Tick Bites and Lyme Disease

Tick bites are more common in the late spring and summer months.  Lyme disease is a tick-transmitted disease caused by a bacterium, Borrelia burgdorferi.  This organism is carried by the deer tick and the white-footed mouse is the primary animal reservoir for Borrelia burgdorferi and the preferred host for nymphal and larval forms of the deer tick.  Deer are hosts for adult ticks but do not carry Borrelia.

Lyme disease has been reported in 49 states, but most cases occur from Massachusetts to Maryland, in Wisconsin and Minnesota, and in California and Oregon.

Deer tick nymphs attack humans and are very small and hard to see.  Infection does not usually occur until the tick has been in place for more than 36 hours.  Looking for and removing ticks quickly can prevent development of Lyme disease. 

The proper technique for tick removal includes the following:

• Use tweezers to grasp the tick as close to the skin surface as possible.
• Pull backwards gently but firmly without jerking or twisting.
• Do not squeeze, crush, or puncture the body of the tick.
• 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. 

Ticks that transmit Lyme disease are usually brown and about the size of a poppy seed (nymphs).  Larger ticks that are brown with a white collar are usually dog ticks and do not transmit the disease.

Even a deer tick must first take a blood meal which takes 36 to 48 hours and transmit the organism that causes Lyme disease.  That is why early removal of the tick before it is engorged with blood will help prevent the disease.

Lyme disease usually manifests on the skin with a red area at the bite site.  The area expands, often with central clearing.  If untreated, other smaller areas develop on the skin over time.  Flu-like symptoms then develop with malaise, fatigue, chills, fever, headache, muscle aches and joint pain.  These and other symptoms may continue for weeks.  Neurologic symptoms may develop in some patients including numbness and sensory changes.  A small number of patients will develop cardiac symptoms such as heart block, decreased cardiac output and inflamed heart muscle with chest pain.

Untreated Lyme disease will develop late stage symptoms months or years after the initial infection.  This can include arthritis with joint pain and swelling.  Mood changes, sleep disturbance and memory problems are also late stage manifestations.

Lyme disease is treated with antibiotics.  Patients that have been bitten by a suspect tick but with no clinical manifestations are often treated with a single dose of doxycycline.  Patients with symptoms of disease are treated with doxycycline for 14 to 21 days.  Other antibiotics are also used depending on the situation.

There is currently no vaccine available to prevent this disease, so careful monitoring for tick bites is the best prevention.