Epidemic field investigation as applied to allegations of chemical, biological, or toxin warfare.

It is proposed that the established epidemiologic framework normally used for investigation of civilian epidemics can usefully be adapted to provide a more structured approach to future investigations of allegations of chemical, biological, or toxin warfare. Using this framework, investigations of such allegations during the past decade are reviewed. These investigations took place during the yellow rain affair in Laos and Kampuchea, the Iran-Iraq war, and the Iraq-Kurd war. Further allegations are likely and will require investigation.