Germs Turn Deadly After Space Flight

Deadly germs from outer space attack Earth! It may sound like the ridiculous plot of 1950s B movie, but it could happen.

In an experiment to see how space affects germs, scientists sent some salmonella germs along on a 2006 space shuttle trip -- carefully sealed, of course. Salmonella is the germ that causes food poisoning. When the space-borne germs were fed to mice back on Earth, the mice were three times more likely to get sick and died faster than mice fed earthbound salmonella.

The act of being in space caused the germs to mutate, making them stronger and more virulent. Researchers found 167 gene changes in the salmonella sent into space. Of the mice who received the space germs, only 10% survived, compared to 40% of the mice who received the earthbound salmonella.

"Wherever humans go, microbes go, you can't sterilize humans," said Cheryl Nickerson, associate professor at the Center for Infectious Diseases and Vaccinology at Arizona State University. "Wherever we go, under the oceans or orbiting the earth, the microbes go with us, and it's important that we understand ... how they're going to change."