Jon Snow is remarkably well informed compared to us...

...because we clearly know almost nothing when it comes to the specifics of where Ebola virus (EBOV) can, in some portion of survivors, hide. 

What triggers EBOV to come out of hiding? If indeed that is what it has done within PC, the United Kingdom nurse who seems to have recently become ill while (or due to) hosting a reappearance of EBOV in her blood - 9 months after her blood was defined as containing no detectable EBOV. 

This is not a new infection - but a return of a virus that had not been cleared from its hidey hole(s).

There are obvious concerns to be discussed around this, including:

1. What triggered its re-emergence
2. Is this a strange and rare event or a more common one?
3. Was the virus hiding in PC's central nervous system (she has meningitis-like symptoms reportedly) or in another place or places? 
4. Is the thyroid a site of persistence? 
5. Did the mysterious antiviral treatment she was given alongside a plasma treatment in 2014/15 act to push the virus into hiding? 
6. Has the activated virus mutated in any significant way during its holiday out of the bloodstream? 
7. Can EBOV become truly latent or at least dormant (still producing proteins, but not infectious virus particles) when off the beaten track, or is it constantly replicating?
8. Is PC suffering from full-blown Ebola virus disease (EVD) now, or a disease due to tissue or organ damage from her earlier infection - although if she has detectable EBOV in her blood, one would assume it is EVD. 
9. What the hell are a "lucky set of genes" in the context of a return to systemic EBOV infection? 

Below are some known and some proposed/possible/unproven sites at which EBOV may linger, avoiding or not exposed to clearance by the full force of our immune response.

In the future, perhaps tomorrow, in a non-rich nation, will others become infected from a convalescent patient who experience a return of EBOV long after they were declared virus-free based on a their blood test results. Has that happened already? Will they be our colleagues, friends or family members? The sooner we hear more about what is going on with PC, the better prepared those on the ground will be to intervene. Also, those tending to convalescent health workers in countries around the globe. 

Communication has always been a key issue for EVD and other emerging diseases. Have we been listening?

We know nothing but we can learn. Will we?