Polio Virus Created From Scratch in Lab

Will Smallpox Be Next? Not Likely, Scientists Say

Medically Reviewed by Charlotte E. Grayson Mathis, MD
From the WebMD Archives

July 12, 2002 -- Just to show it could be done, scientists have reconstructed the polio virus in their laboratory -- using information they pulled off the Internet and materials available by mail order. It's the first time this has been done. Others are asking: What impact does this have on bioterrorism?

"I think it would be wrong to close our eyes to this," study author Eckard Wimmer, PhD, professor of microbiology at The University of New York at Stony Brook, tells WebMD.

His paper appears in the July 11 issue of Science.

"We have taken information that's in the public domain to re-create the virus in a test tube. It's something any good laboratory could do," says Wimmer.

The virus' chemical sequence, genetic map, and three-dimensional structure were actually outlined two decades ago. However, this is the first time that a genome has been reconstructed without a natural virus to build from, he says.

In his experiments, Wimmer injected the virus into mice to show it worked to paralyze the animals. The mice were then killed.

"Poliovirus normally grows in the gut," he explains. "Only rarely does it find its way into the central nervous system. Once it's there, it looks for [nerves located] in the muscles, and the result is paralysis."

Polio has been virtually eradicated worldwide due an extensive vaccination campaign by the World Health Organization.

"When we say it's been eradicated, that means eradicated from circulation in global populations," says Wimmer. "But there's still an enormous amount of virus available in laboratory freezers around the world -- tens of thousands of laboratories. Efforts are only under way now to contain these laboratory specimens."

Those polio samples are kept for research, he says. Other laboratories may have specimens simply by accident. "Specimens of common diarrhea may actually contain poliovirus. It's very difficult to eradicate from laboratories."

But does this unveil a new smallpox threat? No, says Wimmer. "Polio is a very simple virus," he tells WebMD. "The smallpox virus is much, much larger, and to put it together from scratch right now is almost impossible. Smallpox could not be re-created now, but maybe in 20-30 years when technology is more advanced. You could re-create hepatitis B or C, but these are not terrorist agents."

In fact, any poliovirus released into the population right now "wouldn't do any harm whatsoever because we're all so protected," Wimmer tells WebMD. "Some say that poliovirus isn't necessarily a bioterrorist agent because it doesn't kill. We can debate whether killing is necessary to really cause terror. I don't think it is."

Patrolling the Internet for information, or screening buyers, is not necessary, he adds. "A bioterrorist would be sophisticated enough to use samples from laboratories.

"It would be a big mistake to curtail dissemination of information, because information even about dangerous pathogens leads to useful research to combat impact of these pathogens, including development of drugs against it or means to protect our immune systems. Curtailing free flow of information I believe is counterproductive," says Wimmer.

"We wanted to make sure that everybody knows -- and is put on notice -- that this kind of work can be done," he tells WebMD. "This kind of work is only a warning message. But we should note the possibility that such misuse of modern biomedical research and biotechnology could cause harm. Once we know that, we can begin to think of safeguards."

He says the WHO has already planned to stockpile polio vaccines to contain any outbreak and is continuing the vaccination program.

There's always the fear of the mad, isolated scientist not connected with any terrorist organization, Wimmer says. "That's the problem with anthrax, which we suspect was done by a very sophisticated U.S. citizen, yet we can't find him. You always have the fear of somebody crazy and intelligent. If that's the case, that person could have done what we did without our paper."

Re-creating a virus, however, "is a real complicated thing," he says. "It sounds easy, but in fact it is not easy."

"I would downplay idea that there's a threat to the public," Frederic Bushman, PhD, associate professor in infectious diseases at the Salk Institute for Biologic Studies in La Jolla, Calif., tells WebMD.

Bushman, a virologist, agreed to comment on Wimmer's research for WebMD.

In truth, the ability to assemble packages of DNA [to create an organism like the polio virus] has been available since the early 1980s, says Bushman. "There's nothing terribly new about this development -- the methods have been around a long time. But I'd like to emphasize that it's not terribly easy. It would take several people in a lab working for a couple years, and there aren't that many labs outside the U.S. that could do it."

Replicating a smallpox virus DNA "would be difficult to the point of impossible," he tells WebMD. "It would take an industrial plant doing experiments for many years to do it."

Also, pox viruses present special problems: They need to bind with proteins in order to replicate, "so you would have to put together a more sophisticated package than just the DNA," Bushman says.

Rather than focusing on "the nastiest thing possible," he would like to see researchers stick to studies of new medicines or vaccines, "and avoid grandstanding about what awful things might come of our research. There's the risk of a backlash from this kind of thing."