Missing details keep U.S. plague response on hold

U.S. plague response remains on hold due to missing details: officials don't know which pathogen killed a Russian researcher or how well contained it is. A worker at the Anti-Plague Research Institute of Siberia died after contracting pneumonia, with conflicting accounts of whether it was pneumonic plague. Secretary of State Marco Rubio said Monday the administration is monitoring closely, adding it's not cause for alarm but for focus.