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Tick Surveillance, 2019-2020 Water Year

March 2020 update

During February 2020, laboratory staff continued surveillance for adult Ixodes pacificus (Western black-legged ticks). Ticks are collected by dragging a 1 meter square sheet of white flannel over the vegetation alongside trails. Ixodes pacificus ticks will be tested for the presence of bacteria Borrelia burgdorferi, the causative agent of Lyme disease, as well as Borrelia miyamotoi and Anaplasma phagocytophilum. Parks and neighborhoods that were surveyed in February were Butano State Park near Pescadero, Año Nuevo State Park and trails near the Costanoa resort near Pescadero, and neighborhoods in Hillsborough. Additionally, laboratory staff conducted tick surveillance at several schools adjacent to tick habitat in Portola Valley, Pacifica, and Montara. Adult tick surveillance will continue through March, and nymphal tick surveillance is planned for spring.

Park/NeighborhoodNearest City/TownNumber of Ixodes pacificus
Los Trancos WoodsPortola Valley300
Año Nuevo State ParkPescadero312
CostanoaPescadero31
Spencer LakeHillsborough153
Bluebell LaneHillsborough273
La Honda Open Space PreserveLa Honda37
Butano State ParkPescadero226
Junipero Serra ParkSan Bruno20

Laboratory staff Angie Nakano and Tara Roth met with Dr. Scott Smith’s Parasites and Pestilence class at Stanford University to survey Wunderlich Park in Woodside and educate students about ticks and tick-borne disease on February 29, 2020. The students and staff members collected ticks along trails together, observed and sorted them in the park. These ticks will be tested in the District laboratory and included as part of the seasonal tick surveillance. 

January 2020 Update

Laboratory staff began winter surveillance for adult Ixodes pacificus (Western black-legged ticks) in December. Ticks are collected by dragging a 1 meter square piece of white flannel over the vegetation alongside trails. Ixodes pacificus ticks will be tested for the presence of bacteria Borrelia burgdorferi, the causative agent of Lyme disease, as well as Borrelia miyamotoi and Anaplasma phagocytophilum. Parks and neighborhoods that were surveyed in January were Los Trancos Woods in Portola Valley, Año Nuevo State Park and Costanoa campground near Pescadero, La Honda Creek Open Space Preserve near La Honda and neighborhoods in Hillsborough.

This winter, the laboratory is also focusing on assessing the risk of tick exposures at schools. Six schools have been sampled for ticks, and more are planned to be surveyed in February.  In general, ticks have not been detected on mowed and maintained athletic fields, but can occur on surrounding vegetation along the edges of the school grounds. The unmanaged vegetation, often growing through perimeter fencing, is a potential source of tick exposure for students. Following surveillance, the District provides each school with a detailed assessment of tick risk, including areas where ticks were found.  Recommendations for schools often include landscaping or maintenance activities and tick safety education.

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