The primary objective is to evaluate to what extent and in what way (through which mechanisms) H. suis infection of the blood-brain barrier & egrave; re and the blood-cerebrospinal fluid barrier & egrave; re be ISOLATED Affects and the onset of neurodegenerative changes at the central nervous system works in hand. In the second place, the effect of an H. suis infection on the course of the disease Parkinson's and Alzheimer's disease are investigated. In the third place, the role of the gamma-glutamyl transpeptidase (GGT) of H. suis to be examined. Finally, it will be examined whether autoantibodies are built up during a H. suis infection.