|A map shows reported cases of human plague in the United States from 1970 to 2012.|
Nearly all cases occur in the western U.S., for reasons that are not entirely understood.
Plague first came to the U.S. in 1900 via rats on steamships from Asia.
Lawrence said ... Is there a potential carrier species that has a habitat range that resembles the red area? ifthethunderdontgetya™³²®© said ... Mormons?