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Lyme Disease

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Western Black-legged Tick

Prevention Tips And Ways To Protect Yourself

What is Lyme Disease?
Lyme disease is a bacterial disease spread by the bite of a Western Black-legged tick in California.  The effects of the disease may persist in the human body for several years.  Lyme disease has been reported from many areas of the country, including most counties in California.  It is quite rare in San Diego County and is usually found in the rural areas.

The Western Black-legged Tick
In California, these ticks are most common 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. Males are smaller and all brownish-black.

L-R: Adult Female, Adult Male, Nymph, Larva

Spread of Lyme Disease
Ticks in the larval, nymph and adult stages attach to hosts in order 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. Tick-to-human transmission of Lyme disease occurs after several hours of feeding.

Human Symptoms
Stage 1:

  • Bull's Eye Rash (common in most but not all cases)
  • Flu-like symptoms
  • Joint aches

Stage 2:

  • Patients may have pain in joints, tendons, muscles and bones
  • Multiple rashes
  • Problems involving the heart and nervous system

Stage 3: (If the patient is not treated, he/she may progress to this stage weeks to months after infection).

  • Swelling and pain of one or more joints ( typically large joints like the knee)
  • Neurological symptoms including fatigue, personality changes, and difficulty sleeping and concentrating  

Lyme disease is rarely fatal.

Preventing Lyme Disease  
You can seriously reduce the risk of Lyme disease by following the tips below:

  1.  Know how to identify the Western Black-legged Tick:
  • The nymph is about the size of a poppy seed and the adult is around 1/8 inches.  Females are larger than males.

2. Know where ticks occur:

  • Stay on trails and avoid trail margins, brush and grassy areas in places where ticks are found

3. Dress Correctly:

  • Wear long-sleeved shirts and long pants
  • Tuck pant legs into socks
  • Wear light-colored clothing so ticks can be seen if they are crawling on you
  • Examine yourself for ticks and remove them right away

4. Use repellents containing DEET or Picaridin:

  • Apply insect repellent to clothing and exposed skin; follow directions careful

Treatment Of Lyme Disease
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 may not go away completely.

Tick Removal
If you find an attached tick, it is important that you remove it right away. Follow these directions for proper tick removal:

  1. Grasp the tick with tweezers as close to your skin as possible.
  2. Pull the tick straight out, using a firm, steady motion. Do not twist, squish or burn an attached tick.
  3. Apply an antiseptic to the bite area after removing the tick. Wash your hands with soap and water.
  4. Save the tick for identification. Submit the tick to your doctor or contact the Vector Control Program.
  5. If redness or pain develops at the tick bite site or the tick cannot be removed, consult your doctor.

Removal of a Tick with Tweezers

Lyme Disease in Pets
Lyme disease has been diagnosed in dogs, cats, horses, goats, cattle and a number of 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.

Life Cycle Of The Western Black-legged Tick
The life cycle of a tick takes 2 years to complete, and has four stages:

  1. Egg: Adult female ticks lay eggs on the ground in the spring.
  2. Larva: Eggs hatch into larvae. They attach to a host, begin feeding and over a few days, swell up with blood. They feed on small mammals, deer and birds.
  3. Nymph: After feeding, most larvae drop off their hosts and transform into nymphs.  Nymphs then attach to their host and feed for 4 to 5 days, while swelling with blood. They feed on rodents, small mammals, birds and humans.
  4. Adult: Once swollen, nymphs drop off their host and molt into an adult.  Adult ticks climb up to 3 feet above ground on the tips of grasses and shrubs and wait for new hosts. Ticks do not jump or fly.  They attach onto their hosts by climbing onto them as they pass by.  Adult ticks feed on deer, humans, dogs, cats, horses and other domestic animals.

In San Diego County the Western Black-legged ticks are most commonly found during the rainy season, October-April.

For More Information On 
Lyme Disease Or Other Vectors Contact: 
(858) 694-2888  
vector@sdcounty.ca.gov
 Vector Control Program