Borreliosis or Lyme disease

Lyme disease is transmitted by a tick bite

Borreliosis, or Lyme disease, is caused by Borrelia bacteria which is carried by ticks and can be transferred to the skin through a tick bite or, rarely, through a horse fly bite. The risk of transmitting Lyme disease from a tick to the skin only increases significantly after the tick has been attached to the skin for 24h. As early Lyme disease can be treated effectively with antibiotics, it is important to know how the disease spreads and what the symptoms are.

Symptoms of Lyme disease

According to estimates, 3,000–4,000 people in Finland contract early-stage Lyme disease each year. If the early stage is not treated with antibiotics, approximately half of the patients develop later symptoms of the disease, which can be diverse and severe and cause permanent changes.

Symptoms of early-stage Lyme disease

Early-stage symptoms of Lyme disease are typically skin changes. Lyme disease is accompanied by erythema migrans, which is a circular rash. Sometimes a red or blue soft lymphocytoma, a benign tumour, may appear on the skin. Symptoms of arthritis may also be associated with the early stage.

Skin symptoms of Lyme disease:

• Lyme disease rash. A ring-shaped or evenly flush rash with a diameter of more than 5 cm begins to spread over the bite site of the tick.
• Lymphocytoma. A red or blue soft benign tumour may appear on the skin.

You should see a doctor if you notice early-stage symptoms of Lyme disease, as they can usually be treated with antibiotics.

Symptoms of late-stage Lyme disease

If Lyme disease is left untreated at an early stage, the bacteria can spread from the skin to other parts of the body. The symptoms of late-stage Lyme disease are diverse and can occur in one or more organs after weeks, months or even years. The skin, brain, nerves and joints are the most common areas affected by the disease.

• Joint symptoms. Up to half of patients experience joint symptoms, but only one in five develops clear joint swelling inflammation, or arthritis. It is typical that the joint symptoms caused by Lyme disease vary and there are asymptomatic and symptomatic periods. The symptoms may resemble rheumatism. Usually only a few large joints, such as the knee or ankle joint, are affected.
• Meningitis. Lyme disease also quite often causes meningitis, which can recur. However, the inflammation may be milder than that caused by other bacteria and may cause very few symptoms. Borrelia can also nest in the brain tissue itself.
• Cardiac symptoms. Cardiac symptoms may also occur, but are less common as they occur in less than 10% of patients. Cardiac symptoms typically appear within a few months of the tick bite. Borrelia can cause a sudden bradycardia phase, which may even require a temporary pacemaker. Lyme disease can sometimes also manifest as silent myocarditis.

Lyme neuroborreliosis

Lyme neuroborreliosis is a disease that causes inflammation in the central nervous system. Lyme neuroborreliosis can develop quite quickly, within weeks or months of a tick bite and Lyme disease infection.

Symptoms of Lyme neuroborreliosis

The most common neurological symptoms caused by Lyme disease are a tearing pain in the limbs and body, which are caused by the bacteria nesting in the nerve roots originating from the spinal cord. Borrelia bacteria can also infect nerves that stem directly from the brain, such as the facial, auditory and optic nerves. Facial palsy is one of the most typical neurological manifestations of Lyme disease.

Progression of Lyme disease

The progression of Lyme disease can often be prevented with medical treatment, even if the symptoms of late-stage Lyme disease have persisted for a long time. Permanent changes caused by the disease, such as nerve damage, can be difficult to repair.

Lyme disease differs from many other bacterial infections in that the course of the disease is usually not particularly severe. Inflammation can progress slowly for years while the patient is living a relatively normal life. The same person can repeatedly contract Lyme disease. Even if antibodies are formed in the body, they do not protect against disease recurrence.

Examination of Lyme Disease

The diagnosis of Lyme disease is mainly based on information obtained from the patient and their symptoms. The patient is asked to provide information from several years. The most important information is related to the patient’s stay or visits in areas with a large tick population as well as possible tick bites and associated rashes.

Laboratory tests support the information and symptoms reported by the patient. The most common laboratory test for Lyme disease is the measurement of antibodies to Lyme disease in a patient’s blood sample. The formation of antibodies in the early stages of the disease is low, so antibody testing only reveals a little over a third third of the cases. Early-stage erythema migrans is, therefore, usually diagnosed solely on the basis of the appearance of the rash. If a bite has not been detected and a ring-shaped rash does not develop, early-stage Lyme disease almost always remains undiagnosed.

Lyme disease test for antibodies

If Lyme disease bacteria remains in the human body for a longer period of time, antibodies can develop. Antibody testing is crucial in the diagnosis of late Lyme disease. If the patient has symptoms related to the brain or nerves, antibodies are tested in the spinal fluid sample in addition to blood.

The biggest problem with an antibody test is its uncertainty. The test may be positive, but it does not indicate whether an infection is ongoing or whether the antibodies indicate a previous infection that has already healed. In addition to antibody tests, a culture and duplication of Borrelia DNA can be used, but unfortunately they are complex and time-consuming tests.

Treatment of Lyme disease

Early-stage Lyme disease is treated with antibiotics. The inflammation is almost completely cured when the oral antibiotics are started during the skin change phase.

The aim is to concentrate the treatment of late-stage Lyme disease in central hospital-level locations. Late-stage Lyme disease requires longer-term treatment, often starting with intravenous antibiotics followed by oral antibiotics.

Chronic Lyme disease

If the treatment of Lyme disease is prolonged, it is often referred to as chronic Lyme disease. Despite long-term treatment, some patients may experience partially unchanged symptoms or relapse after treatment. The symptoms may continue in the brain, for example, if the tissue damage has already caused changes that cannot be repaired.

Lyme disease can also trigger a so-called autoimmune reaction, in which the body’s defence mechanisms cause damage in its own tissues. This means that the symptoms of the disease can continue even if the Lyme disease bacteria has already been eliminated with antibiotics.

Prevalence of Lyme disease

In Finland, Lyme disease occurs in the same areas as ticks. The most cases have been found in the coastal regions of the Åland Islands, southwestern Finland and southern Finland. Cases also occur elsewhere in Finland, except in Lapland.

Prevalence of Lyme disease outside Finland

The first cases of Lyme disease were diagnosed in Finland in the 1980s, but it has occurred in Europe for at least a hundred years. In America, Lyme disease is the most common disease transmitted by ticks. Lyme disease is also very common in Central Europe and Sweden.

Prevention of Lyme disease

The best way to prevent Lyme disease is to protect yourself from tick bites. There is no vaccine against Lyme disease for humans available. TBE vaccine is commonly referred to as a tick vaccine, but it only protects against tick-borne encephalitis, not against Lyme disease.

How to prevent Lyme disease:

• Wear protective clothes when you are out in nature. Wear long trousers, long-sleeved shirt and boots. It is advisable to tuck your trousers inside your socks. Wearing light-coloured clothing makes it easier to detect ticks.
• Regular tick checks. It is advisable to perform the check at least once a day, as the risk of Lyme disease caused by a tick is greatly reduced if the attached tick is removed from the skin in good time.
• Tick repellent: Use tick repellents on the parts of the skin which are not covered.
• If possible, avoid tick areas: Ticks usually thrive in humid environments with lots of vegetation. Such terrain includes, for example, bogs, field edges, tall grass and bushes.

Tick checks should also be carried out regularly on any pets that move outdoors, as ticks can travel with the pet indoors and infect people.