[arcticbull]

It's quite possible that it's environmental suppression of immunity, aging and/or degradation of the blood brain barrier that permits the viruses to make their way topside. There's some evidence that the amyloid plaques actually exhibit antimicrobial activity and may be an immune response to infection. [1]

In my unsubstantiated opinion it's likely to be herpesviridae that make their way to the brain due to their affinity for nerve tissue and the fact up to 80% of Americans have HSV1. Separately 50% of Americans have cytomegalovirus, another herpes virus. And yet more have HSV6 and HSV8. It's safe to assume over 90% of Americans have some latent herpes-family virus.

It also explains why acyclovir and valacyclovir dramatically reduces the risk of developing dementia.

[1] https://www.nature.com/articles/s41598-024-55423-9

[2] https://www.infectiousdiseaseadvisor.com/news/antivirals-for...

[parhamn]

> In my unsubstantiated opinion it's likely to be herpesviridae

Curious, would this be hard to verify? To a layman that sounds like something that would be easily detectable under a microscope using samples of brain.

[nradov]

Viruses aren't detectable under a regular light microscope. We have other assays that can detect certain viruses but they aren't completely accurate. And getting a sample of brain tissue from a living patient is quite hazardous.

[shandor]

> It also explains why acyclovir and valacyclovir dramatically reduces the risk of developing dementia.

Sounds fascinating, where could one read more about this? I don’t think I’ve come across this before.

[arcticbull]

Here's a couple of studies.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7882534/

[2] https://alzres.biomedcentral.com/articles/10.1186/s13195-021...

And here's a clinical trial that's been running since 2018, scheduled for conclusion at EOY 2024.

[3] https://clinicaltrials.gov/study/NCT03282916

This is a very in-depth hypothesis paper that explains more.

[4] https://core.ac.uk/download/544294788.pdf