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In epidemiology, an epidemic (from Greek epi- upon + demos people) occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is "expected," based on recent experience (the number of new cases in the population during a specified period of time is called the "incidence rate"). (An epizootic is the analogous circumstance within an animal population.) In recent usages, the disease is not required to be communicable; examples include cancer or heart disease. Another example includes the infamous Black Plague of the Middle Ages.

Contents 1 Classification 1.1 Endemic diseases 1.2 Syndemics 1.3 Non-infectious disease usage 2 Factors stimulating new epidemics 3 Pre-emptive measures 4 Renewed concern 5 See also 6 Notes 7 External links

[edit] Classification

Defining an epidemic can be subjective, depending in part on what is "expected". An epidemic may be restricted to one locale (an outbreak), more general (an "epidemic") or even global (pandemic). Because it is based on what is "expected" or thought normal, a few cases of a very rare disease may be classified as an "epidemic," while many cases of a common disease (such as the common cold) would not.

[edit] Endemic diseases

Common diseases that occur at a constant but relatively low rate in the population are said to be "endemic." An example of an endemic disease is malaria in some parts of Africa (for example, Liberia) in which a large portion of the population is expected to get malaria at some point in their lifetime.^{[citation needed]}Another is the bubonic plague or "Black Death" that swept through Europe in the 1340s, killing millions.

[edit] Syndemics

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The term syndemic refers to interacting epidemics that increase the health burden of affected populations. Social conditions that heighten the health risk of populations (e.g. poverty, discrimination and stigmatization, and marginalization) by increasing stress, malnutrition, interpersonal violence, and the experience of deprivation, increase the clustering of epidemic diseases and the likelihood of their interacting.

[edit] Non-infectious disease usage

The term "epidemic" is often used in a sense to refer to widespread and growing societal problems, for example, in discussions of obesity or drug addiction. It can also be used metaphorically to relate a type of problem like those mentioned above.

[edit] Factors stimulating new epidemics

Factors that have been described by Mark Woolhouse and Sonya Gowtage-Sequeria to stimulate the rise of new epidemics ^[1] include:

1. Alterations in agricultural practices and land usage
2. Changes in society and human demographics
3. Poor population health (e.g., malnutrition, high prevalence of HIV)
4. Hospitals and medical procedures
5. Evolution of the pathogen (e.g., increased virulence, drug resistance)
6. Contamination of water supplies and food sources
7. International travel
8. Failure of public health programs
9. International trade
10. Climate change

Several other factors have also been mentioned in different reports, such as the report by professor Andy Dobson ^[2] and the report by professor Akilesh Mishra ^[3].These include :

1. Reduced levels of biodiversity (e.g. through environmental destruction)
2. Bad urban planning

[edit] Pre-emptive measures

To protect the population against the emergence of new epidemics, several preemptive measures have been proposed by the World Health Organization ^[4].

[edit] Renewed concern

1. Mar. 2009 - The Influenza A, aka the "H1N1" virus, a subtype of influenza virus A and the most common cause of influenza in humans.

2. Aug. 2007 - the World Health Organization reported an unprecedented rate of propagation of infectious diseases.^[5]

[edit] See also

Look up epidemic in Wiktionary, the free dictionary.

• List of epidemics
• Overpopulation
• Bugchasing and giftgiving
• Biosecurity
• OpenEpi
• Epi Info
• European Centre for Disease Prevention and Control
• Epidemic model
• Syndemic

[edit] Notes

[edit] External links