The SARS virus can
survive on common surfaces at room temperature for hours or even days,
which could explain how people can catch the deadly lung infection without
face-to-face contact with a sick person., scientists have found.
New laboratory studies,
being released today, have produced the first scientific data on how long
the SARS virus can live in various places and conditions, demonstrating
for the first time that the microbe can linger outside an infected person's
One study showed the
virus survived for at least 24 hours on a plastic surface at room temperature,
which suggests it might be possible to become infected from touching a
tabletop, doorknob or other object [such as a toilet seat]. Another found
the microbe remained viable for as long as four days in human waste, a
crucial finding that could clarify how the virus can spread through apartment
buildings, hospitals and other facilities.
found that a common detergent failed to kill the virus, indicating that
some efforts to sterilize contaminated areas may be ineffective.
An experiment conducted
in Japan concluded that the virus could live for extended periods in the
cold, suggesting it could survive the winter.
The long-awaited findings
should be crucial for containing the epidemic, and they could solve one
of the most important mysteries about the new disease: how the virus spreads
without direct exposure to infected individuals.
"It's the first
time we have hard data on the survival of the virus. Before, we were just
speculating," Klaus Stohr, the World Health Organization's top SARS
scientist, said Saturday. "There has been a lot of speculation that
the touching of objects could be involved. This shows that transmission
by contaminated hands or contaminated objects in the environment can play
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In addition, the findings
will help researchers develop better tests for the virus and possible
treatments. Now that they know what temperatures kill the virus, researchers
can purify serum from sick people to use in calibrating tests and possibly
to give other patients as a therapy. Serum contains antibodies that are
measured by tests. In addition, the antibodies could work as a treatment
if they can neutralize the virus.
The findings were
produced by laboratories in Hong Kong, Japan, Germany and Beijing that
are part of a scientific network organized by WHO to study the previously
unknown virus. The findings were compiled and analyzed over the past few
days and were to be posted on WHO's website today so public health workers
aroudn the world can begin using them to keep the virus from spreading,
said Stohr, who described the findings in a telephone interview.
Stohr emphasized that
by far, the primary mode of transmission was through droplets that spray
out when an infected person sneezes or coughs.