Tuesday, 21 August 2018

Natural Disasters and Family Misfortunes 16: Plague

People may be unaware of the fact that the Plague, that devasted Europe centuries ago, is still with us.

Yup! That PLAGUE!

Of course, we have come a long way in the recognition and treatment of the disease. There has not been a major outbreak since the 17th century, at least ones that resulted in mass deaths. But it did affect the population of several European cities into the early 1800s.

Three pandemics of the disease are well described in articles about The History of Plague by John Frith:
·         First (Justinian) – “The first great pandemic of bubonic plague where people were recorded as suffering from the characteristic buboes and septicaemia was the Justinian Plague of 541 CE, named after Justinian I, the Roman emperor of the Byzantine Empire at the time. The epidemic originated in Ethiopia in Africa and spread to Pelusium in Egypt in 540. It then spread west to Alexandria and east to Gaza, Jerusalem and Antioch, then was carried on ships on the sea trading routes to both sides of the Mediterranean, arriving in Constantinople (now Istanbul) in the autumn of 541.”
·         Second (Black Death) – “In 1346 it was known in the European seaports that a plague epidemic was present in the East. In 1347 the plague was brought to the Crimea from Asia Minor by the Tartar armies of Khan Janibeg, who had laid siege to the town of Kaffa, a Genoese trading town on the shores of the Black Sea. . . In panic the Genoese traders fled in galleys with ‘sickness clinging to their bones’ to Constantinople and across the Mediterranean to Messina, Sicily, where the great pandemic of Europe started. By 1348 it had reached Marseille, Paris and Germany, then Spain, England and Norway in 1349, and eastern Europe in 1350.”
·         Third – “The plague re-emerged from its wild rodent reservoir in the remote Chinese province of Yunnan in 1855. From there the disease advanced along the tin and opium routes and reached the provincial capital of K’unming in 1866, the Gulf of Tonkin in 1867, and the Kwangtung province port of Pakhoi in 1882. In 1894 it had reached Canton and then spread to Hong Kong. It had spread to Bombay by 1896 and by 1900 had reached ports on every continent, carried by infected rats travelling the international trade routes on the new steamships.”

Since the beginning of the 20th century, there have been occasional infection of individuals around the world, the latest reported in June 2018 of probable bubonic plague in an American teenager in Idaho.

The bacterium, Yersinia pestis, is hosted in rodents and spread by fleas that live on these hosts.

The generally accepted theory of how the disease develops expands and spreads is during periods of climate change, in particular in regions that are normally dry and that become wet through an increase in rainfall.

In nature, the bacteria live in wild rodents and in the soil of their habitat. In areas that are hot and dry, the populations of these animals are stable, as are the numbers of fleas that live on them. During the latter part of the 13th century, in central Asia, the climatic conditions changed, bringing more rainfall over many years. The semi-arid habitat was transformed allowing the entire grassland ecosystem to grow. The rodent numbers – marmots, susliks and gerbils – exploded along with the accompanying pathogen-carriers, the fleas. There is a great summary of the history of the plague and its attack on Europe, beginning in the 14th century, in The Great Transistion by Bruce M. S. Campbell (2016).

The wild rodents were eventually overpowered by the bacteria and began to die in large numbers, possibly aided by occasional droughts. That fostered the jump to other rodent and small mammal populations which had a wider range, including many that coexisted with humans. The infected rodents and their parasitic insects moved westward with the trade caravans. Eventually the domestic rats began to die off en masse and the infected fleas and lice transferred to humans. The result, with people interacting on a wide regional scale, was a pandemic that quickly spread across all of Europe.

The bacterium has mutated over the centuries, with different strains causing epidemics. Antibiotics now assist in the recovery of plague victims. Death tolls have been reduced from 50% of those affected to about 10%, or better if treatment is begun within 24 hours of diagnosis.

Plague bacteria still exist in many locations around the world, mainly in particularly warm and dry regions. The diagram below shows the Global Distribution of Plague
(A) Map showing countries with known presence of plague in wild reservoir species (red). For US only the mainland below 50° N is shown. (B) Annual number of human plague cases over different continents, reported to WHO in the period 1954–2005. (C) Cumulative number of countries that reported plague to WHO since 1954

In North America, plague cases have been restricted to the western regions. Plague was first seen in the US in 1900, introduced by rats from steamships that had arrive from affected areas in Asia. The last urban outbreak occurred in Los Angeles in 1924-25. Thirty people died during a two-week period (Viseltear, 1974).

Since the Los Angeles occurrence, isolated cases have been diagnosed, mostly in rural areas. Over 80% have been of the bubonic form. People of all ages have contracted the disease at the rate of about seven cases per year.
Reported cases of human plague in the United States between 1970 and 2016; one dot placed randomly in most likely county of exposure for each confirmed case (retrieved 21 August 2018 from Centers for Disease Control and Prevention website
The modern world does not have much to fear from this disease anymore, but genealogists my find many of their ancestors were exposed to it, possibly succumbing as the survival rates were very low.

What is interesting is that it has never gone away!


Campbell, Bruce. M. S. (2016). The Great Transition. Cambridge, UK: Cambridge University Press.

Chodosh, S. (2018). Five things you might not know about the plague (not including the fact that it still exists). Popular Science website. 

Frith, John. (2012). The History of Plague – Part 1: The three great pandemics. Journal of Military and Veterans’ Health. 20(2).

Stenseth, N. C., B. B. Atshabar, M. Begon, S. R. Belmain, E. Bertherat, E. Carniel, K. L. Gage, H. Leirs & L. Rahalison. (2008). Plague: Past, Present, and Future. http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0050003

Viseltear, A. J. (1974). Pneumonic Plague epidemic of 1924 in Los Angeles. Journal of Biology and Medicine. Volume 1, pp 40-54. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2595158/pdf/yjbm00152-0044.pdf

Plague (disease) – Wikipedia