Alzheimer's disease may not be a spirochetosis.

It has been reported previously that spirochetes could be one of the causes of Alzheimer's disease (AD). In this study, we have attempted to reproduce these findings by examining fresh blood samples from 22 patients diagnosed with early stage (n = 16) and late stage (n = 6) AD. The patients were participants in a clinical drug trial. Fresh necropsy brain cortical specimens from AD patients (n = 7) were also examined. Spirochetes were observed microscopically in the blood of only one late-stage AD patient. None of the brain tissues showed the presence of spirochetes. Our results suggest that spirochetes are probably not associated with AD.