We already know that planes are airborne petri dishes, and that one open-mouthed sneeze can spread influenza through a cabin faster than you can say "Blue Christmas." But a new study suggests that it’s not so much what you inhale on planes that causes the really big problems, but what you touch.
Researchers from Auburn University dabbed surfaces in an airplane with two especially virulent bugs: Methicillin-resistant Staphylococcus aureus (better known as the superbug MRSA, which kills about 19,000 people in the U.S. every year), and E. coli bacteria, a germ responsible for abdominal cramping, nausea and diarrhea. The goal of the experiment--conducted on behalf of the Federal Aviation Administration--was to find out how long these germs can survive and remain transmittable in the cabin of a typical airplane.
Researchers chose six surfaces that people frequently touch, like armrests, seatback tray tables, cloth magazine pockets, and the metal handle used to flush the toilet. Temperature and humidity in the cabin were controlled to emulate actual conditions, and researchers mixed the germs with three solutions that are common on airplanes: saline, simulated sweat and simulated saliva.
Here’s what they found:
MRSA survived for up to 168 hours on cloth seatback pockets.
E. coli survived for 96 hours on armrests, 72 hours on tray tables, and 48 hours on toilets.
The germs were not, however, transmittable for the duration of their lifespans on all of the surfaces. When carried in sweat or saliva on porous materials (like cloth magazine pockets and armrests), MRSA was only transmittable about 1.1 percent of the time after 24 hours and lost its impact entirely after 48 hours. But, when deposited in sweat on nonporous surfaces like tray tables, its transmission rate was nearly 45 percent.
E. coli remained highly transmittable on tray tables even after 72 hours.
The big caveat for all of these results is that researchers did not test the effect of cleaning products on the germs. If airline personnel are doing their jobs, the rate of transmission for these and other pathogens should, at least theoretically, be much lower.
The takeaway from these findings is that we should keep doing what we should have already been doing – washing our hands early and often. That, along with choosing a bit more carefully what we touch (if you can avoid sticking your hand into the seat pocket, that would probably be a good idea) should be enough to keep infection rates manageable.
Oh, and best to think twice before eating your pretzels or peanuts right off the tray table.
The study results were presented at a meeting of the American Society for Microbiology.
You can find David DiSalvo on Twitter @neuronarrative, at his website The Daily Brain, and on YouTube at Your Brain Channel. His latest book is Brain Changer: How Harnessing Your Brain’s Power To Adapt Can Change Your Life.
