When two US astronauts returned from a nine-month stay on the International Space Station (ISS), NASA sent them straight to the doctor’s office for a checkup. That’s because residents of the ISS often come home with a number of illnesses. Scientists think they know why. It’s too clean up there. “Your immune system needs exposure to a wide range of beneficial microbes," Robb Knight told The Wall Street Journal. We can find these, he said, in "places like soil, healthy animals, and healthy plants.” Knight is the head of the center that studies microbiomes at the University of California, San Diego. He co-wrote a study on germs on the ISS. It was published in the journal Cell. Astronauts first noticed the problem when they began coming home with rashes, sores, and even shingles. Skin conditions such as these often happen because of an imbalance between the bacteria on human skin and the bacteria that exists around us. Knight’s team tested more than 800 samples brought back from the ISS. It found that the space station had far too few of the good microbes we live with on Earth. That allows the harmful microbes to thrive. “There’s a big difference between exposure to healthy soil from gardening versus stewing in our own filth," Knight said. That, he added, "is kind of what happens if we’re in a strictly enclosed environment." A solution? Bring more bacteria to space, the study's authors say. But it must be done with caution, they add. Reflect: Do you think it's important for your body to be exposed to different environments, or do you prefer to keep things clean and controlled? Why? Gif of astronaut from GIPHY.
