The World Health Organization (WHO) has asked Russian authorities for more information regarding the death from a possible case of pneumonic plague of a worker at a laboratory studying dangerous pathogens in the Irkutsk region (Siberia) on October 2.
"The WHO has not yet received official notification through the International Health Regulations (IHR) regarding this matter," said Christian Lindmeier, the spokesperson for the United Nations health agency, during a press conference.
Lindmeier clarified that on October 3, after this case was detected by the internal surveillance system, the WHO contacted Russian authorities under the IHR and has since "maintained contact" with them.
Between October 3 and 5, the WHO has deployed technical experts from its regional office in Copenhagen and its headquarters in Geneva to monitor the situation, including specialists in high-risk threats and pathogens.
This is what is known about the case so far:
A worker at a laboratory researching the plague in Irkutsk (Siberia, Russia) died on October 2 from severe pneumonia. According to reports, the deceased is Daria Shipilova, a technician at the research center. She was admitted to a hospital in Shelekhov at the end of September, as reported by local and international media.
The hypothesis causing alarm points to an accident that occurred in the laboratory on September 25. It appears that a test tube containing dangerous biological material - some sources mention the 'Yersinia pestis' bacterium, responsible for the plague - broke during handling.
The researcher fell ill shortly after, and her condition rapidly deteriorated.
According to Russian media, authorities placed several hospitals in Irkutsk, including a pediatric center, under quarantine due to suspected plague cases, a claim not confirmed by the WHO and denied by Russian authorities.
On Tuesday, Russia denied the existence of a possible case - attributing the death to pneumonia of unknown etiology - and denied imposing health restrictions in the Siberian region of Irkutsk following the death of an employee at an institute combating the plague.
The Russian consumer health watchdog, Rospotrebnadzor, reiterated on Tuesday that a document circulating online about alleged tightening of health and epidemiological measures and restrictions in the Irkutsk region is false.
"The document and the information in question do not come from official sources and are false," the agency stated via Telegram.
"No such decision has been made at this time," they reported, emphasizing that "the health-epidemiological situation in the Irkutsk region (...) remains stable."
However, the Russian outlet 'People of Baikal,' citing anonymous sources close to regional security services, stated on Friday that the deceased woman may have contracted pneumonic plague through a broken test tube.
This Russian outlet reported that up to 200 people she may have had contact with are in quarantine.
For now, the WHO considers the health risk in Europe "very low" following the death, although it raises it to 'moderate to low' in Irkutsk, the Siberian region where the incident occurred.
The U.S. government issued an alert on October 4 regarding this case, to which the Kremlin responded the following day by calling for calm and to rely solely on information from the Russian consumer protection service.
The plague is an infectious disease caused by Yersinia pestis, a zoonotic bacterium usually found in small mammals and the fleas that parasitize them.
Historically, the plague has caused major pandemics with high mortality rates. In the 14th century, the so-called "Black Death" resulted in the death of around 50 million people in Europe. Today, however, plague cases can be treated with antibiotics.
There are different types of plague. The most common is bubonic plague, which causes the characteristic inflammation of lymph nodes known as buboes. The more severe forms are septicemic, which occurs when the bacteria enter the bloodstream, and pneumonic, the most virulent form and the one that, according to reports, the deceased researcher may have had.
Transmission occurs through flea bites, contact with fluids and secretions from infected animals, and in the case of pneumonic plague, also through inhalation of aerosols from infected individuals.
As explained by Nacho de Blas, an Epidemiology specialist and Associate Professor in the Department of Animal Pathology at the Faculty of Veterinary Medicine of the University of Zaragoza, the incubation period for pneumonic plague is very rapid, "it can be less than 24 hours." The disease's progression, which in this case can be transmitted from person to person through respiratory droplets, is also very fast.
Antibiotic treatment in these cases is very effective, De Blas points out. However, it is crucial to administer it promptly. "A delay in diagnosis can mean that the treatment comes too late." The mortality rate, when treated with antibiotics, can reach 5%. "Without any medical treatment, it can reach 100%," he warns.
Since it is a disease circulating in animals, the plague is present on all continents except Oceania. The bacterium circulates in small mammals and the fleas that parasitize them, and can be transmitted to humans. "80% of current plague cases occur in Africa," De Blas notes, clarifying that another 15% have been reported in Asia, mainly in Mongolia and directly related to contact with marmots.
Europe has been free of plague for five decades.
How are pathogens like the plague handled in the laboratory?
Research involving pathogens like 'Yersinia pestis' must be conducted in at least Biosafety Level 3 (BSL3) laboratories, which allow for the handling of biological agents causing potentially lethal infectious diseases for individuals but with low transmission to the community.
This level includes strict sterilization, access, and containment controls. "Among other measures, work is always done under negative pressure, and when studying agents like 'Y. pestis,' full isolation suits are used," explains De Blas.
"If the laboratory is at level 3 and meets the standards, there should not have been any contagion because it should be under negative pressure and the personnel should have been in full isolation gear, not just masks, goggles, and gloves," he clarifies.
Sources from the Carlos III Health Institute (ISCIII) state that there is currently no specific research line on plague at the center, although molecular diagnostic detection of the bacterium in a possible case is possible.
The National Microbiology Center has an accredited PCR for detecting 'Yersinia pestis' in its service portfolio. Additionally, it also has a Rapid Response Unit that, through the Biological Alert Laboratory Network (RELAB, coordinated by the CNM-ISCIII), "would immediately intervene to process a hypothetical sample in the Level 3 Biological Safety Laboratory."