Nearly 200 people have been placed under medical observation after a laboratory worker died from suspected pneumonic plague in Siberia’s Irkutsk region, according to a report by The Moscow Times.
According to the World Health Organization (WHO), plague is caused by the bacteria Yersinia pestis, zoonotic bacteria usually found in small mammals and their fleas.
People infected with Y. pestis often develop symptoms after an incubation period of one to seven days, it notes.
Bubonic plague is the most common clinical form of plague. Bubonic plague is characterised by painful swollen lymph nodes or ‘buboes’. Less common, but severe forms include septicaemic and pneumonic plague.
According to the WHO, plague is transmitted between animals and humans by the bite of infected fleas, direct contact with infected tissues, and inhalation of infected respiratory particles.
“Plague can be a very severe disease in people, with a case-fatality ratio of 30% to 60% for the bubonic type, and it is always fatal for the pneumonic and septicaemic kinds when left untreated. Antibiotic treatment is effective against plague bacteria, so early diagnosis and treatment can save lives,” the UN body says.
It adds that human plague remains endemic in several countries. During 2019-2025, most cases reported to WHO occurred in the Democratic Republic of the Congo and Madagascar.
There have been three plague pandemics in the history of humanity. The first was The Plague of Justinian that lasted from 541 to 750 Common Era.
The pandemic likely originated in Central or Eastern Africa (or Central Asia) and traveled along trade and shipping routes into the Mediterranean basin. It severely hit Constantinople, the capital of the Byzantine Empire (Justinian was the Byzantine emperor).
The plague, caused by Yersinia pestis, killed an estimated 25 to 100 million people over its various waves, weakening the Byzantine economy and stalling Emperor Justinian’s efforts to reunite the Roman Empire.
The second pandemic was the infamous Black Death which began in 1347 and lasted till 1353. According to researchers led by Maria Spyrou and Johannes Krause of Germany’s Max Planck Institute for Evolutionary Anthropology (2022), the Black Death likely originated in Central Asia, near Lake Issyk-Kul in modern-day Kyrgyzstan.
The Black Death wiped out half the population of Europe. It also led to profound labor shortages, social upheaval, and the eventual transformation of the feudal system.
The Third Pandemic began during the 19th century. It started in 1855 in Yunnan province of southwest China and travelled via steamship rats to all inhabited continents.
This plague claimed over 15 million lives globally, with the heaviest losses occurring in India and China. By 1960, the pandemic had ebbed away.