Look Out for Lyme Disease

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Now that warmer weather is near, numerous pests will emerge and become a nuisance for people who enjoy the outdoors. One of the most threatening of these pests is the deer tick. While several different types of ticks have been linked to Lyme disease throughout the world, the black-legged or deer tick of eastern North America (Ixodes scapularis) transmits the disease in the eastern and upper Midwestern United States.Over the past few years, deer ticks and the Lyme disease they often carry have become an increasing concern to New Englanders. This article will describe where deer ticks survive, what effects they have on humans and what home gardeners can do to avoid coming into contact with ticks.

Lyme disease was first recognized in 1975 by a Yale scientist investigating an unusual prevalence of arthritis among the children of Lyme, Connecticut. By 1981, the disease was determined to be an infection caused by bacteria. This infection can cause skin, heart, nervous system and arthritic problems.

After this finding, Lyme disease was recognized from coastal regions in New England through Maryland, also in Wisconsin and in northern California. Similar cases have even been round in northern Europe, Canada and Eurasia. Lyme disease and the deer ticks which carry it pose a serious threat to people who live in the Northeast, where 80 percent of all known cases are found.

Deer ticks are parasites and have a three-stage (larva, nymph, adult), two-year life cycle. In the larval stage, ticks are about the size of a grain of sand.

They get their blood meal from a mouse or other small rodent. The most important host is the white-footed mouse. If the host is infected with the bacterium that causes Lyme disease, the larvae may become infected.

Nymphs, which have eight legs and are the size of a pin head, are the least particular about their host. This stage, present in the summer, is the most likely to bite humans. It does take a tick several hours to attach itself to a body and 12 to 48 hours for an infected, feeding tick to transmit the Lyme disease bacterium.

Ticks molt into mature adults in the fall. Adult ticks are twice as likely as larvae to have the bacterium because they have had two blood meals. However, the normal host of this stage is the white-tailed deer. If no deer are present, ticks may feed on a cow, horse, dog or human. In addition, this stage is associated with fewer cases of Lyme disease, partly because the ticks are larger and easier to spot and remove prior to transmission of the bacterium.

If you spend a good deal of time outdoors in a wooded or brushy area, follow these preventive measures:

Prevention

Preventing deer and white-footed mice from inhabiting your property can also help decrease the tick population. If your house is in an area bordered by woods or populated by deer, you may have a high risk of deer ticks on your property. While mice and deer can be a nuisance to homeowners' vegetable gardens and ornamentals, they pose a more serious problem by providing host sites for infected ticks.

Home gardeners can take several preventive measures. The first step is to make thee landscape as inhospitable as possible for ticks and hosts by clearing away brush and leaf piles. Remove wood piles, or at least keep them neat and off the ground, so that mice and other small mammal hosts cannot nest in them. To discourage deer from feeding on your property, utilize plants, shrubs and trees that deer do not usually feed on, such as barberry or boxwood shrubs. A garden center or your local Cooperative Extension System Center may be able to suggest others.

Also, a fairly recent innovation is the commercial distribution of bobcat, coyote and wolf urine. The scent of these natural predators may keep deer away. However, more research is needed to confirm this theory. Since ticks avoid areas where direct sunlight can reach the ground, keep your lawn neatly mowed at all times. Mow surrounding fields to keep them relatively short. In the fall, mow the entire field to prevent a thatch build-up where mice and other tick hosts may overwinter.

Seemingly innocent yard ornaments and landscape designs can also encourage tick populations. Bird feeder litter may attract rodents, which can carry infected ticks. Keep the ground beneath the feeder bare and clean so as to limit the amount of food available for rodents. If you live in a Lyme disease endemic area, it is best to suspend bird feeding during late spring and summer, when infected ticks are most active. Despite their beauty, stone walls on your property can attract small mammals and increase the potential for ticks. Especially do not sit on the wall or use it as a picnic table during late spring or summer months.

If you live in a deer populated area, constructing an 8-foot-high fence will keep out deer and, hence, reduce the abundance of ticks.

If you live in a known high-risk area, you may consider treating your property with an appropriate acaracide or pesticide. Contact your local Cooperative Extension System Center for help in determining which acaracide to use. Three pesticides registered for tick control are chlorpyrifos (Dursban ), carbaryl (Sevin ) and cyfluthrin (Tempo ). Tempo is only available through pesticide specialists. Hence, the hiring of a professionally-trained applicator should be considered if you choose chemical control. If you decide to apply pesticides yourself, follow the label instructions and do not use near any stream or body of water. Two applications, one in May to control nymphs and one in September to control adult ticks, should significantly reduce the tick population.

Symptoms of Lyme disease:

Marie Krupa, Editorial Intern, University of Connecticut

Adapted from:UMASS Tree News #41, Lyme Disease in New England by Dr. John D. Edman, Dept. of Entomology., Agriculture Research, May 1994, Deer Scents May Guide Ticks to Hosts by John F.Carroll, Edward T. Schmidtmann and Jerome A. Klun, USDA-ARS specialists., A Homeowner 's Guide to the Ecology and Environmental Management of Lyme Disease,American Lyme Disease Foundation, Inc., Somers, New York.

Information on our site was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.

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