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Tick Surveillance, Water Year 2023-2024

Tick Collections from parks, 2023-2024 Season (November 2023 through June 2024)

Laboratory staff continued winter surveillance for adult Ixodes pacificus (Western black-legged ticks) in January. Ticks are collected by dragging a one-meter square sheet of white flannel over the vegetation alongside trails: a technique called “flagging.” Ixodes pacificus ticks will be tested for the presence of Borrelia burgdorferi (the causative agent of Lyme disease), as well as Borrelia miyamotoi (the agent of hard-tick relapsing fever) and Anaplasma phagocytophilum (the agent of granulocytic anaplasmosis).

Our efforts in January were directed toward parks that had not previously undergone tick surveillance. Notable locations included Sign Hill Park, Hillside Park, Garret Park, Twin Pines Park, and Mussel Rock Park. Many of these were smaller than our usual sites, but they were prioritized as they represented unexplored territories for our tick monitoring program. It's worth noting that few ticks were discovered at these locations.

Additionally, we collaborated with personnel from the Centers for Disease Control and Prevention (CDC) to conduct tick collection activities at various sites, including Windy Hill Open Space Preserve, Skyline Open Space Preserve near Portola Valley, Edgewood Park, Pulgas Ridge Open Space Preserve in Redwood City, San Pedro Valley Park in Pacifica, and Hidden Canyon Park in Belmont. The primary aim of this collaboration was to gather Ixodes pacificus ticks for their research purposes, particularly for prospective testing for the Borrelia miyamotoi bacteria.

District staff also continued inspecting front yards and backyards of homes for ticks as part of an ongoing study of ticks on residential properties. This season, the District is focusing on homes in Hillsborough, but will check residential properties in other areas as well, upon request.

Photograph of a person squatting on the ground in the forest while looking closely at a white sheet of cloth.
Vector Ecologist Theresa Shelton checks a sampling flag for ticks. 


Tick Collections from parks and neighborhoods, 2023-2023 Season (through January 2024)

Park/NeighborhoodNearest City/TownNumber of Ix. pacificus adults
Garrett ParkRedwood City3
Sign Hill ParkSouth San Francisco0
Twin Pines ParkBelmont0
Hillside ParkDaly city0
Hillsborough southHillsborough114
Mussel RockDaly City1

Page last reviewed February 14, 2024

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