I’ve heard that shingles are caused by the dormant chicken pox virus becoming active long after you had the chicken pox. It hides from your immune system in your nerve cells, and decades later can reactivate. How does it get into the nerve cell to hide, why can’t your immune system fight it there, and why don’t more viruses do the same thing?
According to thisthey think “… the varicella-zoster virus adapts within nerve cells in a way that enables it to escape complete destruction by the immune system.”, however it’s still not understood how this actually works.
I believe both herpes I and II can do the same thing. Aren’t they in the same general class as chicken pox?
VZV produces enzymes that break down the nerve cell’s membrane. Once it passes through the cell wall it infects the nerve cells, very little in our autoimmune system can cross that cell barrier. VZV “chicken pox virus” is closely related to other herpesviruses, many of which do use the same method.
This phenomenon is known as Latency (the virus/viral genome remaining in the cell) and re-activation (the virus ‘waking up’ and causing an infection).
In vertebrates this behavior is pretty much restricted to the Herpes family (simplex, zoster, CMV, roseola and a few other variants, plus the dreaded HIV and one of its proviral subtypes which doesn’t generally cause disease.
Here’s some more info about latency and re-activation with more links contained: http://viralzone.expasy.org/all_by_protein/3970.html
Is cytomegalovirus one of these diseases? I read a mayo clinic article about it last week that certainly sounded like re-activation. It’s in the herpesviridae family, which obviously starts with herpes.
Yes, that is the CMV of his list above. (And I had forgotten roseola one of them was myself!)
Also there are reports of returning problems with polio survivors. Dementia from syphilis is also a common problem - IIRC it’s what eventually got Al Capone. (“Trixie? She died of the clap.” “Don’t be silly, you don’t die of the clap.” “you do when you give it to the boss.”)
I’ve often wondered if many of the “random onset” diseases are actually flare-ups like this from some earlier, mild to unnoticed illness; everything from Type I diabetes, autism, alzheimers, Parkinsons - these show up in a quasi-random patter for no discernible reason. Even artery blockages, could be a result of some infection of the blood vessel lining - which means a person could experience this problem, then have it go away.
The cause of post polio syndrome is unknown. One hypothesis (out of a dozen or so) is that the virus may persist in neural tissue. Not yet proven.
Neurosyphilis is well-known to be caused by the syphilis spirochete (not a virus) remainin in the system alive and well (i.e. not hiding its genetic code inside a cell) and working its way into the nervous system.
The other diseases you mention could possibly have some origin or trigger from a viral infection, but there are other explanations for how they work that may be more likely. As usual, more research is needed.