Lyme Disease
Steadily increasing cases,
while entirely preventable

Lyme disease is an illness caused by a bacterium after being bitten by an infected tick. These bacteria are carried by the black-legged tick, also known as the deer tick. The disease is wide-spread and changes in climate make ticks carrying the bacterium prevalent in areas where it did not exist before. It also makes infections more frequent. The incidence of tick-borne diseases have doubled in the the last decade.

If not diagnosed or treated early, Lyme disease can develop into a chronic illness that leads to long-term, serious health problems. In rare cases, Lyme disease can result in death.



New infections per year




Chronic Lyme disease yearly


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Dead per year

What causes Lyme disease

Lyme disease, or Lyme borreliosis, is a bacterial disease transmitted to humans through the bite of infected ticks. An infected tick usually carries the Borrelia burgdorferi bacterium. In Europe and Asia, Borrelia afzelii and Borrelia garinii are also causes of the disease. In North-America, Borrelia mayonii occasionally is involved.

In the United States, ticks of concern are usually of the Ixodes scapularis type. In Europe, ticks of the Ixodes ricinus type may spread the bacteria more quickly.

The length of time for a tick to transmit disease can vary based on the type of tick and the stage of the tick, but generally contact longer than 24 hours is needed to transfer the bacteria. Ticks can be the size of a seed when initially attached to the body and difficult to spot. It is important to remove an attached tick as soon as it’s found, and to remove it properly to avoid the spread of pathogens.

Lyme disease affects both humans and animals.

Photo: Adult deer tick, Ixodes scapularis

Where is Lyme disease found

Lyme disease has been found across North America, Europe, Australia and parts of Asia. Recent findings include presence in South and Central America. In America, Lyme Disease is most prevalent in mid-Atlantic and the northeast.

Different genospecies of the disease are more common in certain areas of Europe. For example, infections from B. afzelii are most common in Northern Europe, B. burgdorferi in Western Europe, and B. lusitaniae in the Mediterranean.

Recent cases of B. burgdorferi were found in Brazil. Isolation reports from Mexico and Colombia also show prevalence of Lyme Disease.

Ticks are not just a suburban problem, they are everywhere including urban areas and cities.

Image: Geographical distribution of reported Lyme disease cases

What are the symptoms of Lyme disease

When a person is bitten by an infected tick, the only symptom in the first stage consists of a red skin rash or lesion (called erythema migrans) that spreads in ring form from the site of the bite. This occurs in about 60–90% of cases within 2–30 days of the tick bite.

Sometimes the skin lesion can be accompanied by symptoms similar to a flu where there is fatigue, fever, headache, muscle and joint pain, and a stiff neck. Initial symptoms usually last for a few weeks and can stop showing without any treatment.

If left untreated, a disseminated infection affecting the nervous system (10% of cases), the joints, the skin and/or the heart (rare) may follow within days or weeks.

After months or years, it is possible to develop chronic symptoms which include neurological abnormalities, chronic arthritis, and acrodermatitis chronica atrophicans, which is a skin condition usually seen on the limbs. This skin condition can occur anywhere from six months to a few years after initial symptoms.

Photo: Erythema migrans in Lyme disease.

How can Lyme disease be prevented

Prevention involves avoiding tick bites by using special repellents, wearing long pants and long sleeves as well as avoiding areas inhabited by ticks. Skin and clothing should be frequently examined for the presence of ticks and in case ticks are found, they should be removed without touching them with bare hands. (refer to ‘How is Lyme disease treated’ below)

Several vaccines to prevent the disease are in development. For pets a vaccine exists.

How is Lyme disease diagnosed

No laboratory tests are required to diagnose erythema migrans (the characteristic rash). A clinical evaluation and an assessment of the risk of tick exposure suffice.

Laboratory tests are necessary to confirm a diagnosis of late-stage infection. B. burgdorferi antibodies are usually detectable within 4 to 8 weeks of infection: patients with late-stage infection usually test very strongly positive for these antibodies. However, the occurrence of false-positive tests in patients with other infections or conditions, such as autoimmune diseases, can lead to misdiagnosis and inappropriate treatment.

Polymerase chain reaction (PCR) tests, capable of identifying the specific bacteria are available from the WoIDMo.

How is Lyme disease treated

An attached tick should be removed using tweezers or fine-pointed forceps, grasping it as closely as possible to where it is attached to the skin and pulling it gently upwards, trying not to break off the mouth parts. The risk of Lyme infection is not increased if the mouth parts are left behind. A skin disinfectant, such as alcohol – HAC – iodine, should be applied after removal of the tick to prevent infection. (If you remove the tick yourself, store the tick in a closed container in the freezer for a couple of weeks, until you are sure not to have developed symptoms)

Those who do develop Lyme disease should be treated for several weeks with appropriate antibiotics (amoxicillin, cephalosporin, and macrolides for disseminated infections). Early treatment can prevent the risk of developing late-stage complications.

Patients with late-stage Lyme disease can also benefit from antibiotics but if severe tissue damage occurs prior to treatment, complete recovery may not be possible.

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