Alzheimer's disease and infection: do infectious agents contribute to progression of Alzheimer's disease?

Alzheimers Dement. 2009 Jul;5(4):348-60. doi: 10.1016/j.jalz.2008.12.001.


Infection with several important pathogens could constitute risk factors for cognitive impairment, dementia, and Alzheimer's disease (AD) in particular. This review summarizes the data related to infectious agents that appear to have a relationship with AD. Infections with herpes simplex virus type 1, picornavirus, Borna disease virus, Chlamydia pneumoniae, Helicobacter pylori, and spirochete were reported to contribute to the pathophysiology of AD or to cognitive changes. Based on these reports, it may be hypothesized that central nervous system or systemic infections may contribute to the pathogenesis or pathophysiology of AD, and chronic infection with several pathogens should be considered a risk factor for sporadic AD. If this hypothesis holds true, early intervention against infection may delay or even prevent the future development of AD.

Publication types

  • Review

MeSH terms

  • Alzheimer Disease / microbiology*
  • Alzheimer Disease / physiopathology
  • Alzheimer Disease / prevention & control
  • Animals
  • Brain / microbiology*
  • Brain / pathology
  • Brain / physiopathology
  • Central Nervous System Bacterial Infections / complications
  • Central Nervous System Bacterial Infections / microbiology
  • Central Nervous System Bacterial Infections / physiopathology
  • Central Nervous System Infections / complications*
  • Central Nervous System Infections / microbiology*
  • Central Nervous System Infections / physiopathology
  • Encephalitis / complications
  • Encephalitis / microbiology
  • Encephalitis / physiopathology
  • Encephalitis, Viral / complications
  • Encephalitis, Viral / microbiology
  • Encephalitis, Viral / physiopathology
  • Humans
  • Risk Factors
  • Vaccines / therapeutic use
  • Virus Diseases / complications
  • Virus Diseases / microbiology
  • Virus Diseases / physiopathology


  • Vaccines