Borreliosis / Lyme

Borreliosis (Lyme disease) is transmitted by Borrelia from tick bites. Acute: bull's-eye rash, flu-like symptoms. Later: joint inflammation (Lyme arthritis), nerve inflammation (neuroborreliosis) and chronic skin changes; heart involvement with conduction disturbances usually occurs in the first weeks to months. Whether persistent exhaustion after borreliosis is due to surviving pathogens is disputed. Diagnostics run in stages: ELISA (screening test) → immunoblot (confirmation) → ELISpot (measures the reaction of T cells to Borrelia; its diagnostic value is disputed among specialists). All tests require a blood draw at the practice.

How Borrelia live and are transmitted

Lyme borreliosis is caused by corkscrew-shaped bacteria from the Borrelia burgdorferi sensu lato group; in Europe mainly by B. afzelii, B. garinii and B. burgdorferi in the strict sense. Their reservoir is mice, other small mammals and birds, and in Central Europe they are transmitted by the castor bean tick. The Borrelia live in the tick's gut. Only when the tick sucks blood do they swap their surface protein OspA for OspC and migrate to the salivary glands – this takes hours, which is why the likelihood of transmission rises with the duration of feeding. A protein in tick saliva attaches to OspC and protects the Borrelia from the skin's first line of defence.

How Borrelia affect tissue and the immune system

Borrelia do not produce toxins. The complaints arise mainly from the body's inflammatory reaction to the pathogens. At first they spread in the skin – the bull's-eye rash is the visible defensive reaction. They can then travel via the blood to joints, nerves, the heart and other areas of skin. With adhesion proteins they bind to collagen and other components of connective tissue, they capture the body's own defence inhibitors to escape the complement system, and they continually alter a surface protein to evade antibodies. The species differ: B. garinii prefers the nervous system, B. afzelii the skin, and B. burgdorferi in the strict sense more often the joints.

What do Borrelia antibodies in the blood show?

Antibodies of the IgM class usually form a few weeks after infection, IgG later. In the early phase with a bull's-eye rash, antibodies may therefore still be absent. Conversely, IgG antibodies often remain detectable for years, even when the infection has long been overcome; a positive result therefore does not distinguish between past and active infection. Because many people in Germany have had contact with Borrelia during their lives without becoming ill, the proportion with antibodies rises with age. Tests that measure the reaction of T cells to Borrelia, such as the ELISpot, are disputed among specialists as to their diagnostic value.

What happens when complaints persist after borreliosis?

Some people experience exhaustion, muscle and joint pain or concentration problems for months after treated borreliosis. What lies behind this is disputed. Researchers are investigating residual fragments of Borrelia that continue to stimulate the immune system, persistent inflammation, autoimmune processes in which antibodies also recognise the body's own structures, and lasting tissue damage, for example to nerves. Whether living Borrelia survive in the body after treatment has not been demonstrated in humans and is disputed in research.

The interpretation is given in your report.