Miami Herald - Thursday, January 24, 2002
Robert S. Boyd, Herald Washington Bureau

Deeper understanding of viral diseases -- and fresh defenses against them -- are coming along just when experts are warning that the smallpox virus could be the most fearsome weapon of a bioterrorist attack.

Scientists say we are just entering an "antiviral era" comparable to the amazingly successful antibiotic era that began with the discovery of penicillin during World War II.

"There are parallels to antibiotics," said Frederick Hayden, a researcher at the University of Virginia in Charlottesville, who has developed a new antiviral drug that reduces the length and severity of the common cold. It works by altering the shape of the cold virus so it cannot sneak through a human cell's protective membrane.

"It makes more sense to treat the primary cause of a viral infection than just provide relief for the symptoms," Hayden said.

Viruses are tiny bits of genetic material, so small they can be seen only when magnified 100,000 times. Like miniature burglars, they sneak into a cell, take over its nucleus, multiply wildly and destroy it.

They are responsible for a host of ailments ranging from pesky common colds to the devastating HIV epidemic and incurable killers like Ebola, again on the prowl in Africa.

Unlike bacteria -- much larger germs that can usually be controlled by antibiotics -- most viruses cannot be defeated with existing medications. Antibiotics work only against living organisms, and viruses lack most of the features of life. They cannot move, eat or reproduce on their own, but must depend on the genes they steal from their unwilling host.

In addition, viruses evolve rapidly. A new strain capable of causing a global epidemic, like the flu virus that killed 25 million people in 1918-19, could emerge, according to Dorothy Crawford, a microbiologist at the University of Edinburgh, Scotland, who wrote about the potential threat in her recent book, The Invisible Enemy: A Natural History of Viruses (Oxford University, 2000).

Some scientists even speculate that a future "doomsday virus" combining the worst features of smallpox and Ebola could wipe out the human race. Joshua Lederberg, a Nobel Prize-winning biologist at Rockefeller University in New York, has called viruses "the single biggest threat" to human life on the planet.

"Barring what we do to one another, if anything is going to wipe out humankind, it will be a virus," Lederberg said.

But now, 60 years after the discovery of penicillin, the battle lines against viruses are being redrawn.

New medicines to treat the flu, herpes and shingles viruses hit the market in the 1990s.

In the past decade, limited success against the Human Immunodeficiency Virus, the cause of AIDS, has been achieved with the use of a "cocktail" of antiviral agents.

In recent weeks, researchers have reported a number of seemingly minor advances that illustrate the accelerating progress against viruses.

For example, German scientists announced in November that they have made the first live-action movies of a virus breaking into a human cancer and gliding on tiny protein "tracks" toward the nucleus.

The feat was accomplished by attaching fluorescent molecules to a virus and taking videos of the lights as they moved.

The video technique "will be significant for helping us understand how the virus enters the cell," said Jude Samulski, a researcher at the University of North Carolina's Gene Therapy Center in Chapel Hill. "Previously no one knew what exactly was happening during the first hour or two after the original virus attack."

Jonathan Yewdell, a viral expert at the National Institute of Allergy and Infectious Diseases, announced the discovery of a new flu gene that could explain why some flu strains are deadlier than others.

David Sanders, a biologist at Purdue University in West Lafayette, Ind., found a flaw in a protein that allows viruses to cause cancer in mice. The discovery might lead to ways to block viruses from entering human cells, he said.

According to Crawford, most scientists used to think it was impossible to kill viruses without harming healthy cells. Now, however, "this pessimism has been proved wrong," she wrote.

"Several safe antiviral drugs are now on the market [and] we are likely to see an explosion of these products over the next 10 to 20 years."

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