Russian ‘Plague’ Death: What We Know and Don’t Know

While initial reports said a 28-year-old Russian researcher from an infectious diseases institute in Siberia died of pneumonic plague, Russian health authorities have denied that story, according to World Health Organization (WHO) leadership.

WHO also said there are reports that a second researcher from the institute has developed pneumonia of an undetermined cause.

Russian health authorities told the WHO that no case of plague has been registered in the Irkutsk region, where the institute is located, WHO Director-General Tedros Adhanom Ghebreyesus, PhD, said in a post on X. And Russia’s public health watchdog said in a tersely worded statement that “extensive” testing found no evidence the researcher’s death was caused by any of the pathogens she worked with, according to the AP.

The AP also reported that initial reports pointing to plague as the culprit have been pulled from Russian state media.

Russian authorities further said on Wednesday that the researcher had been vaccinated against the pathogens she worked with, according to the New York Times.

“WHO has requested further information to clarify the cause of the severe pneumonia, the pathogen that prompted the public health measures, and media reports of a second employee with pneumonia of undetermined cause,” Ghebreyesus wrote in the X post.

The late researcher, Darya Shipilova, died on Oct. 2. Initial reports said she was hospitalized on Sept. 29 with severe pneumonia, and had broken a test tube holding the pneumonic plague pathogen, Yersinia pestis, on Sept. 25.

If that’s all true, “this is a textbook course of pneumonic plague disease,” virologist Angela Rasmussen, PhD, wrote in a Substack post. “The initial response from Russian officials suggests they thought it was plague.”

Russian authorities had quarantined about 200 of her contacts, as well as the hospital where she died, according to reports. Those authorities also told WHO that no high-threat pathogens were detected among the contacts, Ghebreyesus wrote.

Yersinia pestis is highly treatable with antibiotics, but it must be done prophylactically after an exposure or soon after symptoms appear because it progresses rapidly.

There are three main types of plague, all caused by the same bacterium, but they differ mostly based on route of exposure. Bubonic plague pervades the lymph nodes and usually results from the bite of an infected flea. Septicemic plague affects the bloodstream and multiple organs, and occurs after a flea bite or bubonic plague spreads to the blood.

Finally, pneumonic plague occurs after breathing in respiratory droplets from an infected person or animal. It’s the more concerning form since this kind can be transmitted from person to person. However, it takes prolonged, close contact — such as taking care of someone who is sick — to be transmitted.

The Irkutsk Anti-Plague Research Institute doesn’t just focus on Yersinia pestis. It also works on anthrax, cholera, tularemia, and other diseases.

Russia is also known to have a bioweapons program, which has had accidents in the past, including a 1979 anthrax outbreak that the government blamed on contaminated meat. It wasn’t until about 15 years later that Russian leadership came clean, acknowledging the outbreak was caused by a military bioweapons program.

Indeed, such a bioweapons program could modify Yersinia pestis to be antibiotic-resistant, for instance. However, there’s no evidence so far that the death is due to a bioweapon or modified form of the bacteria.

Rasmussen noted that in the “absence of a confirmed diagnosis, evidence of an alternative explanation, or any verifiable details, it’s hard to say what happened.”

“It’s possible that officials initially suspected plague, but then Shipilova tested negative and the cause of her illness remains unknown,” she wrote. “It’s possible Shipilova had plague but that is being covered up. It’s also possible Shipilova had something other than plague, and that is being covered up. There is simply not enough evidence to say.”