Description & Biology

As ticks go through their life stages (larva, nymph, and adult), they usually change hosts. The seed or larval ticks will attach to small animals and be dispersed by them. Nymphs will climb up higher plants to latch onto larger hosts. Adult ticks can perch on plants for months waiting for a host to come by. Ticks may also seek out prey by detecting heat and carbon dioxide emanating from a potential host. Adult female ticks can feed for several days up to a month.

On humans, ticks migrate around the hairline, the area behind the ears, or in the armpits. On dogs, they attach to the ear, shoulder, and upper leg areas. It takes five to six hours for a tick to become firmly attached and up to ten days for it to become fully engorged with blood. The female needs a bloodmeal in order to lay her eggs. Ticks have been known to survive for one year without a bloodmeal.

The deer tick (Ixodes scapularis) is a small tick mostly inhabiting the coastal areas of York and Cumberland Counties. It is capable of transmitting Lyme Disease. The early signs of the disease show up as a rash at the bite site and then flu-like symptoms. Untreated cases may lead to arthritic conditions and possible neurological problems. Two factors to keep in mind are that not all deer ticks carry Lyme disease causing spirochete (bacterium) and, a tick must remain attached to the host for at least 24 hours in order to infect the host. For more information on deer ticks and Lyme Disease, refer to the Public Health Fact Sheet entitled: "Lyme Disease in Maine", available from the Pest Management Office, Forest & Insect Disease Lab and the Bureau of Health.

American dog ticks--- (Dermacenter variabilis), also called wood ticks, are larger than deer ticks and the unengorged female has a whitish shield on its back. This tick readily attaches itself to humans and is one of the most commonly encountered ticks in Maine. The highest populations of the wood tick are found in southern Maine—in Oxford County and surrounding areas. However, ticks have turned up recently in great abundance in areas north of Oxford County and into Kennebec County. Some wood ticks outside of Maine may carry the organism that causes Rocky Mountain spotted fever, a serious disease that can be transmitted to humans. The symptoms of Rocky Mountain spotted fever are headache, fever, and aching muscles two to 14 days after an encounter with a tick. Two to three days after the fever starts, a rash develops on the wrists and ankles, spreading to the palms, soles, and trunk of the body. Wood ticks are most likely to be found in open areas with tall grass or brush. Adults are first noticed in late April and remain to abundant through June. Numbers seem to decline sharply after that, but some occur all summer.

The brown dog tick (Rhipicephalus sanquineus) is rarely found in Maine. It is transported here from areas south of Massachusetts on pets and occasionally on clothes. Although this species is not likely to feed on humans, it has been found in homes- even on beds. Dogs are the brown tick’s most common host and source of bloodmeals. This is why the tick is most often found in kennels and pet beds. Rats and mice may also be intermittent hosts. This tick does not overwinter in Maine.

Management

Ticks can be controlled only on very limited basis. The most important consideration is personal preventive measures such as wearing full-length garments that are tight around the wrist, ankle, and neck and treating exposed areas with a repellent. A permethrin-based repellent is available for treating clothes. Adults should check themselves and children immediately after visiting a tick-infested area. If possible, avoid such areas. Keep brush and grass around your home cut short. Keep stray dogs out. Keep pets out of tick infested areas. Repellent pet collars may help keep pets tick free. Infested pets can be freed of ticks with an insecticide available from pet shops. Ticks can be eliminated from homes by using carbaryl (Sevin), malathion, or propoxur (Baygon) as crack- and-crevice treatments, or by using household sprays containing pyrethrins or resmethrin.