Six Microbes Living in You

  • By Ana Aceves
  • Posted 05.09.18
  • NOVA

Microbes colonize our skin, guts, and bodies—but we wouldn’t be ourselves without them.

Running Time: 03:43


Six Microbes Living in You

Published May 9, 2018

Onscreen: These six microbes may be living in you.

1. Dermatobia hominis

This parasite, also known as a botfly, grows on animals in the rainforests of central and south America. The female botfly glues her eggs to a mosquito. When the eggs detect the host’s body heat, they hatch and the larvae crawl into the host.

They grow for about 3 months—until they’re the size of large peanuts. They then drop to the ground and pupate. After a month, the adults emerge to mate and repeat the cycle.

2. Demodex brevis and Demodex folliculorum

These parasites live on your face…and all over your body. At night, they come out of your pores and have sex on your face. Then they retreat into your pores to lay eggs. You can’t get rid of them. Not even showering or washing your face helps.

3. Helicobacter pylori

For years, doctors believed ulcers were caused by stress and unhealthy life choices. But in the 1980s, two Australian doctors examined biopsies of gastric ulcers. They discovered a new bacterium, H. pylori.

To prove the cause of ulcers was the bacteria, one of the doctors used himself as a test subject. It worked. Before long, his stomach was teeming with H. pylori and he developed ulcers. Antibiotics killed off the bacteria, curing him.

And in 2005, they won the Nobel Prize for this medical breakthrough. But today some researchers think that killing off all our H. pylori might contribute to other diseases

4. Escherichia coli

There are dozens of E. coli strains and they’re mostly harmless. Some help break down your last meal and produce vitamins your body needs. But some strains can cause illness, putting thousands of Americans in hospitals and killing about 30 people every year.

5. Clostridium difficile

This bacterium can cause colon inflammation and diarrhea. It lives in your gut naturally and it’s usually kept at bay by good bacteria. But C. diff can run rampant if you’re taking antibiotics that kill off these good bacteria.

Every year, thousands of people can die from C. diff infections. In some cases, doctors may suggest a fecal transplant to restore your G.I. tract’s healthy gut bacteria. And it works ~90% of the time!

6. Toxoplasma gondii

This parasite infects the brains of mice. Healthy mice are scared of the smell of cat urine. But infected mice don’t run away, so they have a greater risk of being eaten. Which is what the parasite wants since it can only breed if it reaches the stomach of a cat.

But you don’t have to eat mouse to get toxoplasmosis. You can get it from raw meat, unwashed vegetables, or from kitty litter. Which is why pregnant woman are advised to not handle kitty litter. The infection can cause miscarriage and premature birth.

Viruses, fungi, and bacteria are all around us.They colonize our skin, guts, and bodies. We’re outnumbered. But without them, we wouldn’t be ourselves.



Digital Producer
Ana Aceves
Written, Produced, and Directed by
Peter Yost


Images Provided by
Getty Images
Science Photo Library
© WGBH Educational Foundation 2018

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