Signs of a Biological Attack

Biological agents are difficult to detect since they are often odourless, invisible and take hours or days to impact public health. Health care providers such as hospitals, medical clinics, and family physicians tend to be the first to notice and report abnormal rates of peculiar symptoms to Public Health officials.

Indicators of a biological attack include:

• Large numbers of ill persons with a similar disease or syndrome
• Large numbers of cases of unexplained diseases or deaths
• Unusual illness in a population
• Higher morbidity and mortality in association with a common disease or syndrome or failure of such patients to respond to usual therapy
• Single cases of disease caused by an uncommon agent
• Several unusual or unexplained diseases coexisting in the same patient without any other explanation
• Disease with an unusual geographic or seasonal distribution
• Illness that is unusual for a given population or age group
• No illness in persons who are not exposed to common ventilation systems (have separate closed ventilation systems) when illness is seen in persons in close proximity with a common ventilation system
• Unusual pattern of death or illness among animals that precedes or accompanies illness or death in humans