What is Lyme disease?

Lyme disease, also called borreliosis, describes a clinical picture that is transmitted by ticks. However, infection from person to person can be ruled out. The disease can take on different forms and manifest itself to varying degrees. Lyme disease mainly affects the skin, but can also affect the nervous system, the joints and the heart. The disease is caused by bacteria. These are the so-called Borrelia burgdorferi bacteria. Lyme disease is particularly common in Germany between June and August due to the high incidence of ticks. So far, there is no vaccination against Lyme disease.

Incidentally, the disease of Lyme borreliosis was named after the place where it was discovered in 1976. In Lyme, Connecticut/USA, a conspicuously large number of patients developed joint inflammation after tick bites. Although skin manifestations associated with Lyme borreliosis were already known in Europe at the turn of the last century, the pathogen was only described and examined in detail for the first time in 1981.

What types of Lyme borreliosis are distinguished?

Lyme borreliosis is triggered by different species of the bacterium of the genus Borrelia. These belong to the so-called bacterium Borrelia burgdorferi sensu lato (Bbsl complex). There are more than 20 described species, of which at least the following six are considered to be human pathogens:

• Borrelia afzelii,
• Borellia bavariensis,
• Borellia burgdorferi sensu stricto,
• Borellia garinii,
• Borellia mayonii,
• Borellia spielmanii.

The pathogenicity of the species Borrelia bissettiae, B. lusitaniae and B. valaisiana is currently still being researched. All of the above-mentioned human pathogenic species can cause the so-called migratory rash (erythema migrans). The pathogens Borellia bavariens and Borellia garinii can manifest neurologically, while B. burgdorferi sensu stricto is associated with the development of so-called Lyme arthritis. Borellia afzelli, on the other hand, can contribute to the development of acrodermatitis chronica atrophicans.

In which regions do the human pathogenic Lyme species appear?

All of the human pathogenic species mentioned above, with the exception of Borellia mayonii, occur in Europe. In the USA, however, only Borellia burgdorferi sensu stricto and Borellia mayonii have been detected. In Asia, all human pathogenic species except Borellia burgdorferi sensu stricto and Borellia mayonii have been detected. Lyme borreliosis thus occurs worldwide in the temperate climate zones. In the tropics and subtropics, however, other Borrelia diseases such as louse or tick-borne relapsing fever are also common. In rare cases, this is brought to Germany by travellers.

How common is Lyme disease in Germany?

The exact number of cases of Lyme disease within Germany is unknown. The reporting incidence in the federal states with mandatory reporting of the disease varies between 26 cases/100,000 inhabitants (2015) and 41 cases/100,000 inhabitants (2013). However, regardless of the exact number of cases, researchers agree that Lyme disease is widespread and should be taken seriously. The main difficulty is that the disease can appear years after the tick bite.

How is Lyme disease transmitted?

The pathogens of Lyme borreliosis, the so-called Borrelia bacteria, are transmitted to humans through tick bites. In Central Europe, this is mainly done by the tick (Ixodes ricinus). In Germany, about one third of all ticks are carriers of Borrelia. However, not every tick bite necessarily leads to an infection. For example, if the tick is removed early, the risk of infection is significantly lower. If, on the other hand, the tick remains attached for more than twelve hours, the risk of infection increases significantly. Studies have shown that in Germany only about one in 100 tick bites leads to Lyme disease. Incidentally, a person infected with Lyme disease cannot transmit the disease to other people.

How exactly is Lyme disease transmitted?

In the shield tick (Ixodes ricinus), the Borrelia bacteria are found in the intestine. After sucking, the borrelia migrate into the salivary glands and are transmitted from here together with the saliva of the tick to the person bitten. However, transmission of the borrelia is only possible after a longer period of time. This means that the tick must have sucked for at least several hours for disease transmission to occur.

Which reservoir is known for Lyme borreliosis?

Mice, but also birds, are considered to be the most important pathogen reservoir for Lyme borreliosis. However, hedgehogs, foxes, rabbits and even reptiles are also considered host animals and pathogen reservoirs for the bacterium Borrelia burgdorferi.

When does Lyme disease manifest itself after a tick bite?

Most diseases are asymptomatic. However, Lyme borreliosis can be detected about a few days to weeks after the tick bite by the so-called wandering redness. More rarely, late forms of Lyme borreliosis can occur months to years after the tick bite.

What are the symptoms of Lyme disease?

In most cases, Lyme borreliosis goes unnoticed. Should the patient experience symptoms, they can manifest themselves in very different ways, start at different times or occur in combination. This makes it difficult to diagnose the disease at an early stage. In 90 percent of all cases, however, Lyme disease becomes noticeable through the so-called migratory redness (erythema migrans). This is a ring-shaped reddening of the skin at least 5 cm in size, which usually has a paler colour contour in the middle than at the edges. The reddening of the skin extends outwards over several days and is noticeable for the first time about three to 30 days after the tick bite, usually in the area of the bite site. However, wandering redness can also develop in other parts of the body. These include:

• the legs,
• the head or neck area.

As the disease progresses, the following flu-like symptoms may also occur:

• Fever,
• Swelling of the lymph nodes,
• Muscle and/or joint pain.

In children, nodular and/or blue-red skin swellings may also appear. These occur mainly on the ear, on the nipples or in the genital area. Very rarely, chronic skin inflammation (acrodermatitis chronica atrophicans) occurs in some patients. The skin changes, especially on the inside of the arms, legs, fingers and/or toes. In the course of acrodermatitis chronica atrophicans, the skin becomes paper-thin and takes on a bluish colour.

What are the manifestations of neuroborreliosis, Lyme arthritis and Lyme carditis?

Lyme disease can affect the nervous system. Doctors call this neuroborreliosis, but it only occurs in about three out of 100 patients. Neuroborreliosis usually manifests itself a few weeks to months after the tick bite. It is rather rare for neuroborreliosis to develop years later. The disease is accompanied by the following symptoms:

• burning nerve pain, which increases in intensity especially at night,
• unilateral or bilateral facial paralysis,
• inflammatory nerve irritation, which can lead to numbness, impaired vision and/or hearing,
• more rarely, paralysis of the trunk, arms and/or legs.

If neuroborreliosis develops in children, it manifests itself as a non-purulent meningitis, which is associated with severe headaches or sudden one-sided facial paralysis (in up to 90 percent of all cases). In facial paresis, the eye on the affected side cannot be closed and the forehead cannot be furrowed. It can also happen that one corner of the mouth hangs down limply.

In addition to neuroborreliosis, so-called Lyme arthritis can also occur. This develops in almost five out of 100 patients and causes inflammation of the joints. Lyme arthritis mainly affects the knee joints and more rarely the ankle or elbow joints. The disease usually progresses in episodes and occurs again and again.

Very rarely, Lyme disease can affect the heart and cause inflammation, cardiac arrhythmia or conduction disorders. Doctors refer to this as Lyme carditis.

What symptoms should a doctor be consulted for?

If the migratory redness described above occurs, it is advisable to contact a doctor immediately. This also applies if you do not remember being bitten by a tick. In addition, medical assistance should be sought if symptoms such as fever and/or muscle aches and headaches begin.

What are the different stages of Lyme disease?

Lyme disease is usually divided into the following three stages:

• Stage I:In many cases of the disease, a so-called migratory redness (erythema migrans) develops between three days and several weeks after the tick bite. This does not necessarily have to appear at the site of the bite, but can also develop on other parts of the body. The latter, however, indicates a spread of the bacterium in the organism. In this first stage of the disease, some patients complain of general infection symptoms such as fever, headache, muscle and joint pain. There may also be swelling of the lymph nodes and/or general fatigue. In this stage of the disease, the diagnosis of Lyme disease is more clinical.
• Stage II:After a few weeks to six months after the tick bite, burning nerve pain may occur near the erythema migrans. In particularly severe cases, this can be accompanied by sensory disturbances and paralysis.
• Stage III:After six months to years after the tick bite, about 5 percent of all adults and children complain of Lyme arthritis, with increasing joint pain. The knee and ankle joints are particularly affected. The pain either occurs in episodes or is permanent.

How is Lyme disease diagnosed?

Lyme borreliosis can be diagnosed by the attending physician through a physical examination if the wandering redness is present. If the patient has other symptoms that point to Lyme disease, these can be clarified by a blood test.

Neuroborreliosis can be diagnosed intrathecally, i.e. by testing the nerve fluid for antibodies against Borrelia. In this case, the so-called CSF/serum index is used to determine the borrelia-specific intrathecal antibody formation. In the majority of patients, the CSF/serum index can be determined between 6 and 8 weeks after the onset of the disease. In many cases, inflammatory changes in the cerebrospinal fluid can also be detected. These may include lymphocytic pleocytosis and/or blood/ CSF barrier disorder.

How is Lyme disease treated?

If the disease is diagnosed early and treated with antibiotics, the patient usually recovers quickly. Severe courses of the disease, but also late manifestations can be prevented by administering antibiotics at an early stage of the disease. The following antibiotics for oral use are usually used:

• Amoxicillin: mostly used for children and pregnant women,
• Doxycycline: usually used to treat adults

Alternatively, cefuroxime axetil or azithromycin can be administered. Severe courses of the disease can also usually be prevented by administering antibiotics. Depending on the severity of the disease, intravenous therapy may also be necessary in a chronic stage. Ceftriaxone, cefotaxime or penicillin G are mainly prescribed for this purpose. The duration of administration of the respective drug depends on the type of disease, but also on the severity, and can be between 10 and 30 days. Taking antibiotics for months or repeating them several times, or prescribing a combination of several active substances is not recommended by doctors. In 82 percent of all cases, the disease subsides after the end of the first treatment cycle. In particularly severe cases, it takes up to four infusion series until the disease is over.

If a patient has been bitten by a tick but does not experience any symptoms of the disease, preventive administration of antibiotics is strongly discouraged. The risk of side effects from antibiotic administration cannot be outweighed by the health benefits of administering the drug.

What is the prognosis of Lyme disease?

The prognosis of Lyme disease depends on starting treatment quickly, but also on how much time the bacteria have had to spread and multiply in the body. If Lyme disease is treated properly, the symptoms usually disappear completely. However, it can also happen that the symptoms of Lyme disease remain. For example, some patients suffer from mild facial nerve paralysis and persistent joint pain for the rest of their lives after contracting the disease. This can be explained by a persistent reaction of the immune system. Complications occur mainly when the disease is diagnosed at an advanced stage and is therefore difficult to treat.

Many media report about a so-called post-Lyme disease syndrome. However, no clear clinical picture could be presented here so far. Patients suffering from it would often complain of muscle pain, a general feeling of weakness and difficulty concentrating. However, studies show that these symptoms occur just as often in people who have never had Lyme disease. Therefore, many medical experts doubt the existence of post-Lyme disease syndrome.

Recognised late effects of the disease, on the other hand, are persistent skin changes, neurological complaints or joint inflammation. There are no long-term effects of a Lyme disease infection that could have a negative impact on life expectancy, for example.

Who tends to get Lyme borreliosis particularly often?

People who are bitten particularly often by ticks are most likely to contract Lyme disease. Ticks are mainly found in the wild, i.e. in the forest and in the grass. They can be found on blades of grass, in undergrowth or on bush branches. From here, they can penetrate the skin on closer contact and then into other parts of the body. However, ticks can also be transmitted to humans by wild and domestic animals that spend time outdoors. Lyme disease can develop again and again through tick bites. Once you have overcome Lyme disease, it does not protect you from contracting Lyme disease again.

Is Lyme disease dangerous during pregnancy?

Smaller studies from pregnancy initially led to the conclusion that a Lyme borreliosis infection does not affect the foetal development of the unborn child. However, this assumption has not yet been confirmed by more recent studies.

A pregnant woman who has Lyme disease is treated with antibiotics just like other patients. However, the doctor makes sure that the agent does not harm the expectant mother or the unborn child. It is considered unproven that mothers can transmit Lyme disease to their child through breastfeeding.

How can one protect oneself against Lyme disease?

So far, there is no vaccination against Lyme disease. The vaccination against the viral infection early summer meningoencephalitis (FSME), which is also transmitted by ticks, does not protect against Lyme disease. To effectively prevent infection, you should take care not to be bitten by ticks. To do this, you should take the following to heart when you are outdoors:

• Wear long-sleeved shirts, trousers and closed shoes when in the forest. If possible, wear socks over your trousers so that ticks cannot slip under the trouser leg.
• Wearing light-coloured clothing to detect and remove ticks as early as possible.
• Apply tick repellent. Follow the exact manufacturer's instructions on the effectiveness of the product over time and renew it at regular intervals to ensure that you are always optimally protected.
• After spending time outdoors, the body should be thoroughly checked for ticks. Keep in mind that ticks prefer warm, soft areas of skin such as the back of the knees, the groin, the area behind the ears or under the armpits as well as the head and hairline.

However, should a tick bite occur, it should be removed quickly to minimise the risk of contracting Lyme disease.

How should ticks be removed?

Ticks should be removed as soon as possible. This is done as follows:

• 1. The tick should be grasped as close to its head area as possible, i.e. as close to the skin as possible. Pull the tick slowly and straight out of the skin. It is best to use tweezers or a so-called tick card to remove the tick.
• 2. The puncture site should then be carefully disinfected.

In order to release as few pathogens as possible, the tick should not be treated with oils and/or creams. Also, do not try to squash the tick. It is possible that remains will be left behind when the tick is removed. This can lead to a slight inflammation of the skin, but it does not increase the risk of contracting Lyme disease.

Does a nationwide obligation to report Lyme disease make sense?

The obligation to report a disease does not depend on the significance or severity of the disease. Whether a disease is subject to compulsory notification depends primarily on the question of whether the health protection of the population can be improved by reporting the disease. Therefore, especially those diseases are subject to compulsory notification that require the health authority to act with regard to the sick person in order to prevent the disease from spreading further. However, Lyme disease cannot be transmitted from person to person. Therefore, a nationwide obligation to report this disease does not necessarily make sense, especially since an obligation to report is always associated with a certain bureaucratic effort. For the future effective control of Lyme borreliosis, on the other hand, it makes more sense if both laboratory diagnostics are standardised and therapeutic guidelines are developed.

Lyme borreliosis: a summary

Lym borreliosis is an infectious disease caused by the so-called Borrelia burgdorferi bacteria. Humans can become infected with the disease through tick bites unless the tick is removed early. In most cases of the disease, Lyme borreliosis becomes noticeable through the so-called wandering redness. This is a ring-shaped reddening that can occur around the site of the bite, but also on other parts of the body. After the appearance of the wandering redness, many patients complain of flu-like symptoms. Lyme disease can usually be treated well with antibiotics. Every year, about 3 out of 10,000 people in Germany contract Lyme borreliosis. The disease is not life-threatening.