Ticks can pass disease on to humans. Learn how to protect against their bites.

There are approximately 850 species of ticks. Blood-feeling parasites, they live all over the world.

Ticks bite into the skin of a host and feed by slowly taking in blood. Their hosts are usually rodents and other small animals, but they also prey upon larger animals, such as dogs, horses and people.

Ticks require high humidity to survive, and usually live in wooded, brushy, grassy and shaded areas—often where fallen leaves have accumulated on the ground. They usually prove most active beginning in early spring and remain active through the summer months, but ticks can also survive year-round, and even be active on warm winter days. Some species of ticks can survive for years without feeding.

Exhaled carbon dioxide, heat and movement stimulate “questing” behavior in ticks. Many species perch on the edges of grass stems or leaves on the ground, waiting for indications of a nearby potential host. Then—in questing position, with front legs extended—they prepare to climb onto a host. Ticks do not fly or jump; the host must come into actual contact with the tick.

The tick’s saliva transmits diseases. In the United States, infected ticks spread Rocky Mountain spotted fever, Lyme disease and other illnesses to people. The American dog tick (Dermacentor variabilis), found throughout the United States, and the Rocky Mountain wood tick (Dermacentor andersoni) carry Rocky Mountain spotted fever. Lyme disease is spread by infected deer ticks (Ixodes scapularis), which are most common on the East Coast. Usually, a tick must be attached for several hours for disease to be transmitted. Ticks in the nymphal stage can be so small that they appear almost invisible to the naked eye—yet they can still bite and spread disease.

Tick prevention proves difficult, but you can discourage infestation by keeping grass mowed, as well as removing dead leaves and brush from your yard. Another effective precaution involves pruning trees so as to allow more sunlight to penetrate to the soil surface and reduce humidity. You will also find insecticides labeled for outdoor tick control; however, they are not very effective in eliminating large numbers of ticks in brushy, heavily wooded areas.

Prevent tick-borne illness through personal tick-repellent protection, careful personal inspection, as well as the prompt and safe removal of attached ticks. Parents should inspect children after they’ve been outside, especially their hair. Also, keep in mind that ticks can be carried indoors on pets and ordinary clothing.

Go to instructions for proper tick removal, as well as more detailed information on tick-borne illnesses.