Endemic (epidemiology)
In
For example,
Mathematical determination
For an infection that relies on person-to-person transmission, to be endemic, each person who becomes infected with the disease must pass it on to one other person on average. Assuming a completely susceptible population, that means that the
In this way, the infection neither dies out nor does the number of infected people increase
If a disease is in an endemic steady state in a population, the relation above allows us to estimate the
Misuse
While it might be common to say that
Some in the public wrongly assume that endemic COVID-19 means the disease severity would necessarily be mild.[3] Endemic COVID-19 could be mild if previously acquired immunity reduces the risk of death and disability during future infections,[7] but in itself endemicity only means that there will be a steady, predictable number of sick people.[3][4]
Related terms
Categories of endemic diseases
- Holoendemic
- An endemic disease with an extremely high rate of infection,immunity.[9]
- Hyperendemic
- An endemic disease with a high rate of infection,[8] especially one affecting people of all ages equally.[9]
- Mesoendemic
- An endemic disease with a moderate rate of infection.[8] This term is often used to describe the prevalence of malaria in a local area, with 10 to 50% of children showing evidence of prior infection being considered a moderate level for that disease.[8][10]
- Hypoendemic
- An endemic disease with a low rate of infection.[8][9] Typhoid fever is a hypoendemic disease in the US.[11]
Categories for non-endemic diseases
- Sporadic
- A disease that appears occasionally, but, unlike endemic disease, is not always present at a steady and predictable level.[12]
- Outbreak
- An epidemic, especially one affecting a very small area, such as the people in one town or attending a single event.unvaccinated people.[3]
- Epidemic
- A new disease that is spreading or a previously endemic disease whose infection rate is increasing significantly.Seasonal flu frequently appears as an epidemic.[8]
- Pandemic
- An epidemic affecting a very large part of the world, generally multiple countries or multiple continents.[8] Seasonal flu is sometimes a global pandemic.[8]
Examples
This is a short, incomplete list of some infections that are usually considered endemic:
Smallpox was an endemic disease until it was eradicated through vaccination.[13]
Etymology
The word endemic comes from the Greek: ἐν, en, "in, within" and δῆμος, demos, "people".[citation needed]
See also
- Syndemic – when two or more public health problems coincide and exacerbate each other
- Eradication of infectious diseases – when an infection declines until it no longer exists
- Vaccine-preventable diseases
References
- ^ "Principles of Epidemiology in Public Health Practice, Third Edition An Introduction to Applied Epidemiology and Biostatistics". Centers for Disease Control and Prevention. Retrieved 19 April 2018.
- ISBN 978-1-5297-8581-4.
Terms used to describe distribution include: Endemic: a condition that is generally present in a group or area, such as a cold
- ^ S2CID 246277859.
- ^ ISBN 978-3-031-17650-0.
- ISBN 978-0-323-95389-4, retrieved 28 February 2023
- PMID 34548826.
- PMID 34626549.
- ^ ISBN 978-0-12-803708-9.
- ^ ISBN 978-0-19-997673-7.
- ISBN 978-92-4-003840-0.
- ^ ISBN 978-1-4625-2006-0.
- ISBN 978-1-317-38291-1.
- ^ S2CID 246277859.
Yes, common colds are endemic. So are Lassa fever, malaria and polio. So was smallpox, until vaccines stamped it out. [...] learning to live with endemic rotavirus, hepatitis C or measles.
External links
- The dictionary definition of endemic at Wiktionary