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Space Travel, Viruses, and the Hidden Universe in Your Saliva 🦠✨
Urbaniak, C., Lorenzi, H., Thissen, J. et al. The influence of spaceflight on the astronaut salivary microbiome and the search for a microbiome biomarker for viral reactivation. Microbiome 8, 56 (2020). https://doi.org/10.1186/s40168-020-00830-z
SPACE MEDICINE
3/1/20251 min read
Imagine you’re an astronaut floating in microgravity aboard the International Space Station (ISS), watching Earth from 400 km above. Your body adapts to the weightlessness, your bones and muscles weaken, your immune system struggles… but something even stranger is happening inside your mouth.
Your salivary microbiome—the bustling community of bacteria in your saliva—is undergoing a cosmic transformation. Some bacteria vanish, new ones appear, and a silent war begins between microbes and dormant viruses lurking in your system.
💡 The Mission: Unravel the Microbiome Mystery A team of scientists, led by NASA’s microbiologists, set out to understand how spaceflight affects the oral microbiome and its connection to viral reactivation—specifically, the Epstein-Barr virus (EBV), which can cause mononucleosis and even increase cancer risk.
For the first time, astronauts had their saliva analyzed before, during, and after space missions, revealing shocking discoveries:
🔬 Microbes Mutate in Space:
The diversity of bacteria increases in microgravity.
Some bacteria, like Actinobacteria, decline, while others, like Proteobacteria and Fusobacteria, flourish.
New bacteria appear that weren’t even detectable before flight!
🦠 Viruses Wake Up in Space:
EBV, the virus responsible for mononucleosis, reactivates in some astronauts.
A specific set of bacteria, Gracilibacteria and Abiotrophia, seems to fuel viral reactivation, while others, like Veillonella and Haemophilus, may protect against it.
🔄 Astronauts’ Microbiomes Change Forever:
After returning to Earth, some astronauts’ oral microbiomes never fully return to their pre-flight state, hinting at a lasting biological impact of space travel.
Interestingly, astronauts who had flown before experienced fewer changes, suggesting their bodies might be adapting to space conditions.
🌌 Why Does This Matter?
As humans prepare for long-term space missions—to the Moon, Mars, and beyond—understanding how microbial shifts impact immune health is critical. If astronauts are more vulnerable to viral reactivation during missions, could we develop microbiome-based countermeasures? Probiotics for space travelers? Saliva-based virus detectors?
🚀 The Future of Space Medicine:
This study opens the door to designing personalized microbiome monitoring and immune-boosting interventions for future astronauts. The next time we send humans to Mars, their oral microbiome might be just as important as their oxygen supply.