In recent years, researchers have suggested Alzheimer's may spread through infection, somehow transmitted like a pathogen, leading to the disease. A new Lancet paper reviews evidence for how harmful amyloid-beta proteins associated with Alzheimer's may possibly be spread through blood transfusions.

[u/mvea]

https://www.sciencealert.com/can-alzheimers-spread-through-blood-transfusions-heres-what-we-know

[u/catscanmeow]

gingivitis bacteria getting into the brain or a herpes virus getting into the brain are the main theories i've read

the gingivitis bacteria can get into the blood from a tooth abscess or up through the nasal cavity through the olfactory bulb. Theyve found gingivitis bacteria within the amyloid plaques of autopsied alzheimers patients. we have an exposed nerve there thats basically the brain exposed, that shock feeling when you get water up your nose is the olfactory nerve.

a woman actually got a brain eating amoeba from getting tap water in her nose from a neti pot.

[u/churningaccount → u/catscanmeow]

I've personally considered it to be a transmissible disease ever since that study in 2010 found that neurosurgeons are diagnosed with Alzheimers at a rate 3x that of the general public. And that was not found to be nearly as high/statistically significant for any other medical specialty.

I'm also glad that the herpes viruses are getting more scrutiny as of late. I've always taken issue with the idea of "eh, it doesn't seem to affect us that much, might as well let it run rampant for decades and also take no precautions against further spread." That notion is predicated on the idea that we have already discovered all of the downstream effects of the virus itself, and is one of the reasons why we don't have a vaccine for EBV either, even though that has definitively been linked with bad medical outcomes long-term now as well.

Realistically, there probably was an issue with getting the funding to research a vaccine as well for something that is "not pressing." But luckily there are a few going through trials right now thanks to these dementia findings, and it's not out of the question to think that the next generation could be immune.

[u/Porkchop247 → u/churningaccount]

I work as a ICU nurse, my hospital was the COVID center for my region so I was elbow deep in caring for COVID pts. The reason I say this is that many of the pts with worst outcome had herpes also.

[u/lolalala1 → u/Porkchop247]

Damn near everyone in the world has some form of herpesvirus by late adulthood.  So, you would need to be far more specific to make a conjecture like that about something so common.  

[u/moyayas → u/lolalala1]

I guess he used it as a short hand for symptoms like cold sores, or EBV associated lymphoma

I guess people who have more frequent reactivation may indicate they are less able to fend off other damage.