Do herpesviruses play a role in Alzheimer’s disease pathogenesis?

Recent studies have brought renewed interest to the hypothesis that infection plays a role in the pathogenesis of Alzheimer’s disease (AD). In particular, herpesviruses such as herpes simplex virus-1 (HSV-1) and human herpesvirus-6 (HHV-6) have had an extensive history of association with AD. The interplay between viral infection and a variety of neurological diseases has long been an area of interest but proving causality has been elusive. Two recent studies, Readhead et al. (2018) and Eimer et al. (2018) have again renewed the debate concerning the role of pathogens (herpesviruses) in AD. In this review, we will briefly discuss the literature in support of a herpesvirus role in AD pathogenesis and try to bridge two main observations in AD research; the ability of Aβ to aggregate with pathogens, and the detection of herpesviruses in AD brain material compared to non-AD controls. While the data linking AD and human herpesviruses suggest that these pathogens may contribute to disease progression, further work is needed to determine the significance of these observations, if any, to the etiology of the disease.