(BMJ) "Where do viruses hide in the human body?", 2023, Extance

[Tom Kindlon]

https://www.bmj.com/content/382/bmj.p1156

Feature Covid Unanswered Questions
Where do viruses hide in the human body?
BMJ 2023; 382 doi: https://doi.org/10.1136/bmj.p1156 (Published 04 July 2023)Cite this as: BMJ 2023;3821156

1. Andy Extance, freelance journalist

The question of how SARS-CoV-2 persists in the body has refocused scientists on the question of where viruses persist in humans more generally. Andy Extance summarises a complex situation

 

[Hutan]

Virus particles often hide in “immunoprivileged sites” around the human body, also sometimes called sanctuary sites, that our immune systems don’t monitor or protect as closely as the rest of our bodies.1 These include the brain, spinal cord, pregnant uterus, testes, and eyes, for which damage by immune cells would be highly problematic. The testes can harbour Zika2 and Ebola3 viruses, for example.

Over the past 20-30 years laboratory measurements have become sensitive enough to pick up on viral RNA outside the known sanctuary locations.1

“We were surprised to find that this was common in measles—its main site of persistence is lymphoid tissue,” says Diane Griffin, a microbiologist and immunologist at Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland. “Anybody who looks will now find RNA persistent, probably, after acute virus infection.” Such signs have been found in blood, joints, the respiratory tract, gastrointestinal tissues, and kidneys.

Some viruses can remove external signs that a cell is infected, allowing them to escape the attention of the immune system in places outside conventional sanctuary sites.

Could something like persisting measles account for the sore throats that some of us experience in PEM?

Another positive development is the spotlight now being shone on virus reservoirs because of the pandemic. “This has not been an area that has received much attention until now,” says Griffin. In her opinion, research into SARS-CoV-2 is likely to teach humanity about older viruses, particularly the role of persistent RNA.

 

[Ravn]

Could something like persisting measles account for the sore throats that some of us experience in PEM?

Quite a few pwME seem to have coldsore reactivation with PEM so it wouldn't be entirely surprising if some other virus did the same in the throat. I doubt it would be measles though as these days most people would have been vaccinated. More likely something like adenovirus

Following a reference trail I've now lost, there seem to have been a few saliva studies, mostly relating to dentistry, showing herpes viruses quite frequently reactivate asymptomatically in healthy people, i.e. no coldsore or other symptoms but evidence of viral shedding in the saliva. Has anyone ever looked at the amount of viral shedding in saliva during PEM?

As an aside, ref #20 for possible viral persistence in ME is an old 2006 paper going on about the supposedly crucial role of emotions during a viral infection in causing problems down the track. Surely the author could have found something more recent and more sensible