A disease cluster is an unusually large aggregation of a relatively uncommon

medical condition A disease is a particular abnormal condition that negatively affects the structure or function (biology), function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medica ...

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 Anecdotal evidence is evidence based only on personal observation, collected in a casual or non-systematic manner. The term is sometimes used in a legal context to describe certain kinds of testimony which are uncorroborated by objective, independ ...

Epidemiologist Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and risk factor, determinants of health and disease conditions in a defined population. It is a cornerstone of public health, and shapes policy decision ...

s 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 Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...

departments in the local area. If clusters are of sufficient size and importance, they may be re-evaluated as

outbreak In epidemiology, an outbreak is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire ...

John Snow John Snow (15 March 1813 – 16 June 1858) was an English physician and a leader in the development of anaesthesia and medical hygiene. He is considered one of the founders of modern epidemiology, in part because of his work in tracing the so ...

's pioneering investigation of the 1854 cholera outbreak in

Soho, London Soho is an area of the City of Westminster, part of the West End of London. Originally a fashionable district for the aristocracy, it has been one of the main entertainment districts in the capital since the 19th century. The area was develo ...

, is seen as a classic example of the study of such a cluster.

References

External links

Disease Clusters: An Overview
introduction to a course held by the

Agency for Toxic Substances and Disease Registry The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agency within the United States Department of Health and Human Services. The agency focuses on minimizing human health risks associated with exposure to haza ...

{{disease-stub Spatial epidemiology

Cluster may refer to: Science and technology Astronomy * Cluster (spacecraft), constellation of four European Space Agency spacecraft * Asteroid cluster, a small asteroid family * Cluster II (spacecraft), a European Space Agency mission to study t ...