And the latest is a doozy although we don't know many of the details yet.
So what do we know about this new finding of a seeming return of infection in a former EVD case? Or is this new disease because of damage from the old infection?
- A 39 year old nurse, PC, was originally infected with EBOV while working for 3 weeks in the Save the Children’s Kerry Town Treatment Centre in Sierra Leone. She did not show signs of illness until after arriving home in Scotland 
- PC was believed to have become infected while treating EVD patients in some way related to her use of a visor as part of her personal protective equipment, rather than goggles, 
- PC entered a Gartnavel Hospital isolation unit on 29-DEC-2014, and was subsequently flown to the Royal Free Hospital (RFH) in Hampstead, North London on 30-DEC-2015. She stayed there for around a month [2,4]
- During her time in the RFH, PC was treated with convalescent blood plasma and an experimental antiviral drug
- PC was declared free of EBOV in January 2015 but continued to report thyroid problems afterwards as she described just a week ago [3,4]
- On Tuesday 06-OCT-2015, PC was admitted to the Queen Elizabeth University Hospital (QEUH) in Glasgow, Scotland after feeling ill. She was then readmitted to the RFH, 06-OCT-2015, 9 months and 7 days after being declared free of Ebola virus.
- She is described as being in serious condition. However, it is unclear what her signs and symptoms were at presentation, or have become since.
Descriptions note that PC is "not thought to be contagious". Presumably this means she is not symptomatic with EVD and if so the testing that must have identified EBOV somewhere in her system must have does so from a part of her system that is not readily in contact with the environment. Nonetheless, she is once again isolated at one of the world's best infectious diseases hospitals.
There are also recent reports of PC having had thyroid problems after recovering-perhaps virus has been replicating in this tissue. PC's "condition is a complication of a previous infection with the Ebola virus". Which leaves a lot of room for idle speculation but could just be that she is ill because of what the fallout from what EBOV previously did to a tissue/organ rather than because of EVD itself. Perhaps follicles in the scalp have been a site for virus replication, relating to her earlier hair loss. Another site may be the central nervous system...
All speculation. Again, nothing is known about PC's signs and symptoms of disease when she presented herself to the QEUH, what tissue(s) are involved in her current illness, which samples tested positive first and where the virus may have been replicating all this time. While we understand that some tissues are sites for EBOV persistence, there is clearly much more to learn about the frequency and full range of tissues that harbour infectious EBOV once it becomes undetectable in the blood.@amymaxmen I've heard she has a meningitis like syndrome, probably CSF is where #Ebola virus is replicating— Ahmed Tejan-Sie MD (@AhmedTejanSie) October 9, 2015
Apart from how shocking and scary this must be for PC herself, another issue is how this will impact on the fragile processes of accepting of EVD survivors back into their West African communities. Extending the length of time that some male survivors are known to harbour EBOV already put pressure on their acceptance by some, but the potential for virus to return to the blood or other tissues - if indeed that is what has happened here - even after that time frame, will require a lot of communication to explain. It will be vitally important for this process that the facts underpinning what's happened here are deduced soon and communicated in ways that can be understood in West Africa. This is a chance for the World Health Organization to show off their shiny new intent to do better at communicating and reacting.
This is not the first time EBOV has been found to persist in a convalescent former EVD case.[5,6,7,8,9] But this may be the first documented time that the virus has re-emerged into the blood and caused symptoms in the same former EVD case (correct me if I'm wrong - are there other examples?).
Shingles has been thrown up today as an example of a similar disease that results from a virus recurring but it's not the same thing at all. Although, we don't know that with absolute certainty. The viruses are very different - that we know for certain. Varicella Zoster virus (VZV) is the herpesvirus that first causes chickenpox, usually in childhood,. Decades later after lying dormant and not exciting our immune system, VZV can reactivate to produce whole virus that results in shingles. As far as we know, EBOV does not go dormant, but remains active at some sites, like the testes and the eyeball,[5,7] where our immune system is programmed not to venture in full force, so as to protect those sites from unwanted inflammation (in a nutshell).
Hopefully, some key information will be made clear soon (as opposed to in the scientific literature weeks or months from now) as it will be vitally important for the continued management and support of EVD survivors in West Africa. It is also important knowledge for communicating real risks, and informing and toning down perceived but unrealistic ones. What falls into which category is however becoming harder and harder to discern.
I'll update this blog post as more information comes to hand.