Swine Flu's Next Move Impossible To Predict

[Purveyor]

Scientists have yet to figure out how this strain of the influenza virus spreads, or what makes it lethal. It could continue spreading or fizzle out, they say.

By Karen Kaplan
April 27, 2009
Sometime in the last few years, as the world's attention was focused on the bird flu that killed more than 250 people in Asia, another bird flu strain infected pigs.

It mixed with two kinds of flu that are endemic in swine and a fourth that originally came from people.

The resulting concoction spread among pigs, then recently -- no one yet knows where or when -- started infecting humans. Since late March, it seems to have sickened people in California, Texas, New York, Kansas and Ohio, as well as in Canada and Mexico, where there have been 20 confirmed deaths.

Scientists said Sunday they are unable to predict what this new swine flu will do next.

"It's impossible to say with any assurance what's going to happen," said Dr. Christopher Olsen, a molecular virologist who studies swine flu at the University of Wisconsin School of Veterinary Medicine in Madison. "Influenza viruses can evolve quite quickly."

Inspecting the virus itself is of little help, since scientists have yet to identify which features help it spread or kill, said Dr. Scott Layne, an epidemiologist at the UCLA School of Public Health.

"The microscope doesn't tell you anything," Layne said. "What are the genetic correlates of virulence? Unknown. Transmissibility? Unknown."

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LA TIMES: http://www.latimes.com/features/health/la-sci-swine-explain27-2009apr27,0,3803534.story