Disease cluster

Large incidence of a medical condition in a particular location or time frame

A disease cluster is an unusually large aggregation of a relatively uncommon disease (medical condition) or event within a particular geographical location or period.^[1] Recognition of a cluster depends on its size being seen as greater than would be expected by the play of chance.^[1] Identification of a suspected disease cluster may initially depend on anecdotal evidence.^[1] Epidemiologists and biostatisticians need to assess whether the suspected cluster corresponds to an actual increase of disease in the area.^[1] Typically, when clusters are recognized, they are reported to public health departments in the local area.^[2] If clusters are of sufficient size and importance, they may be re-evaluated as outbreaks.^{[citation needed]}

John Snow's pioneering investigation of the 1854 cholera outbreak in Soho, London, is seen as a classic example of the study of such a cluster.^{[citation needed]}

References

^ ^a ^b ^c ^d 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". cdc.gov. Archived from the original on 21 March 2021. Retrieved 21 March 2021.

External links

Disease Clusters: An Overview, introduction to a course held by the Agency for Toxic Substances and Disease Registry

Concepts in infectious disease

Determinants

Agent	Infectivity Infectious dose Pathogenicity Attack rate Virulence Endotoxin Exotoxin Case fatality rate Antimicrobial resistance
Host	Susceptible individual Burn Comorbidity Diabetes Immune response Immunodeficiency Immunosuppression Postoperative Opportunistic infection Risk of infection
Environment	Access to water, sanitation and hygiene Climate change El Niño Tropical diseases Commerce Deforestation Ecology Humidity Injection drug use Natural disaster Flood Poultry and livestock Poverty Travel Urbanization Vector control War and conflict

Transmission

Basic concepts	Asymptomatic carrier Chain of infection Fomite Host Incubation period Index case Infectious period Latent period Natural reservoir Opportunistic infection Subclinical infection Super-spreader Window period
Modes	Human-to-human transmission Horizontal Vertical Neonatal Cross-species transmission Spillover infection Vector Zoonosis Reverse zoonosis Breakthrough infection
Routes	Air Blood Breastmilk Food Feces Fomite Hospital Mosquito Respiratory droplet Sex Tick Water
Modelling	Animal disease model Attack rate Basic reproduction number Compartmental models in epidemiology Critical community size Force of infection Herd immunity Infection rate Serial interval
Occurrence levels	Cluster Endemic Epidemic Holoendemic Hyperendemic Incidence Mesoendemic Outbreak Pandemic prevention Prevalence Sporadic Syndemic

Prevention and
Control measures

Pharmaceutical	Antibiotic Antifungal Antimicrobial Antiseptic Antiviral Combination Immunization Immunotherapy Monoclonal antibody therapy Inoculation Phage therapy Pre-exposure prophylaxis Post-exposure prophylaxis Repurposed drugs Vaccination efficacy/effectiveness booster resistance Vaccine-preventable disease
Non-pharmaceutical	Contact tracing Cordon sanitaire Disease surveillance Disinfection Hygiene Food hygiene Hand washing Gloves Isolation Lockdown Protective sequestration Public health Health communication Quarantine Respiratory source control Surgical mask PPE Safe sex Sanitation Screening Social distancing Sterilization Travel restrictions Vector control