A lab worker at a Russian anti-plague institute has died of severe pneumonia, raising fears of a possible plague leak — bad news for public health and another reason to distrust Russia's bioweapons record.

• A 28-year-old researcher at Russia's Kutz Anti-Plague Institute in Siberia died after reportedly breaking a test tube holding plague bacteria.
• Russia put nearly 300 of her contacts under watch and quarantined a hospital, but says the cause was only "pneumonia of unknown origin."
• Marco Rubio said the US is monitoring closely and sees no cause for alarm, while noting such a thing could spread fast if it got out.
• The bigger worry is China: 25,000 travelers a month fly from that Siberian city to Beijing, Shanghai, and Hainan.
• The incident revives the fact that Russia had a bioweapons program Yeltsin promised to shut in 1992, with no outside inspections since.

Outlook: Expect continued monitoring and pressure for travel restrictions, with the real risk being spread into northern China rather than directly to the US.