The Third Pandemic, 1855 to 1959
The Third Pandemic shares some strong similarities with both the Plague of Justinian and the Black Death. Like both of these, it was an outbreak of Yersinia pestis originating in China. While the plague originated in the Yunnan Province of China, it spread through the rest of China due to political unrest. In Canton, 60,000 people died in only a few weeks. The numbers were higher in Hong Kong. The plague spread rapidly along shipping routes, reaching ports as far away as Australia and San Francisco.
Two different strains of Yersinia pestis were common during the Third Pandemic. The first was bubonic, the second pneumonic. The pneumonic variant was prevalent in Manchuria and Mongolia. Pneumonic plague likely had strong person-to-person transmission.
Most notably, the Third Pandemic did not die out quickly. In fact, recurrences of the Third Pandemic continued well into the 20th century. Colonial India was particularly impacted by the Third Pandemic, with 12.5 million people dying over a thirty-year period. In India, the British developed a vaccine against bubonic plague in 1897 and began a mass vaccination campaign to reduce the prevalence of the illness. Vaccination was not compulsory, but the management programs created to reduce the plague were key in developing India’s public health system.
The last significant outbreak of the Third Pandemic occurred in Peru and Argentina in 1945. The Third Pandemic is considered to have ended in 1959; however, there are approximately 5,000 cases of plague each year. Pneumonic plague continues to have relatively high fatality rates, if treatment is not initiated quite rapidly. Bubonic plague is typically successfully treated with antibiotics.