“Complications due to unaddressed microbial infection” will read as pretty confident, too,

but it’s still pretty vague once you’ve really dug in.

That's why I was emphasizing "one way" and "can begin".

Clearly viral infection may be a distal factor but it is not the proximate cause of Alzheimer's... which is quite conclusively due to protein aggregates.

I don’t find any of it conclusive.

Protein aggregates seem like the effect, with many causes.

Yes, exactly. Whether it APOE mutation, traumatic injury, metabolic dysfunction, Herpes infection, or some other inflammation that upregulates kinases, you end up with hyperphosphorylated tau which in turn forms the neurofibrillary tangles that destroy nutrient transport in neurons and eventually kills them.

"Neuron death by protein aggregates" is the best way to define Alzheimer's. Anything more specific refers to only one of those aforementioned causes; anything less is just "brain don't work no more."

These clickbait headlines are so frustrating, especially since the article itself explains the tau mechanism and all the progress that has been made in understanding the disease.

Sure is a line of inquiry worth pursuing either way, no?

It very much has been. Which is why it's tiring to see these articles (and HN comments) portraying it otherwise. Search HN for Alzheimer's and you will find lots of updates on the research and lots of the same uninformed comment threads.