Lyme Disease

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About Lyme disease
Prevention
Symptoms and treatment
Lyme disease in San Diego County
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About Lyme disease

Lyme disease is caused by a bacterium and spread when an infected tick attaches and feeds on a human or animal. Although Lyme disease is reported across the U.S. and in most counties in California, it is rare in San Diego County.

In California, Lyme disease is spread by the bite of the Western blacklegged tick (Ixodes pacificus), which is mostly found in the coastal regions and along the western slope of the Sierra Nevada mountain range. The adult female is reddish-brown with black legs, about 1/8-inch-long while males are smaller and brownish-black. In San Diego County, these ticks are more prevalent during the rainy season, October – April.

Ticks in the larval, nymph, and adult stages attach to hosts to take a blood meal. If the host is already infected with Lyme disease from a previous tick bite, the tick will likely become infected as well. When the tick attaches to its next host, the tick can transmit the disease to the new host.

comparison in size of different tick life stages

Prevention

These tips will help protect you from spotted fevers:

Stay on paths and trails
- Ticks are found in grassy, brushy areas and on the plants that line trails
- Keep pets on leash and on trail while hiking
Dress for protection when outdoors
- Wear long-sleeved shirts and long pants
- Wear light-colored clothing that shows ticks crawling on you
Use Environmental Protection Agency (EPA)-registered insect repellent
- Look for repellent containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), or para-menthane-diol (PMD).
- Apply repellent to clothing and exposed skin; follow the directions carefully
Check yourself for ticks
- After you are in a tick-infested area, examine yourself and your companions for ticks and remove them right away
- If you remove a tick within 24 hours, you can greatly reduce your chances of getting Lyme disease.
- Tick nymphs may be very small, about the size of a poppy seed

Symptoms and treatment

Symptoms

A small bump or redness at the site of a tick bite that occurs immediately and resembles a mosquito bite is common. This irritation generally goes away in 1-2 days and is not a sign of Lyme disease.

Early signs and symptoms (3 to 30 days after tick bite)

Bull's Eye Rash (see image at right - common in most but not all cases, may appear differently on darker skin tones)
Flu-like symptoms
Aching joints

Later Signs and Symptoms (days to months after tick bite)

Severe headaches and neck stiffness
Facial palsy (loss of muscle tone or droop on one or both sides of the face)
Arthritis with severe joint pain and swelling
Intermittent pain in tendons, muscles, joints, and bones
Heart palpitations or an irregular heartbeat
Episodes of dizziness or shortness of breath
Shooting pains, numbness, or tingling in the hands or feet

Treatment

Lyme disease is rarely fatal. If the disease is found early enough, treatment with antibiotics can cure the infection and prevent further problems. In the late stages of Lyme disease, symptoms should improve from use of antibiotics, but effects may persist in the human body for years and may never go away completely.

Lyme disease in pets

Lyme disease has been diagnosed in dogs, cats, horses, goats, cattle, and several wild animals. While some animals may display no symptoms, others may develop fever, loss of appetite, painful joints, fatigue, and vomiting. If left untreated, the disease can damage the eyes, heart, kidneys, and nervous system. Check your pets for ticks and consult your veterinarian if you think they may have been infected.

Lyme disease in San Diego County

The Vector Control Program routinely collects, identifies, and tests ticks for lyme disease and other tick-borne pathogens. If tests come back positive, results are posted to our website.

No ticks have tested positive for the bacteria that causes Lyme disease over the past 5 years.