The arrest of several individuals in London on suspicion of producing the poison ricin has reawakened concerns about bioterrorism. Biological warfare has a long history; the first recorded use occurred in 1346, when Tartars catapulted corpses infected with plague into a city they held under siege. Yet, despite that history -- and even more recent attacks -- most nations are woefully unprepared for terrorist attacks using biological weapons. Even Japan, which experienced its own terrorist attacks a few years ago, has been slow to respond.

Public consciousness of the threat of bioterrorism spiked immediately after the Sept. 11 terrorist attacks, when letters carrying anthrax spores killed several people in the United States. Al-Qaeda was originally suspected of being behind the mailings, but no individual has been arrested for the acts. The investigations appear to have made no progress in over a year.

Fears have receded despite repeated warnings that most nations are unprepared for a large-scale emergency or the panic that might follow the mere threat of such an attack. The discovery of ricin in London should spark renewed concern.