A disease cluster is an unusually large aggregation of a relatively uncommon medical condition or event within a particular geographical location or period. Recognition of a cluster depends on its size being seen as greater than would be expected by the play of chance. Identification of a suspected disease cluster may initially depend on anecdotal evidence. Epidemiologists and biostatisticians need to assess whether the suspected cluster corresponds to an actual increase of disease in the area. Typically, when clusters are recognized, they are reported to public health departments in the local area. If clusters are of sufficient size and importance, they may be re-evaluated as outbreaks.
- Miquel Porta, ed. (2008). A Dictionary of Epidemiology. Oxford University Press, USA. pp. 42–43. ISBN 978-0-19-971815-3.
Aggregations of relatively uncommon events or diseases in space and/or time in amounts that are believed or perceived to be greater than could be expected by chance. Putative disease clusters are often perceived to exist on the basis of anecdotal evidence, and much effort may be expended by epidemiologists and biostatisticians in assessing whether a true cluster of disease exists.
- "Guidelines for Investigating Clusters of Health Events". www.cdc.gov. Archived from the original on 21 March 2021. Retrieved 21 March 2021.