidence of the disease. Skeletal remains found in modern day
India indicate that leprosy was active in at least 2000 BCE. That places
it as one of the top ten oldest diseases known today. Medieval images of people with leprosy
involved deformed features sunken noses, shriveled hands and feet that’s not because those extremities
just fell off. Without treatment, leprosy bacteria caused damage to tissues
throughout the body including lesions on the skin, cysts on the bones, and
destruction of the peripheral nerves. As this damage continues, the body’s
resources for healing wounds becomes seriously taxed. It doesn’t help that
with nerve damage you’re not always aware of minor injuries so you might not
take steps to protect and heal hurts as they happen. Eventually, the body begins mining its own tissues
for resources to fix the damage. Cartilage becomes particularly valuable.
The body steals it from everywhere, but the effects are the most obvious in your
extremities: fingers, toes, and nose. So, what diseases morbidly fascinate you?
Get in touch and let us know and we might make a video about it! Give us a like, and subscribe if you
learn something here but to learn lots more, check out ‘How Leprosy Works’ and
thousands of other articles at howstuffworks.com


8 thoughts on “5 Infectious Facts About Leprosy | What the Stuff?!

  1. Armadillos already cured leprosy. They are anteaters and are fire ants predator. http://www.understandinganimalresearch.org.uk/news/staff-blog/armadillos-roll-out-treatments-for-leprosy/

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