A young lab worker at a Russian institute that studies the plague has died of a pneumonia that officials say has not yet been traced to a specific cause. Russian media report the death has sent hundreds into medical observation and put at least one hospital in Siberia under quarantine. Canada’s health minister says Ottawa is watching closely, though officials stress there is no risk to Canadians. Marjorie Michel says Canada is working with the World Health Organization and other countries to stay on top of the situation. The Public Health Agency of Canada (PHAC) told CTV News it is tracking the case through its Global Public Health Intelligence Network to better understand the risk and context of the potential exposure. “At this time, no risk to Canada has been identified,” the agency said. PHAC noted that human plague is very rare in Canada. The last case here was reported in 1939. But one Canadian expert warns that much about the young woman’s death remains a mystery. “We don’t even know if this was the plague. All we know is that she worked in a lab where that pathogen was likely featured,” said Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital. Who was the Russian lab worker? The woman worked at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East. The facility studies plague in Siberia, where the disease still circulates in wild rodents such as marmots. Russian media outlets identified the deceased worker as 28-year-old lab technician Daria Shipilova. They say she was taken to hospital in the small town of Shelekhov, near Irkutsk, with severe pneumonia and died days later. A changing story According to Russian media reports, Alexei Tsydenov, head of the neighbouring republic of Buryatia, initially wrote that she had died of plague and later changed his post to say she “may have” died of it. Russia’s health watchdog, Rospotrebnadzor now says she had “pneumonia of unknown etiology,” meaning the cause is not known. The agency says tests found no microorganisms linked to her work, and that no accident involving dangerous pathogens was detected at the research institute. Irkutsk’s governor says no new cases of infectious disease have been reported among institute staff. Still, Bogoch says the changing story is reason to be cautious about what Russian officials are saying. “I think there has to be a healthy degree of skepticism, especially that we’re clearly getting filtered information and limited information,” he said. “This is a time where you obviously want to have the utmost of transparency, not just to the world at large, but also to the community that surrounds this laboratory.” According to Russian media, the hospital where the worker died was placed under quarantine, and those who came in contact with her have been under medical observation. Meanwhile, Kremlin spokesperson Dmitry Peskov told reporters Monday to rely on information from Russia’s official public health watchdog, rather than “rumours” and “speculation.” ‘The plague is not COVID’ The case has revived memories of COVID-19, and the still-unresolved question of whether that virus came from a lab leak in Wuhan, China, which Beijing denies. But experts say the two aren’t really comparable. “The plague is not COVID,” Bogoch said, noting that it’s caused by a bacterium and that cases occur every year in parts of the world. “We know how to prevent, detect, and respond to plague.” Asked whether it could spread widely, Bogoch stressed that much remains speculation, and said “something like this could be a local issue and at worst a regional issue.” Angela Rasmussen, a virologist at the University of Saskatchewan’s Vaccine and Infectious Disease Organization, told CNN most people don’t need to be particularly concerned. She noted plague is endemic in wildlife across that part of Siberia and Mongolia. “So that’s actually why they have a research institute there. They’re very used to dealing with this,” she said. Rasmussen explained that people usually catch pneumonic plague by breathing in a large dose of bacteria, and that infected patients don’t release much of it. “So while it can be transmitted in hospital and household settings, it’s actually not like COVID in the sense that it just spreads rapidly through populations,” she said. “It’s not actually very transmissible.” What is pneumonic plague? Pneumonic plague is caused by the same bacterium behind bubonic plague, the disease linked to the Black Death that killed tens of millions in the Middle Ages. People usually catch plague from flea bites or contact with infected animals, especially rodents. The pneumonic form attacks the lungs. It is the only form that can spread between people, through coughing, usually with close contact. PHAC says early diagnosis is important, as plague is treatable with widely available antibiotics. For Bogoch, the case is another wake-up call about lab safety around the world. “This just highlights the need for ensuring that labs all over the world adhere to the highest standards of biosafety and biosecurity,” he said. With files from The Canadian Press