Story highlights The plague has been in the United States since about 1900

The U.S. West has one of the highest concentration of plague-carrying animals in the world, but few human cases

A new model predicts where "significant plague risk" could be

(CNN) Scientists have created a predictive map that may help identify areas of the United States likely to see cases of plague in the near future.

Yersinia pestis, the bacterium that causes the plague, has been around the United States since at least 1900. In fact, the American West still has one of the largest concentrations of plague -carrying animals in the modern world, even though there are far fewer cases of humans catching the disease than in countries with fewer infected animals. Madagascar, Peru, India and the Democratic Republic of Congo have seen the most cases, with the Congo topping the list at more than 10,000 cases from 2000 to 2009

The plague came to the West Coast via rodents that hitched rides with early industrial ships during the third major pandemic that started in China . These Chinese pests mingled with urban harbor rats. The fleas that bit these rats bit humans, causing the disease to spread. The last plague epidemic in the United States was in Los Angeles in 1924 to 1925. It killed only about a dozen people.

Why we still have plague

Thankfully, with the invention of antibiotics and modern supportive care, a disease that wiped out 60% of the European population in the 14th century has turned into one that you can recover from if caught and treated early.

Read More