You will get plenty of answers when you search for the death toll of plague - there are answers on Wikipedia and on Encyclopedia Britannica. There are nice visualizations made by the National Geographic and the Visual Capitalist, and many books or scientific publication on plague will list a death toll somewhere in their introduction.

But they are all wrong, in one of these two ways:

1. Most websites are just parroting each other's random numbers (BBC, Reuters, etc), and then get cited by Wikipedia as a credible source.
2. The most commonly returned answer by search engines is specific to the 1346-1351 Black Death epidemic in Europe. That is not the question that we asked!

So, let's see how far we can get in answering how many people died of the plague.

The Time before the Three Plague Pandemics

The first thing you need to know is that plague has been killing people for at least 5,000 years¹. And when you move that far back in history it becomes extremely difficult to assess how many people lived, let alone how many people died of a particular disease. However, it does look like that 5,000 years ago plague was already wrecking havock: remnants of the plague bacterium have been found across Eurasia², in a surprising large fraction (like 2.5%) of the corpses that were tested for the presence of ancient plague DNA.

If it turns out to be a reasonable assumption that 2.5% of all people that lived between 3000BC and 541AD died of the plague, then we can leverage demography datasets like (https://easy.dans.knaw.nl/ui/datasets/id/easy-dataset:74467)[HYDE 3.2], and birth rate estimates of 80 per 1,000 before CE and 60 per 1,000 until 1750CE used in (https://www.prb.org/articles/how-many-people-have-ever-lived-on-earth/)[this blog post] to get to a total number of people that died of plague. One difficulty is to extrapolate the map above to the full range across which plague was common. Without going into the details, I have picked all the countries in Eurasia west of the China-India axis, the countries in Africa that border the Mediterranean, and an expanding triangle of African countries from the Democratic Republic of Congo east to the Arabian Peninsula. In this geographic area, we will just assume that plague was there all the time.

That will get you a rough approximation of 224.6 million people that died of plague between 3000BC and 541AD.

CAVEATS: There is a huge range of uncertainty - both on the spatiotemporal extent of plague in this 3,500 year period (I excluded India and China, two of the most populous regions at that time!), and on the share of all-cause mortality that plague took (now set to 2.5%). In addition, we also don't know much about plague in the time before 5,000 BCE, and the population estimates we took from HYDE are their baseline - not their high or low estimates.

The First Plague Pandemic

Fast forward to the year 541 AD in Pelusium, Egypt. The outbreak recorded in the historic records in Pelusium is typically considered the start of the First Plague Pandemic, which lasted until 750 AD. The plague spread across Europe, and DNA of the plague bacterium has been recovered from dozens of sites, confirming that this was indeed a plague pandemic^3,4. The plague may have well spread into Africa and Central Asia as well - we just have very little information about what happened outside of Europe.

There is a very lively scientific discussion ongoing on how deadly this first plague pandemic actually was^5,6, and it is worth reading both sides to get a feeling for the challenges of tallying up the dead in historic times.

The upper range is at the 15-100 million people in those 250 years, limited to Europe. Translating back to all-cause mortality, that would be X to Y %. Say that Asia and Africa suffered similarly, and we are at an upper level of 1 billion people prior to the first pandemic, and another 300 million during the first pandemic.

In between the First Two Pandemics

If you somehow succeeded in tackling the challenges of enumerating the dead from prehistoric plague outbreaks and from the First Plague Pandemic, be mindful that you do not skip over the period between the end of the First Pandemic in 750 AD and the traditional start of the Second Pandemic in 1346 AD⁷.

It has been something of an entrenched idea that the Black Death was the start of the Second Plague Pandemic, which means that outbreaks between 750 AD and 1346 AD were not considered in the context of possibly being plague. That idea is changing now with a recent publication on plague in Baghdad, Iraq in 1258 AD⁸, and it wouldn't do to forget those places in an accurate tally of the total death toll of the plague.

But the period is in between the pandemics, so perhaps the assumed all-cause mortality can fall back again to lower levels. Leveraging hyde, and assuming a 2% all-cause mortality, we add an upper limit of 50 million for this period, coming up to 1350 million people.

The Second Plague Pandemic

The Second Plague Pandemic was fairly brutal. Besides wiping out half of Europe to start with, the disease also kept recurring at lower city-wide mortality levels. Common pattern for urban areas are visible in Haarlem (Davis), which is still comparable to (the uncommonly large) London - as in every 40 years a 20% mortality crisis, and every 3-4 years a 5% crisis. That tallies up to a 1.5% all-case mortality, or With roughly half the world exposed to plague, you get to (~12 billion people lived that period) another 90 million people that died in total, or an upper limit of 1440 million people.

One caveat is that we don't know if plague was ever introduced to the Americas prior to the Third Pandemic, but just failed to establish itself permanently. The current plague reservoirs in the Americas appear to be genetically derived from the Third Pandemic plague strains that spread around the world. That does not rule out earlier introductions of plague to, say, the east coast of the United States. Rather it signals that any introductions on the east coast failed to establish or failed to maintain itself in wildlife reservoirs in the time until 1900.

I would guess though that these epidemics would have been noticed by now by demographers if they were on the scale of the Black Death, so I assume they were limited and can be neglected in the uncertainty of our tally.

In between the Second and Third Pandemics

It has also become embarrasingly clear the outbreaks that were typically considered the end of the Second Pandemic (the plague of Marseille in 1720-1722 or the plague in Moscow in 1770-1772), were only so from a rather narrow western-Europe perspective.

When you take older compendiums of plague, such as that of Georg Sticker ⁹, you will find records of (presumably) plague present from Eastern Europe to India between 1723 to 1893. With the Third plague pandemic starting in 1788 or 1855 in Southwest China, depending on who you ask, there is not much time or space left between the end of the Second and the start of the Third pandemic.

In short, there is not much time between the Second and Third Pandemic. Perhaps a 100 years for Asia? With 1 billion people living there, and a 1.5% annual all-cause mortality, that adds another 15 million people, so a higher limit of 1455 million people.

The Third Plague Pandemic

The Third Pandemic we can best split up continent by continent, but roughly speaking, almost everyone died in India or Southern China, adding about 21 million people, which makes the total tally 1465 million people.

https://lrhmatters.com/drivers-of-health/the-virtual-eradication-of-plague

The Americas

We can look at Schneider how long plague remained in Latin American countries, and use Kugeler for the United States.

Plague was introduced into the United States around 1900. For the number of cases and deaths prior to 1954, we can combine Kugeler's work with the numbers we have from WHO from 1954 onwards to learn that the number of reported plague cases in the United States during the Third Pandemic is 525 cases (496 cases before 1926, 17 cases between 1926 and 1941, and 25 cases between 1942 and 1964, minus the 13 cases registered by WHO in the period of 1954 to 1964). From the cases before 1942, 336 died, and two had an unknown outcome. Between 1942 and 1964, 11 died (4 of which are registered in the post-1954 WHO records), making the total deaths 336 + 11 - 4, or 343 deaths, possibly with 1-2 more deaths.

(TODO Canada)

Between Moll, A.A. and O’Leary, S.B. (1941) ‘Plague in the Americas: an historical and quasi-epidemiological survey’, and the meeting report from the Pan American Health Organization (1963) ‘Plague in The Americas’, we get a decent estimate for Latin America as well. Where Moll and O'Leary provide conflicting numbers, we use the numbers from the table, rather than the summary. Missing from Moll are El Salvador and Panama, but these countries are listed in Schneider, so likely had plague.

Argentina: 6,453 cases. The reported death rate for one of its cities is 35.27%, which would suggest 2308 deaths. (1899-1938). Plague in the Americas doesn't tabulate more cases after that, but mentions a few in the text. Bolivia: 3,148 cases , 2046 deaths (1921-1938) * many missing. Adding the additional cases in PiTA from the entry "1938-1939" (which means the end of 1939) onwards, gets us an addition 593 cases until 1954, with 319 deaths. Some missing data indicated, but that sums up to 3741 cases, 2365 deaths. Brazil: 7,462 cases between 1899 and 1938, and another 2012 cases and 445 deaths until 1949. PiTA lists a case fatality rate of ~28.5%, which would suggest that of the 7,462 cases recorded between 1899-1938, about 2126 would have died, coming to a total until 1949 of 9474 cases and 2571 deaths. PiTA reports another 422 cases for between 1950 and 1962. Do we apply the same 28.5%? We have nothing better to go on, so that makes another 120 deaths to get to 1962 (total of 9896 cases and 2691 deaths). Chile: 5,121 cases (1903-1931) Cuba: about 68 cases, 22 deaths (1912-1915) Ecuador: about 11,154 cases (1908-1938) El Salvador: ? Mexico: about 632 cases (1902-1923) Panama: ? Paraguay: possibly 500 cases (1899-1936) Peru: some 21037 cases (1903-1938); Puerto Rico about 88 cases (1912,1921): Uruguay: 133 cases ,58 deaths in Montevideo, 25 cases, 14 deaths in the rest of the country (1901-1929) Venezuela about 534 cases, 236 deaths (1908-1939)

We still have a bit of a gap between the end of the reports here, and 1954.

Complete: Quasi-epdemic: For Chile - between 1903 (introduction) and 1931 (last case), we have two tallies: 5121 cases, 2094 deaths (Machiavello), or 4386 cases, 1680 deaths (Gallinatto). Machiavello estimates himself that his numbers are about a 20% under-count.

For Equador - 11465 cases reported until march 1940. Deaths, (see page 91f)

Also Ruiz, A. (2001) ‘Plague in the Americas’, Emerging infectious diseases, 7(3 Suppl), pp. 539–540. doi:10.3201/eid0707.017718.

"As estimated by Moll and O'Leary (1945) the number of plaguecases in Argentina from 1899 to 1930 amounted to about 6,200. Thefurther incidence of the disease up to 1952 is shown in the follow-ing table:" "So between Moll and Ruiz, that puts us to 195 for Argentina, which is everything.

Australia and Oceania

Plague came to Australia early 1900 (Cumpston), initially lasting until 1909 and causing 1,212 cases, of which 468 fatal. Australia was revisited by plague in 1921-1922, during which 151 cases were recorded, of which 73 fatal.

Cumpston's summary of Plague in Australia is well worth the read, given its detail not only on human plague, but also rat-borne plague, the surveillance and seasonality of both, and the instances of plague transport by ships. Some records are extremely detailed, such as the outbreak in Brisbane in 1921, which includes case descriptions and addresses, as well as weekly prevalences of plague in rodents.

The cases and death toll for Australia between 1900 and 1922 was 1363 cases and 541 deaths, after which no plague was recorded. There are slightly different numbers floating around on the internet - https://www.sydney.edu.au/medicine/museum/mwmuseum/index.php/Bubonic_Plague_comes_to_Sydney_in_1900 for example lists 1371 cases and 535 deaths, possibly because there are slight inconsistencies when adding up the year by year entries in the tables versus the summary tables in Cumpston. We will use the 541 number here.

Oceania is home to hundreds of islands, and I have no overview what happened on each of them - we are visting New Zealand (21 cases, 9 fatal [https://surv.esr.cri.nz/PDF_surveillance/AnnualRpt/AnnualSurv/2018/2018AnnualNDReport_FINAL.pdf]), New Caledonia, and Papua New Guinea. (Indonesia, Japan and the Phillipines belong to Asia.)

Cavert, W. (2016) ‘At the Edge of an Empire: Plague, State and Identity in New Caledonia, 1899–1900’, The Journal of Pacific history, 51(1), pp. 1–20. doi:10.1080/00223344.2015.1130121. More info might be in Cumpston.

According to Dr Primet, who headed the medical response in New Caledoniaduring the first epidemic and signed the daily published health reports, a total of 124cases occurred, with 80 deaths; of those, theasiatique and océaniennepopulationaccounted for 79 cases and 59 deaths, while the European population counted 45cases and 21 deaths, though 14 of those deaths were convicts from the penalcolony.87 (is that only for the first wave, or all three together?. Only the first, as it is published in 1901). Primet "rapport sommaire sur l'epidemie de peste qui a regne en nouvelle-caeldonie"

See https://uhpress.hawaii.edu/title/the-people-trade-pacific-island-laborers-and-new-caledonia-1865-1930/ for the whole pandemic.

After the Third Pandemic.

There is not really a well-defined end of the Third Pandemic, but looking at various papers from different continents (Bramanti, Kuguler, Sun, Neerincxk, Jones), plague stopped being an epidemic disease around the 1950's, with case numbers returning globally to close to 0. Plague kept flaring up in outbreaks spilling over from local wildlife reservoirs after the '50s, but there is nothing that signals that plague was still spreading across large areas.

We can compile the summary reports published by the WHO, and get a total (reported!) number of cases and deaths from 1954 until 2018. These reports contain some copy-paste errors and typos, but by browsing the WER archives and by doing some comparative work between WER reports, we can remove most of these errors.

The global total for the period of 65 years from 1954 to 2018 sums up to 1,149,952 cases and 9874 deaths, or about 150 deaths per year.

What is fairly clear is that the largest reporting gap in the WHO are the information from China and from the former USSR, which we should get from other sources to get a more complete tally for the Third Pandemic.

With just 10,000 deaths, we can leave the final tally at between half a billion to 1.5 billion people over a period of 7,000 years. Smallpox is supposed to have killed nearly 500 million people in its last 100 years (about 5% of everybody), and has been around for 10,000 years. With a 100 billion births in 10,000 years , and say, half of those not accessible to smallpox for reasons of continent or inoculation, that puts smallpox at 5 billion total deaths, almost a factor 10 worse than the plague. For comparison, COVID ~20 million, HIV ~30 million and the Spanish flue ~40 million are at about 5%-10% of the lower range of plague in total mortality, albeit that COVID and the Spanish Flue reached those numbers in single sweeps.

Footnotes