Professor says bird flu on its way but may not cause pandemic in U.S.
(Published Friday, February 16, 2007 11:07:19 AM CST)
A d v e r t i s e m e n t
By Carla McCann Gazette staff
WHITEWATER-Biology professor Edward Holmes has no doubt the bird flu spreading across Asia will arrive in the United States with migrating birds.
But whether the infection will evolve into a human pandemic is anyone's guess, said Holmes, a biology professor at Pennsylvania State University's Center for Infectious Disease Dynamics.
"We don't know," he said during a speech Thursday at UW-Whitewater. "There isn't enough data there to test. It looks like it would take from 20 or 30 mutations for that to happen," Holmes said.
As the guest speaker at the Ninth Annual Darwin Day celebration at UW-Whitewater, Holmes' lecture on "Life on the Edge: The Evolution of Emerging Viruses" attracted a large audience.
Edward Holmes
The goal of Darwin Day is to show why evolution matters and illustrate the value of Darwinian thinking when addressing societal challenges.
Holmes said it's been 3,000 years since an Egyptian artist carved the likeness of a young man, crippled from what appears to be polio.
The stone carving is seen as proof that the poliovirus caused paralysis and death from ancient Egypt into the 20th Century.
Volumes have been chronicled about the history of viruses and other diseases, such as the bubonic plague or "Black Death."
The plague, for example, started in Asia and traveled to Europe in 1347 with rat-infested Italian ships. By 1351, the disease had killed more than 1 million people and one-third of Europe's population, Holmes said.
"It spread and killed for hundreds of years," Holmes said.
It was scientists such as Louis Pasteur, Robert Koch and Joseph Lister whose works changed the course of history for such diseases, Holmes said.
Even the number of people diagnosed with tuberculosis declined, because we understood that microbes caused disease, Holmes said.
But in the past 20 or 30 years, evolution has disrupted the calm.
A strain of tuberculosis and e-coli have grown resistant to antibiotics, and much of the reason is overuse and misuse of antibiotics, he said.
And new viruses are emerging all of the time.
"Emerging diseases also are a perpetual thing," Holmes said. "Most human pathogens come from another animal species through cross-species transmission."
The Severe Acute Respiratory Syndrome (SARS) that made headlines in 2002 in China was believed to have been spread by the civet cat, a nocturnal mammal similar to a mongoose. But now, it appears the main host is the horseshoe bat, Holmes said.
Scientists have traced the origin of AIDS to wild chimpanzees, Holmes said.
It's possible someone was bitten by a chimp or cut while butchering one and contracted the disease, Holmes said.
Cross-species transmissions can be attributed to deforestation, changing land use, the spread of cities into animal habitats, international travel, wars and political unrest, Holmes said.
The future onslaught of pathogens is inevitable, Holmes said.
Disease surveillance and global cooperation are essential, Holmes said, to fight the war against the evolution and cross-species transmission of disease.
