A new study is expected to provide the first detailed information on how infectious diseases may be transmitted aboard commercial airliners. Sponsored by aircraft manufacturer Boeing Co., the research will document patterns of passenger movement inside aircraft cabins and inventory the microbes present in cabin air and on surfaces, such as tray tables and lavatory fixtures.

The information provided by the three-year study could help improve health and safety for both passengers and airline flight crews. Researchers from two Atlanta universities, the Georgia Institute of Technology and Emory University, are working together on the project, in collaboration with environmental sustainability personnel from Atlanta-based Delta Air Lines.

"The ultimate goal of this project is to reduce the transmission of infectious diseases on aircraft," says Howard Weiss, a professor in the Georgia Tech School of Mathematics. "We will learn how people move around in aircraft, and study the microbes that are there at different times during flights. From that information, we can start modeling the disease transmission and developing intervention strategies."

Airborne infectious diseases transmitted during commercial air travel are of concern to public health officials. In 2002, 20 people on an international flight were infected by a single patient with severe acute respiratory syndrome (SARS), which showed how air travel could serve as a conduit for the rapid spread of both emerging infections and pandemics of known diseases.

Researchers know that bacteria and viruses can be transmitted in three ways on aircraft: inhalation of small droplets coughed or sneezed by infected persons and carried significant distances in cabin air; inhalation of larger droplets that tend to fall within a meter of their sources, and transfer of droplets from surfaces into the eyes or noses of susceptible individuals. The latter, which may account for as much as 80 percent of the disease transmission, can occur when passengers touch contaminated surfaces, such as seat tray tables, lavatory door knobs, or sink handles.

"By understanding the patterns of how infectious diseases may be transmitted from an infected person to an uninfected person, companies like Boeing may be able to design aircraft that better protect passengers and crew members," says Vicki Hertzberg, of Emory University's Rollins School of Public Health. "That will put us in a better position from a public health perspective."

Using radio-frequency identification tags, Hertzberg has been studying how people interact—and potentially transfer infectious diseases—in medical facilities such as hospital emergency departments. On aircraft, however, the researchers won't be able to use such technology because of potential interference issues.

However, the researchers will use sophisticated sampling equipment carried aboard the aircraft to gather information about what's in the cabin air. They will also swipe certain touch surfaces, and both the wipes and air-sampling filters will be analyzed to identify the microbes present. To study passenger movements around the aircraft, the researchers plan to watch and record movement on an iPad.