A 6-Year Analysis of Tick Surveillance in San Mateo County

Entomology Report February 2007, San Mateo County Mosquito Abatement District

% Infection of I. pacificus in San Mateo County Parks
Location             # Ix. pacificus Tested  % Infection
Pulgas Ridge                    60                3.3
Los Trancos Woods              733                2.5
Huddart Park                   140                2.1
Big Canyon Park                507                1.8
Crystal Springs Trail          556                1.6
San Pedro Valley Park          333                0.9
Laurelwood Park                428                0.7
Edgewood Park                  195                0.5

An analysis of tick surveillance data from 2002 through February 2007 in San Mateo County was performed. Adult Ixodes pacificus ticks have been collected from 11 parks. Thus far Lyme disease spirochetes have been detected in ticks from 8 parks (Big Canyon Park, Crystal Springs Trail, Edgewood Park, Huddart Park, Laurelwood Park, Los Trancos Woods, Pulgas Ridge, and San Pedro Valley Park). The prevalence of infection in ticks at these parks ranged from 0.5% - 3.3%. Ticks collected from Costanoa, Sweeney Ridge, and Water Dog Lake have not yet tested positive for Lyme Disease spirochetes.

Previous related entries:

Tick Surveillance in San Mateo County, January 2007, January 2007
Tick Surveillance in San Mateo County, December 2006, December 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, June 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, April 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, March 2006
San Mateo County: Lyme Disease Surveillance 2006, February 2006
San Mateo County: Lyme Disease Surveillance 2006, January 2006
San Mateo County: Lyme Disease Surveillance, November/December 2005
San Mateo County: Lyme Disease Surveillance, October 2005
San Mateo County: Lyme Disease Surveillance, January 2005

Tick Surveillance in San Mateo County, January 2007

Entomology Report January 2007, San Mateo County Mosquito Abatement District

In January, tick collections were made from Edgewood Park, (Redwood City), Huddart Park, (Woodside), Laurelwood Park (San Mateo), Water Dog Lake (Belmont), and Costanoa (Pescadero). So far, a total of 827 ticks from 5 parks were collected. Evidence of infection with Lyme disease spirochetes was detected for the first time in Edgewood Park (1 positive) and Laurelwood Park (3 positives).

The District was contacted from residents of Belmont (near Water Dog Lake) and Pacifica with concerns about ticks in their neighborhoods. In Pacifica, questing ticks can be found in the open spaces between homes. In Belmont, western black-legged ticks were found inside a home adjoining the open space around Water Dog Lake, presumably brought in by the family cat. These instances illustrate the need to watch out for ticks even if one does not engage in outdoor activities at this time of year.

Previous related entries:

Tick Surveillance in San Mateo County, December 2006, December 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, June 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, April 2006
San Mateo County: Lyme Disease Surveillance Winter/Spring 2005-06, March 2006
San Mateo County: Lyme Disease Surveillance 2006, February 2006
San Mateo County: Lyme Disease Surveillance 2006, January 2006
San Mateo County: Lyme Disease Surveillance, November/December 2005
San Mateo County: Lyme Disease Surveillance, October 2005
San Mateo County: Lyme Disease Surveillance, January 2005

San Mateo County: Results of the Efficacy of Suspend on Density of Ticks Along a Recreational Trail

Entomology Report January 2007, San Mateo County Mosquito Abatement District

The insecticide Suspend (Deltamethrin) was evaluated for its ability to control Dermacentor ticks along a recreational trail in San Mateo County. Three days post treatment, showed a 98% decline in ticks. One week post treatment resulted in 100% control and after seven weeks the trail was still at a density of 0 ticks. This study showed that the material is very effective in controlling Dermacentors. In the future, another study will be performed to evaluate the efficacy of Suspend on Ixodes pacificus ticks.

Previous related entries:

San Mateo County: Trial Application of Suspend for Control of Ticks, May 2006
San Mateo County: Trial Application of Suspend for Control of Ticks, April 2006

San Mateo County: Results of the Evaluation of Trailside Mowing as a Tick Control Method, January 2007
San Mateo County: Effects of Mowing on Summer Tick Populations, June 2006