Tick	Lyme borreliosis is found around the world. 40,000 new cases are reported in Germany alone every year. The borrelia, spiral-shaped bacteria, can attack various organs: skin, joints, nervous system, eyes and heart. The borrelia are transmitted almost exclusively by ticks.
Animated film	Since the arachnids can use their "drilling and cutting tools" to penetrate the skin without pain, many infections are initially not noticed. The borrelia enter the puncture while the tick is sucking blood and spread from that point.

Borreliosis causes widely differing symptoms. Most of them are so uncharacteristic that borreliosis can easily be confused with other diseases. The diagnosis is correspondingly difficult. Fortunately, the pathogen can be detected in the blood and can normally be treated successfully with antibiotics. The only existing vaccine is for the borrelia found in the USA. A vaccine for the borrelia found in Europe is currently in the development stage.

Tick

The Immune Defence against Borrelia

Bullseye (EM) rash

If borrelia are transmitted by a tick bite, the bacteria begin to multiply in the area of the bite, then radiate from that point outward in a circular form. This happens very slowly. It takes two weeks until there is a noticeable immune reaction. Defence cells march to the front to fight the borrelia. Starting at the point of the bite, the skin becomes infected and the typical erythema migrans appears. It does not cause any discomfort and even disappears after a certain time.

If, however, the tick hits a blood or lymph vessel, the borrelia quickly move through the blood and lymph systems to spread throughout the body. The fight against them then takes place in these systems, not in the skin, and the EM does not appear.

Normally the spread of the borrelia through the blood and lymph systems does not occur until ten weeks after the infection. This period is also known as the latent phase. Antibodies to fight the borrelia are formed, and as a consequence of the immune reaction the patient suffers from fever and pain in the joints and muscles. Typically, the symptoms disappear again, but relapses occur repeatedly after long phases often lasting months without any symptoms.

Borrelia

Borrelia - Masters of Disguise
The borrelia are effectively combated by antibodies and the accompanying defence activities. But the success is not permanent, because borrelia can spontaneously change their appearance, just like chameleons: the bacteria put on a shell with new antigens. The previously formed antibodies are ineffective, and as long as the camouflage goes undiscovered, the borrelia remain invisible to the immune system. It must first form new antibodies. Since the borrelia repeat their camouflage manoeuvres at long intervals, the immune system must repeatedly launch new attacks to drive away the modified strains of the bacteria. This results in periodic relapses, accompanied by the symptoms described above, for the patients.

Borrelia are particularly attracted to connective tissue. Once they settle in this "hideout," the body's own defence as well as antibiotics have a difficult time finding them. This can lead to chronic infections in connective tissues. Early diagnosis and prompt treatment are therefore very important.

Be careful with ticks. Anyone who spends a lot of time in wooded areas or in the garden should always examine his body carefully for ticks after returning home. If one of these creatures has attached itself, use suitable tweezers to remove the tick as quickly as possible. The tick can also be examined to determine if it is carrying any pathogens.