Third Plague Pandemic (1855-1960): Bubonic Plague Returns

The third plague pandemic was a worldwide outbreak of bubonic plague that began in Yunnan, southern China, in the mid-19th century and spread across the globe after reaching Hong Kong in 1894. It killed an estimated 12 to 15 million people, most of them in India and China. During this pandemic scientists finally identified the plague bacterium and discovered how rats and fleas spread it.

Plague returns: Yunnan

Plague is caused by the bacterium Yersinia pestis. It lives mainly in wild rodents and is carried by their fleas. When infected rats die, their fleas seek new hosts, including humans. The most common form, bubonic plague, causes fever and painful swollen lymph nodes called buboes; without treatment it kills perhaps half its victims. Earlier pandemics included the Plague of Justinian in the 6th century and the Black Death of the 14th.

Plague had long been present among rodents in the mountains of Yunnan. In the late 18th and early 19th centuries a mining boom brought migrants and trade into the province, and outbreaks became more frequent. From 1855 the disease flared more widely, helped by the upheaval of the Panthay Rebellion, a Muslim uprising in Yunnan that lasted until 1873. Armies, refugees and traders carried plague along roads and rivers towards the coast.

Hong Kong, 1894

By the early 1890s plague had reached the coastal province of Guangdong. In the spring of 1894 a severe epidemic struck the city of Canton (Guangzhou), where tens of thousands of people died. Because of constant traffic between the two cities, plague soon reached the British colony of Hong Kong, where it was confirmed in May 1894.

The colonial authorities responded with harsh measures. Sick people were moved to hospital ships and temporary hospitals, houses were searched, and soldiers cleaned and disinfected homes in the crowded Chinese district of Taipingshan, much of which was later demolished. Many Chinese residents resented the searches and Western treatments, and tens of thousands left for the mainland. The Tung Wah Hospital, a Chinese charitable institution, negotiated with the government on behalf of the community and was allowed to treat some patients with Chinese medicine. About 2,500 deaths were recorded in Hong Kong in 1894, and plague returned there almost every year for three decades.

As a busy steamship hub, Hong Kong became the springboard for a global pandemic. Ships carried infected rats and fleas from port to port across the world.

Finding the bacterium

Two scientists rushed to Hong Kong in June 1894. Kitasato Shibasaburō, a Japanese bacteriologist who had trained with Robert Koch in Berlin, arrived with a well-equipped team. Alexandre Yersin, a Swiss-born doctor working for the French Pasteur Institute, arrived soon after and worked in a simple hut with limited access to bodies.

Both reported finding a bacterium. Yersin’s description, based on samples from buboes, was clear and accurate, while Kitasato’s early reports were less consistent. Yersin is now generally credited with the discovery, and the bacterium was eventually named Yersinia pestis in his honour.

How the disease spread remained a mystery. In 1898 the French physician Paul-Louis Simond, working in Karachi, showed that fleas could carry plague from a sick rat to a healthy one. His findings were not fully accepted until the work of the British Plague Research Commission in India in the early 1900s.

India: the heaviest toll

Plague reached Bombay (Mumbai) in 1896 and spread through India for decades. Roughly 10 to 12 million people died there between 1896 and the 1930s, making India by far the worst-affected country. The disease spread from Bombay into the Deccan, Punjab and the United Provinces, following railways and grain stores where rats thrived. In the worst years, in the middle of the 1900s, recorded plague deaths exceeded one million a year.

British authorities used strict measures, including house searches, forced hospitalisation, segregation camps and travel inspections. These caused deep anger. In Pune in June 1897 the plague commissioner, Walter Charles Rand, was assassinated by the Chapekar brothers, partly in protest against the harsh searches. The response to plague became an important grievance for the growing Indian nationalist movement.

In 1897 the bacteriologist Waldemar Haffkine, working in Bombay, developed an early plague vaccine and tested it on himself. It offered partial protection and was given to millions of people in India in the following decades.

A global pandemic

Between 1896 and 1901 plague reached ports on every inhabited continent. Outbreaks occurred in Porto in Portugal, Glasgow in Scotland, Sydney, Cape Town, Buenos Aires, Rio de Janeiro, Honolulu and San Francisco, among many others. In Honolulu, an attempt to burn infected buildings in January 1900 got out of control and destroyed much of Chinatown.

Each city reacted according to its own fears and prejudices. In Porto in 1899 the physician Ricardo Jorge identified the disease, and the government imposed a military cordon around the city that angered its merchants. Sydney’s outbreak in 1900 killed about 100 people and led to large-scale clearing of old dockside housing in The Rocks. In Cape Town in 1901 the authorities used plague as a reason to force many Black African residents out of the city to a new location at Ndabeni, an early step towards urban segregation in South Africa. Glasgow’s outbreak in 1900 was small and quickly contained by isolating contacts.

In San Francisco, plague arrived in 1900. Officials at first denied it, fearing damage to trade, and the Chinese community was subjected to quarantine and discrimination. The disease spread from city rats into wild ground squirrels and other rodents, and plague remains present among wildlife in the western United States today.

A related but distinct epidemic of pneumonic plague, spread directly between people through coughing, struck Manchuria in 1910 and 1911, killing around 60,000 people.

Decline

Governments slowly learned to cooperate. An International Sanitary Conference held in Venice in 1897 was devoted largely to plague and agreed common rules for notifying cases and inspecting ships. Over the following decades, fumigation of ships’ holds and metal rat guards on mooring ropes became standard in ports around the world. Better understanding of rats and fleas led to rat control, improved housing and port inspections. From the 1940s antibiotics such as streptomycin made plague treatable, and insecticides helped control fleas. The World Health Organization considered the pandemic active until worldwide cases fell to a low level around 1960. Plague still exists in rodent populations in parts of Africa, Asia and the Americas, but is now rare in humans and curable if treated early.

Timeline

• 1855: Plague flares widely in Yunnan, southern China.
• 1856-1873: The Panthay Rebellion helps spread plague through Yunnan.
• 1894, spring: Plague kills tens of thousands in Canton.
• 1894, May: Plague is confirmed in Hong Kong.
• 1894, June: Alexandre Yersin and Kitasato Shibasaburō identify the plague bacterium.
• 1896, September: Plague appears in Bombay.
• 1897: Waldemar Haffkine develops a plague vaccine; Rand is assassinated in Pune.
• 1898: Paul-Louis Simond demonstrates spread by rat fleas.
• 1900: Plague reaches San Francisco, Sydney and Honolulu.
• c. 1960: The WHO considers the pandemic over.

Why it matters

The third plague pandemic showed that an ancient disease could still devastate the modern, connected world through steamships and growing cities. It led to the discovery of the plague bacterium and its spread by fleas, and it shaped colonial politics in India and Asia. Its legacy includes modern quarantine practice and the plague that still lingers among wild rodents today.