With air filters and weekly wipe-downs and vacuuming, NASA goes to great lengths to keep the International Space Station clean so that astronauts stay healthy. But astronauts still often experience health problems like immune dysfunction, skin rashes and other inflammatory conditions. One reason may be because the ISS might be too clean, a new study suggests.
Microbes, tiny living organisms like bacteria and viruses, play an important role in human health. But samples of surfaces in the ISS reflect a striking lack of microbial diversity, Rodolfo Salido Benítez, a bioengineer at University of California, San Diego, and colleagues report February 27 in Cell.
Astronauts swabbed surfaces in the kitchen, bathroom, dining space and other areas on the ISS. They then sent the 803 samples to Benitez and colleagues for analysis.
The ISS has lower microbial diversity than most buildings on Earth. And nearly all of those microbes come from humans and building materials, while less than 0.3 percent are from natural environmental sources like soil and water. Like most indoor environments on Earth, the vast majority of microbes originate from human skin.
Inside and outside the body, microbes compete for resources and space, so maintaining a diverse set keeps any one of them from taking over and causing an health problems. Low microbial diversity in hospitals, for example, leads to a higher risk of infection. Even the microbes in your house can affect your health. One study found that Amish communities have a lower risk of asthma than other communities with similar lifestyles because their household dust contains microbes from farm animals.
