Insects are vectors, or transmitters, of disease. In the United States, the chief culprits are ticks — in particular, the deer tick (also called the black-legged tick), which can carry and transmit the bacterium responsible for Lyme disease.
Lyme disease is the predominant tick-borne illness in the United States, but it's not the only one. Ticks can spread other bacterial and viral diseases, including babesiosis, anaplasmosis, ehrlichiosis, tularemia, Rocky Mountain spotted fever, relapsing fever, Colorado tick fever, and southern tick-associated rash illness (STARI). Most tick bites won't give you a disease, but some can, and there is no vaccine to protect you from the vast majority of these diseases. It's almost impossible to avoid ticks completely, especially if you spend time outdoors. But you can take steps to lower your risk of getting bitten or, if you're bitten, of becoming ill.
It's not clear how long an infected tick must be attached before it transmits a disease (a crawling tick doesn't transmit anything). For Lyme disease, it probably takes one to three days. "It's a spectrum, but the faster you get it off, the less likely you are to get sick from it.
How to remove a tick
To remove the tick, use narrow-tipped tweezers and grasp it as close to the skin as possible; then pull upward slowly and steadily. If the mouthpart remains in the skin, try to remove it. If you can't, check with your clinician. Never crush or squeeze an attached tick, don't try to burn it with a lighted match, and don't apply any substance like petroleum jelly, fingernail polish, alcohol, or pesticides. If you do, the tick may regurgitate its stomach contents into your skin, increasing the chance of infection.
Signs, symptoms, and treatment
Tick-borne diseases occur throughout the United States, chiefly in late spring and summer, when ticks are most active and most likely to come in contact with humans. Symptoms vary but usually include fever, chills, muscle aches and pains, headache, and sometimes nausea or a rash. Lyme disease is usually heralded by erythema migrans (EM), an expanding area of redness surrounding the tick bite. Rocky Mountain spotted fever and tick-borne relapsing fever start with sudden high fever and chills.
Most tick-borne illness is caused by bacteria, so it can be treated with antibiotics. But it's important to diagnose the problem early, to avoid complications. Luckily, most people develop EM, the telltale early sign, although you can miss it if it appears on the scalp or another hard-to-see area. Some EM clears centrally to form a "bull's eye," which is regarded as a diagnostic sign of Lyme disease and a reason to start antibiotic therapy.
How to protect yourself
If you may have been exposed to ticks and you develop flulike symptoms or a rash, see your clinician — even if the symptoms go away on their own. Tick-borne infection usually causes no lasting harm if it's recognized and treated early. Of course, it's better to avoid getting infected in the first place. To that end, here are some measures you can take:
Protect yourself. Whenever possible, avoid tick habitats — wooded, bushy, or grassy areas, including those near beaches and sand dunes. If you'll be outdoors in tick-infested areas, wear light-colored clothing (to make ticks easier to spot) with long sleeves and long pants tucked into your socks (to keep ticks away from your skin). Use a DEET-containing insect repellent on exposed skin.
Do a tick drag. This is a way to find out whether there are ticks in your yard. Attach a square yard of white flannel to a 3-foot stick and tie a rope to each end of the stick. Drag the cloth over the lawn and leaves, and examine it for ticks that have latched on. Do this several times. To check bushy or grassy vegetation, use a tick "flag," which is similar to the drag but mounted like a flag on a stick. Reduce the number of ticks in your yard by clearing leaf litter, low brush, and tall grasses. You may also want to contact a pest-control professional about chemical options and wildlife control.
Check yourself. If you're in an area inhabited by ticks, check yourself once a day. (Check children and pets in your care, too.) To remove ticks from clothing, you can use an adhesive lint brush or masking or cellophane tape rolled around your hand, sticky side out. Undress and examine your skin, using a mirror for hard-to-see places. If you find a tick attached to your skin, remove it as soon as possible. Note the date, and save the tick for a month for reference or testing in case you develop symptoms.July 2009 update