Dozens quarantined in Siberia after plague reports

A laboratory worker at a plague research institute in Siberia has fallen ill and died in undisclosed circumstances, prompting authorities to quarantine dozens of people, and the head of Russia's health watchdog to fly to the Irkutsk region.

The death has sparked public health fears on social media, but authorities said today that the situation was under control.

Plague is endemic to Siberia, location of the first known prehistoric human outbreak, as the bacterium that causes it, Yersinia pestis, is present among the small wild mammals and their fleas in Siberia's vast wilderness.

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

Local media named the woman as Darya Shipilova, an employee at the Irkutsk Anti-Plague Research Institute of Siberia and the Far East.

There were conflicting reports about how and where the laboratory worker, whose age was given as 28, had fallen ill, but the authorities said she had died of pneumonia of an as-yet unestablished origin.

But Irkutsk regional governor Igor Kobzev said today that a special expert commission inspection in the region had found that "the cause of death was pneumonia of undetermined etiology".

He said on Telegram that Russia's consumer and health watchdog Rospotrebnadzor had determined, following tests, that "no microorganisms linked to the young woman's professional work were found in her biological samples".

He added that there had been "no new cases of staff from the anti-plague institute seeking medical attention" since the woman's death.

Mr Kobzev said the sanitary-epidemiological situation in Irkutsk was "stable".

"The situation remains under our control and that of the experts," he added.

Asked about the situation, Kremlin spokesman Dmitry Peskov told reporters to "rely on Rospotrebnadzor's official statements rather than ... rumours and speculations".

Plague is a bacterial disease that can occur in several forms, including pneumonic plague, the most contagious type.

Pneumonic plague can be fatal if not treated early, according to the World Health Organization.

US Secretary of State Marco Rubio said his country was monitoring the situation but saw no "cause for alarm".

"There's very limited travel between the US and Russia, obviously, but like anything else, something like that gets out, it could quickly spread," Mr Rubio told reporters before taking off for a visit to Iceland.

"So we're watching and monitoring it closely. I don't think it's cause for alarm, but it is cause for focus and a cause to just keep an eye on it. And we're doing that," he said.