The Plague in the 21st Century—How Dangerous Is It?
Following the death of a lab technician in Irkutsk who worked at an anti-plague institute, there has been talk in Russia of a possible case of pneumonic plague. This news has raised fears of a new outbreak, but the woman’s death alone does not mean that an epidemic has begun in Russia. Infectious disease specialist Larisa Moroz explained how dangerous the plague is today, how it is transmitted, and whether it could reach Ukraine.
The plague is a bacterial infection caused by Yersinia pestis. It was this bacterium that caused the medieval “Black Death,” which claimed millions of lives. But modern plague is very different from the one humanity faced hundreds of years ago. Today, the disease can be diagnosed and treated with antibiotics. The key is to recognize the infection in time and begin treatment. The World Health Organization also emphasizes that early treatment significantly increases the chances of recovery.
At the same time, the plague remains a particularly dangerous infection. According to Larisa Moroz, the severity of the disease depends largely on its form. “The plague can take several forms—localized and generalized. Localized forms include the cutaneous, cutaneous-bubonic, and bubonic forms, where animals are the primary source of infection. A person can transmit the infection to another person in the case of the pneumonic form, because the pathogen can then spread through airborne droplets,” the doctor explained.
The most common form is the bubonic form. People usually become infected through the bite of an infected flea. Afterward, the bacteria enter the lymphatic system, and the lymph node swells, becoming hard and very painful. Such a node is called a bubo.
Person-to-person transmission of bubonic plague is rare. The situation is different with the pneumonic form. It affects the lungs and can be transmitted from an infected person to another through infected droplets when coughing or breathing. This is why pneumonic plague is considered the most dangerous in terms of its spread among people. There is also a septic form, in which the bacteria enter the bloodstream. It can develop as a complication of other forms of plague and quickly lead to a critical condition.
Can the plague be treated today?
Yes. Unlike in the Middle Ages, the plague is treated with antibiotics today. “There are antibiotics to which the plague pathogen is sensitive. If diagnosed in time, it can be treated. And the effectiveness of treatment depends primarily on how quickly the disease is detected and on the sensitivity of the specific pathogen to the medications,” Moroz noted.
The WHO also emphasizes that treatment should begin as early as possible. This is especially important for the pneumonic form, which can become fatal very quickly if left untreated. According to the organization, symptoms of plague usually appear one to seven days after infection, although for the pneumonic form, this period can be significantly shorter. The diagnosis is confirmed by laboratory testing. To do this, samples from a bubo, blood, or sputum may be examined.
The doctor also drew attention to the specific requirements for handling material that may contain the plague pathogen. Such samples cannot simply be left unattended. Handling them requires special protocols, record-keeping, storage, and laboratory procedures.
That is why, according to Moroz, theories about the accidental disappearance or unnoticed damage to a hazardous sample must be evaluated with caution. Without official investigation results, it is too early to draw conclusions about the cause of human infection.
How quickly does the plague progress?
The incubation period depends on the form of the disease and the route of infection. In general, the WHO indicates a period of one to seven days. With the pneumonic form, symptoms can appear very quickly—sometimes within a day. The initial symptoms may resemble a common acute infection. These include high fever, chills, weakness, muscle aches, and headache. In the bubonic form, painful, swollen lymph nodes are also present. In the pneumonic form, symptoms include cough, shortness of breath, and other severe respiratory symptoms.
According to Moroz, in severe generalized forms, a person’s condition can deteriorate very rapidly. Therefore, in such a situation, one cannot wait for the symptoms to “go away on their own.” At the same time, it would be incorrect to state a specific number of days after which treatment would no longer be effective. The course of the disease depends on the form of the infection, the patient’s overall health, and how quickly treatment was initiated.
Can the plague really be transmitted from person to person?
Yes, but this applies primarily to the pneumonic form. A person with pneumonic plague can shed bacteria through respiratory secretions. Another person can become infected through close contact. That is why, if this form of the disease is suspected, the patient is isolated, and people who may have come into contact with them are placed under medical observation. “If a person is confirmed to have the plague, they are required to be hospitalized. Isolation applies to everyone—a quarantine is imposed in the area, with no entry or exit permitted. People who have been in contact with the patient are isolated separately,” said the doctor.
According to her, such people are not simply left at home under the supervision of a family doctor. In the event of a real threat, special anti-epidemic measures are implemented. The WHO also recommends isolating patients with pneumonic plague and monitoring their close contacts. Prophylactic antibiotic treatment may be administered to close contacts. Therefore, the mere appearance of a single suspected case does not automatically mean widespread transmission of the infection. For that to occur, cases of human-to-human transmission must be confirmed.
Could the plague spread from Russia to Ukraine?
According to Larisa Moroz, the risk for Ukraine is currently very low. There are no known natural foci of plague in Ukraine where the bacterium circulates continuously among animals and fleas. It is precisely these natural foci that are the main source of most plague cases worldwide. “If plague is detected in a certain area, strict quarantine measures are implemented there. Only medical workers, researchers, and others are allowed in, and no one is allowed out. Even if there really is a plague focus in Siberia, the likelihood that it will spread today is extremely low,” the doctor noted.
The greatest danger arises not from the mere presence of the bacterium somewhere in the wild, but when people become ill and the infection is transmitted. This is especially true for the pulmonary form. Therefore, a scenario in which a single case in Siberia automatically leads to a large-scale outbreak of the plague in Ukraine is unlikely.
At the same time, isolated imported cases cannot be completely ruled out. That is why suspected cases must be identified quickly, and people with relevant symptoms and an epidemiological history must undergo testing.
Where the Plague Still Occurs
The plague has not disappeared from the planet. Isolated natural foci of the pathogen exist in various parts of the world. One of the best-known places where plague cases are regularly reported is Madagascar. The WHO notes that cases of bubonic plague are recorded there almost every year, particularly during the peak season, which lasts from approximately September through April.
This is because the bacterium continues to circulate among wild animals and fleas. Humans can become infected after contact with infected animals or through the bite of an infected flea. That is why, in regions where plague is endemic, people are advised not to touch dead animals, to avoid flea bites, and to follow the recommendations of local health authorities.
What Should the Average Person Be Worried About?
There is no reason to panic over reports of a possible plague outbreak in Russia. Plague is a serious infection, but today it is no longer the incurable disease it was hundreds of years ago. The most important thing is not to confuse a suspected isolated case with a confirmed outbreak. In the case of Irkutsk, final conclusions must be based on laboratory test results and official information.
If a person suddenly develops a high fever, severe weakness, chills, painful swollen lymph nodes, or severe respiratory symptoms, they should seek medical attention. It is especially important to inform the doctor if there has been prior contact with wild animals, fleas, or a person with a confirmed infection. Modern medicine has diagnostic tools, antibiotics, and anti-epidemic measures that make it possible to control the plague. Therefore, the most important thing today is not to panic, but to detect the disease in a timely manner and begin treatment.
In Russia’s Irkutsk region, 189 people were hospitalized following the death of a 28-year-old woman linked to a plague research institute. In total, authorities identified 197 people who may have come into contact with the deceased.
