Outbreaks

An outbreak is usually defined as two or more linked cases of the same illness. Outbreaks may be confined to one family, or they may be spread locally, nationally or internationally. In the event of an outbreak, a multidisciplinary outbreak investigation team is formed to control the outbreak and reduce an ongoing risk to consumer health. Investigations play an important role in identifying reasons why an outbreak occurred, factors that led to its spread and lessons that can be learnt to prevent reoccurrences. The HPSC monitor all outbreaks of infectious disease including food - and waterborne disease. Annual outbreak reports are available from the HPSC website.

Definitions:

• Infectious intestinal disease: Diarrhoea ± vomiting, it may also apply to situations where other symptoms predominate
• Food- or waterborne disease: Any disease of an infectious or toxic nature caused, or thought to be caused, by the consumption of food or water
• Outbreak: Two or more linked cases thought to have a common exposure that experience a similar illness or proven infection. Outbreaks may be general or confined to one household (family) and may involve cases locally, nationally or internationally
• General Outbreak: An outbreak affecting members of more than one private residence or residents of an institution
• Family outbreak: In the investigation of household contacts of apparently sporadic cases of enteric infection, often ill family members or asymptomatic laboratory positive cases are identified. Obviously with small numbers, no analytical epidemiology can be undertaken on these outbreaks and no food or faulty practices may be identified. However useful information is collected such as the numbers ill, the numbers hospitalised and the pathogens involved.