<p>Microorganisms and toxins have been used in warfare since antiquity (Christopher et al 1997, Kortepeter and Parker 1999), but have been relatively ineffective until modern attempts to ‘weaponise’ them. The potential number of victims following the use of a biological weapon could be enormous and as well as the threat of illness, an important feature of bioterrorism is its ability to produce panic and fear. In addition the clinical features of these agents are often vague and non-specific in the early stages and can be easily mistaken for something else.</p>