San Diego Natural History Museum--Your Nature Connection[San Diego County Bird Atlas Project]

A New Threat to San Diego Birders: Lyme Disease

tick

On remote and lonesome Bucksnort Mountain (square C20) thoughts of mountain lions sneaking up from behind occasionally cross my mind. Much farther down on the list of dangers is ticks. We've all had them, pulled them off by the dozen. No big deal. Those are the words of someone without the proper respect--me, until this year.

Sunday was a beautiful, warm day for walking the ridge, the birds were singing, and, as usual, hiding in the dense thickets of manzanita chaparral. I checked for ticks on my return, before my shower that night, and after another the next morning. I felt something on the back my arm, and, using a mirror, I saw a bite of some kind, sore with an inflamed area around a dark spot. By the next day the inflammation was bigger and the area tender to the touch had grown. At Adams Elementary School that morning, I had better eyes to check it out, "Oh," the kids said, "you have a tick, and its legs are moving." Yuk. The tick was buried in my arm and, with the morning sunlight, was enjoying exercising its legs. Thanks to Virginia Moran, who lent me the reams of material on the Western Black-Legged Tick and Lyme disease she had acquired at a recent Wildlife Society meeting, I am up on Lyme disease and knew I had to seek medical help immediately. The tick does not disgorge its Lyme disease bacteria until 24 to 48 hours after embedding.

At the clinic's acute care center I was the queen. All the clinic's personnel wanted to observe this novelty, excision of a tick. So, in my crowded cubicle, my surgeon reached in, got only a couple of legs, went back for the body, and finally had to take the head with a plug of skin attached. The sucker had swum down and almost through my supposedly protective skin. Her incomplete remains, the reddish brown body with dark brown thoracic shield, are sitting on my desk, too small to be seen much without a microscope. I am on precautionary antibiotics for ten days, and the lab is analyzing my blood for a baseline antibody reading. Although blood tests are unreliable as a diagnostic tool for Lyme disease, a positive test in the future may be important.

Lyme disease is a serious infection caused by the bacterium Borrelia burgdorferi and transmitted by the Western Black-legged Tick (Ixodes pacificus). The tick may also carry other diseases that can be transmitted along with the Lyme bacterium: Colorado tick fever, human granulocytic ehrlichiosis, human monocytic ehrlichiosis, Rocky Mountain spotted fever (one confirmed case in California in 2000), tularemia, relapsing fever, tick paralysis, and babesiosis. Infection offers no immunity: a person can be infected more than once. Currently there is no consensus on how to diagnose Lyme disease, and there is intense debate among doctors--and insurance companies--about diagnosis and length of treatment. Without proper and early treatment it can become a chronic illness with persisting infection. Lyme disease is diagnosed clinically; it is recommended that afflicted people be treated with antibiotics immediately and until all the symptoms are gone.

As of 31 October 2000, 95 cases of Lyme disease had been reported to the California Department of Health Services. Ticks have been collected and tested positive for Lyme disease at Will Rogers State Historic Park and Charmlee Park, both in Los Angeles. According to some doctors this disease is greatly underdiagnosed and underreported. A few cases are reported in San Diego every year.

Nymphal ticks and adult females can transmit the disease. Nymphal ticks are the most serious transmitters, infecting people at rates many times those of adult ticks. The nymphs are about the size of a poppy seed, readily attach to humans, and feed about twice as fast as the adults. They are most commonly found from March to July in moist leaf litter in oak woodland, mixed chaparral, madrone forest, and redwood forests. Nymphs feed on mice, lizards, birds, rabbits, raccoons, deer, cows, horses, dogs, cats, and humans. Wood rats (pack rats) have been found to be a reservoir for the disease. Migrating birds spread Lyme disease. The Western Fence Lizard has an unknown component in its blood that can clear the infection from the nymphs.

Adult ticks are active from October to June and peak in December, January, or February, depending on the area. In a behavior called "questing," they cling to the tips of leaves and stems, about 24 inches off the ground, waiting for a prospective host to pass. Ticks concentrate in shaded moist areas where grass and shrubs come together on north-facing slopes, on the uphill side of a trail. The females are more likely to transmit the disease since they need a large blood meal to develop eggs.

Symptoms: a flat or slightly raised red lesion at the site of the tick bite, expansion of the red lesion to several inches over several days, fever, headache, lethargy, muscle pains, stiff neck, inflammation in the knees and other large joints. Additional symptoms could include itching overall and unusual or strange behavior.

Long-term complications can include heart and nervous system disorders, migratory pain in joints, tendons, muscles, and bones, arthritis especially in the large joints (knees most often affected), Bell's palsy, neuropsychiatric and cognitive disorders, and organ disorders.

To avoid ticks, wear long pants, tuck pants into boots, and shirt into pants. Pull socks over pants. Wear a hat. Wear light colored clothing so ticks can be seen easily. Apply Permanone (0.5% Permethrin) on clothing to repel or kill ticks. Apply insect repellents containing 25% or less of DEET on exposed skin of adults and 10% on children. Check yourself, your children, and your pets for ticks frequently. Educate yourself about Lyme disease and other tick-borne illnesses.

If you find an attached tick on your body have it removed properly. Record any symptoms or changes you may have daily. Photograph the bull's-eye rash if you have one. It will disappear with or without antibiotics. Seek Lyme-literate doctors.

To remove an embedded tick, do not twist it or cover it with Vaseline. The sooner you remove the tick the less the chance of infection. Use either a tick-removing device ($3.50 from Pro-tick Remedy from SCS Limited, P.O. Box 573, Stony Point, NY 10980; 800-749-8425; sales@scslimited.com) or a fine-point tweezers. Do not squeeze the tick or hold a cigarette or match to it (you could inject the possibly infected body contents into the wound). Grasp it as close to the skin as possible, where the mouth parts enter the skin. Tug gently and repeatedly until it releases its hold by withdrawing its barbed mouth parts from your skin. Above all, be patient, as proper tick removal takes time. Don't squash the tick with your hands.

To have a live tick tested for infection, put it into a clean pill bottle or film container with a piece of damp cotton, then contact the Department of Environmental Health or send it to a reliable laboratory (IgeneX, Inc., 797 San Antonio Rd., Palo Alto, CA 94303; 800-832-3200; fax 415-424-1196).

Inform yourself on the Internet
Lyme Disease Resource Center
Lyme Disease Foundation
Center for Disease Control
San Diego County Department of Environmental Health, Vector Control

-- Pat Flanagan

birdatlas@sdnhm.org

Summer 2001 Wrenderings | Wrenderings Archive | Bird Atlas Introduction