San Mateo County: Lyme Disease Surveillance

Entomology Report January 2005, San Mateo County Mosquito Abatement District

Surveys for western black-legged tick, Ixodes pacificus, continued through January. This tick is a vector of the Lyme disease bacteria, Borrelia burgdorferi. Adults of this species feed on large mammals such as deer, humans and dogs. They are abundant along recreational trails from November through May. Ticks have been collected at 6 sites thus far. Two out of 147 ticks collected in Los Trancos Woods this year (1%) tested positive for the bacteria.