http://www.ncbi.nlm.nih.gov/pubmed/24910016
The conclusion of the study is that 'IB* consisting of CMV, HSV-1, B. burgdorferi, C. pneumoniae and H. pylori is associated with AD. This study supports the role of infection/inflammation in the etiopathogenesis of AD.'
*IB: 'Infectious Burden' (the burden of previous infections by the viruses and bacteria mentioned)
This particularly interests me because my wife's dementia followed a long period, maybe 15 years, when she more or less constantly suffered from debilitating infections (I know that she tested positive for, amongst many viruses, CMV and HIV-1 and B. burgdorferi - which she has never been tested for - causes Lyme Disease which may be relevant in S's case see this). I suspect others will be interested for similar reasons.
I've previously seen it suggested that repeated infections might lay the groundwork, so to speak, for Alzheimer's but, for us, this conclusion takes things to a new level and might put a number of jigsaw pieces together - for what that's worth at this stage.
