Advertisement

Germs have the upper hand in space, but the strategies from an Earth-based doctor will help keep astronauts safe

When he was asked to speak at NASA-Johnson Space Center symposium in April of last year, Dr. Leonard Mermel, a professor of medicine at Brown University who specializes in the study and prevention of hospital-acquired infections, especially from drug-resistant pathogens, had to admit that he didn't know very much about the environment that astronauts dealt with while in space.

"I've been involved for two decades with trying to prevent infections in the intensive care unit and general hospital settings and I've been involved with national and international guidelines, but there are a lot of constraints in space I had never thought of before," he said, according to Science Daily.

In his efforts to come up with recommendations for the space program, he read hundreds of papers on the effects of microgravity on both the human body and on the germs that cause infectious diseases, and consulted with a number of experts these subjects.

Sifting through all the information, Mermel found several key facts about being in space that tip the balance of power in favour of the germs:

  1. Living in a microgravity environment diminishes the human immune system.

  2. Microgravity increases the virulence of microorganisms, making it easier for them to infect us.

  3. Antibiotics have less of an effect on microorganisms in microgravity.

  4. Here on Earth, germs put into the air by sneezing or coughing usually settle to the ground within a reasonably short amount of time, and within about a metre or two of their source. In microgravity, they have the potential to spread far and wide as they will float around indefinitely until they meet up with some surface.

Other than studies done of microbes in the microgravity environment, there have been a total of 29 reported incidences of infection among the 742 crew members that have gone on space shuttle missions. Dealing with those illnesses is relatively easy from Earth, given that communication can happen with relative ease. For astronauts on a mission to Mars, a doctor-patient consultation would have to deal with a round-trip communications lag ranging between about 6 minutes at the closest approach between Earth and Mars, and around 44 minutes at their farthest distance.

[ Related: New technologies could help provide answers in our search for extraterrestrial life ]

"It's going to be radically different in terms of the ability to communicate with someone on Earth," said Mermel. "And what if there was something that happened that put someone at risk? Could they, or would they, turn around before they accomplished their mission?"

Mermel had several suggestions to add to the already impressive prevention methods NASA has put into place its space missions.

He recommended that the vaccinations that astronauts already receive, such as for the flu, could be expanded to include ones for meningitis and pneumonia. Screenings for illnesses, such as tuberculosis, should also include screening the natural flora and fauna of several areas of the astronauts' bodies for all strains of Staphylococcus aureus, including drug-resistant strains, and their stool should be screened for Salmonella.

Next, he suggested that all astronauts receive formal training in infection control, including hand hygiene and environmental cleaning.

Other suggestions involved the design of spacecraft, such as finding a way to work HEPA filtration technology into the energy budget of the International Space Station, making toilets and potable water outlets operated by foot pedals, to reduce the chance of spreading infection by hand, and including dispensers for waterless hand-hygiene products.

Food was another point he raised, since NASA currently irradiates the food that astronauts eat, to kill off any microorganisms present in it. However, that could end up harming the astronauts more than helping them.

"We've evolved to have those microbes go into our gastrointestinal tracts, our immune system interacts with them and is stimulated by them and it's part of our homeostatic mechanism," Mermel said.

[ Related: Mars Curiosity rover scoop tests turn up bright Martian 'schmutz' ]

He also recommended something that NASA is currently working on, which is diagnostic testing kits that are low-energy (to fit into the vehicle's energy budget) and easy to use for the astronauts.

Mermel had some unanswered questions for NASA in his paper, including whether or not they would irradiate food sent with the astronauts, whether microgravity truly increases the risk of infectious disease (something that hasn't yet been measured), what antimicrobial coatings might be used on space vehicle surfaces, what would be the best hand-sanitizer for the astronauts to use and finally exactly why does microgravity weaken our immune systems while making microorganisms more virulent?

Still, even with these questions, Mermel is still confident that, even if they left tomorrow, any long-term space mission could be completed without any problems from illness or infection.

"It would remain a risk, but I'd feel comfortable with it," he said. "They have a lot of bright people invested in doing the right thing."