US monitors Siberian lab worker's death as Russia quarantines hospitals

A 28-year-old employee at Siberia's Irkutsk anti-plague institute died on 2 October after falling ill at work, prompting quarantine measures at several hospitals. Russia says tests found no pathogens linked to her job and calls it pneumonia of unknown cause, but unconfirmed reports suggest pneumonic plague. The US says it is monitoring closely.