Summer is the time for gardening, hiking, relaxing at the lake and traveling to wooded and coastal vacation sites. It's also the time for ticks, putting people and pets at risk of exposure to infections such as Lyme disease, a condition which often is misunderstood.

What causes Lyme disease?

Ticks carry a bacteria in their salivary glands called Borrelia burgdorferi. When the skin-burrowing tick bites, the bacteria is injected into the host and replicates. Replication can take up to 36 hours, so if the tick is removed before it has been attached for more than 24 hours, infection is less likely.

What are the symptoms of Lyme disease?

Signs and symptoms of Lyme disease can be divided into three phases, although patients can present in any stage.

1. Early localized infection. A large bulls'-eye rash is typically the first sign of Lyme disease. Appearing usually within 7 to 14 days, it can be larger than a grapefruit, often found in the armpit, belt line or groin area. Not everyone with the rash has other symptoms, which may include fatigue, headache, muscle and joint aches and fever.

2. Early disseminated infection. Here Borrelia appears to target the nervous system and heart. Patients may have headache and be found with an inflammation of the lining of the brain called meningitis. They may exhibit a "Bell's palsy" weakness of one of the nerves of the face which controls one or both sides of the mouth and eye. The heart also may become involved, with some patients having irregularities in rhythm and signs of inflammation.


3. Late Lyme disease. This least common stage can be seen months or even longer after initial infection. There may be no sign of earlier stages. The most common late symptom of Lyme disease is acute swelling and arthritic pain in one or a few joints, most often the knee.

Can Lyme disease be accurately diagnosed?

Some patients report they have been told that testing for Lyme disease is not accurate and often not detected. This is true in patients who present with a rash or symptoms within the first 7 to 10 days, when antibody levels may not be high enough to be detected. For patients with second-phase symptoms, repeat testing usually is positive. Testing of patients with late disease symptoms is always positive. Research is looking into more accurate testing for early stage. At this time, diagnosis is made by clinicians looking for signs and symptoms and repeating testing over time to confirm diagnosis.

How is Lyme disease treated?

Oral antibiotic treatment with doxycycline, amoxicillin or cefuroxime is effective for those with early disease. The second, early disseminated stage is usually treated with intravenous, followed by oral antibiotics. Late disease, particularly neurologic or severe arthritis, is often treated with two weeks of intravenous antibiotics such as ceftriaxone.

Some patients treated for the later stages may experience fatigue, muscle pains and difficulty with brain function for three to six months after treatment. It is not understood why some patients experience this "post Lyme disease syndrome," similar to the prolonged symptoms that may follow infections like mononucleosis. Some clinicians argue that extended courses of intravenous or oral antibiotics are necessary to treat it, although studies have not been able to document a benefit of those treatments.

Can Lyme disease be prevented?

Prevention of tick bites is the primary approach to avoiding Lyme infection. Use of tick and mosquito repellent, wearing long pants and putting socks over the pant leg may decrease the likelihood of acquiring a tick. Showering after outdoor activities and carefully examining people and pets can allow ticks to be removed before they transmit disease. For older children and adults in an area where there is a high percentage of ticks infected with Lyme disease, two tablets of doxycycline given on the day the tick is discovered may prevent Borrelia infection.

Paula Aucoin, MD, is an Infectious Disease consultant and Medical Director of Infection Control and Prevention at Berkshire Medical Center.