Definitely hasn't been ruled out. Researchers have hypothesized that the amyloid plaques are a protective mechanism; unfortunately, we still don't know why they form.
One hot area of research is currently focused on herpesviruses such as HSV1. Here [1] is a paper summarizing some of that research.
The thing about viruses is that they are weird things with unexpected behaviours. For example, we are still learning about Epstein-Barr (EBV, which is another type of herpesvirus); only this year did researchers come to suspect that EBV could be responsible for MS.
One hot area of research is currently focused on herpesviruses such as HSV1. Here [1] is a paper summarizing some of that research.
The thing about viruses is that they are weird things with unexpected behaviours. For example, we are still learning about Epstein-Barr (EBV, which is another type of herpesvirus); only this year did researchers come to suspect that EBV could be responsible for MS.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8234998/