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There are thirteen known species of ticks in Minnesota. Of these, three kinds are commonly encountered by humans:

Figure 1. Adult female (left) and male American dog tick, approximately 10 times actual size.

American Dog Tick [also called wood tick] (figure 1). The adult female can be distinguished by the grayish markings on her back.

Figure 2. Adult female (left) and male blacklegged tick [formerly deer tick] approximately 10 times actual size.

Blacklegged Tick [formerly deer tick] (figure 2). The adult female is smaller and brownish-orange with black legs and a black scutellum (the round area behind the head). This tick is a potential carrier of Lyme disease.

Figure 3. Adult female (left) and male brown dog tick, approximately 10 times actual size.

Brown Dog Tick (figure 3). The adult female is reddish-brown and also smaller than the American dog tick.

The adult males of these three species differ in color and size compared with the females (figures 1, 2, 3). All three ticks are hard-bodied. Occasionally, soft-bodied ticks are encountered in the home (figure 4). They are associated with bats, birds, and poultry.

A generalized tick life cycle consists of egg, larva, nymph, and adult. The immature larva and nymph stages are very similar in form to the adult, but are smaller and often differ in color. A larva has six legs, while nymphs and adults have eight legs. The tick feeds once in each stage before maturing to the next stage.

American Dog Tick
American dog ticks are most commonly seen in the spring in open fields and the underbrush of hardwood forests. They feed on a wide variety of mammals, including white-footed mice, voles, chipmunks, raccoons, squirrels, dogs, cats, and people.

These ticks usually take two years to complete their life cycle. During the summer of the first year, the eggs hatch into larvae. These larvae do not feed until the following spring. After their blood meal, they turn into nymphs. After feeding a second time, these immature ticks develop into adults during late summer of the second year. The adults do not feed until the following spring, when the weather turns warm. Adults are common April through June but die after laying eggs, thus completing the life cycle.

Adult ticks bite humans and are found in grass, shrubs, brush, and other vegetation--particularly along animal trails or footpaths. When brushed by a moving body, they quickly let loose of the plant on which they are resting and attach to the animal or human.

There is a superstition that these ticks crawl up trees and drop down on humans and animals. Another superstition contends that ticks twist their mouthparts into the bite wound and have to be "unscrewed" to be removed. Neither is true.
Often people are completely surprised to find ticks attached to their body because the ticks can bite without being felt. If you are in a tick-infested area, examine your body carefully for ticks at night before retiring. The American dog tick may be carried into human living quarters but will not establish itself as a continuous pest there.

Dogs must be examined closely for ticks during the tick season. Examine them daily if they have had an opportunity to become infested. The female tick must feed on the dog for several days before she is full of blood and ready to drop off and lay eggs.

The American dog tick can be a carrier of several infections of humans including tularemia, or "rabbit fever," and Rocky Mountain spotted fever. Fortunately, these diseases are uncommon in Minnesota.

Blacklegged Tick (formerly Deer Tick)
The primary hosts of blacklegged ticks are white-footed mice and white-tailed deer, although other mammals, birds, and humans can be bitten.

Blacklegged ticks require at least two years to complete their life cycle. Larvae hatch in June or July and feed in August or September on white-footed mice or other small mammals. They spend the winter either as engorged larvae or as nymphs. The following year the nymphs take blood meals in spring or early summer, feeding on small mammals, birds, or humans. They usually turn into adults in late summer. Adults take blood meals in the fall or the following spring. They feed on white-tailed deer, dogs, horses, raccoons, or humans. Females lay eggs in May, completing the life cycle.

The blacklegged tick is important because it is a potential carrier of Lyme disease. Lyme disease is most prevalent in the east central region of Minnesota. Most cases of Lyme disease occur in June and July, although cases have been reported in Minnesota from February through November.

A person bitten by a Lyme disease-infected tick may develop a red skin lesion. The lesion expands to form a large bright red ring with a clear center which often is hot to touch. Other symptoms at the onset may include malaise, fatigue, chills, fever, headache, myalgia (muscle pain), sore throat, nausea, or vomiting. Several days to a month later, arthritis can develop. Cardiac abnormalities and other maladies may also occur.

See a doctor immediately if you believe you have been bitten by a tick carrying Lyme disease. Correct identification is important in Lyme disease diagnosis. Have suspected blacklegged ticks identified at the University of Minnesota.

For more information see Lyme Disease in Minnesota, Minnesota Extension Service fact sheet FS-3753.

Brown Dog Tick
Dogs are the only host for this tick. It cannot winter outdoors in Minnesota, but it may be found year-round on dogs in heated kennels and homes. Frequently, the family pet becomes infested with ticks when placed in a kennel, and carries the ticks home. The ticks then reproduce in the home. They may be found on carpeting, furniture, draperies, and walls and can become most annoying.

The female tick obtains a large blood meal from the dog and then drops off to seek a hiding place under baseboards, behind radiators, or in floor spaces. Here she may lay up to 3,000 eggs. Within three weeks to two months, the small "seed" ticks hatch and crawl around in search of a dog. They attach to the dog, fill up with blood in a few days, and again drop off and hide. Then they shed their skins, which permits them to grow and prepare for a second blood meal. A third blood meal is necessary to become an adult. After mating, the female lays a single batch of eggs, then dies.

Bat Ticks

Another tick that occasionally annoys humans in Minnesota is the bat tick--a type of soft-bodied tick that is brownish-gray or dirty gray in color. It is found in homes where bats roost in the upper floors of buildings. Other soft-bodied ticks are associated with birds and poultry. In the absence of their normal hosts, these ticks may wander into the home and bite humans. However, they cannot survive for long periods without their hosts because they are unable to reproduce on human blood.

Figure 4. Adult bat tick, approximately 10 times actual size.

Removal Methods
Whenever you find a feeding tick attached to an animal or human (the host), grasp it as close as possible to the skin of the host with tweezers or tissue paper: avoid squeezing the abdomen. Gently, yet firmly, pull the tick off. You are most likely to remove the tick if you follow this procedure. Always treat the wound with a good germicidal agent such as iodine.

Methods using tape, alcohol, or Vaseline to induce the tick to voluntarily pull its mouthparts out of the skin are not effective; tweezers are the surest removal method. Never destroy ticks by crushing them in the fingers; this practice has been known to cause infection.

Prevention and Control Measures

American Dog Tick and Blacklegged Tick

1. Keep grass and vegetation short around the home, along paths, and in areas where people are likely to contact ticks. It is unnecessary to treat your lawn for ticks; ticks are rarely found in maintained yards. In most cases, it is not suggested to treat adjacent wooded or grassy areas. In unusual cases where high numbers of ticks exist, you can spray a tall, grassy area with an insecticide such as:

   carbaryl (Sevin)
   chlorpyrifos
   diazinon
   

   Do not spray such an area more than once a year.
   

2. Wear protective clothing, such as long-sleeved shirts and long pants when walking in known tick areas. For added protection, tuck pants inside socks. Stay on trails; avoid walking through grassy areas. Check yourself for ticks after returning from trips into known tick-infested areas. Save any suspected blacklegged ticks for identification.
3. Use repellents for additional protection. Apply to socks, trouser cuffs, pant legs, and parts of clothing that may brush tall grasses. The repellents remain effective for several wearings if the garments are not washed.

   Effective repellents include DEET (N, N-diethyl-m-toluamide) and Permanone (permethrin). DEET can be applied to clothing and skin while Permanone should be applied to clothing only. Be careful not to overapply repellents; apply only enough to cover the desired area.

   Use a repellent on dogs that contains the active ingredient permethrin. Permethrin not only repels ticks on dogs but also kills the ticks.

   Recently, a vaccine (Borrelia burgdoferi bacterin) was approved to protect dogs against Lyme disease. Consult your veterinarian about the advisability or necessity for vaccinating your dog.

4. Kill ticks on dogs and cats and protect them for a limited time from ticks encountered later by using one of the following approaches:

Dips containing one of the following insecticides:

permethrin
chlorpyrifos
phosmet [listed as
  N (mercaptomethyl) phthalimide
  S-(O,O-dimethyl phosphorodithioate)]
rotenone/pyrethrins
pyrethrins

Sponge or swab the pet with the insecticide until the pet is thoroughly wet to the skin. Allow to dry. Do not rinse or towel the pet.

Sprays containing one of the following insecticides:

permethrin
chlorpyrifos
carbaryl [may be combined with pyrethrins]
propoxur (listed as o-isopropoxyphenyl
  methylcarbamate
phosmet [listed as
  N-(mercaptomethyl) phthalimide
   S-(O,O-dimethyl phosphorodithioate)]
resmethrin
pyrethrins

Spray until damp to the skin; spray against the natural lay of the hair to better allow the insecticide to penetrate to the skin.

Dusts containing one of the following insecticides:

carbaryl [may be combined with methoxychlor
   or pyrethrins and/or silica gel]
chlorpyrifos (dogs only)
phosmet [listed as
  N-(mercaptomethyl) phthalimide
   S-(O,O-dimethyl phosphorodithioate)]

Rub the dust into the fur against the natural lay of the hair until it penetrates to the skin.

Shampoos containing one of the following insecticides:

Wet the fur thoroughly with warm water and apply enough shampoo to lather; work thoroughly into coat and skin.

An insecticide containing pyrethrins is the least toxic treatment. However, pyrethrins only control ticks they come in contact with; they have no lasting power to kill ticks that are encountered later. Tick/flea collars are not suggested for use on pets; they work too slowly to effectively control ticks on animals.

Caution: Do not combine treatments. A pesticide overdose may occur.

Brown Dog Ticks and Bat Ticks
Larval and adult ticks can crawl considerable distances. They can be found along door and window casings and even on curtains. Spray these hiding places, along baseboards, and on rugs, so that crawling ticks have to come in contact with the insecticide. Insecticides such as chlorpyrifos, permethrin, and tetramethrin, available in aerosol or liquid ready-to-use containers, provide good tick control in the home. Caution: Some insecticides may damage carpeting and rugs. Test treat a small area first if you are unsure whether a product will stain carpeting or rugs. Elimination and exclusion of bats from roosts in homes is also necessary to control bat ticks. For more information, see Bats, Minnesota Extension fact sheet.

Caution: Always read pesticide labels carefully before buying and again before using these products. While the insecticide suggestions are current at the time of publication, pesticides and uses change. The label on the product you are using is the final authority on how you may legally use the pesticide.

Note: The pesticide names listed in this publication are common names of active ingredients of insecticides available for use against ticks. You will find these insecticide names on the label under the heading Active Ingredients. These names are often listed in fine print, so look carefully.

Jeffrey D. Hahn
Entomology

Produced by Communication and Educational Technology Services, University of Minnesota Extension.

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