Pneumonic Plague: Will There Be an Outbreak in Russia, and Should Ukrainians Be Concerned?

It all began with an incident in Russia, where a 28-year-old lab technician at the Irkutsk Research Institute for Plague Control in Siberia died, and 197 employees of the hospital where she was being treated are now under strict quarantine. Now everyone is wondering the same thing: Will there be an outbreak of pneumonic plague in Russia, and should Ukrainians be concerned about this?

What happened in the Irkutsk region?

Shelekhov is a small town three kilometers from Irkutsk in Eastern Siberia. It has a population of about 40,000. In Russia, of course, they are concealing the true cause of the lab worker’s death. As is always the case in such situations, they claim that the situation is under control. However, more and more information is emerging about a probable case of death from pneumonic plague.

The U.S. State Department is monitoring reports of the incident and is calling on Moscow to promptly provide accurate information. And the WHO has initiated a verification process, as the lack of transparency complicates the assessment of risks to other countries. Meanwhile, Donald Trump stated during a conversation with journalists that he would help Russia in its fight against the plague.

Infectious disease specialist Yevgeny Dubrovsky shared an interesting hypothesis regarding the pneumonic plague in Russia.

The claim that a lab technician “broke a test tube” is too simplistic. If a test tube breaks in a laboratory but is left untouched and no one sniffs the spilled material, nothing will happen. In reality, her test tube exploded inside a freeze-dryer – a special device used to dehydrate substances by freezing them and then removing the ice in a vacuum, bypassing the liquid phase. Once released into the air, the plague microparticles became highly accessible. The woman instantly inhaled them deep into her lungs. And that’s how she contracted the pulmonary form of the plague, 
he believes.

The doctor speculates that the lab technician concealed this incident, and when she fell ill and was admitted to a general hospital, she was mistakenly diagnosed with “severe COVID-19 with massive lung damage” and placed on a ventilator.

“That was the critical mistake – through the ventilator, the bacteria easily began to spread outside the ICU and became dangerous to the staff who were nearby,” says the infectious disease specialist.

The patient died. COVID-19 was not confirmed, at which point epidemiologists and public health officials stepped in. The entire hospital staff was placed under strict quarantine.

Could the plague spread across Russia, and should Ukrainians be concerned about this? And what can the average person do to protect themselves and reduce the risk of infection? We asked Iryna Ben, a candidate of medical sciences and assistant professor in the Department of Infectious Diseases at King Danylo I Lviv National Medical University, to advise our readers.

Iryna Ben

What is pneumonic plague? How can you tell if someone has contracted this disease?

Pneumonic plague is one of the clinical forms of plague, which can occur as either a primary or secondary infection and has a similar clinical course.

The primary pulmonary form has the most severe course, with an acute onset, chills, and a fever reaching 40 degrees or higher. From the very first hours, patients experience sharp chest pain, cough, shortness of breath, and delirium. The cough is initially dry but quickly becomes productive, with the production of clear, mucous sputum. Over time, the sputum becomes watery, frothy, bloody, and eventually contains blood.

The secondary pulmonary form most often develops from the bubonic form as a result of the spread of the infection. Its clinical course resembles that of the primary pulmonary form.

Mortality is high. Patients die 3–5 days after the onset of the disease due to acute respiratory failure and infectious-toxic shock. The pulmonary form is extremely dangerous from an epidemiological standpoint, as it is transmitted from person to person via airborne droplets. The bubonic form occurs after a bite from infected fleas (transmission route).

When was the last recorded epidemic of this disease?

The last major plague epidemic in the world (as part of the Third Plague Pandemic), involving both pneumonic and bubonic forms, occurred in India in 1994. Serious plague outbreaks with fatalities were also reported in the Congo in 2006 and on the island of Madagascar in 2014 and 2017.

Early diagnosis and antibiotic treatment of patients, prophylactic treatment of close contacts, isolation of patients with the pneumonic form, epidemiological contact tracing, and control of flea vectors helped to contain these outbreaks. In cases of pneumonic plague, infection control and the safe handling of the bodies of the deceased were also critical. The WHO provided technical, epidemiological, and organizational support to the countries, while national health authorities carried out the main epidemic control measures.

Do objects, clothing, transportation, or premises where a patient has been present, as well as the bodies of those who have died from pneumonic plague, pose a risk?

Clothing and personal belongings pose a high risk if they are contaminated with the patient’s secretions (sputum, respiratory tract mucus) or if they harbor infected fleas. The Yersinia pestis bacterium can remain viable in a moist environment (such as sputum) for several days to weeks. However, it cannot withstand drying, and at a temperature of 55 degrees, it dies within 10–15 minutes.

Indoor spaces and public transportation pose a risk both due to the presence of aerosol droplets (in enclosed, poorly ventilated spaces while a patient is present) and because of the risk of vectors (fleas) or contaminated surfaces.

The bodies of those who have died from pneumonic plague pose an extreme epidemiological hazard. The plague pathogen persists in corpses for a long time (in tissues and organs – for weeks or even months, depending on the temperature). During an autopsy, transportation, or preparation of the body, secondary aerosols may form, or there may be direct contact with bodily fluids.

What can the average person do to reduce the risk of infection?

Avoiding contact and self-isolation are the most effective measures for personal protection. If pneumonic plague is suspected, any close contact with an infected person (within 2 meters) without protective equipment is considered a high risk of infection.

Standard medical or cloth masks are ineffective against the Yersinia pestis bacterial aerosol. It is necessary to use FFP3-rated respirators (or at least FFP2/N95) that fit snugly against the face.

Increasing the distance reduces the risk of inhaling large droplets of sputum and mucus expelled by the patient when coughing, but distance alone is insufficient in an enclosed space. Thorough ventilation of rooms significantly reduces aerosol concentration. The plague pathogen is sensitive to sunlight (ultraviolet light), drying, and standard disinfectants.

You can use repellents, treat your home and pets with flea control products, avoid contact with wild rodents, and refrain from touching dead or sick animals (ground squirrels, marmots, rats).

Are there currently effective treatments for the plague?

Yes, the plague is a bacterial infection that is successfully treated with antibiotics. The doctor selects the medication based on the severity of the disease in accordance with medical protocols. You cannot prescribe medication for yourself “online.”

Are there vaccines against the plague, and who absolutely needs them?

Vaccination is used only for high-risk groups (for example, laboratory staff who work with the pathogen). Close contacts are isolated and given emergency prophylaxis with antibiotics for 6 days.

What are the possible scenarios in Russia? Is an outbreak possible?

With the pneumonic form of the plague, an outbreak is entirely possible due to the disease’s high contagiousness – that is, its ability to spread from an infected person or animal to a healthy individual.

How quickly can this disease spread, and what consequences might it have for Russia?

Pneumonic plague is the most dangerous and rapidly spreading form of infection caused by Yersinia pestis.

The speed of its spread is determined by several key factors:

• a short incubation period – 1 to 3 days (sometimes ranging from a few hours to 24–48 hours);
• direct airborne transmission: the patient releases the pathogen into the environment in the form of an aerosol when coughing, sneezing, or even speaking. The infection rate in enclosed spaces approaches 100%;
• rapid clinical progression: the patient’s condition deteriorates within the first 12–24 hours (severe pneumonia, shortness of breath, hemoptysis, and septic shock develop). Without immediate administration of antibiotics within the first 24 hours after the onset of symptoms, the case fatality rate approaches 100%.

In the absence of epidemic control measures, the chain of transmission grows exponentially: a single patient can infect dozens of people in their immediate circle within a short period of time.

What are the possible consequences? If a case leads to uncontrolled human-to-human transmission, the consequences will depend on how quickly the healthcare system and epidemiological surveillance respond.

The most likely scenario (containment and suppression): thanks to the availability of effective antibiotics and well-established anti-epidemic protocols for particularly dangerous infections (PDIs), the outbreak can be stopped at the initial stage. This requires strict quarantine, isolation of all contacts for 7 days, administration of emergency preventive antibiotic therapy to them, and disinfection of the outbreak sites. Under these conditions, the outbreak is limited to isolated cases.

Can a person with pneumonic plague cross a border or travel a significant distance before symptoms appear?

Theoretically, this is possible during the incubation period (1–3 days), but the time available for travel is extremely limited. As noted above, after the first signs appear, the patient’s condition deteriorates critically within the first 12–24 hours (severe pneumonia, shortness of breath, and septic shock develop). Without medical care, the patient quickly loses the ability to move.

Should Ukrainians be afraid? How quickly could the disease reach us, given that Ukrainian troops are clashing with Russian forces on the battlefield and prisoners of war are being taken?

Ukrainians should not panic. The current outbreak of the infection in Russia’s Irkutsk Oblast has been recorded thousands of kilometers from the front lines. Moreover, modern medicine effectively treats this disease with widely available antibiotics.

Despite the combat clashes and the capture of Russian soldiers, the risk of direct transmission of the infection on the battlefield is currently minimal. However, strict medical and sanitary-epidemiological monitoring of prisoners of war is mandatory to prevent the spread of any dangerous infections.