Roger L. Simon

Avian flu relief

… or something… from the latest research which indicates that the transmission of the dreaded bird flu to humans will not be as easy as anticipated:

The avian influenza virus tends to penetrate so deeply in the respiratory tract it cannot be easily spread through coughing and sneezing, observations that may explain why there has been only negligible human-to-human spread, scientists report today.

To be easily spread from one person to another, the pathogen must first localize itself in the upper reaches of the “bronchial tree,” where droplets can be propelled and sprayed.Virologist Yoshio Kawaoka of the University of Wisconsin in Madison reports in the journal Nature today that only cells deep within the lungs possess the surface molecule — the receptor — to which the virus can dock and enter. Once inside the cell’s inner labyrinths, the virus can commandeer cellular genes, using them to crank out scores of new viruses. While this scenario is potentially lethal, it is not ideal for disease transmission, Kawaoka said.

“We looked from the nasal mucosa all the way to the bottom of the lungs,” Kawaoka said. “We examined eight people who had been infected with H5N1 and all of them had avian viral receptors in the lungs, but not in the upper portion of the lungs.”

He said his findings provide a rationale for how H5N1 can replicate itself efficiently in the lungs, but rarely spread from one person to another.

Phew… Well,can we all relax now? [At least until the next study.-ed And what about mutation? I thought you were going to relax.]