Lyme Disease. Ecology and Tick-borne Disease Prevention

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1 Lyme Disease Ecology and Tick-borne Disease Prevention

2 What is a vector? any animal capable of transmitting the causative agent of human disease or capable of producing human discomfort or injury California Health and Safety Code

3 What are ticks? Ticks are blood feeding arachnids (8 legs) 47 species in California Only 8 known to bite humans 2 major families of ticks: Ixodid (hard), and Argasid (soft) People mostly encounter hard ticks. Ticks are vectors of many diseases Hard (Ixodid) tick Soft Argasid tick

4 Locally Common Ticks

5 Lyme Disease Basics Lyme disease is caused by a spiralshaped bacteria (spirochete) called Borrelia burgdorferi In California, the Western blacklegged tick (Ixodes pacificus) is the only vector of Lyme disease Borrelia burgdorferi Ticks pick up the spirochetes from biting infected rodents Ixodes pacificus

6 Lyme Disease Symptoms Bulls eye rash: Large, non itchy, 7 10 days after bite Small, immediate, itchy rash is NOT a sign of LD There are a wide range of symptoms, including: Localized: Flu like symptoms Disseminated: Neurological issues, arthritis, facial palsy

7 How common is Lyme disease? Lyme disease is the most common vectorborne disease in the U.S.: ~30,000 cases/year reported to CDC. CDC study: more likely ~300,000 cases/year 96% from 14 Northeast and Midwest states California: ~100 cases reported/year Lyme Disease Cases in Marin County 8 Marin County: ~3 cases reported/year

8 When is Tick Season? Adult Tick Habitat Nymphal Tick Habitat

9 Lyme Disease = not infected = infected Larva Rodent Nymph

10 Lyme Disease = not infected = infected Larva Rodent Nymph

11 Lyme Disease and Deer? The exact relationship between deer and Lyme disease risk is complicated Ticks feed on deer, but do not pick up the Lyme spirochetes from them Complete exclusion of deer may reduce ticks Partial reduction of deer may or may not affect tick density in the environment Deer infested with adult ticks

12 District activities Unlike our mosquito program, we do not conduct tick control. Acaricides may affect a wide variety of invertebrates. We provide public education on tick safety We conduct tick surveys to assess and track disease prevalence in recreational areas We investigate locally acquired vectorborne disease cases We collaborate with other agencies on tick research Flagging for ticks

13 Landscape management While many Northeastern U.S. Lyme infections are acquired near the home, most California cases stem from tick bites in recreational wilderness areas Shady woodland edge and leaf litter habitats are tick hot spots. Good practices include: Keep grass mowed Remove leaf litter, brush, and weeds at edge of lawn Open up land to direct sun exposure Discourage rodent activity. See the Tick Management Handbook for more information (available online) Flagging for ticks

14 Avoiding Tick Bites Before entering tick habitat, take the following precautions: Use repellent containing DEET to exposed skin. Consider treating clothes/personal outdoor equipment with a product containing permethrin. Wear light colored clothing (easier to spot ticks). Wear long pants, long sleeves, and long socks when possible. While in tick habitat: Stay on trails (usually more adult ticks on uphill side of trails). Avoid contact with nymph habitat (leaf litter, logs, tree trunks, mossy rocks). Periodically check for ticks on people and animals. After exiting tick habitat: Wash all clothes in hot water and dry on high heat. Shower after coming indoors and carefully check for ticks. Properly remove any attached ticks immediately. Be trail smart!

15 Removing a tick Do not squish, burn, smother or twist ticks. Ideally, use tweezers to grasp the head of the tick as close to the skin as possible, and pull straight out. Use gloves, tissue or another barrier if you must use your fingers to remove the tick. Wash your hands and the bite site with soap and water after tick removal. Apply an antiseptic to the bite site.

16 If bitten, CDPH recommends Promptly/properly remove tick and clean bite site with soapy water If you experience any symptoms 1 30 days after bite, consult your physician and be sure to let them know you have been bitten by a tick CDPH does not recommend that ticks be tested for Lyme disease for individual clinical management for the following reasons: 1. The results may not be timely 2. A positive result does not necessarily mean the patient has contracted Lyme disease 3. A negative result does not necessarily mean the person has not been exposed to the bacteria because there is the possibility that another infected tick went undetected If you would like to get a tick tested (for a fee) Sonoma County Public Health (707) Marin Public Health (415)

17 Need more information? Tick Management Handbook (just type tick in search queue)