Spiders and Ticks and Bugs—Oh My!

By Dr. Vicki L. Short, M.D.

As winter slowly gives way to the beautiful spring and summer that we enjoy on the Palouse, we are more likely to encounter “bugs” of all types. Here are some tips on avoiding bad encounters with two types of these little guys while enjoying the outdoors.

SPIDERS

There is one spider you should get to know (from a distance!) on the Palouse. The Hobo spider, Tegenaria agrestis, is also known as the aggressive house spider, and is very common in the Pacific Northwest. The Hobo spider is especially active from July to September, when males search for females. This spider will build funnel-shaped webs in dark, moist areas, often in basements, window wells, wood piles, around the perimeter of homes, and around debris like boards, wood and brush. It tends to be large (up to 4-5 cm in diameter), and brown in color.

What is so special about the Hobo spider? The bite of the hobo spider can be severe. The initial bite is relatively painless. The area around the bite will become hard in about 30 minutes, with an expanding red area that may reach 5-15 cm in diameter. Blisters may form within 15-36 hours—these eventually crust over the cratered wound. The venom kills tissue, with bite wounds occasionally reaching a depth of 3 cm or more. Lesions can take several months to heal, and often leave a scar. The bite is often mistaken for the bite of a brown recluse spider (a species not found in the Pacific Northwest), or an infection. Rarely, the “victim” may experience nausea, headaches, sweating or joint pain. No deaths have been reported.

Bites usually occur when a person picks up firewood or objects with a spider on it, or when a spider finds its way into clothing or bedding. Here are some ways to avoid a bite from the Hobo spider:

• Wear gloves when working in the yard, cleaning your basement, or reaching in dark areas.
• Use care when picking up clothes or objects which have been stored on the floor, especially in the basement.
• Prevent debris like boards, brush and wood from accumulating where spiders can live.
• Keep long grass trimmed around home
• Seal cracks in foundation and around windows and doors.
• Chemical control has both risks and benefits—trapping may be the most effective non-chemical control. Sticky traps placed along walls, in corners and window sills are effective.

TICKS

Tick bites are more common in the spring and summer months, and some bites can cause illness. The more common tick-borne diseases in the United States are Lyme disease, ehrlichiosis, Rocky Mountain spotted fever and tularemia. Ticks can be found at the top of grassy plants and low bushes, where people or animals can brush up against their perch. Ticks will often crawl upward on the clothes or body for several hours before attaching to the skin. Here are some simple things you can do to avoid tick trouble:

• When hiking or camping, wear light-colored clothing so that you can spot ticks more easily
• Wear long pants and tuck the legs into socks or boots. Tape around the area where pants and socks meet for added protection.
• Stick to the middle of hiking trails—avoid brushing against leaves or grasses.
• If you use insect repellent, DEET products on the clothing are most effective.
• Once home, inspect yourself carefully. If you find a tick, don’t panic. Removing it quickly can help prevent transmission of disease.
• To remove the tick: grasp the tick with fine tweezers as close to your skin as possible, and pull straight out. Then clean the area with disinfectant. DO NOT: use a lighted match or cigarette, or cover the tick with Vaseline. If you kill the tick in place, it makes matters worse.