About Tick-borne Diseases
Tick-borne diseases are diseases and conditions that are transmitted to humans and other animals through the bite of an infected tick. Tick-borne diseases can include:
We have a special tick surveillance program focused on collecting and testing ticks from parks and other locations in the county and test them for diseases like Lyme disease and other tick-borne diseases.
What are the most common ticks in the County of Santa Clara?
- The Western blacklegged tick (Ixodes pacificus)
- They can transmit Lyme Disease and Hard Tick Relapsing Fever (HTRF).
- Adults are mostly active November to March and nymphs from March to May.
- They generally live in oak woodlands.
- The Pacific Coast tick (Dermacentor occidentalis).
- They can transmit Pacific Coast Tick Fever, tularemia, and Rickettsiosis.
- They are mostly active from March to June.
- They generally live in shrub lands.
- The American dog tick (Dermacentor variabilis) which can transmit tularemia and RMSF.
- They are mostly active from May to August.
- Primarily live in grasslands and forest edges.
To learn more about ticks, visit our tick informational page.
What tick information do we collect?
We record the following information for each tick:
- Date of collection.
- Location of collection (for example park name and trail name).
- Species (type).
- Sex.
- Stage of development (for example larva, nymph, or adult).
This is done to:
- Record the time of year the different type of ticks are active.
- Record changes in tick population (numbers).
- Inform you about the risks associated with ticks.
How do we collect ticks?
There are few different methods we use to collect ticks.
- Flagging: a 1 meter by 1-meter light-colored flannel cloth is attached to a pole and swept along small shrubs, grasses, and the ground near them. This method is used for ticks that quest
- Dragging: a 1 meter by 1-meter light-colored flannel cloth is attached to a pole that is held behind someone and dragged across the ground. This method is used for ticks that quest
- Carbon Dioxide Bait Trap: Dry ice (a solid form of carbon dioxide) is placed on a light-colored flannel cloth where ticks are to be collected. This stays in the area for a couple of days. This method is used for ticks that actively go after a host.
Once ticks are collected, we bring them back to our District lab and test Western Black-legged ticks for Lyme disease and HTRF and Dermacentor ticks for Pacific Coast Tick Fever.
How is testing done?
- The ticks are placed in vials with glass beads. The glass beads break up the hard bodies of the ticks so that the DNA (protein) of pathogens inside the ticks is released. This is what we refer to as DNA extraction.
- PCR amplification is used to make many copies of the proteins so that the pathogens can be detected.
