The Medical Minute: Time to think about ticks again

May 13, 2004

By John Messmer
Penn State Milton S. Hershey Medical Center

Ticks have returned with the warmer weather, bringing with them the risk of tick-borne illnesses. Most people know that ticks can cause Lyme disease, but the little bugs can also transmit other diseases such as Rocky Mountain spotted fever, tularemia, ehrlichosis, babesiosis and Colorado tick fever. Lyme disease can cause a variety of short-term and long-term health problems, and because the symptoms mimic the flu, infected individuals sometimes don't recognize when they're infected with Lyme disease. As summer approaches, it's time to think about ways to avoid tick bites and all the major health problems these tiny critters can cause.

First, a little history. In the 1970s a cluster of cases of arthritis in Lyme, Conn., were linked to an organism transmitted by tick bites. It is believed that Lyme disease was introduced into the United States by a herd of deer brought to Long Island, N.Y., from Europe in the early 20th century.

Because they are smaller than common ticks, Lyme disease ticks are difficult to see. When tick eggs hatch, the larva finds a passing mouse and attaches itself, feeds, drops off and sheds its outer skin changing into a nymph. Nymphs wait on grass or other vegetation for a passing mammal, commonly a deer, but also sheep, bears, dogs and humans. After feeding, the tick drops off and sheds its skin to become an adult. After fertilization the adult female will feed one more time, lay her eggs and die. Lyme disease is spread almost exclusively by the nymph. Because it is so small, about the size of a poppy seed, it is not commonly seen on its hosts. Adult Lyme ticks are more often infected, but are usually seen and removed before they feed.

If you find a tick on yourself or your child would you know what to do? Burn it? Smother it with Vaseline? The answer is: none of the above. There is one proper way to remove a tick. If it is crawling, you can pick it up with tissue, brush it off outside or grasp it with tweezers. Ticks will crawl around a person's skin looking for a good place to feed for an hour or two. Once the tick bites, it secretes an adhesive that helps it stick to the skin. If you see a tick that has bitten, don't panic. Lyme disease ticks feed for a long time and it takes 24 to 48 hours of feeding to transmit the disease (Rocky Mountain spotted fever takes eight to 16 hours to be transmitted). As it feeds, it swells from flat to round. If it is flat, you have plenty of time so don't rush. If it is round, it is still important to proceed carefully.

Ticks should be grasped with tweezers just behind the head. Using the tweezers, the tick should be pulled gently up. It might not come off immediately due to the adhesive. Just keep traction on the tick and it will open its jaws. As the adhesive pulls away, it will resemble a bit of skin coming off. Avoid pulling forcefully or the head may stay in the skin and will require removal by a medical professional. Do not use matches, Vaseline, kerosene, smoke or any other method of removal. Lyme disease organisms live in the tick's stomach. Heat and squeezing may cause a tick to regurgitate infection into the skin.

If you find a tick that has fed and remove it, wash the area with soap and water. Commonly there will be a millimeter or two of redness around the bite in a day or two. This is normal. The rash of Lyme disease is large -- inches across -- and occurs in 90 percent of cases within two weeks after the bite. At this point it is easily treated with antibiotics. If not treated, in days or weeks a flu-like illness occurs with fever and aches. It can be distinguished from the flu by its lack of respiratory symptoms, such as cough and sore throat, and its occurrence in spring and summer, a time when flu normally does not occur. Medical treatment is vital since untreated Lyme disease can affect the heart and brain and cause arthritis.

As with many illnesses, prevention is key. Ticks avoid mowed lawns, which are too hot and dry. They favor dense, mature woods with thick undergrowth of shrubs and small trees and along the edges of woods adjacent to lawns or fields. People living near woods, farmers, hunters, campers and landscapers are at greatest risk. Pets can carry ticks into the house where they can find humans. If you expect to be in an area where you may be exposed to ticks, wear light colored clothing and tuck your pants into your socks if possible. Use tick and insect spray containing Permethrin or DEET according to the package directions to repel ticks. Do not use products designed for dogs on yourself. When you go indoors, examine your entire body for ticks remembering that Lyme disease ticks are very tiny.

A Lyme disease vaccine was available for a couple years but it was not completely effective, was expensive and required regular boosters. It was withdrawn from the market due to poor sales in 2002.

With a little care, there is no reason to stay indoors now that the nice weather is here. For more information on Lyme disease, visit

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Last Updated March 19, 2009