Federal Health Minister Marjorie Michel said Monday that there is “no risk for Canada” following the death of a Russian laboratory worker at a plague research institute in Irkutsk Oblast, Siberia, who Russian authorities say died of pneumonia of an unknown cause last week.

“We are following very closely, working with WHO and other countries to make sure that we are on top of the situation,” she said, adding that the government was coordinating with the U.S., “for the benefit of the world.”

U.S. Secretary of State Marco Rubio said Monday that he does not believe there is cause for alarm, but said that U.S. authorities were carefully monitoring the situation, and that they were aware “it could spread quickly.”

The death prompted Russian health officials to quarantine a hospital and dozens of individuals in the town of Shelekhov, where the researcher, identified by local media as Darya Shipilova, an employee at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East, died last week.

Her death sparked public health fears on social media, amid unconfirmed media reports suggesting she might have died of pneumonic plague, a severe, rapidly developing form of pneumonia caused by a bacterium known as Yersinia pestis.

Irkutsk Oblast Gov. Igor Kobzev has not identified the illness but said it was a suspected case of “a particularly dangerous infection,” later calling it  “pneumonia of unknown etiology,” The Associated Press and Reuters reported.

The quarantined hospital is no longer discharging or admitting patients; individuals who came into contact with the employee are being monitored, the AP said.

Anna Popova, head of Russia’s public health watchdog, Rospotrebnadzor, flew to Irkutsk to meet with Kobzev and other officials on Friday.

Rospotrebnadzor was implementing “a full range of anti-epidemic measures,” Kobzev stated.

Russian authorities said they have found no evidence that the illness was caused by pathogens the researcher worked with.

Plague is endemic to Siberia. It is the location of the first known prehistoric human outbreak of Yersinia pestis, which is present among the small wild mammals in its vast wilderness and their fleas.

It is rare for Russians to fall ill with plague, though cases in other parts of the world – notably Africa – occur every year.

Kobzev noted that over the past few days “no new cases of staff from the Anti-Plague Institute seeking medical attention have been identified.”

The Irkutsk Aluminum Plant in Shelekhov required staff to wear masks as a precaution, its director Artyom Fominykh said Saturday on Telegram, calling for calm and adding: “Better be safe than sorry.”

Dr. Malick Gibani, clinical associate professor in bacterial vaccinology at Imperial College London, told the Associated Press, “in the event of a potential laboratory exposure, it would be normal to identify individuals who might have been exposed and to monitor them according to the assessed level of risk.”

Plague comes in three forms affecting different parts of the body. Pneumonic plague, an infection of the lungs, prompts the patient to cough out infectious airborne droplets, which can be passed from person to person.

The incubation period of pneumonic plague following inhalation can be as short as +1 day, according to the CDC.

If identified quickly, it can be treated with antibiotics. But if left untreated, it can be fatal in one to six days.

— with files from Reuters and the Associated Press