A research team backed by a federal grant has created a genetically engineered mousepox virus designed to evade vaccines, underscoring biotechnology's deadly potential and stirring debate over whether such research plays into the hands of terrorists. The team at Saint Louis University, led by Mark Buller, created the superbug to figure out how to defeat it. Buller spliced a gene known to suppress the immune system into the mousepox virus, then injected the combined strand into vaccinated mice. All of them died. The research highlights a contentious discussion among scientists and security experts: Does publication of such work help or hinder the biodefense effort? Should such studies be conducted at all? When Buller presented his results last week at an international biodefense conference, it prompted debate. Some feared that publication of such information, regardless of whether scientists' intentions are altruistic, could help terrorists create biological weapons laced with genetically modified superbugs. Such germs are created by splicing drug-resistant genes in viruses normally defeated by vaccines. Alibek, a director of George Mason University's National Center for Biodefense, believes Buller's work and similar research should be confidential to impede terrorists and rogue nations from acquiring knowledge about genetically engineered bioweapons. Buller counters that publicizing such work will deter terrorists by showing that scientists can build defenses against souped-up bioweapons. Buller also believes scientists must genetically engineer pathogens to understand how to defeat them.