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The Marin Sonoma Mosquito and Vector Control District Urges Residents to Take Precautions Against Ticks 

Cotati, CA-  May 26, 2024-According to the U.S. Centers for Disease Control and Prevention, Lyme disease is the most prevalent vector-borne illness in the United States. Officials from the Marin/Sonoma Mosquito and Vector Control District (District) are encouraging the public to take preventive measures before, during, and after being in tick habitat to protect against ticks and tick-borne diseases. 

Ticks are active year-round in Marin and Sonoma counties. The most commonly found ticks in Marin and Sonoma counties are the American dog tick, Pacific Coast tick, and the western black-legged tick. All three of these ticks can transmit a variety of tick-borne diseases, but only the western black-legged tick can transmit Lyme disease. 

Adult western black-legged ticks (Ixodes pacificus) are commonly found in the fall through early spring, while the tiny nymphs are most active in the spring and early summer. Both stages of this tick can transmit Lyme disease. 

 "Tick nymphs are extremely small, about the size of poppy seeds, and are particularly active during this time of year," explained Dr. Kelly Liebman, the Scientific Programs Manager for the Marin/Sonoma Mosquito and Vector Control District. "It's crucial to  thoroughly check yourself and your pets for ticks after spending time outdoors." 

Ticks can be found in grassy, brushy, or wooded areas, especially along sides of trails. Adult ticks wait on the tips of vegetation for people or other animal hosts to pass by, while nymphs are commonly found in leaf litter, on logs, and on mossy rocks. 

The District regularly conducts tick surveillance in various parks and public lands across Marin and Sonoma counties. Collected ticks are tested for Borrelia burgdorferi, the bacterium responsible for Lyme disease. According to collection data, the average infection rate of adult western black-legged ticks is 1.78 % and the  average infection rate of the nymphal stage is 4.11%. 

Follow these three simple steps to help minimize exposure to ticks and tick-borne diseases: 

  • REPEL - Apply an EPA registered insect repellent such as DEET (at least 25%), IR3535, oil of lemon eucalyptus (OLE) or picaridin. Treat clothing and equipment with permethrin. Wear light-colored long-sleeved shirts and long pants. 
  • INSPECT - Periodically conduct tick checks on yourself, your children, and your pets during and after being in tick habitat. 
  • REMOVE - Remove attached ticks promptly and correctly. Use a fine-tipped tweezer, grasp the tick as close to the skin as possible, and pull straight out. Remove clothing and place in the dryer on high heat for 10 minutes to kill ticks before washing. Showering after being outdoors will help identify attached ticks and wash off those that have not yet attached themselves. 

Lyme disease may produce a wide range of symptoms. If you believe you have been exposed to the bacterium that causes Lyme disease, contact your health care provider. If Lyme disease is left untreated, the infection may spread to other parts of the body, with many patients experiencing severe pain and swelling associated with arthritis. Untreated patients may also develop chronic neurological problems. 


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