Alameda County Lyme Disease Surveillance, 2002-2003

Annual Report FY 2002-2003, Alameda County Vector Control Services

As part of the Lyme disease surveillance program, staff collect and identify ticks, and may recommend testing for tick borne disease when appropriate. Seventeen field surveys were conducted at nine locations, which resulted in the capture of 182 adult Ixodes pacificus ticks. Three of these ticks were confirmed to be Lyme disease positive by direct immuno-fluorescence (IFA). The three positive ticks represented about 1.6% positive for Lyme disease from the samples taken so far. This number is slightly below the two percent figure, which is the typical average for endemic Lyme disease areas in California. Alameda County continues to have a low incidence of locally acquired Lyme disease, mainly due to its’ isolated number of suitable habitats for the reservoir and vector.

Twenty-seven residents of Alameda County were bitten by ticks, and submitted them to the Sonoma County Public Health Laboratory for Lyme disease testing. All of the twenty-seven ticks acquired in Alameda County tested negative for the Lyme disease spirochete. Two Lyme disease case histories from the previous year were completed in 2002. The areas where these victims had frequented were surveyed several times, but none of the tick samples yielded positive results for the Lyme disease spirochete, Borrelia burgdorferi.