"Plague, which arrived in the United States through San Francisco in 1900, has persisted in rodents in the American Southwest. Their [rodents'] fleas may carry the Yersinia pestis [that is the name of the bacterium, the singular form; plural: bacteria] bacterium, which causes the illness, and the parasites [fleas] sometimes bite pets and humans.
"Last week, New Mexico reported its third human case of plague this year. (The once-unstoppable disease can be cured with antibiotics if it’s caught early.)
Note:
(a) prairie dog https://en.wikipedia.org/wiki/Prairie_dog
(section 1 etymology)
(b) There are plague vaccines for human injection, but US Center for Disease Control and Prevention does not recommend it (for humans) because the disease is rare among humans