Scientists in St. Louis have created a genetically altered strain of mousepox virus that is so potent it kills mice vaccinated against the mouse disease, rekindling concerns that some avenues of biotechnology research may be generating lethal knowledge useful to bioterrorists.
Health officials emphasized that the federally financed work posed no threat to people. Although the mousepox virus -- a close relative of the smallpox virus -- is highly contagious and lethal in mice, it does not cause illness in humans.
But given the similarities between the mousepox and smallpox viruses, scientists said, the same technique might be useful for making a beefed-up strain of smallpox virus that could kill people despite their having been vaccinated.
The lead researcher, virologist Mark Buller of Saint Louis University, said he had already heard from many people distressed about his work, details of which he presented at a scientific meeting in Geneva recently.
"I've received all this hate mail," Buller said. "The whole focus was to contribute to the biodefense agenda of the country."
Buller spliced a gene known to suppress the immune system into mousepox virus, then injected the combined strand into vaccinated mice, who all died.
The research and its reverberations in recent days highlight an ongoing debate in the scientific community, the federal government and the public about the relative risks and benefits of microbiological research that might be adapted for bioterrorism purposes.
Since the anthrax attacks of 2001, the government has looked for ways to curb the dissemination of new and dangerous knowledge about disease-causing organisms. At the same time, experts have argued, the best way to prepare for a possible bioterrorism attack is to allow research to proceed as unimpeded as possible.