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.
TIcks in Illinois were found to be carrying Heartland Virus.
“Bites from Ticks can result in multiple types of infections, which can cause serious illness in some people,” said IDPH Director Dr. Ngozi Ezike. “It is important to take precautions and protect yourself from tick bites by using insect repellent and checking regularly for ticks when in wooded areas or high grass.”
Heartland virus was first identified in 2009 when two Missouri farmers who had been bitten by ticks were admitted to a hospital. Heartland virus is a viral disease that can be spread to people through the bite of an infected Lone Star tick. Reported cases of Heartland virus disease are relatively rare, however almost all individuals with Heartland virus have been hospitalized. Although most people infected have fully recovered, a few have died. There are no vaccines to prevent Heartland virus infections.