Weightlessness may be doubly dangerous for fending off infection
Space travel seems to weaken the immune system, and it may also make a range of microbes deadlier than they are on Earth.
A flight of the space shuttle Atlantis in 2006 showed that the bacterium Salmonella typhimurium (shown here in red) was nearly three times as likely to kill mice.
Microgravity also seems to boost the virulence of methicillin-resistant Staphylococcus aureus, an antibiotic-resistant superbug that is a common cause of infection in hospitals.
A firm called Astrogenetix is now studying this increased potency to isolate factors responsible for virulence in the hopes of producing vaccines.