Importantly, testing this concept in human patients is possible, for example, by identifying patients who display AD brain pathology at the pre-clinical stage, either by Amyloid-PET imaging [135, 136], or by testing AD-specific biomarkers (eg. Aβ and p-tau) in the blood and CSF [137, 138], and examine prospectively whether a high infectious load is associated with brain atrophy. Here, MAPT is linked to Alzheimer disease.