■ The investigation requires rigorous preparation.
■ The effectiveness of the response depends primarily on how quickly the outbreak is identified.
■ The case definition should be simple, clear, standardised and constant throughout the entire period.
■ Laboratory confirmation should be done on the first 5 to 10 cases, at a minimum.
■ Demographic data should be reliable and the choice, made by consensus, should be justified.
■ Describe the epidemic in terms of Time - Place - Person: scale and evolution, geographic spread, groups at risk.
■ The definition of an outbreak varies according to the context.
■ For each area, assess the outbreak’s severity and potential for spreading using the analysis table.
■ Assess the initial actions taken to manage the outbreak.
■ Write an accurate, concise investigation report and distribute it.