The Geneva Protocol of 1925 commits the signatory nations to refraining from the use of biological weapons. However, the terrorist assaults of September 2001 and, subsequently, the anthrax-containing letters are cause for great concerns: new threats to the security of nations are expected, as terrorist organizations seem to increasingly explore novel ways of spreading terror. In this context, naturally emerging diseases such as SARS, monkeypox or West Nile fever assume new importance because it is difficult to distinguish between natural epidemics and possible bioweapon assaults. Great efforts on the part of governments and public health authorities are necessary to counteract these threats.