Lyme Disease


Cause: Spiral shaped bacterium (spirochete) Borrelia burgdorferi.

Illness and treatment: There are skin and systemic “flu-like” symptoms, such as fatigue, headache, fever, and muscle and joint aches. The classic symptom is a target-shaped (bull's-eye) rash. Joint, nervous system, or heart complications can occur.

Sources: Only certain hard tick species transmit Lyme disease from the rodent or deer reservoirs. In the Pacific coastal United States, the western blacklegged (or deer) tick (Ixodes pacificus) is the primary vector. These ticks live in heavily-forested or dense brushy areas, not open areas. It is likely these ticks must attach for at least 24 hours to transmit the disease.

Prevention: During outdoor activities in endemic areas avoid tick bites by wearing appropriate clothing and using repellents. Check the body for ticks. If bitten by a tick, be alert for "flu-like" symptoms or rash over the next month. If symptoms develop, contact a health care provider.

Recent Washington trends: Each year there are 7 to 23 reports. Most Washington cases are the result of a tick bite out of state. The few endemic cases have tick exposures predominantly on the west side of the Cascade Mountains, reflecting the distribution of the Ixodes ticks.

Purpose of Reporting and Surveillance

  • To determine the incidence of Lyme disease, the degree of endemicity, and potential risk of contracting Lyme disease in Washington State
  • To identify endemic geographic areas within Washington State
  • To educate people about how to reduce their risk of infection

Legal Reporting Requirements

  • Health care providers and Health care facilities: notifiable to local health jurisdiction within 3 business days
  • Laboratories: notifiable to local health jurisdiction within 24 hours; submission on request – specimen associated with positive result, within 2 business days.
  • Veterinarians: animal cases notifiable to Washington State Department of Agriculture on a monthly basis (see:
  • Local health jurisdictions: notifiable to the Washington State Department of Health (DOH) Communicable Disease Epidemiology (CDE) within 7 days of case investigation completion or summary information required within 21 days