From the County of Santa Clara Vector Control District, via Facebook:

Pacific Coast Tick Fever (PCTF) is a newly emerging tick-borne disease in Northern California, transmitted by the Pacific Coast tick (Dermacentor occidentalis).

Symptoms of PCTF include fever, headache, and an eschar formation [dead tissue] at the tick bite site.

The first case of PCTF within Santa Clara County was reported in 2011 and the second human case was reported in August 2021, both in the same geographic area.

Over a six-month period, the District conducted monthly sampling at the resident’s home and surrounding parks within a one-mile radius. The ticks were collected, identified, and tested for the presence of the pathogen. The pathogen was detected in 5.2% (7 out of 134) of the ticks tested.

The District will continue to monitor for the presence of PCTF and reminds the public to take proactive steps to protect themselves from tick bites by staying in the middle of trails, wearing long sleeves and pants when hiking, and checking themselves, children, and pets after spending time in tick habitat.