What they are: Bloodsucking parasites related to spiders and chiggers that insert barbed probes into the skin to feed.

Where they are: Ticks are found all over the country. But Lyme disease–carrying ticks are most prevalent in Minnesota, Wisconsin, and the Northeast. (See The Lowdown on Lyme.)

How to keep them away: Clothes are your best armor: Cover up as completely as possible. If you’re walking in a woodsy area, wear long pants tucked into your socks and a long-sleeve shirt. For the most effective tick deterrent, try products with the chemical permethrin (Repel Permanone or Sawyer Permethrin Clothing treatment), which not only repels but also kills ticks. Spray it on your clothing, where it can last up to two weeks, and be sure not to miss the edges of garments, like around wrists and ankles. Avoid spraying it on the skin.

The best way to heal bites: Use tweezers to remove a tick, pulling straight out without twisting. (If you’re in an area where Lyme disease is common, save the culprit so you can bring it with you to the doctor.) Wash the bite area with soap and water and apply a topical antiseptic (such as Polysporin) to prevent infection. Tick bites don’t usually hurt or itch as much as other bites, but watch them carefully for any sign of Lyme disease. If Lyme disease is a problem in your area, your doctor may treat you right away with the antibiotic doxycycline as a precaution.