San Mateo County: Lyme Disease

Entomology Report April 2008, San Mateo County Mosquito and Vector Control District

The district continues to survey for Lyme disease in San Mateo County recreational parks. Disease-causing spirochetes have been detected for the first time in ticks at two additional parks this year: Water Dog Lake in Belmont and Huddart Park in Woodside (refer to table). The average prevalence of infection for San Mateo County is between 1 and 3% for adults and nymphs.

Park/Trail     Tick Stage  # Collected  Positive  Prevalence
Huddart Park
Bay Tree       Nymph            91          0         0
Richards Rd    Nymph            21          0         0
Chickadee      Nymph            84          3         3.6%*
Waterdog Lake
Lake           Adults          114          1         0.8%

*Prevalence at this site is preliminary due to small sample size.