Russia plague quarantine following lab death: Should we be worried? 

Dozens of people have been quarantined in Russia’s Siberia after a laboratory worker at a plague research institute fell ill and died in undisclosed circumstances.

Russian news outlet People of Baikal reported the woman may have contracted pneumonic plague from a broken test tube and died.

Plague is a severe, life-threatening infection caused by the bacterium Yersinia pestis. Between 1346 and 1353, the bubonic plague – one of three forms of the disease – was known as the Black Death. It caused one of the most fatal pandemics in the world across Eurasia and North Africa. Some 30-60 percent of the population of Europe is believed to have died in that outbreak.

Pneumonic plague is less common than bubonic plague. It is a severe form of the infection that can spread from person to person.

What happened in the Russian lab and should we be worried?

Here’s what we know:

What happened in the Russian lab?

On Monday, Russian media reported that a 28-year-old woman named Darya Shipilova, who had been working at the Irkutsk Anti-plague Research Institute of Siberia and the Far East, died from suspected pneumonic plague last week.

According to some Russian media reports, Shipilova became ill while at work on September 30 and died two days later at a hospital in the nearby town of Shelekhov. A number of media reports suggest there may have been an accident at the lab, but this has not been officially confirmed.

About 200 people who came into contact with the dead woman have since been quarantined, and parts of the hospital where she died have also been cordoned off. An aluminium plant nearby has instructed its workers to wear masks.

Anna Popova, head of Russia’s public health watchdog, Rospotrebnadzor, flew to Irkutsk to meet with Governor Igor Kobzev and other officials four days ago.

In a statement quoted by the TASS news agency, Rospotrebnadzor said officials in Irkutsk region had, however, detected two cases ⁠of COVID and two cases of rhinoviruses among people who had been in contact with the researcher. No other cases of infectious diseases were noted.

Later on Monday, Russian authorities said they found no evidence that the woman’s illness was caused by any of the pathogens she worked with and said the situation was under control.

Kobzev said in ⁠a statement that the woman had died of “pneumonia of unknown aetiology”, adding: “Importantly, over the past few days, no new cases of staff from the Anti-Plague Institute seeking medical attention have been identified.”

He added that the situation was under control and that all known contacts with the dead woman had been identified, examined and placed under medical supervision.

What is plague and what are its symptoms?

The bacterium which causes plague, Yersinia pestis, is carried by small wild mammals and their fleas. In Siberia, where it is endemic, it is rare for Russians to fall ill with plague, however, though cases occur every year in other parts of the world, notably in Africa.

According to the Centres for Disease Control (CDC) in the US, plague has been detected in people of all ages, from babies to those aged in their 90s. Half of cases occur in people aged from 12 to 45. Men and women are both susceptible, although historically it has been slightly more common among men.

There are three main types of plague, affecting different parts of the body. These are bubonic, septicaemic and pneumonic. According to the World Health Organization (WHO), bubonic plague is the most common clinical form. Symptoms include painful swollen lymph nodes or “buboes”.

Septicaemic plague infects the blood while pneumonic plague affects the lungs.

The WHO describes septicaemic and pneumonic plague as “less common, but severe forms” of plague.

A fourth type, pharyngeal plague, is rare. It can be contracted by eating infected meat.

According to the US-based Cleveland Clinic, besides swollen lymph nodes in the case of bubonic plague, those infected can display the following symptoms:

• Fever and chills.
• Headaches and body aches.
• Weakness and fatigue.
• Dizziness.
• Nausea.
• Vomiting and diarrhoea.

Complications can arise from plague if it is untreated, according to the Cleveland Clinic. These include:

• Meningitis – a severe infection which causes the inflammation of the lining of the brain and spinal cord.
• Tissue death and loss of limbs from gangrene.
• Respiratory failure.
• Organ failure.

Bubonic plague has a fatality rate of 30 percent to 60 percent. Pneumonic and septicaemic plague are both fatal if left untreated within one to six days, the WHO says.

If identified quickly, however, all forms can be treated with antibiotics.

How does plague spread?

Plague most commonly spreads through the bites of fleas carried by rodents, but can also be transmitted from person to person.

According to the CDC in the US, people can also become infected through exposure to sick pets, especially cats.

These are the main ways the disease can be transmitted:

Flea bites

According to the CDC, people and animals can contract plague from dead rats carrying the disease as well as being bitten by fleas which have bitten infected rats. “Dogs and cats may also bring plague-infected fleas into the home. Flea bite exposure may result in primary bubonic plague or septicemic plague,” the CDC states.

Direct contact

Humans can contract plague through contact with the tissue or body fluids of an infected animal. This form of exposure most commonly results in bubonic plague or septicaemic plague, according to the CDC.

Infectious droplets

Droplets coughed out by humans and animals infected with pneumonic plague can hang in the air and be inhaled by another person. The CDC states that this requires direct and close contact with the person or animal with pneumonic plague, and it is the only way the disease can be transmitted from person to person.

According to the CDC, the last documented case of person-to-person pneumonic plague transmission was in 1924. However, there have been more recent cases of pneumonic plague transmitted to humans by sick cats.

“Cats are particularly susceptible to plague and can be infected by eating infected rodents. Cats with plague pose a risk of transmitting infectious plague droplets to their owners or to veterinarians,” the CDC states.

Where does plague exist?

Ian Jones, professor of virology at the University of Reading, told The Associated Press news agency that “plague carries a huge history and is still present in many parts of the world, including Russia”.

Worldwide, there are between 1,000 and 2,000 cases of plague every year, according to the Cleveland Clinic in the US.

Plague is endemic to Siberia, which is the location of the first known prehistoric human outbreak. Besides Russia, plague is also endemic in several other countries, according to the WHO. Between 2019 and 2025, the majority of new cases recorded by WHO occurred in the Democratic Republic of the Congo and Madagascar.

There have been rare cases elsewhere. In July 2025, Arizona a man who worked with cats died from pneumonic plague – the first such death since 2007.

There was a major outbreak of bubonic plague in Los Angeles1924 to 1925 after it was first recorded in the US in 1900, brought by infected rates in steamships. Bubonic plague has made up 80 percent of an average of seven cases per year in the US since then. Most of these have occurred in northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon and western Nevada, according to the CDC.

Why has this incident triggered global alarm?

While authorities in Russia have stressed that postmortem tests carried out on the woman did not detect that she had plague, the incident has raised global alarm.

Several authorities have called on Russia to give more clarity about what exactly happened to the woman at the lab.

In Washington, United States President Donald Trump said he was watching the situation with concern and said the US would be willing to help, though he said he had not spoken to Russian President Vladimir Putin about the situation.

“It’s a rough disease. You know, that’s a disease we used to be able to control, but somehow those microbes have gotten stronger and smarter. They’re like an army,” Trump told reporters outside the White House.

“Even with great advancement, the germs have really become relatively stronger than they were, and things that used to work on pneumonia don’t work as well any more,” he added.

US Secretary of State Marco Rubio said on Monday that he does not believe there is cause for alarm, but said the US is watching the case closely, aware that “it could spread quickly” despite the quarantine and other public health protocols.

Should the world be worried?

On Monday, Kremlin spokesman Dmitry Peskov said the public and media should follow official statements from Rospotrebnadzor, rather than “rumours or speculation”.

“It is difficult to comment with confidence given the relatively limited information currently available,” Malick Gibani, clinical associate professor in bacterial vaccinology at Imperial College London, said in a statement to the media.

“Based on reports, there appears to be a suspected index case, and contacts have been quarantined. If there is an exposure in a laboratory to a potentially dangerous pathogen, the usual procedure would be to undertake a risk assessment of who may have been exposed and the nature of their contact.”

He added: “People considered at risk can then be monitored and, where appropriate, screening, quarantine, or post-exposure prophylaxis with antibiotics may be offered. I think it’s important that we see how this pans out, and ideally, there’d be good communication between the public health authorities and the wider global health community.

“I think this emphasises the need to be aware of ongoing outbreaks of serious bacterial pathogens and highlights the need for investment in biosecurity, particularly for preventing biological risks. This could include developing medical countermeasures like better diagnostics or vaccines,” Gibani said.