O’Neil and Naumova recently highlighted the controversy of imprecise public health definitions of outbreak, epidemic, and pandemic. They observed, “the public health community has not settled on a solid definition of ‘outbreak’ except in a very broad sense”. 1 While neither the United States Centers for Disease Control and Prevention’s public website, nor the American Public Health Association (APHA)’s Control of Communicable Diseases Manual, provide a definition for the term outbreak, APHA defines epidemic as “the occurrence in a community or region of cases of an illness (or an outbreak) with a frequency clearly in excess of normal expectancy”. 2 Merriam-Webster defines outbreak as “a sudden rise in the incidence of a disease” and defines the term epidemic as “affecting or tending to affect a disproportionately large number of individuals within a population, community, or region at the same time”. 3 The terms outbreak and epidemic are often used interchangeably in the literature, by practitioners, and especially by the media. The term pandemic is generally reserved for epidemics that span multiple continents.
A recent publication offered definitions of a health emergency as “those [incidents] whose scale, timing or unpredictability threaten to overwhelm routine capabilities” and a disaster as a “situation (incident) or event which overwhelms local capacity, necessitating a request to a national or international level for external assistance”. The authors proposed “epidemics and pandemics are always public health emergencies” due to their propensity to easily overwhelm indigenous public health capacity. However, a deeper analysis to challenge this assertion may reveal finer criteria for what constitutes a transition from the routine infectious disease event to the non-routine crisis and socially disruptive disaster.
From the perspective of disaster analysis, pathogens are not considered hazards to a society unless the intersection of the pathogen and local vulnerability results in perception of a “problem”. Therefore, an infectious disease event may be defined as any issue involving a pathogen that is perceived as noteworthy in local social commentary, be it in mass media or other broadly disseminated forms of communication. Infectious disease events encompass a broad range of etiologies that may or may not be referred to as an outbreak or epidemic, depending on the context of presentation. An infectious disease event typically is considered to be a social interest, however is routine, expected, and normal for the involved community.
Rosenthal’s concept of crisis as an “accumulation of adverse conditions: severe threat, uncertainty, and the necessity for prompt decision making”5 is observed at the micro-level in the daily decisions made by healthcare providers treating individual patients to the macro-level in the decisions made by public health practitioners in the World Health Organization. Rosenthal acknowledged non-routine response to be a key indicator of crisis decision-making. 5 Gilbert proposed a modification to Rosenthal’s view that drew out uncertainty as a key indicator that may be revealed through reporting of “collective stress” or social anxiety. 6 The phrase “collective stress” refers to Barton’s definition of “when many members of a social system fail to receive an expected condition of life from the system”. 7 Gilbert further postulated that a crisis might be considered to be an “upsetting of the system of meaning”. 6
Temporal progression of an infectious disease event transitioning to a crisis often proceeds with documentation of the struggle to resolve diagnostic uncertainty. Diagnostic uncertainty may or may not be able to be resolved by local indigenous laboratory capacity. This is of central importance, as countermeasures depend heavily on the nature of the infectious disease hazard. Resolution of uncertainty is also critical for effective risk communication. Long time delays in resolving and communicating diagnostic uncertainty stoke public concern and anxiety during crises.
In summary, an infectious disease event becomes a crisis when there is a recognized requirement for time-sensitive, non-routine organization-level decisions that may affect a local community’s activities of daily living. It is more common such decision-making falls within the organizational roles and responsibility of a public health institution than a public or private hospital or individual healthcare provider. This becomes a community level decision-making activity in countries where there is no public health capacity.
Rosenthal proposed the term “crisis” to be an umbrella concept, of which disaster is a subcategory.5 Carr proposed the definition of a disaster to be a collapse of cultural protections.8 Gilbert suggested disasters are the result of the intersection of hazard and vulnerability within the context of uncertainty. 6 Dobromsky proposed failure of cultural knowledge as another facet to this concept. 9
Horlick-Jones observed that disasters contribute to a public sense of betrayal and thus, to an erosion of trust in organizations responsible for controlling risk. 10 This is a particularly sensitive point for medical and public health institutions involved in risk communication to the public. Medical and public health institutions function optimally, as with most disaster response organizations, within the context of public trust and cooperation. Therefore, public trust is maintained when locally expected standards of healthcare are met, which includes local expectation for timely resolution of diagnostic uncertainty.
Kreps’ proposed definition of a disaster is perhaps most poignant when attempting to distinguish between crises and disasters:
non-routine events in societies or their larger subsystems (e.g., regions, communities) that involve social disruption and physical harm. Among the key defining properties of such events are (1) length of forewarning, (2) magnitude of impact, (3) scope of impact, and (4) duration of impact. 11
The current state of the art in disease surveillance is limited in its ability to provide pre-event warning or forecasting. Here it could be argued that lack of an early warning and situational awareness capability impairs effective risk communication by officials and thus facilitates an erosion of public trust. Oliver-Smith proposed that disasters are signs of systemic weakness that reveal adaptive fitness.12 Adaptive fitness is dependent on social expectation for a given standard of care, and proactive risk communication is essential to manage this expectation. Perceived violations in this social contract may result in social outcry and in extreme cases, civil unrest. It may be argued that an early warning system for infectious disease crises and disasters must include monitoring indicators of social reaction in order to anticipate needed adjustments in risk communication to the public.
Stallings suggested that disasters should be considered as disruptions to daily-expected routines to the point where social functioning is threatened without action. He posits that a disaster should not be considered as such if it does not affect all facets of society. 13 This confounds an attempt to categorize patient- or hospital-level infectious disease events as disasters. Stallings’ viewpoint drew upon Coleman’s original theory of community integration, which proposed “vital processes” of a community “keep it alive as a community and prevent its disorganization”. These processes included:
- education of children
- religiously related activities
- organized leisure activities
- unorganized social play of children and adults
- voluntary activities for charitable or other purposes
- treatment of sickness, birth, death (healthcare)
- buying and selling of property
- buying consumable goods (food, etc.)
- saving and borrowing money
- maintenance of physical facilities (roads, sewers, water, light)
- protection from fire
- protection from criminal acts14
Compromise of these vital processes may result in transient features of disintegration, which refers to dissolution of the social unit. Social disruption refers to the process where a community moves from a given level of integration towards disintegration. The concepts of integration and disintegration are not absolute: each community is associated with a given balance of factors that promote integration and disintegration. Disasters tip this balance towards disintegration. This concept therefore encompasses more than simply public health response capacity but a broader social context. This follows Barton’s concept of collective stress, where the “expected conditions of life” are defined as “the safety of the physical environment, protection from attack, provision of food, shelter, and income, and guidance and information necessary to carry on normal activities (italics added)”. 7
In summary, an infectious disease crisis becomes a “disaster” when crisis mode decision making by public health officials or institution fails to control the situation, either from an informational or response perspective and substantial social disruption associated with features of community disintegration occurs as a result.
Refinement of terms used to describe infectious disease incidents represents a valuable exercise to understand the relative importance of infectious disease incidents that occur on a daily basis throughout the world, including the United States. This understanding may assist in prioritization of early warning and situational awareness capabilities as well as public health preparedness efforts.
1. O’Neil Eileen A. and Naumova Elena N. “Defining Outbreak: Breaking Out of Confusion.” Journal of Public Health Policy. 2007; 28:442-455.
2. American Public Health Association (APHA). http://www.apha.org. Accessed 7 July 2008.
3. Merriam-Webster. http://www.merriam-webster.com. Accessed 7 July 2008.
4. Burkle FM Jr, Greenough PG. Impact of public health emergencies on modern disaster taxonomy, planning, and response. Disaster Med Public Health Prep. 2008 Oct;2(3):192-9.
5. Rosenthal U, ‘t Hart P, Charles MT. The World of Crises and Crisis Management. In: Rosenthal U, ‘t Hart P, and Charles MT, eds Coping with Crises: The Management of Disasters, Riots and Terrorism. Springfield: Charles C. Thomas; 1989:3-33.
6. Gilbert C. Studying Disaster: Changes in the Main Conceptual Tools, In: Quarantelli HL, ed. What is a Disaster? Perspectives on the Question. New York: Routledge; 1998:11-18.
7. Barton AH. Communities in Disasters: A Sociological Analysis of Collective Stress Situations. New York: Doubleday; 1969.
8. Carr LJ. Disaster and the Sequence-Pattern Concept of Social Change. The American Journal of Sociology. 1932; 38(2): 207-218.
9. Dombrowsky WR. Again and Again: Is a Disaster What We Call a “Disaster”? In: Quarantelli HL, ed. What is a Disaster? Perspectives on the Question. New York: Routledge; 1998:19-30.
10. Horlick-Jones T. Modern disasters as outrage and betrayal. International Journal of Mass Emergencies and Disasters 1995; 13:305-316.
11. Kreps GA. Disaster: Systemic Event and Social Catalyst. In: Quarantelli HL, ed. What is a Disaster? Perspectives on the Question. New York: Routledge; 1998:31-55.
12. Oliver-Smith A. Disasters, Social Change, and Adaptive Systems. In: Quarantelli HL, ed. What is a Disaster? Perspectives on the Question. New York: Routledge; 1998:56-72.
13. Stallings RA. Disaster and the theory of social order. In: Quarantelli HL, ed. What is a Disaster? Perspectives on the Question. New York: Routledge; 1998:127-145.
14. Coleman JS. Community Disorganization. In: Merton RK and Nisbet RA, eds. Contemporary Social Problems. New York: Harcourt, Brace & World, Inc.; 1966:670-722.