Deer Tick

What it is

The blacklegged tick (Ixodes scapularis), commonly called the deer tick, is the tick that spreads Lyme disease in the eastern United States. It is a small hard tick, and in the Mid-Atlantic it is the tick most closely tied to the region's serious tick-borne illnesses. CDC identifies it as the vector for Lyme disease, along with several other infections.

Life cycle

Like other hard ticks, the blacklegged tick has three active stages after the egg: larva, nymph and adult. Each stage needs a blood meal from a host before it can molt into the next stage, and the whole life cycle typically takes about two years.

• Larvae hatch in summer. They are about the size of a period and feed mostly on small animals like mice, birds and chipmunks. Larvae are not born carrying the Lyme bacterium; they pick it up from infected hosts during this first meal.
• Nymphs are active in spring and summer. They are about the size of a poppy seed and are the main source of human Lyme infections, because they are tiny, hard to see, and active when people spend time outdoors.
• Adults are active in the fall, continuing into winter and early spring on mild days. They prefer larger animals, especially white-tailed deer, and can also bite people and pets.

Why "deer tick" is only part of the story

Deer are important for adult ticks, which mate on them, but the bacteria that cause Lyme disease are maintained mostly in small mammals and birds. Removing deer alone does not eliminate the disease risk.

How to recognize it

Size and look

Blacklegged ticks are smaller than American dog ticks.

• Larvae: about 1 millimeter, six legs.
• Nymphs: about 1 to 2 millimeters, eight legs, light brown to translucent; easily overlooked.
• Adult females: about 3 millimeters, with a reddish-orange body behind a dark brown to black shield. She swells to a gray-brown color as she feeds.
• Adult males: smaller and almost entirely dark.

Unlike the American dog tick, the blacklegged tick has no white ornate markings, and its mouthparts are relatively long.

Where on the body

Ticks seek warm, moist, hidden places: scalp and hairline, behind ears, underarms, waistband, groin, behind the knees and between the toes. A nymph can be as small as a freckle, so look carefully for a new "dot" that doesn't wash off.

Look-alikes

• American dog tick: larger, with white or silvery markings. See the American dog tick page.
• Lone star tick: a female has a single white spot on her back.
• Brown dog tick: uniformly reddish-brown.
• Other things: freckles, scabs, moles, dirt specks and tiny beetles can resemble nymphs.

If you're not sure what you've found, photograph it and keep it in a sealed container or in alcohol until you decide whether you need to talk to a doctor.

Where you will find it

Habitat

Blacklegged ticks thrive in humid, shaded places with leaf litter. They are common in:

• Woodlands and the edges between woods and lawn
• Leaf litter, brush and tall grass
• Stone walls and wooded trails
• Shaded yards that border natural areas

They need humidity, and dry, sunny, well-mown lawns are less hospitable.

Questing

Ticks "quest" by climbing vegetation and holding out their front legs. They cannot jump or fly. When a host brushes past, they climb aboard and move to a protected spot before attaching.

Geography and season

Blacklegged ticks are established across the Northeast and Mid-Atlantic and parts of the Upper Midwest, and are in the Southeast. Nymphs peak in late spring and summer. Adults are active in the fall and can be active on mild winter days when it's above freezing. CDC encourages thinking of tick season as year-round, because mild weather can bring ticks out at any time.

Why it matters

Lyme disease

Lyme disease is caused by the bacterium Borrelia burgdorferi (and in some places Borrelia mayonii) and is the most commonly reported tick-borne disease in the United States, according to CDC. Typical early signs include:

• A rash called erythema migrans, which often expands over days, sometimes with a clear center like a bull's-eye. It does not appear in every case.
• Fever, chills, fatigue, body aches, headache, swollen lymph nodes.

If untreated, Lyme disease can spread to the joints, heart and nervous system. Symptoms may include severe joint pain and swelling (especially the knees), facial drooping (Bell's palsy), heart rhythm changes, nerve pain and memory problems. CDC notes that most cases are treated successfully with a course of antibiotics, and early treatment gives the best outcome.

Other infections

The blacklegged tick can also spread other pathogens, including those that cause anaplasmosis, babesiosis, Powassan virus disease and, in some areas, other illnesses. Symptoms overlap with Lyme and with flu, so tell your doctor about any tick exposure.

Transmission timing

Generally, a blacklegged tick has to stay attached for a day or more before it can pass on the Lyme bacterium, and the sooner it is removed the lower the risk. This is a reason to check daily and remove ticks quickly. However, other pathogens, such as Powassan virus, may be transmitted faster, so prompt removal is always best.

Pets

Dogs can get Lyme disease and other tick-borne illness, and they bring ticks into the home. Talk to your veterinarian about prevention.

What to do

Prevent bites

• Know the habitat. Wear long pants and closed shoes in wooded, brushy and grassy areas, and walk in the center of trails.
• Use repellent. Apply an EPA-registered repellent to exposed skin, following the label. CDC lists DEET, picaridin, IR3535, oil of lemon eucalyptus, para-menthane-diol and 2-undecanone among the active ingredients.
• Wear light colors so ticks are easier to spot. Tuck pant legs into socks.

After being outdoors

• Check your whole body within a couple of hours, including scalp, ears, underarms, waist, groin, behind the knees and between the toes. A mirror or a helper makes it easier.
• Check children and pets, and the gear you carried.
• Put clothes in the dryer on high heat for about 10 minutes to kill ticks. If clothes are damp or need washing, they may need longer in the dryer; hot-water washing alone may not kill all ticks.
• Shower soon after coming in.

Removing an attached tick

Follow CDC's steps:

1. Use fine-tipped tweezers to grasp the tick as close to the skin as possible.
2. Pull upward with steady, even pressure. Don't twist or jerk.
3. Clean the bite and your hands with soap and water or rubbing alcohol.
4. Dispose of the tick by placing it in alcohol, sealing it in a bag or tape, or flushing it down the toilet. Never crush it with bare fingers.

Avoid folk remedies like petroleum jelly, nail polish or heat, which can make the tick release more fluid into the skin.

Watch afterward

Note the date and where the bite happened. Over the next few weeks, watch for a rash, fever, aches or fatigue. Contact a doctor right away if these appear, and mention the tick bite.

Yard and pets

• Keep lawns mown and leaf litter raked back from play areas and living spaces.
• Place play equipment away from woodland edges.
• Ask your veterinarian about tick prevention products for pets.
• For persistent tick pressure around your property, a licensed professional can assess the edges and suggest a plan. Avoid using pesticides yourself.

When to call a professional

Call a doctor

• After a bite if you develop a rash (especially one that expands), fever, chills, severe headache, muscle or joint pain, or fatigue, in the days or weeks that follow.
• If you develop facial drooping, severe neck stiffness, heart palpitations, dizziness, or numbness. Seek care promptly.
• If you have questions about whether treatment is needed after a bite. Your doctor can advise based on how long the tick was attached, where you live and your health.

Call a veterinarian

• For tick prevention for dogs and cats, and if your pet becomes lethargic, limps, loses appetite or has a fever after tick exposure.

Call a pest professional

• When you regularly find ticks in your yard, particularly if your home backs onto woods or you have a lot of wildlife activity.
• To assess landscape edges and plan a property-specific approach.