Keeping Ticks Where They Belong -- Away From Humans

Ticks live in a variety of environments, including birdbaths, bird feeders, leaf litter, woodpiles, woodland, tall grasses, high weeds, and cat and dog fur.
Ticks live in a variety of environments, including birdbaths, bird feeders, leaf litter, woodpiles, woodland, tall grasses, high weeds, and cat and dog fur. (Photos By Sandra Leavitt Lerner For The Washington Post)
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By Joel M. Lerner
Saturday, May 31, 2008

Lyme disease is a concern for gardeners and anyone else who spends time outdoors.

Reports of the disease, which can cause joint stiffness and neurological problems, are on the rise. Lyme disease cases in Maryland more than doubled last year, to about 2,600. In Howard County, they more than tripled, to 358, according to state health officials. In Virginia, reported cases almost tripled.

The tiny deer tick ( Ixodes scapularis) is the primary culprit in transmitting Lyme disease, a bacterial infection. Deer are the most common host, though the parasites live on other animals, too, including mice. Even though most Lyme disease cases are still in rural areas, deer increasingly live close to humans. They are plentiful throughout Rock Creek Park and other natural areas in this region, such as along the C&O Canal.

Peter Beilenson, a physician who is county health officer in Howard, said that part of the increase in reported cases is due to better awareness of the disease but that many cases still go unreported.

Housing sprawl is also to blame, said David Gaines, public health entomologist for the Virginia Department of Health. New subdivisions have reduced forest, leaving narrow tree buffers between neighborhoods and greatly reducing the areas where deer hunting is allowed. At the same time, those developments are stocked with plants that deer love to eat.

People who work or play outdoors should familiarize themselves with initial symptoms of Lyme disease -- onset of a bull's-eye rash, fever, headache, flulike symptoms and fatigue.

If you are vigilant and check yourself several times a day when outside, you should find the ticks in time to avoid any infection. Tick environments include but are not limited to leaf litter, woodpiles, birdbaths, feeders, woodland, tall grasses, high weeds, moist areas, and cat and dog fur.

According to Gaines, the bull's-eye rash that appears on many people, which is redder in the center and pink in the outer area, is one of the best ways to differentiate this disease from others. Symptoms can take three to 32 days to appear. But sometimes early warning signs never appear or go unnoticed. If you are exposed to Lyme disease, you would be lucky to get a rash or fever. Early diagnosis and treatment with antibiotics offer the best chance of a cure.

Ticks normally feed from May to September. Newly hatched larva will not infect hosts, but nymphs are infectious when they acquire the bacteria from the larval stage. The nymphal stage is when most infections occur in humans because the ticks can barely be detected. They can be about the size of the period at the end of this sentence. You must know what you are looking for. The male is black and the female dark reddish, like a speck of dirt that doesn't brush off.

In fall, ticks feed for a final meal, drop off, lay eggs and die. Eggs hatch into larvae in spring and travel mainly on white-footed mice, squirrels, and other small mammals and birds. Bird migration might play a part in spreading deer-tick larvae.

According to the Centers for Disease Control and Prevention, the number of available tick and insect repellents has been increasing, with several active ingredients now registered by the Environmental Protection Agency. Herb-based formulas are increasingly popular. However, when traveling to areas where the prevalence of disease-transmitting vectors is high, it may be wise to use a product containing DEET or another chemical, picaridin, rather than an herbal preparation. DEET is the most studied repellent, and the military and civilian travelers have had the most experience with it.

Many people worry about using a strong chemical such as DEET. It has been proved to have the same effectiveness in a 25 percent solution as a 100 percent solution, with far less chance of ill effects. Though the lower concentrations are considered equally effective, they work for shorter periods of time. For children, use a maximum concentration of 5 to 6 percent. Follow labeled instructions on all insect-repelling products. Factors such as high temperature, humidity, sweating and water exposure may cut short a repellent's effectiveness.

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© 2008 The Washington Post Company

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