New tick causes epidemic of Rocky Mountain spotted fever

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A new kind of tick is causing an epidemic of Rocky Mountain spotted fever in Mexico, and it’s threatening to spread to the U.S., researchers said Wednesday.

Rocky Mountain spotted fever is already dangerous, and the new carrier is more likely to bite people than the ticks that usually spread it, the team of U.S. and Mexican researchers said.

As ticks in general become more common as the climate warms, they’re a bigger threat, they added.

“Rocky Mountain spotted fever, caused by the bacteria Rickettsia rickettsii, is responsible for more human deaths than any other tick-borne disease in North America,” the team wrote in the journal Emerging Infectious Diseases.

Rocky Mountain spotted fever was reported in 4,269 people in the U.S. in 2016, according to the Centers for Disease Control and Prevention. It can kill up to 10 percent of victims, depending on the outbreak.