Red Cross workers removing the body of an influenza victim from a home in St. Louis, Missouri, 1918
11 May 2020
Pandemic, epidemic, and endemic are three words that are most often used to describe the prevalence of a disease in a population. The World Health Organization (WHO) defines a pandemic as “the worldwide spread of a new disease,” and it defines an epidemic as “the occurrence in a community or region of cases of an illness, specific health-related behaviour, or other health-related events clearly in excess of normal expectancy.” In contrast, an endemic disease is one that is normally found at a given level in a population. While all three words come from the same root, their paths into English have been different.
The oldest of these three in English is epidemic. It was borrowed into English from the French épidémique, which in turn came from Latin, which got it from Greek. The Greek ἐπί- (epi-) means on, over, or at, and δῆμος (demos) means people. (In contrast, an epizootic disease is one that has an outbreak among non-human animals.) The word appears in the form epidemy as early as 4 November 1472 in a letter by John Paston found in London, British Library MS Add. 43491, fol. 18 (the collected letters and papers of the Paston family are a rich source of historical data for that period):
And men seye that ther is many off the sowders þat went to hym into Bretayne been dede off the fflyxe and othere ipedemye.
(And men say that there many of the soldiers that went to him into Brittany are dead of the flux and other epidemics.)
English use of the modern form can be found as early as 1603 in Thomas Lodge’s A Treatise of the Plague:
An Epidemick plague, is a common and popular sicknesse, hapning in some region, or countrey, at a certaine time.
Pandemic was formed within English from Greek roots, presumably modeled on the example of the earlier epidemic. The Greek παν- (pan-) means all. So, a pandemic is a disease that affects all people, not a specific population. The word appears as early as 1666 in Gideon Harvey’s Morbus Anglicus, but not in the modern sense. Harvey uses it as a synonym for endemic:
Diseases; which instances do evidently bring a Consumption under the notion of a Pandemick, or Endemick, or rather a Vernacular Disease to England; that is a common disease owing its rise to some common external and perennal cause of a Countrey; as a Consumptive Air, or a Consumptive Diet. viz. eating much Flesh, drinking Hopt drink, &c. And beyond this denomination the disease may not improperly be stiled Epidemick, that is, surprizing many at a certain season of the year.
The modern distinction between endemic and pandemic was being made about a century later. From Richard Brookes’s 1754 An Introduction to Physic and Surgery:
Diseases are likewise ENDEMIC and PANDEMIC. The endemic are proper to certain Places, and as it were Inmates, and arise from the Air, Situation, common depraved Diet, and bad Water. The pandemic affect the People in general at one and the same Time, with Regard to Sex, Age, Condition, or Temperament; such as pestilential Diseases.
But Brookes’s usage of pandemic is still not in the present-day sense, as he uses it for what we today would call an epidemic. The present-day sense of pandemic is in place by 1883, when Lyon Playfair uses it in speech in the British House of Commons in reference to an 1871 outbreak of smallpox:
This epidemic became pandemic; for it not only devastated Europe, but invaded both North and South America, as well as the South Sea Islands.
Finally, as we have seen above, endemic makes its English appearance by 1666 when Harvey uses it. As with pandemic, the word was formed within English from Greek roots. The Greek ἐν- (en-) means in. Endemic is also used in contexts other than disease, specifically to denote plants and animals native to a region. This particular usage is a nineteenth century borrowing from the French endémique.
Sources:
American Heritage Dictionary, fifth edition, 2020, s.v. epidemic, Appendix of Indo-European Roots.
Brookes, Richard. An Introduction to Physic and Surgery. London: J. Newbery, 1754. Eighteenth Century Collections Online.
Harvey, Gideon. Morbus Anglicus, 1666. Early English Books Online.
Letter, Sir John Paston to John Paston, 4 November 1472. The Paston Letters, A.D. 1422–1509, vol. 5. James Gairdner, ed. London: Chatto and Windus, 1904, 157.
Lodge, Thomas. A Treatise of the Plague, London: Thomas Creede and Valentine Simms, 1603. Early English Books Online Text Creation Partnership.
Middle English Dictionary, 2018, s.v. epidemie, n.
Oxford English Dictionary, second edition, 1989, s.v. epidemic, adj. and n., and endemic, adj. and n.
Oxford English Dictionary, third edition, March 2005, s.v. pandemic, adj. and n.
World Health Organization. “Emergencies Preparedness, Response: What Is a Pandemic?” 24 February 2010.
World Health Organization. “Humanitarian Health Action: Definitions: Emergencies.” Accessed 31 March 2020.
Photo credit: St. Louis Post-Dispatch, 1918.