An astronaut's least worries should be dormant viruses like herpes flaring up when they go into space on board the Space Station or Space Shuttle. But NASA research has found astronauts are not free from infectious viruses in space.
Before they are accepted into the space program, astronaut candidates are thoroughly tested for garden variety STDs to ensure they are medically fit for space travel 17,500 miles above earth.
"NASA astronauts endure weeks or even months exposed to microgravity and cosmic radiation," Dr. Satish K. Mehta said in a news release Friday in Frontiers in Microbiology.
"This physical challenge is compounded by more familiar stressors like social separation, confinement and an altered sleep-wake cycle," he added.
Mehta and his research colleagues analyzed saliva, blood and urine samples from astronauts before, during and after spaceflight.
The research shows the highest levels of genital and oral herpes viral shedding in urine and saliva during spaceflight.
The viruses detected after flight include oral and genital herpes, chickenpox and shingles, which remain in nerve cells their entire lives.
"During spaceflight there is a rise in secretion of stress hormones like cortisol and adrenaline, which are known to suppress the immune system," Mehta said. He added that astronaut's immune cells are less effective during spaceflight.
Mehta said 53 percent of astronauts on shorter space shuttle flights and 61 percent of astronauts on longer International Space Station missions had traces of herpes viruses in their saliva or urine samples during spaceflights.
These rates are higher in frequency and quantity than in samples tested before and after spaceflights.
Though the findings don't jeopardize current short space flights, longer missions, such as a mission to Mars, could be impacted by the potential of herpes flare ups.
"The magnitude, frequency and duration of viral shedding [flare ups] all increase with length of spaceflight," Mehta said.
Mehta also said vaccination for astronauts show little promise, so the present focus is on developing targeted treatment regimens for astronauts suffering from herpes flare ups during spaceflight.
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