Severe and Fatal Confirmed Rocky Mountain Spotted Fever among People with Recent Travel to Tecate Mexico

 CDC issued a Health Advisory through the CDC Health Alert Network to notify clinicians, health departments and the public about an outbreak of Rocky Mountain spotted fever (RMSF) among people in the United States with recent travel to or residence in the city of Tecate, state of Baja California, Mexico. The CDC Health Advisory is attached to this LINCS message and can also be accessed at the following link: Severe and Fatal Confirmed Rocky Mountain Spotted Fever among People with Recent Travel to Tecate, Mexico

• As of December 8, 2023, five patients in the United States have been diagnosed with confirmed RMSF since late July 2023; all had travel to or residence in Tecate within 2 weeks of illness onset. New Jersey has not identified any cases related to this outbreak.
• RMSF is endemic in multiple border states in northern Mexico, including but not exclusive to Baja California, Sonora, Chihuahua, Coahuila, and Nuevo León, and areas of the southwestern United States. In these regions, the pathogen (Rickettsia rickettsii) can be transmitted by brown dog ticks which are closely associated with domestic dogs in urban and peri-urban environments.
• RMSF signs and symptoms can be relatively mild and non-specific during the first 1–4 days of illness and include a low-moderate fever, headache, gastrointestinal symptoms, abdominal pain, myalgia, rash, and edema around the eyes and on the back of hands.
•      RMSF is a rapidly progressive disease and without early administration of doxycycline can be fatal within days. Healthcare providers should consider initiating doxycycline based on presumptive clinical and epidemiologic findings, and do not delay treatment pending the result of a confirmatory laboratory test. Early treatment with doxycycline saves lives.

Action Items:  

Healthcare providers:

1. Know that RMSF signs and symptoms can include fever, headache, and rash. The absence of a classical “spotted” rash does not exclude the diagnosis, particularly during the first few days of illness.
2. Consider RMSF in your differential diagnosis of patients who have reported recent travel to Tecate, Mexico or other areas of northern Mexico and subsequently develop signs or symptoms of RMSF or unexplained severe febrile illness.
3. Inquire about recent travel history and exposure to ticks or tick-infested dogs when evaluating patients with signs and symptoms suggestive of RMSF.
4. Collect whole blood and serum samples from acutely ill people for testing.  Rickettsia by molecular and serologic testing is available at commercial laboratories.
5. Do not delay treatment pending the result of a confirmatory laboratory test. Doxycycline is the recommended antibiotic treatment for RMSF in adults and children of all ages, including pregnant people.
6. Report cases of RMSF to the local health department where the patient resides. A directory of local health departments can be found at: nj.gov/health/lh/community/