San Diego State Study Finds Tiny Frequent Fliers
May Pose Health Hazard
Biologists Find Opportunistic Bacteria on Airplanes, Mostly in Lavatories

Contact: Jason Foster
SDSU Marketing & Communications
Tel: (619) 594-2585/ Cell: (619) 992-0772
foster@mail.sdsu.edu

SAN DIEGO – (Wednesday, Nov. 30, 2005) – For many people, the prospect of traveling on an airliner makes them shudder at the possibility of getting sick.

That fear may have some merit, according to a new study by San Diego State University researchers who examined levels of bacteria on various airplane cabin surfaces and found that “airplane lavatories present an especially significant concern to public health.”

SDSU Assistant Professor of Biology Scott Kelley, Ph.D., and undergraduate biology student Collin McManus examined bacterial contamination on passenger aircraft and identified airplane environments posing the greatest potential health risks. They examined bacterial DNA from 10 environmental samples collected on four different flights (three domestic, one international) from a variety of surfaces frequently touched by passengers.

The results, recently published in the Journal of Applied Microbiology, show that there is a large diversity of bacterial contamination on airplanes, especially on several lavatory surfaces. The organisms found included opportunistic pathogens that potentially can cause infections in humans ranging from strep throat to meningitis.

“What’s important is that this study indicates how many different kinds of bacteria can exist in this environment and therefore the tremendous potential for airplanes to spread an enormous diversity of bacterial species,” Kelley said.

This is not just a concern for individual passengers, Kelley said. The possible health ramifications could be global.

“Airplanes bring more numbers of all sorts of people together from very different places more quickly than perhaps any other common setting,” Kelley said. “We found a potentially hazardous array of bacteria on just four flights. When you consider how many flights are in the air each day from place to place all over the world, you have to think that these airplanes in general pose a significant health concern.”

The researchers used sterile wipes to wipe down tray tables, armrests, toilet seats and handles, sink handles and doorknobs. Samples were taken from the bathroom floor and paper towels as well. The tray tables and armrests had almost no detectable bacteria. The lavatories, the most commonly visited area of the airplane, had the most.

“The substantial diversity of human-associated bacterial species found on numerous lavatory surfaces on every flight tested, including a paper towel, suggests that lavatories represent the biggest potential hazard for passengers and crew,” the report states.

A significant number of the species identified in the study (Streptococcus, Staphylococcus, Corynebacterium, Propionibacterium and Kocuria) typically inhabit human oral cavities. The researchers posit “that passengers possibly spread these organisms around the confined space of the lavatory (by) coughing or blowing their noses.”

There is good news, however. Kelley said with the exception of the rising numbers of immune-compromised patients, the organisms detected are not especially threatening to the general public. “However, we see serious potential for ill persons with more threatening conditions to spread disease to other passengers on planes,” he said.

Kelley added he hopes in the future to do a study looking at the presence of viruses on airplanes.

Kelley offered the following suggestions to help airplane passengers minimize their exposure to bacteria on airplanes: 1) Frequent handwashing; 2) Minimize the surfaces you touch, especially in the lavatory; 3) carry a small bag or packet of disinfectant wipes to clean any surfaces you do have to touch.

SDSU is the oldest and largest institution of higher education in the San Diego region. Founded in 1897, SDSU offers bachelor’s degrees in 81 areas, master’s degrees in 72 and doctorates in 16. SDSU’s nearly 33,000 students participate in academic curricula distinguished by direct faculty contact and an increasingly international emphasis that prepares them for a global future. For more information, visit www.sdsu.edu.

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