Russian woman’s death has exacerbated global fears about the plague. Here’s what we know

Open this photo in gallery:This undated photo released by the Irkutsk Anti-Plague Research Institute of Siberia and Far East, shows the institute workers in a lab.The Irkutsk Anti-Plague Research Institute of Siberia and Far East/via The Associated PressThe death of a 28-year-old Russian woman who worked at an anti-plague research institute in Siberia has prompted worries across the world of a much-forgotten disease, despite assurances from authorities that the situation is under control.Local media have identified the woman as Darya Shipilova, who was employed at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East in the city of Irkutsk. On Monday, it was reported that she died from severe pneumonia of an unknown origin in a nearby hospital. The circumstances of her death remain under investigation.Conflicting reports have led to widespread speculation on the cause of her death, including that she died of pneumonic or lung-based plague. Dozens of people who were in contact with Ms. Shipilova at the Shelekhov hospital have been placed under quarantine by Russian authorities. Here is what we know and whether Canadians should be concerned.No plague cases detected among contacts of deceased lab worker, Russia saysWhat questions still need to be answered? Isaac Bogoch, an infectious-disease specialist at Toronto General Hospital who also works in the University of Toronto’s Department of Medicine, said many facts about the case remain unknown, primary among them confirmation of the cause of death.“When someone from the ‘anti-plague institute’ dies of a severe pneumonia, clearly people are going to think that this possibly could be the plague. It’s not difficult to put two and two together,” Dr. Bogoch said.“Having said that, there are a number of pathogens that they may be dealing with in there, or it might not be related to her occupation. We just don’t know.”He said ruling out plague would be premature, but there is no way to be certain until the cause of death is properly investigated.“I gauge how serious it is based on the response of the Russian government. If this was a nothingburger, we probably wouldn’t have the federal Russian government taking control of the situation,” Dr. Bogoch said.He said there should be more transparency from Russia on the death probe, but also regarding the people currently under observation – for example, whether they are receiving any type of antibiotic to prevent possible infection, or any close contacts of Ms. Shipilova have become ill.“Everyone’s jumped on plague and, of course, that’s a very appropriate issue to jump to but that’s still premature because we don’t have confirmation,” he said, noting that Russian authorities have denied any detection of pneumonic plague.Based on what is currently known, Dr. Bogoch said, the issue is very likely local. While concerning, the death is not yet alarming, he said.Open this photo in gallery:A view of the Medical Assistance and Rescue Centre, an infectious diseases hospital, in the town of Shelekhov in the Irkutsk region, Russia, Monday.Stringer/ReutersWhat types of plague are there?The three main types of the plague are caused by the bacteria Yersinia pestis, which is usually found in small mammals, such as rats and squirrels, and their fleas. The most famous in human history is the bubonic plague, which swept across Asia, Europe and North Africa during the 14th century, killing tens of millions of people. It is the deadliest pandemic ever recorded, known colloquially as the Black Death.Bubonic plague, which infects the lymphatic system, is still the most common form of the disease, but modern human cases are rare. The most severe and dangerous form of the plague, however, is pneumonic.“This is the most virulent and least common form of plague,” a Government of Canada web page states. “Typically, the pneumonic form is caused by advanced bubonic plague spreading to the lungs.”Symptoms of pneumonic plague, which attacks the lungs, can start within 24 hours of exposure, including fever, chills and trouble breathing. Recovery rates are high if the disease is caught and treated within the first 24 hours after symptoms appear. It is otherwise difficult to stop and can quickly become fatal. The third is septicemic plague, a life-threatening bloodstream infection that can lead to severe complications, such as organ failure, respiratory distress and possible bleeding into the skin. It is fatal if left untreated.How does the plague spread?Humans are infected through the bite of a flea that fed on an infected animal, or through contact with a sick or dead animal that is carrying the plague.Pneumonic plague is the only form that can spread person to person through the inhalation of respiratory particles. However, it does not spread easily, requiring direct exposure with a sick person. Asymptomatic spread does not occur.Oldest-known plague outbreak came 5,500 years ago in SiberiaWhat symptoms signal pneumonic plague? Signs of the pneumonic form appear quickly postinfection with an incubation period usually between one and four days. They include severe respiratory symptoms, such as shortness of breath and coughing, in addition to bloody mucus or phlegm. Other symptoms include headaches, fever, body aches and digestive issues.As the disease rapidly progresses, so do more severe symptoms, such as chest pain. The pneumonic plague requires emergency medical care.Should Canadians be worried?Dr. Bogoch said his role is not to tell Canadians whether to be concerned, but stressed that the risk of plague cases coming to Canada remains very low.The country’s last reported case of plague was in 1939, according to the federal government. But the disease is still present in other global regions.“Plague exists naturally in 26 countries around the world. There are cases of plague all the time. Not very commonly, but they do exist,” Dr. Bogoch said, noting that a handful of cases occur in the United States each year.The bottom line, he said, is that there’s not enough information about the Russian case: “That’s the key takeaway.”With reports from Reuters, The Canadian Press and Associated Press