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Eeeuww! We just pulled a tick off of one of our kids. Now what?
Not a week goes by every summer without one of those calls to the office. We’ve been getting a lot lately because of the worry about transmitting infections. So, here’s a primer: the risk of developing these diseases depend on geographic location, season, type of tick, and for Lyme disease only, how long the tick was attached to the skin.
While many people are concerned after being bitten by a tick, the risk of acquiring a tick-borne infection is extremely low, even if the tick has attached, fed and is actually carrying an infectious agent. For example, the risk of Lyme disease from a tick bite in an area where the disease is common is only 1 percent, and it’s not even very common here in Indian.
Of Indiana’s 15 types of ticks, only three species are normally encountered by people and their pets. The remaining ticks are found almost exclusively on wild animals and are only rarely encountered by people.
The American dog tick is the largest, the size of a pencil eraser, and accounts for the majority of tick bites during the spring and summer. They have a creamy, white spot on the back. They can very rarely carry a bacterium responsible for Rocky Mountain spotted fever. Symptoms begin three to ten days after tick attachment and include headache, chills, fever and muscle aches. After the fever begins, a rash develops on the wrists and ankles and then spreads to the rest of the body. When diagnosed, spotted fever can be successfully treated with antibiotics. Although rare, the disease can be fatal.
The lone star tick which is slightly smaller, also has a white spot and is very common in southern Indiana. They appear from March to July. They can also harbor the bacterium that causes Rocky Mountain spotted fever.
The deer tick is the smallest, brown and the size of a pencil point or poppy seed. Their preferred host is
the white-tailed deer, and they are of most concern because of their ability to carry Lyme disease. They arrived relatively recently in Indiana – the first specimens were collected in Porter County in 1987. Transmission activity peaks in June. Adult deer ticks are rarely found on humans, but they do feed on dogs and cats.
Lyme disease is a chronic, tick-borne infection caused by the bacteria Borrelia burgdorferi. In the majority of infected people, a rash will develop at the site of the tick bite within one month. The rash begins small and expands, ranging from several inches to a foot or more in diameter. The rash usually appears reddish but may be pale in the center, causing a “target” appearance. It can be flat, raised, blistered or scabbed. Other symptoms during this acute phase of infection include fatigue, fever, headaches, swollen glands and stiffness or pain in the muscles, joints and neck. If these early symptoms are not treated with the appropriate course of antibiotics such as doxycycline, amoxicillin or cefuroxime, the disease becomes more widespread. Medical complications of disseminated Lyme disease can involve the heart, nervous system and joints.
The CDC and NIH websites are excellent sources of more information (www.cdc.gov).
If a person is bitten by a deer tick, a healthcare provider will likely advise one of two approaches, depending on certain criteria:
- Observe and treat if signs or symptoms of infection develop.
- Treat with a preventive antibiotic immediately.
There is no benefit of blood testing for Lyme disease at the time of the tick bite; even people who do become infected will not have a positive blood test until approximately two to six weeks after the infection develops (post-tick bite). The Infectious Diseases Society of America (IDSA) recommends preventive treatment with antibiotics only in people who meet all of the following criteria:
- Attached tick identified as an adult or nymphal I. scapularis (deer) tick.
- Tick is estimated to have been attached for ≥36 hours (based upon how engorged the tick appears or the amount of time since outdoor exposure).
- Antibiotic treatment can begin within 72 hours of tick removal.
- The local rate of tick infection with B. burgdorferi is ≥20 percent (known to occur in parts of New England, parts of the mid-Atlantic states and parts of Minnesota and Wisconsin).
So, a lot depends on information about what kind of tick, whether it was actually attached to the skin, if it was engorged (full of blood), how long it was attached and where you live. A tick that was not attached, flat and tiny and not full of blood or just walking on the skin could not have transmitted disease.
Even if a tick is attached, it must have taken a blood meal with the 36 to 48 hours of feeding required to transmit the organism that causes Lyme disease, B. burgdorferi. That’s because it lies dormant in the tick's midgut and becomes active only after exposure to the warm blood meal entering the tick's gut. Once active, the organism enters the tick's salivary glands. As the tick feeds, it must get rid of excess water through the salivary glands and will literally salivate organisms into the wound, thereby passing the infection to the host—which is why it takes a while to transmit.
What to do if You are Bitten by a Tick
Remove an attached tick as soon as you notice it. The proper way is to use a set of fine tweezers and grip the tick as close to the skin as possible. Do not use a smoldering match or cigarette, nail polish, petroleum jelly (Vaseline), liquid soap or kerosene because they may irritate the tick and cause it to behave like a syringe, injecting bodily fluids into the wound.
The proper technique includes the following:
- Use fine tweezers to grasp the tick as close to the skin surface as possible.
- Pull backwards gently but firmly, using an even, steady pressure. Do not jerk or twist.
- Do not squeeze, crush or puncture the body of the tick, since its bodily fluids may contain infection-causing organisms.
- After removing the tick, wash the skin and hands thoroughly with soap and water.
- If any mouth parts of the tick remain in the skin, these should be left alone; they will be expelled on their own. Attempts to remove these parts may result in significant skin trauma.
Obviously, the best thing to do is to avoid getting a tick in the first place. Stay out of tick infested areas, especially during the height of the tick season – April, May and June. This is not always possible, so use these precautions:
- Wear long pants and a long-sleeved shirt.
- Tuck the shirt into the pants and the pants into the socks.
- Apply insect repellants to clothing to further reduce the incidence of tick bites.
- Conduct thorough "tick checks" immediately after leaving a tick infested area. Inspect the entire body and immediately remove any ticks found. Prompt removal of attached ticks reduces the risk of disease transmission.
Sources: Purdue University Dept of Entomology, CDC, NIH, IN Dept of Public Health
