| Why Does The Flu Virus
Thrive In The Winter?
Virologists investigating transmission of the flu virus found
why it is more likely to spread at colder temperatures. The dry,
cold conditions pull moisture out of droplets released by coughs
and sneezes, which allows the virus to linger in the air.
Additionally, cold, low humidity air dries out the nasal passages
and makes virus transmission more likely. This contradicts the
long-held view that the flu spreads because the immune system
is less active during the winter.
Some researchers have found that in winter, even the flu virus
wears a coat, and it's a coat that helps the virus spread through
the air. Tinkering with that coat might disarm the flu virus.
"Like an M&M in your mouth, the protective covering melts
when it enters the respiratory tract," Joshua Zimmerberg,
PhD, chief of the cellular and molecular biophysics lab at the
National Institute of Child Health and Human Development (NICHD)
says in a news release. "It's only in this liquid phase that
the virus is capable of entering a cell to infect it."
In warmer temperatures, that coating doesn't form. So it's harder
for the influenza virus to spread through warm air.
Virologist doctor Peter Palese has been studying the effects
of heat and cold on the flu virus. He found that at higher temperatures,
the flu virus didn’t spread.
“The virus is probably more stable in cold temperature,
so it hangs in the air much longer,” Dr. Palese told Ivanhoe.
Cold allows the virus to spread easier. Here’s how -- when
we cough or sneeze, microscopic droplets of water and the virus
enter the air. Dry, cold conditions dry out the droplets, helping
the virus linger in the air. The dry air also dries out nasal
passages, which helps the virus stick.
“Cold dry air going over your nasal mucosa gets cracks
in our airways and that allows virus to get in more easily,”
Anice Lowen, researcher at Mt. Sinai School of Medicine told Ivanhoe.
Reference Sources 71, 128
November 23, 2009
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