Sir

Your News Feature “The bugs of war” (Nature 411, 232–235; 2001) brings lucidity to the debate about the threat of biological weapons. Until now, most assessments of this issue have been woefully inadequate in that they have dealt exclusively with political evaluations of possible technical vulnerabilities. Your News Feature gives an up-to-date depiction of the scientific reality behind the lopsided policy deliberations. We would like to add some points.

First is the issue of political motivation. If genetically engineered bioweapons were developed, would they be deployed by nation-states, terrorists or criminals? The problem is that as things stand there are more than enough non-engineered biological agents available to satisfy all these categories. Second, technical expertise is far too often overlooked. Even if a state or non-state actor has the wherewithal to manufacture an engineered bioweapon — which entails extensive technical expertise and a huge budget — there remains the severe problem of adequate dispersal necessary for mass casualties. Bioweapons cannot be spoon-fed to the intended targets. Delivery is an exceptionally difficult science, as has been found in state programmes (for example in the United States, the Soviet Union and Iraq) to create bioweapons. Finally, in any assessment it is important not to fall into the anthropocentric trap. The dangers of bioweapons directed at livestock and crops are as great as, if not greater than, those designed against people.

The conclusion of your News Feature, that whatever advances are made on the offensive side will have beneficial spin-offs on the defensive side, is important. Despite the overwhelmingly positive influence on society of the biomedical revolution, especially in genomics and proteomics, there are still problems, their potential misuse for weapons being just one. Knowledge does not automatically lead to capability. Your Opinion article in the same issue, “A call to arms” (Nature 411, 223; 2001) reminds us that, for terrorists, the gun and the bomb will continue to be the weapons of choice simply because these are more than adequate tools for political violence. As a result, we should be wary of being seduced by talk of a 'threat' of super-bioweapons. A balanced response by governments relies on accurate and proportionate risk assessments of the bioweapon threat. Without these, time and money will be wasted and, perhaps more important, the real threats will be overlooked.