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  • When you think about Lyme disease you probably think of this, a tick.

  • Or maybe more specifically, a tick bite. Which is not wrong, you should.

  • But what exactly is it about a tick bite that makes us sick?

  • This is Borrelia burgdorferi, one of many bacteria that ticks can pass onto humans and

  • the one responsible for Lyme disease.

  • It causes an array of symptoms, which can be anything from fatigue, arthritis, facial

  • palsy and occasionally a bulls-eye rash. (Erythema migrans, if you want to get technical).

  • Weve only known about the pathogen since the early 1980’s, but it’s been around

  • for much longer than that...potentially for thousands of years longer.

  • Traces of its effects were even found in Otzi the Iceman, the 5,300-year old hunter found

  • mummified in the Italian Alps.

  • But while were not sure exactly where and when Borrelia originated, we do know a lot

  • about how the disease works and how it’s spread.

  • My name is Raphael Stricker.

  • I'm a medical doctor. I practice in San Francisco.

  • I have more than 4000 Lyme disease patients in my practice.

  • And I've written more than 200 papers about Lyme disease.

  • Ticks have been called sewers of infection.

  • Anything that they feed on they can pick up and transmit to you.

  • Thesesewers of infectionneed blood to survive.

  • Sometimes that’s bird blood, sometimes that’s reptile blood, but a lot of the time its mammal

  • blood, like mice and deer.

  • If a tick feeds on one of those animals and they are infected with the bacteria, the tick

  • will carry it and then spread it to other animals, who then spread it to other ticks,

  • and so on.

  • Occasionally, those ticks spread the disease to us, and they do that by passing the pathogen

  • through the tick’s saliva, which some people call a pretty fascinating substance.

  • Tick saliva is really a pretty fascinating substance.

  • It has several components.

  • One is it has an anesthetic that numbs the bite site so that the person doesn't know

  • that he or she is being infected.

  • It also has an anticoagulant that keeps the blood from clotting so that the tick can feed

  • continuously at that site. And then it also has this immunosuppressive substance that

  • suppresses the immune response at the bite site so that the host can't fight off the infection.

  • And it's been shown that a tick bite can inject about 70,000 bacteria with the lyme bacteria,

  • so you're getting a pretty hefty dose of this spirochete, it's called a spirochete, with a tick bite.

  • So, what does Borrelia burgdorferi actually do to your body?

  • Technically....nothing.

  • The bacteria itself doesn’t harm your cells, but your body knows the pathogen shouldn’t

  • be there, so it launches an all-out assault.

  • Your immune system will first try to fight off disease by targeting proteins on the bacteria’s

  • cell walls, but the spirochete can just change which proteins it expresses and evade detection.

  • So, so much for that idea.

  • Then, as the pathogen moves through your bloodstream to other parts of your body, your immune system

  • continues to fight it by producing cytokines, which work to regulate your immune system

  • and produce inflammation.This inflammation then occurs in the areas that the bacteria

  • travels to, which, depending on the strain of Borrelia, can occur in the joints, muscles,

  • heart and even the brain.

  • But due to the bacteria’s ability to evade detection, this inflammation does nothing

  • to destroy it and everything to make you feel sick.

  • So that's what really causes the symptoms.

  • It's not the bacteria per say it's the body's response to the bacteria that causes a lot

  • of these symptoms.

  • Basically, Borrelia burgdorferi isn’t doing much of anything other than trying to survive

  • in its host.

  • Well my medical school teacher told me not to anthropomorphize you know bacteria,

  • basically I mean the goal is to survive.

  • The goal of any bacteria or any organism is to survive.

  • So Borelia has evolved a way to do that that's very efficient.

  • Of course, we're doing whatever we can to make sure the disease can't survive.

  • Currently lyme disease is treated with antibiotics.

  • And while a vaccine was created around 16 years ago, it’s no longer being produced

  • due to low usage and potential side effects.

  • But there is interest in developing a new vaccine in two different ways.

  • One idea is to target the proteins expressed by the Borrelia itself, which fights lyme

  • disease, while the other idea would involve fighting the compounds in tick saliva, which

  • would fight lyme as well as a number of tickborne diseases.

  • Because ticks are, after all,

  • Sewers of infection.

  • So, if ticks, mice, deer and any other number of animals can be infected with Borrelia burgdorferi,

  • why don’t they also get Lyme disease?

  • So deer have a kind of protein in their blood that kills the Lyme bacteria.

  • And the question always comes up well why don't why can't we put that into humans?

  • And the answer is because humans aren't deer.

  • So there you go, humans aren't deer.

When you think about Lyme disease you probably think of this, a tick.

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ライム病はあなたの体に何をしているのでしょうか? (What Does Lyme Disease Do To Your Body?)

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    林宜悉 に公開 2021 年 01 月 14 日
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