THE Centres for Disease Control in Atlanta, USA, has issued guidelines asking people with contagious tuberculosis (TB) to stay off commercial airlines. The guidelines also require airlines to notify passengers and flight crew if an infected person was on their plane for more than eight hours. The measure was prompted by The New England Journal of Medicine's report of a case in which a woman spread tuberculosis while on an aircraft, proving that passengers on long flights face a small but significant risk of catching the disease by sitting near an infected person. The 32 year old Korean woman flew to the US as a tourist two years ago, fell ill after making a flight from Chicago to Honolulu and died five days after being hospitalised for an unusually dangerous case of drug resistant tuberculosis.
Investigators later found that four people sitting two rows away from her subsequently showed signs of TB exposure. Two others sitting 12 or 13 rows away also tested positive on the tuberculosis skin test. None has shown any symptoms of the lung corroding illness.
In an editorial in the magazine, Dr Richard Wenzel, of the Medical College of Virginia in Richmond, echoed previous comments that the risk of catching TB as an air plane passenger is no greater than being with an infectious person under other confined circumstances. The air in a plane's cabin is usually sterile, having been scalded to nearly 500 degrees (250 degrees C) by passing through the jet engines before being cooled at high pressure. But about half the air passing through the cabin is recycled.