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Lyme Disease
Lyme disease is an infection caused by a bacterium called Borrelia burgdorferi. On the west coast of the United States it is carried by the Western Black-legged tick (Ixodes pacificus) and can be transmitted through its bite. The disease is named after the town of Old Lyme, Connecticut, where some of the first cases were discovered. Lyme disease was first reported in California 1978 and is now the most common tick-borne disease in California and the United States. The disease has been reported in humans, dogs, horses, cattle, and in other wild animals, but rarely in cats.
In California, Western Black-legged ticks can be found in the Sierra Nevada foothills, generally above 500-700 feet in elevation. They're also found in the coastal range. In our counties, these ticks are commonly dispersed throughout the foothills of Yuba County and also the Sutter Buttes. In some areas of the U.S. where Lyme disease is more common (mainly the northeast), between 25 and 50% of Deer ticks carry the bacteria. Here only about 1 to 2% of the Western Black-legged ticks are infected. In some areas north of the San Francisco Bay area, infection rates in the ticks can be as high as 5%. In foothill areas of eastern Butte County, up to 1 in 4 collected ticks have been Lyme positive.
The life cycle of the tick has 4 stages: egg, larva, nymph and adult. Adult ticks are most active in the Fall, when days are cooler and humidity is higher. They set on the tips of long grass blades or on the end of shrubbery branches waiting for a host to come by (this is known as questing). Ticks do not fly, jump, or drop from trees. They wait with their legs outstretched hoping to grab onto their next host. Once they catch hold of an animal or person, the tick inserts its mouthparts into the skin of the host and slowly draws blood into its own body.
Nymphal ticks are usually present from early Spring to late Summer. They must take bloodmeals like the adult to further their growth. Nymphal ticks are responsible for most Lyme disease transmission. Ticks of all stages except the egg stage, are active and can bite whenever the temperature is over 40°F. However, most bites occur between May and August when people are more active outdoors.
If you are bitten by a tick, or think you have been, it is important to watch for early symptoms of Lyme disease. One of the first symptoms is a rash that slowly enlarges, usually at the site of the bite, from about the size of a half dollar or larger to a large circular rash with a clear area in the center. The rash may have a bull's-eye appearance. It should appear in 7-10 days and sometimes up to 30 days after the tick bites. Keep in mind that the rash will only appear in about 60% of cases. In addition to the rash, flu-like symptoms such as fever, body aches, vomiting and fatigue may be experienced. If you have been to an area where ticks occur, found a tick attached to your skin, or believe you have been bitten by a tick and have any of the Lyme disease symptoms, you should visit your physician immediately. 
When possible, recover and save the tick. To remove a tick, grasp it with a tissue or preferably with a pair of tweezers. Never handle a tick with your bare hands. Pull the tick slowly but firmly straight out from the skin. Soon the tick should come loose. Do not twist the tick or use a burning cigarette or match, Vaseline, nail polish or kerosene in an attempt to remove it. After removal, wash the area with warm soapy water. Also, if you have a rash, take pictures of it. Early recognition of Lyme disease is important.
Most Lyme cases can be successfully treated with antibiotics when started early. If the disease goes untreated, later stages of the disease can be difficult to treat. As time goes by, migratory pain in the joints, tendons, muscles and bones may occur. Long term complications may develop weeks to months later and can include disorders in the heart and nervous system. Months to years after contracting Lyme disease, intermittent joint pain (Lyme arthritis) may become chronic, causing erosion of the cartilage and bone.
You can protect yourself from Lyme disease. When outdoors in tick country, stay in open areas or on maintained trails. Avoid grassy areas. When a tick attaches to you it climbs upward searching for skin. Tucking pant legs into socks or boots can help keep ticks away from your skin. Wearing light colored clothing will help you spot ticks more easily. Use an insect repellant containing DEET on bare skin and clothing. Follow label directions closely. Pets allowed in areas where ticks are present should be thoroughly checked daily.
Other tick borne diseases are being detected in increasing numbers in the U.S. and in California. Human Granulocytic Ehrlichiosis, Babesiosis and Rocky Mountain Spotted Fever occur but are much less prevalent than Lyme disease in California.
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