Health Team

Three dead in outbreak of Rocky Mountain spotted fever, CDC warns

(CNN) -- An outbreak of the tickborne disease Rocky Mountain spotted fever has caused at least five illnesses, including three deaths, in the US since July, the US Centers for Disease Control and Prevention warned Friday.

Posted 2023-12-08T23:51:14+00:00 - Updated 2023-12-09T12:10:56+00:00

**This image is for use with this specific article only** Brown dog ticks can transmit Rocky Mountain spotted fever, but it does not spread from person to person. Photo credit: Marijan Murat/picture alliance/Getty Images/FILE

Katherine Dillinger

, CNN

(CNN) — An outbreak of the tickborne disease Rocky Mountain spotted fever has caused at least five illnesses, including three deaths, in the US since July, the US Centers for Disease Control and Prevention warned Friday.

The five cases were identified in Southern California and involved people who had traveled to Tecate, Baja California, in the previous two weeks. Four were under age 18, and three were US residents, the agency said in a health alert. All five were hospitalized, and three died.

The CDC is warning health care providers that if a patient has symptoms of Rocky Mountain spotted fever and has recently traveled to northern Mexico, they should consider starting treatment with the antibiotic doxycycline right away, rather than waiting for test results to confirm the condition.

“RMSF is a severe, rapidly progressive, and often deadly disease transmitted by the bite of infected ticks, although many patients do not recall being bitten by a tick,” the agency notes. It’s endemic in northern Mexico and in parts of the southwestern US, where it can be transmitted by brown dog ticks. It does not spread from person to person.

Signs of infection can be mild in the first few days, including a low fever, headache, stomach problems, abdominal pain, rash and swelling around the eyes and on the back of the hands. On or after about five days, someone may develop changes in mental state, coma, brain swelling, respiratory problems and multiorgan damage. It’s fatal in 5% to 10% of cases, with about half of those deaths happening within eight days of the onset of illness.

Anyone who’s traveled to northern Mexico and develops symptoms of Rocky Mountain spotted fever within two weeks of their return to the US should get medical attention right away, the CDC says. Protect against tick bites by treating pet dogs, using insect repellent and wearing protective clothing when outdoors. Check yourself and children for ticks after spending time outdoors or around dogs, and immediately remove any ticks you find.