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Lyme disease

Lyme borreliosis is an infectious disease caused by Borrelia infection transmitted via tick bites.


Lyme disease also referred to as Lyme infection or Lyme borreliosis, is a bacterial illness, transmitted to humans by the bite of deer ticks carrying a bacterium called Borrelia burgdorferi. The disease usually spreads in the northeast, Mid-Atlantic, North Central, and Pacific coastal regions of the United States and in Europe. In the United States infection is the most prevalent in the northeast areas especially New York and Connecticut.

Holding tick in fingers

Lyme disease is a potentially serious and debilitating illness, affecting not just the joints, but all parts of the body. The disease produces many symptoms several of which can imitate other diseases. No two cases of Lyme disease are exactly alike. This is due to unique differences in each person’s immune response; variations in the strains of bacteria; the possibility of active co-infections and/or the intensity of a given bacterial load.

If treated early and promptly at the onset of illness, Lyme disease symptoms usually resolve. If left untreated or inadequately treated, the disease can progress to a more complicated chronic form. According to the US Centers for Disease Control (CDC) complications of untreated early-stage Lyme disease include 40%-60% joint disease; 15%-20% neurologic disease; 8% carditis; and 10% or more patients being hospitalized, some with chronic debilitating conditions.


Lyme disease is transmitted when a person is bitten by a tick that is infected with B. burgdorferi bacteria. When an infected tick bites a person, bacteria travel to the tick’s salivary glands and then into the human body through the skin. It takes about 24 hours for a tick to attach itself to the skin and begin to feed. The tick generally must be attached to you for about 36 hours in order for it to transmit the Lyme disease bacteria.

In the United States, the two types of ticks that carry Lyme disease bacteria are:

Deer ticks, which spread Lyme disease in the northeastern and upper midwestern U.S.

Western black-legged ticks, which spread Lyme disease along the Pacific coast-mostly northern California and Oregon.

Dogs, cats, and horses can become infected with Lyme disease bacteria, but they cannot pass the illness to humans. Nevertheless, infected ticks may fall off the animals and then bite and infect humans. Animals may develop symptoms similar to those seen in people, including fever and swollen joints. A vaccine for dogs is available in some states.

There is no convincing evidence that Lyme disease can be spread to humans by insects such as mosquitoes, flies, or fleas. The disease is not contagious and cannot be spread from person to person. But certain precautions should be taken to prevent spread of the illness through ways such as blood transfusions.

  • People with active Lyme disease should not donate blood, because the bacteria that cause the illness can be transmitted this way. People who were previously treated for the disease may be able to donate blood, but they should check with the blood bank first.
  • A pregnant woman may be able to pass Lyme disease to her unborn child, but proven cases are rare. Lyme disease has not been shown to cause birth defects or fetal death.
  • There is no evidence that breastfeeding mothers can pass the illness to their babies through breast milk. But a nursing mother who is suspected of having Lyme disease may be asked to stop nursing until she has completed a course of antibiotic therapy. The baby is also watched closely for symptoms of the disease.

Risk factors

The main risk factor for Lyme disease is exposure to ticks that are infected with Lyme disease bacteria. In areas where Lyme disease is widespread, several factors may increase your risk, including:

  • Spending time outdoors during the warm months of the year when ticks are most active. Most cases of Lyme disease occur in the northeastern United States and Canada when infected ticks are most prevalent-usually between May and November, with peak activity in June and July.
  • Working or playing in grassy or wooded areas doing things like gardening or yard work, hiking, camping, hunting, or fishing.
  • Having indoor/outdoor pets. They can bring infected ticks into the house. Although dogs and cats can become infected with Lyme disease bacteria, they cannot pass the illness to humans. But the infected ticks can drop off the animal and then bite and infect a person.
  • Having a stone fence or a bird feeder near your house. Stone fences often become homes for mice, and mice may feed on spilled seed from a bird feeder. Where there are mice, there are ticks.


Signs and symptoms of Early Local Lyme Disease often start with flu-like feelings of headache, stiff neck, fever, muscle aches, and fatigue. About 60% of light-skinned patients notice a unique enlarging rash, referred to as erythema migrans (EM), days to weeks after the bite. On dark-skinned people, this rash resembles a bruise.

The rash may appear within a day of the bite or as late as a month later. This rash may start as a small, reddish bump about one-half inch in diameter. It may be slightly raised or flat. It soon expands outward, often leaving a clearing (normal flesh color) in the center. It can enlarge to the size of a thumbprint or cover a person’s back. To be considered a local disease the rash must be at the tick bite site with no other major organ system involvement. A rash occurring at other than the bite site is an indication of Disseminated Lyme Disease.

Late-Stage Lyme disease develops if the infection is left untreated and manifests with neurological complications such as impaired consciousness, inflammation of the brain and spinal cord, confusion, seizures, and muscle weaknesses. When the bacteria affect the heart, it results in Lyme carditis presenting with irregular heartbeat or palpitations. An infected person may experience muscular and joint pain as well as occasional swelling of the joints (Lyme arthritis).


A diagnosis of Lyme disease is straightforward if the person meets the following criteria:

  • Lives in an area of tick infestation.
  • Has the tell-tale bulls-eye rash.
  • Has other symptoms (headache, joint aches, malaise, flu-like symptoms).

The enzyme-linked immunosorbent assay (ELISA) or the Western Blot test can be performed to confirm the diagnosis.

ELISA measures antibodies that are directed against the B. burgdorferi spirochete. A newer variant is a rapid test (PreVue) that can provide results within an hour. Positive results from any of these tests still require confirmation with a Western blot test. Negative results do not require further testing. Western Blot test is more accurate. Using this test a visual graph that shows bands of different colors or shading is created and laboratories use that to interpret the immune response.

The polymerase chain reaction (PCR) test detects the DNA of the bacteria that causes Lyme disease. However, it requires technical expertise and expensive equipment and also carries a high risk of false-positive results. Research indicates that blood or urine samples do not provide accurate results, but skin biopsies may be useful in some cases. At this point, the PCR test is reserved for certain patients with specific diagnostic problems. For most patients, standard antibody tests are preferred.

Tests for Neurologic Involvement: Analysis of Spinal Fluid. In patients who have neurologic symptoms, a lumbar puncture (a spinal tap) may be used to test for the bacteria in spinal fluid and may be useful for an early diagnosis of Lyme disease.


Antibiotics are the drugs of choice for all phases of Lyme disease. In nearly all cases they can cure Lyme, even in later stages.

The early stages of Lyme disease are treated with 10 – 28 days of antibiotics. The exact number of days depends on the drug used, and the patient’s response to it. Antibiotics for treating Lyme disease generally include doxycycline, amoxicillin (one of the penicillins) or cefuroxime (Ceftin). Intravenous ceftriaxone may be warranted if there are signs of infection in the central nervous system (the brain or spinal region) or heart. Other types of antibiotics, such as macrolides, are not recommended for first-line therapy.

A 2 – 4 week course of intravenous ceftriaxone is used for treating severe cases of neurological Lyme disease. For milder cases, 2 – 4 weeks of oral doxycycline is an effective option.

There is no surgical treatment for Lyme disease. In severe cases of chronic arthritis, removal of the lining of the affected joints (synovectomy) may be needed if arthritis has not responded to antibiotics.

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