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Tick Surveillance Update for Water Year 2019-2020
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.

Tick Collections from parks and neighborhoods 2019-2020 Winter Season, YTD

Park/Neighborhood

Nearest City/Town

Number of Ix. pacificus

Los Trancos Woods

Portola Valley

300

Año Nuevo

Pescadero

108

Costanoa

Pescadero

16

Spencer Lake

Hillsborough

15

Bluebell Lane

Hillsborough

83

La Honda Open Space Preserve

La Honda

37

his 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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