[Valpal1]

The bacterium Yersinia pestis has jumped from rodents to humans throughout history, and Poinar said rodent reservoirs of plague still exist today in parts of Asia and Ukraine.

There are rodent reservoirs in the American West as well.

[ClearCase_guy]

Natural reservoirs seem to be prairie dogs and the like. In our SW that is the case. In Asia, the marmots that live on the steppes are a reservoir. Historically, when populations love across the steppes they risk entering a plague reservoir and then carrying the fleas to a new destination. In an urban environment, of course, the brown rat is a common way for the disease to spread to humans, but this is not considered a natural reservoir. It's a temporary vector.

Grasslands and deserts are where plague can live for centuries, biding its time.

[bigheadfred]

There are rodent reservoirs in the American West as well.

ah ya but the 'rat infestation is endemic everwhere so what is the new plague i can only guess but only my death panel knows fer sure

[Smokin' Joe]

There are rodent reservoirs in the American West as well.

Yep. Those "oh! So Cuuuute!" Prairie Dogs, for starters. (Not to mention mice and Hantavirus, but that's another bug entirely).