Three Californians die after catching Rocky Mountain spotted fever from ticks in Mexico

The Centers for Disease Control and Prevention confirmed Friday the deaths of three people in California from Rocky Mountain spotted fever.

They caught it in Tecate, Mexico, near San Diego, the CDC said. The disease is spread by bites from dog ticks that are brown.

From July to December, five patients who went to Southern California hospitals were found to have the disease. All of them had just been to Tecate, the CDC said.

Four of the patients were under 18 years old. Three were Americans, two Mexicans. The CDC did not specify the identifying characteristics of the three patients who died.

The disease starts with a headache, fever, gastrointestinal problems, rash and swelling around the eyes and hands, and worsens over time.

Patients can develop more severe symptoms such as an altered mental state, coma, cerebral swelling, multiorgan damage, compromised breathing and cell death, the CDC explained.

Half of all Rocky Mountain spotted fever fatalities occur with eight days of disease symptoms starting.

In Mexico, the fatality rate can exceed 40%, according to the CDC, with the disease endemic in the northern Mexican states of Baja California, Chihuahua, Coahuila, Nuevo Leon and Sonora.