Dr Green Gives Tips for Avoiding Bites by Ticks

Take a few precautions and be vigilant if you're going hiking or camping in an area where ticks may be found.

Lyme disease, carried by the Western black-legged tick, is relatively rare in Sonoma County, but an infection, left untreated, can lead to chronic illnesses that weaken the heart and the nervous system. Other kinds of ticks can also carry diseases that mimic malaria or cause chronic rashes, fever, aches and pains.

Ticks are tiny, eight-legged bugs related to spiders. When hungry, they perch on tall grass or hide in leafy areas and pounce on an animal or person who walks by. They bite through the skin with their hook-like mouthparts and secrete a cement-like substance that attaches them tightly as they feed.

Of 81 cases of Lyme disease statewide in 2006, seven were reported in Sonoma County, according to the state Department of Health Services.

Because of a biological fluke, Lyme disease is not common in California: Fewer ticks here are infected. About 5 percent of black-legged nymphs in Sonoma County carry the disease, compared to 60 percent in high Lyme-disease areas in the Northeast.

The infection rate is different because the preferred host animal is different. In the Northeast, the tick's favored host is the white-tailed deer. One tick infects a deer and any tick that bites the deer thereafter picks up the bacteria and becomes a carrier, said Gary Green, an infectious disease specialist at Kaiser Medical Center in Santa Rosa.

The reverse is true in California, where the tick's favored host is the Western fence lizard. When a Lyme-disease carrying tick bites the lizard, the lizard's blood produces a chemical that disinfects the lizard and the tick as well. Lyme-disease carrying ticks that bite lizards lose their ability to transmit the disease, Green said.

Lyme disease remains a threat only because another tick species, which does not bite humans, transmits it to wood rats. The black-legged tick also bites wood rats, and picks up the Lyme disease bacteria from the rat blood.

Avoiding Ticks

To help prevent tick bites:

• Avoid areas where ticks live. Walk in the center of forest trails, don't take shortcuts through wooded areas, don't sit on the ground. Avoid contact with logs, tree trunks and fallen branches or tree limbs in forests.
• Wear light-colored clothing so ticks can easily be seen. Wear long pants and long-sleeved shirts. Tuck pant legs into boots or socks and tuck shirts into pants.
• Repellents with DEET are effective and can be applied to the skin. Permethrin is good, but should only be used on clothing. Green recommends soaking your usual hiking clothes -- socks, pants and shirts -- in permethrin-based repellents the day before you go so they'll have time to dry. "It will stay in the clothes through three or four washings," Green said. "It's very safe to do, but don't put it directly on the skin."
• Inspect your clothes and skin regularly while you are in tick habitat. Make a more thorough check when you get home and have someone search the areas you can't see, such as the hairline at the back of the neck. "We do a tick check every time we hike and every time we go out picnicking," Green said.

Check your entire body, especially the hairline, armpit, back of knees and groin, each day for up to three days after returning from tick habitat. By this time the tick will have gorged on blood and be easier to find or you may see a swelling from a tick bite that was not noticeable before. Checking bed linens after being in tick-infested areas may also help identify an engorged tick that has completed feeding.

Inspect your pets as well. Pets also can suffer from tick-borne illnesses and may bring ticks in from outside that put you and your family at risk. Pet medicines that repel ticks can be applied 24 hours before the outing.

Tick Removal

The sooner a tick is removed, the less likely you are to get sick from an infected tick bite. The tick should be removed by grasping it at the point of attachment, as close to the skin as possible, with fine-pointed tweezers. Then, gently but firmly, pull it straight out. Insecticides, lighted matches, petroleum jelly or gasoline are ineffective and should not be used.

Apply antiseptic to the bite area. If you want to keep the tick for testing, seal it in a plastic bag and keep it in the refrigerator.

"Most of the time you won't need it. But a rash may not show up for three or four days, and then you'd like to know if the tick was infected with Lyme disease and you might want to get the tick tested," said Leigh Hall, deputy health officer at the county health department.

Early symptoms of Lyme disease often, but not always, include a rash at the bite site resembling a bull's-eye, and flu-like symptoms, such as fever and body aches, headache, a stiff neck or swelling of the knees and other large joints.

Consult a physician if you develop a rash, fever or other symptoms within two to four weeks after being bitten by a tick because prompt treatment with antibiotics can cure the disease.

Your doctor will not test the tick. If you want to have a tick tested for Lyme disease, drop it off or mail it to the Public Health Laboratory at the Sonoma County Department of Health, 3313 Chanate Road, Santa Rosa 95404. For information on submitting a tick, call 565-4715. A test costs $29.

May 5, 2007, By Carol Benfell, The Press Democrat