The U.S. Centers for Disease Control and Prevention is warning travelers to Baja California, Mexico, about Rocky Mountain spotted fever, a potentially fatal bacterial disease that spreads through the bite of an infected brown dog tick, which can be carried by pets. 

The warning comes after a San Diego, California, resident who traveled to Baja California died last month after contracting the disease, San Diego County Public Health Services reported. 

In addition to Baja California, RMSF has been found in the Mexican states of Sonora, Chihuahua, Coahuila and Nuevo León.

In the level 1 travel advisory issued Friday, the CDC urged travelers who develop symptoms of RMSF during travel, or within two weeks of returning to the U.S., to seek medical attention.

Symptoms of RMSF include fever, headache, and rash, which can develop two to four days after the onset of symptoms, according to the CDC. 

The disease can progress quickly in infected patients and can become deadly if not treated early with the antibiotic doxycycline. Children under 10 years of age are five times more likely to die from RMSF, the CDC said.

San Diego County public health officials said the last time someone from San Diego died from RMSF was in 2014.