Cruise ship virus can spread on planes

NEW YORK (Reuters Health) - The norovirus, best known for causing diarrhea and vomiting on board cruise ships, can cause problems on airplanes as well, researchers have found.

On October 8, 2008, a flight from Boston to Los Angeles was diverted to Chicago shortly after take off after multiple passengers suffered acute gastrointestinal illness, including vomiting and diarrhea, thought to be caused by the highly contagious norovirus. The ill passengers were members of a tour company's New England fall foliage bus tour who were returning home to California.

In Chicago, the airline passengers not from the tour group boarded a different plane and continued their trip west, while the tour group remained in Chicago overnight. Several were hospitalized.

A subsequent investigation by the U.S. Centers for Disease Control and Prevention in Atlanta and the New Hampshire Department of Health in Concord found 6 confirmed and 9 probable cases of norovirus infection among tour group members on the plane, as well as 1 confirmed and 6 probable cases of norovirus infection in the non-tour group airline passengers.

"The symptoms and timing of illness" (within 48 hours of the flight) among non-tour group passengers was consistent with norovirus transmission on the airplane, Dr. Daniel Fishbein, the CDC researcher who led the investigation, told Reuters Health. The same strain of norovirus was recovered from stool samples of both the tour group members and one of the ill non-tour group passengers.

Sitting in an aisle seat or near a tour group member were strong risk factors for becoming ill, which suggests to investigators that transmission occurred either directly through person-to-person contact or indirectly via contamination of armrests, tray tables, or seat controls.

"This is the first time passenger-to-passenger transmission (of norovirus) has been documented on an airplane," Dr. Aron Hall, a CDC epidemiologist involved in the investigation, told Reuters Health by email. Hall said only three other norovirus outbreaks on airplanes have been reported in the medical literature.

In an email to Reuters Health, Dr. John Holmes, of the University of Otago in Dunedin, New Zealand, who last year published a paper on a norovirus outbreak on an airplane, noted that the compact layout of bathroom facilities on aircraft hinder good hand-washing techniques that can prevent spread of norovirus and also pose problems for crew cleaning up after contamination from vomiting or diarrhea.

He said travelers can avoid mid-air infection by carrying a small vial of alcohol hand sanitizer to be applied while using aircraft toilets and before eating. "Do not put your fingers into your mouth after you have touched aircraft seats, fittings or other surfaces that may be contaminated," he advised.

Holmes, an official with the New Zealand Health Ministry, said people who feel nauseated should postpone travel. He said ill travelers often are unwilling to postpone trips because airlines and tour companies are reluctant to rebook without extra charges.

Fishbein and colleagues suggest that travelers buy traveler's insurance, so ill people might feel less compelled to travel. Motion-sensing or foot-operated faucets, soap dispensers and drains in plane lavatories could reduce spread of disease.

SOURCE: Clinical Infectious Diseases, May 1, 2010.