The plague has killed a second person this year in the US state of Colorado.
Pueblo County announced on Wednesday that an adult had died of the disease, which was likely spread by fleas from a dead animal.
Cases of the plague are rare, and deaths are even rarer.
Across the United States an average of seven human plague cases is reported each year, although Colorado had eight on its own last year.
In June, a 16-year-old from Larimer County died of septicemic plague that wasn't detected until after he passed away.
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That's a relatively rare form of the plague that is difficult to diagnose, because it isn't accompanied by the tell-tale swelling of the glands seen in most plague cases.
The latest case is also believed to have been the same type.
