A rare outbreak of Rocky Mountain spotted fever has left three people dead and three others infected in California, with all cases traced back to tick exposure in Tecate, Mexico.
The California Department of Public Health reported six cases between July 2023 and January 2024, marking an unusual spike compared to the state's typical average of one case annually.
The infected individuals included three children under five years old, two teenagers, and a 65-year-old man. All had visited or lived in Tecate, Mexico within eight days before showing symptoms. Three patients recovered after antibiotic treatment, while three others succumbed to complications including heart and respiratory failure.
"The rapid progression from moderate illness to life-threatening disease demands immediate treatment once RMSF is suspected," stated the Centers for Disease Control and Prevention (CDC) in their recent report.
RMSF, caused by bacteria transmitted through tick bites, initially presents with fever, headache, nausea, and muscle pain. A distinctive red spotted rash typically develops days after the fever begins. Without prompt antibiotic treatment, the disease can cause severe organ damage and death in 13 to 25 percent of cases.
While northern Mexico has historically seen RMSF cases due to brown dog ticks carried by free-roaming dogs, Tecate had not previously been identified as a high-risk area. This outbreak reveals a new danger zone near the U.S.-Mexico border.
The CDC emphasizes the critical need for healthcare providers on both sides of the border to recognize and quickly treat potential RMSF cases with antibiotics, particularly given the disease's rapid progression and potentially fatal outcome.
This cluster of cases represents a notable increase for California, which typically sees very few RMSF infections compared to southeastern and south-central U.S. states, where the disease is more common.