Bubonic Plague in the Modern World

10. History of Plague in the United States

While common in Europe in the Middle Ages, the plague was introduced to the United States much later, in the 1900s. Rat-infested steamships from Asia were the catalyst for epidemics in port cities. The last widespread outbreak was in Los Angeles in 1924. From there, the disease spread to rural rodents and across the western United States. In modern times, one to 17 cases of plague are reported each year, most occurring in southern Oregon, California, western Nevada, southern Colorado, northern New Mexico, and northern Arizona. Over 80 percent of these are the bubonic form.