Person to Person
The main way that influenza viruses are thought to spread is from person to
person in respiratory droplets of coughs and sneezes. (This is called "droplet
spread.") This can happen when droplets from a cough or sneeze of an infected
person are propelled through the air and deposited on the mouth or nose of
people nearby. Influenza viruses may also be spread when a person touches
respiratory droplets on another person or an object and then touches their own
mouth or nose (or...
The modes of transportation most often blamed for spreading disease are
airplanes, cruise ships, and subway trains. Are they just scapegoats? Or are
these popular conveyances really making us ill? WebMD asked experts who've
studied transportation health.
Up in the Air, Germs Are There
The Ides of March, 2003, was unlucky indeed for the 120 travelers who that
day boarded Air China flight 112. The Boeing 737-300 completed its three-hour
flight from Hong Kong to Beijing without apparent incident. But coughing in
seat 14E -- a middle seat near the center of the plane -- was a person carrying
the deadly SARS virus.
Within eight days, 20 passengers and two flight attendants would come down
with SARS. Some of those who became infected were sitting as far as seven rows
away from the man carrying the SARS virus. Five would die.
It's not just SARS - and it's not just China. In 1979 a commercial airliner
sat on the tarmac for three hours with its ventilation system shut down.
Someone on board had the flu -- and, within three days, so did nearly
three-fourths of the plane's passengers.
SARS and influenza, of course, are only two of the multitude of bugs lurking
out there. But the case of Flight 112 suggests that the current understanding
of the spread of airborne disease aboard aircraft, which is based on
tuberculosis investigations, may be outdated. Emergency medicine specialist
Mark A. Gendreau, MD, senior staff physician at Lahey Clinic Medical Center,
Burlington, Mass., recently reviewed what is and isn't known about infectious
disease spread during air travel.
"The CDC and World Health Organization say you risk getting an infection
only if you are sitting within two rows of someone who has something - and only
if you are sitting there for more than eight hours," Gendreau tells WebMD.
"But Flight 112 was only three hours long, and people sitting as far as
seven rows back were affected. So that says, 'Wait a minute folks.' That old
advice may have worked for tuberculosis, but what about SARS and other
infectious diseases? More study into that is needed."