Possible evidence for human transmission of Alzheimer?s pathology

Although there is no evidence that human prion disease, AD or cerebral amyloid angiopahy (CAA) is contagious (spread from person to person by direct contact), the study of eight patients suggests that amyloid beta (the peptides that form the main components of the amyloid plaques found in the brains of patients with AD) may potentially be transmissible via certain medical procedures.
Human transmission of prion disease has occurred as a result of various medical procedures (iatrogenic transmission), with incubation periods that can exceed five decades.
One such iatrogenic route of transmission was via the treatment in the UK of 1,848 persons of short stature with human growth hormone (HGH) extracted from cadaver-sourced pituitary glands, some of which were inadvertently prion-contaminated. The treatments began in 1958 and ceased in 1985 following reports of CJD among recipients. By the year 2000, 38 of the patients had developed CJD. As of 2012, 450 cases of iatrogenic CJD have been identified in countries worldwide after treatment with cadaverderived HGH and, to a lesser extent, other medical procedures, including transplant and neurosurgery.
John Collinge, Sebastian Brandner and colleagues at UCL conducted autopsy studies, including extensive brain tissue sampling, of eight UK patients aged 36