The District collects western black-legged ticks, Ixodes pacificus, to test for the presence of Borrelia burgdorferi (the bacterium that causes Lyme disease) and Borrelia miyamotoi. The district also collects Dermacentor spp. ticks for collaborative research efforts and disease case follow ups.

Collecting ticks

District staff collect ticks at various parks and other publicly owned lands in Marin and Sonoma counties by a method called flagging. Ticks are sorted by species, gender and collection location, and are frozen until they are tested. 

  Testing ticks

• Western black-legged ticks (I. pacificus) are tested for the presence of B. burgdorferi and B. miyamotoi DNA using Real-Time PCR technology.  
• The 12 year average minimum infection prevalence (MIP) for adult ticks in Marin and Sonoma counties is 1.92%. 
• The 12 year average MIP for nymphal ticks in Marin and Sonoma counties is 4.34%. 

• Marin county-12 year average MIP for adult ticks 2.08%; nymphs 4.32%
• Sonoma county-12 year average MIP for adult ticks 1.80%; nymphs 4.36%
• The District collaborates with other agencies and educational institutions on various research projects related to ticks and tick-borne disease. 

Additional resources

California Department of Public Health Tick-Borne Diseases

CDC “Surveillance for Ixodes pacificus and pathogesn found in this tick species in the United States”