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CDC issues health alert for deadly tick-borne disease

Three deaths resulted from outbreak of Rocky Mountain spotted fever among people who traveled or lived in Mexican border city

Updated December 8, 2023 at 8:42 p.m. EST|Published December 8, 2023 at 6:42 p.m. EST
The community of Ejido Padre Kino seen in June. The small town in Mexico’s Baja California state has seen cases of Rocky Mountain spotted fever. (Michael Robinson Chávez/The Washington Post)
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The Centers for Disease Control and Prevention on Friday warned clinicians and the public about an outbreak of a rare but deadly tick-borne disease that hospitalized five patients in Southern California, killing three of them, after they traveled to or lived in a Mexican border city in recent months.

Rocky Mountain spotted fever (RMSF) is transmitted by the bite of infected ticks that live primarily on dogs. It’s rare in the United States but it has emerged at epidemic levels in northern Mexico, where more than 2,000 cases, resulting in hundreds of deaths, have been reported in the past five years.