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Lyme Disease

Lyme disease is caused by certain bacteria (called Borrelia burgdorferi) that can spread from the bite of an infected western blacklegged tick.

An infected western blacklegged tick must be attached to a person and feed for at least 24 hours before it can transmit the bacteria that cause Lyme disease. 

Transmission of Bacteria that Cause Lyme Disease (Transmission cycle graphic)

click to enlarge (image)

Lyme disease may start as a mild illness that begins 3 to 30 days after a tick bite and might easily be mistaken for other common illnesses like a cold or flu. Signs and symptoms also can include a red, painless rash that may spread over time. If Lyme disease is not treated, it might develop into more severe health problems.

A person may have an allergic reaction to a tick bite that might look like a small rash near the bite area. This reaction may appear soon after the tick bite and be painful, but this is not a Lyme disease rash. 

Lyme Disease Prevention

You can help protect yourself from Lyme disease by protecting yourself from tick bites. Follow these steps to help prevent tick bites: 

Repellent can showing DEET as an active ingredient
  • Use an Environmental Protection Agency (EPA)-registered repellent to keep ticks off your skin and clothing. Use tick repellent with at least 20% DEET as an active ingredient, which is safe when used as directed and is proven to prevent tick bites. 

  • Wear clothing treated with 0.5% permethrin, which is an active ingredient designed to kill ticks. (Permethrin should never be applied to skin.)

  • While walking outside in areas where ticks live, stay in the middle of trails, and avoid grassy areas, leaf litter, contact with rocks, logs, tree trunks, and fallen branches or tree limbs in forests. Ticks are often hiding in these areas, waiting to bite and feed on an animal or person.

Environment showing where ticks are common along a trail

If you find a ti​ck crawling on you, brush it off. If you find a tick attached to your skin, remove it right away with a pair of tweezers.

  • After returning indoors from an area with ticks, thoroughly check yourself and others (including pets) for ticks during and up to three days after being outside in areas with ticks. 

  • Shower as soon as you can after leaving areas with ticks.

  • Place any clothing you were wearing while in areas with ticks in a hot dryer for 10 minutes to kill ticks crawling on clothing.

For more information about preventing tick bites and tick-borne diseases, visit the CDPH Tick-Borne Disease Prevention webpage​. ​

Learn how to remove a tick the right way!

1.      Use tweezers to grab the tick as close to your skin possible.

2.      Slowly and steadily pull the tick up and out – do not jerk or twist the tick.

3.      Clean the bite area (and your hands) with soap and water.

Remove tick with tweezers  


Learn more about Lyme disease and areas where infected ticks have been found in California.​

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