San Jose Mercury News ·
New report flags Lyme-positive ticks on Sonoma County hiking trail
Ticks collected along Umbrella Tree Trail at North Sonoma Regional Park came back positive in pooled tests for Borrelia burgdorferi — the bacterium that causes Lyme disease — at a minimum infection prevalence of 7.41%, meaning two pooled samples tested positive out of 27 adult ticks tested in the Marin/Sonoma Mosquito & Vector Control District’s recently released 2025 Vector Surveillance Report.