As unavoidable mentioned, there are viral theories. In Science, from July, "Can infections cause Alzheimer’s? A small community of researchers is determined to

As unavoidable mentioned, there are viral theories. In Science, from July, "Can infections cause Alzheimer’s? A small community of researchers is determined to find out. Following up tantalizing links between pathogens and brain disease, new projects search for causal evidence", https://www.science.org/content/article/can-infections-cause-alzheimer-s-small-community-researchers-determined-find-out https://www.science.org/content/article/can-infections-cause...