Trump expresses concern over Russian plague reports, mixes up pneumonia

"The pneumonia plague, if you call it. That's a disease we used to be able control. But somehow those microbes have gotten stronger and smarter. They're like an army. The germs have really become relatively stronger than they were, and things that used to work on pneumonia don't work as well anymore," Trump said.

His remarks drew criticism on social media, with medical professionals and observers noting that pneumonic plague is a distinct and severe bacterial infection, not simply a stronger version of common pneumonia. The Centers for Disease Control describes pneumonic plague as one of the "severe and rapidly progressing bacterial infections known."

Separately, Russian authorities have quarantined a hospital in Irkutsk, Siberia, and are monitoring contacts of an employee at a plague research institute who contracted pneumonia of an "unknown" cause. Local state TV reported the woman died last week. Russian authorities stated they found no evidence that her illness was caused by any of the pathogens she worked with, but unconfirmed media reports had suggested she might have died of pneumonic plague.