Russia plague scare: India's past outbreak and concerns around latest episode

A 28-year-old laboratory worker in Irkutsk died after developing severe pneumonia amid reports of possible plague exposure at an anti-plague institute. The episode has drawn scrutiny because nearly 200 contacts are under observation and five hospitals have been closed for quarantine, though officials have not confirmed the plague.

In Short

• Russian authorities described the illness as pneumonia of unknown origin
• Reports suggested exposure to Yersinia pestis at an anti-plague institute
• Pneumonic plague spreads through respiratory particles and can worsen quickly

Reports of a possible plague infection in Siberia have brought back a disease many people associate with medieval Europe rather than modern medicine. A 28-year-old laboratory worker in Irkutsk, Russia, has died after developing severe pneumonia, while nearly 200 people who may have had contact with her have reportedly been placed under medical observation.

The circumstances remain unclear. Russian health authorities have not confirmed that the woman had the plague and have described her illness as pneumonia of unknown origin.

At the same time, reports from Russian media have suggested that she may have been exposed to Yersinia pestis, the bacterium that causes plague, while working at an anti-plague research institute. Russian authorities have said the epidemiological situation in the region remains stable.

The uncertainty has nevertheless attracted international attention.

Dr Ashish K. Jha, US-based physician-researcher, biosecurity expert and former White House COVID-19 response coordinator, said on X that he was concerned by the reports, pointing to the reported laboratory exposure, the woman's subsequent death and the large number of people placed under observation.

His comments – with US health authorities too saying that they are monitoring the development closely – reflect concern about what may have happened, rather than confirmation that a plague outbreak is underway.

For Indians, there is another reason this story is worth understanding. India itself experienced a major plague outbreak in 1994, including an episode of pneumonic plague in Surat, Gujarat.

So what exactly is plague, how does it spread, and should people in India be worried about what is happening in Russia?

HOW PLAGUE SPREADS

Plague is a bacterial infection caused by Yersinia pestis, a bacterium that normally circulates among small mammals and their fleas. Humans can become infected through the bite of an infected flea, contact with infected animals or their tissues, or, in the case of pneumonic plague, by inhaling respiratory particles from an infected person.

There are three main forms of plague: bubonic, pneumonic and septicaemic.

Bubonic plague is the most common form. The bacteria enter the body, usually through a flea bite, and travel to the lymph nodes, which become swollen and extremely painful. These swollen lymph nodes are called buboes.

Septicaemic plague occurs when the bacteria multiply in the bloodstream. It can cause severe systemic illness, tissue damage, bleeding and organ failure.

Pneumonic plague is the form that creates the greatest concern for human-to-human transmission. Here, Yersinia pestis infects the lungs and can spread through respiratory particles.

The World Health Organisation (WHO) describes it as the most virulent form of plague. Its incubation period can be as short as 24 hours and, without early treatment, it can progress rapidly.

Dr Ananya Mohanty, internal medicine specialist with Manipal Hospital, Bhubaneswar, said, “Pneumonic plague is the form that carries the greatest risk for potential human to human transmission by infectious respiratory droplets.”

That is why a suspected pneumonic plague case is treated differently from an isolated case of bubonic plague. A person with bubonic plague generally does not spread the infection directly to others.

A patient with pneumonic plague, however, can potentially transmit the bacteria through respiratory particles, making early recognition, isolation and treatment critical.

The symptoms can initially resemble other serious infections. Sudden fever, chills, severe weakness, headache and muscle aches can occur. Bubonic plague can cause painful swollen lymph nodes, while pneumonic plague can cause cough, breathing difficulty and chest discomfort. Severe cases can also involve blood-stained sputum.

The good news is that plague is no longer the untreatable killer it once was. Appropriate antibiotics can cure the infection when treatment begins early. WHO says untreated pneumonic plague can become fatal very rapidly, while prompt antibiotic treatment can be effective.

WHAT INDIA LEARNT IN 1994

India has a particularly relevant reason to pay attention to plague surveillance.

In 1994, after a gap of 28 years, plague returned to the country. The outbreak was first reported from Mamla village in Maharashtra's Beed district. WHO records say 63 cases of bubonic plague were reported from Mamla and surrounding villages during August and September that year, with laboratory evidence pointing to Yersinia pestis.

The more dramatic episode came soon afterwards in Surat.

WHO's retrospective assessment recorded 876 cases and 54 deaths during that episode, with Yersinia pestis isolated from some patients.

The outbreak generated enormous public fear and had consequences far beyond the people who were infected. Contemporary surveillance reports recorded suspected plague cases across several states, including Maharashtra, Gujarat, Karnataka, Uttar Pradesh and Madhya Pradesh, as well as the national capital, Delhi.

The 1994 experience also demonstrated why surveillance of rodents, fleas and unusual animal deaths is significant, say epidemiologists. Plague is fundamentally a zoonotic disease: the bacteria persist in animal reservoirs, and humans can become infected when they enter that transmission cycle.

LATEST WORRY

While modern sanitation, surveillance, laboratory diagnosis, antibiotics and infection-control measures have made plague far less common and most human cases reported globally in recent years have been concentrated in countries such as the Democratic Republic of the Congo and Madagascar, an important point is that the bacterium itself has not disappeared.

“Plague remains possible wherever a natural focus involving the bacteria, animal reservoirs and vectors such as fleas exists,” said an infectious disease specialist from the Indian Council of Medical Research (ICMR).

And even though there is no evidence so far that the Russian episode represents sustained international transmission, the reported circumstances explain why public-health authorities are taking the episode seriously.

“The woman worked at an anti-plague institute, reports have alleged a possible exposure to plague bacteria, and she subsequently developed severe pneumonia,” underlined the specialist at ICMR.

In his post on X, Dr Jha pointed out that he is concerned about these reports, particularly given the scale of the response, such as five hospitals in Siberia getting closed for quarantine, as per media reports from Russia.

But those concerns should not be confused with confirmation of either plague infection or an outbreak, at least for now, some others insisted.

Dr Mohanty also cautioned against interpreting a suspected case as an established outbreak.

“It would be premature to call the situation a confirmed plague outbreak without appropriate official confirmation and epidemiological evidence,” said Dr Mohanty.

- Ends