![]() |
| Ebola in the air? A nightmare that could happen |
Today, the Ebola virus spreads only
through direct contact with bodily fluids, such as blood and vomit. But
some of the nation's top infectious disease experts worry that this
deadly virus could mutate and be transmitted just by a cough or a
sneeze.
"It's the single greatest
concern I've ever had in my 40-year public health career," said Dr.
Michael Osterholm, director of the Center for Infectious Disease
Research and Policy at the University of Minnesota. "I
can't imagine anything in my career -- and this includes HIV -- that
would be more devastating to the world than a respiratory transmissible
Ebola virus."
The World Health
Organization says its scientists are unaware of any virus that has
dramatically changed its mode of transmission.
"For
example, the H5N1 avian influenza virus... has probably circulated
through many billions of birds for at least two decades. Its mode of
transmission remains basically unchanged. Speculation that Ebola virus
disease might mutate into a form that could easily spread among humans
through the air is just that: speculation, unsubstantiated by any
evidence."
Osterholm and other experts
couldn't think of another virus that has made the transition from
non-airborne to airborne in humans. They say the chances are relatively
small that Ebola will make that jump. But as the virus spreads, they warned, the likelihood increases.
Every
time a new person gets Ebola, the virus gets another chance to mutate
and develop new capabilities. Osterholm calls it "genetic roulette."
As
of October 1, there have been more than 7,100 cases of Ebola, with
3,330 deaths, according to the World Health Organization, which has said
the virus is spreading at a much faster rate than it was earlier in the
outbreak.
Ebola
is an RNA virus, which means every time it copies itself, it makes one
or two mutations. Many of those mutations mean nothing, but some of them
might be able to change the way the virus behaves inside the human
body.
"Imagine every time you copy an
essay, you change a word or two. Eventually, it's going to change the
meaning of the essay," said Dr. C.J. Peters, one of the heroes featured
in "The Hot Zone.
"
That
book chronicles the 1989 outbreak of Ebola Reston, which was
transmitted among monkeys by breathing. In 2012, Canadian researchers
found that Ebola Zaire, which is involved in the current outbreak, was
passed from pigs to monkeys in the air.
Dr.
James Le Duc, the director of the Galveston National Laboratory at the
University of Texas, said the problem is that no one is keeping track of
the mutations happening across West Africa, so no one really knows what
the virus has become.
One group of
researchers looked at how Ebola changed over a short period of time in
just one area in Sierra Leone early on in the outbreak, before it was
spreading as fast as it is now. They found more than 300 genetic changes
in the virus.
"It's frightening to
look at how much this virus mutated within just three weeks," said Dr.
Pardis Sabeti, an associate professor at Harvard and senior associate
member of the Broad Institute, where the research was done.
Even without becoming airborne, the virus has overwhelmed efforts to stop it.
Osterholm
commended groups like Doctors Without Borders but said uncoordinated
efforts by individual organizations are no match for Ebola spreading
swiftly through urban areas.
"This is
largely dysfunctional. Nobody's in command, and nobody's in charge," he
said. "It's like not having air traffic control at an airport. The
planes would just crash into each other."

Commentaires
Enregistrer un commentaire