|Tick Prevention Poster|
Although ticks are commonly thought of as insects, they are actually arachnids like scorpions, spiders and mites. All members of this group have four pairs of legs as adults and have no antennae. Adult insects have three pairs of legs and one pair of antennae. Ticks are among the most efficient carriers of disease because they attach firmly when sucking blood, feed slowly and may go unnoticed for a considerable time while feeding. Ticks take several days to complete feeding.
Ticks have four life stages: egg, six-legged larva, eight-legged nymph and adult. After the egg hatches, the tiny larva (sometimes called a seed tick) feeds on an appropriate host. The larva then develops (molts) into the larger nymph. The nymph feeds on a host and then molts into an even larger adult. Both male and female adults find and feed on a host, then the females lay eggs sometime after feeding.
Ticks wait for host animals from the tips of grasses and shrubs (not from trees). When brushed by a moving animal or person, they quickly let go of the vegetation and climb onto the host. Ticks can only crawl; they cannot fly or jump. Ticks found on the scalp have usually crawled there from lower parts of the body. Some species of ticks will crawl several feet toward a host. Ticks can be active on winter days when the ground temperatures are about 45o Fahrenheit.
There are two groups of ticks, sometimes called the hard ticks and soft ticks. Hard ticks, like the common dog tick, have a hard shield just behind the mouthparts (sometimes incorrectly called the head); unfed hard ticks are shaped like a flat seed. Soft ticks do not have the hard shield and they are shaped like a large raisin. Soft ticks prefer to feed on birds or bats and are seldom encountered unless these animals are nesting or roosting in an occupied building.
Although at least 15 species of ticks occur in Illinois, only a few of these ticks are likely to be encountered by people: American dog tick, lone star tick, blacklegged (deer) tick, brown dog tick and winter tick.
American Dog Tick (Dermacentor variabilis)
Unfed males and females are reddish-brown and about 3/16-inch long. Females have a large silver-colored spot behind the head and will become ½-inch long after feeding or about the size of a small grape. Males have fine silver lines on the back and do not get much larger after feeding. Males are sometimes mistaken for other species of ticks because they appear so different from the female.
In Illinois, the adults are most active in April, May and June. By September, the adults are inactive and are rarely observed. The American dog tick can transmit Rocky Mountain spotted fever, tularemia and possibly ehrlichiosis to humans.
Lone Star Tick (Amblyomma americanum)
The lone star tick is most active from April through the end of July. Although it can transmit Rocky Mountain spotted fever, the lone star tick is not as likely to transmit the disease as the American dog tick. This tick also may transmit tularemia and ehrlichiosis to humans. The lone star tick is not believed to transmit the bacteria that causes Lyme disease (Borrelia burgdorferi), but may be associated with a related bacteria species that has not been completely identified.
Blacklegged Tick, also known as the Deer Tick (Ixodes
These ticks are found in wooded areas along trails. The larvae and nymphs are active in the spring and early summer; adults may be active in both the spring and fall. The blacklegged / deer tick can transmit Lyme disease and possibly ehrlichiosis to humans.
The deer tick has been found sporadically in many Illinois counties. However, in recent years it has been common only in limited areas, mostly in northern Illinois (Geographic distribution by county). Additionally, Illinois residents may encounter the deer tick during trips to Michigan, Minnesota, Wisconsin or the northeastern United States where it is very common in some areas.
Brown Dog Tick (Rhipicephalus sanguineus)
The adult is reddish-brown and about 1/8-inch long, and usually attaches around the ears or between the toes of a dog to feed. After feeding, a female may engorge to ½-inch long. She then drops off the dog and crawls into a hiding place where she may lay as many as 3,000 eggs. This tick is tropical in origin and does not survive Illinois winters outdoors. The brown dog tick is not an important carrier of human disease.
Winter Tick (Dermacentor albipictus)
Preventing Tick Bites and Disease
The best way to protect yourself against tickborne illness is to avoid tick bites. This includes avoiding known tick- infested areas. However, if you live in or visit wooded areas or areas with tall grass and weeds, follow these precautions to help prevent tick bites and decrease the risk of disease:
Prevention and Control of Ticks Around the Home
Make sure the property around your home is unattractive to ticks. Because ticks are sensitive to dry conditions and do not thrive in short vegetation, they are seldom a problem in well-maintained lawns. Keep your grass mowed and keep weeds cut. Clean up items that attract rodents which can carry ticks, such as spilled birdseed, and hiding places like old wood piles. If ticks are present in vegetation along the edge of the property, insecticides labeled for control of ticks can be applied to small areas of high weeds that cannot be mowed. Often, one or two applications per season will be adequate to control ticks in these areas.
Free-roaming dogs and cats are much more likely to encounter ticks than those that are confined to the home or yard. If ticks are found on pets, contact your veterinarian for information about an appropriate tick treatment. Remove the occasional tick found indoors by vacuuming, seal the vacuum bag and place it in the trash. Owners of kennels or homes infested with the brown dog tick may wish to contact a professional pest control company for assistance.
When to Contact a Physician after a Tick Bite
If you experience a rash that looks like a bull's-eye, or a rash anywhere on the body or an unexplained illness accompanied by fever following a tick bite, you should consult your physician and explain that you were bitten by a tick. Disease carried by ticks can be treated with antibiotics. However, the type of antibiotic can vary and individuals should be treated early in the infection.
Fact sheets about symptoms and treatment of tickborne diseases may be obtained from local health departments, by calling the Departments central office at 217-782-2016 or from the Departments Web site at http://www.idph.state.il.us.
Identification of Ticks
During the last several years, about 75 percent of the ticks submitted to Department staff have been identified either as the American dog tick or as the lone star tick. Many people are familiar with the female American dog tick. However, the adults of several species and immature stages must be identified by an entomologist or other professional familiar with ticks. To submit a tick for identification, put it into a leak-proof container with rubbing alcohol along with the date and location where the tick was encountered and contact your local health department for assistance.
This publication is for information and is intended as a guide only. Always read and follow all current label instructions for repellents and pesticides. If any information in these recommendations disagrees with the pesticide label, the label instructions must be followed. For more information, contact the Illinois Department of Public Health, Division of Environmental Health, 525 W. Jefferson St., Springfield, IL 62761; 217-782-5830, TTY (hearing impaired use only) 800-547-0466. Prepared with the assistance of the University of Illinois Extension, University of Illinois Department of Veterinary Pathology and Illinois Natural History Survey.
of Public Health
535 West Jefferson Street
Springfield, Illinois 62761
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