[stem-ebola] Ebola-2014 May Have Altered Phenotype -- Anecdotal Reports

[alex@xxxxxxxxxxxxxx]

Hello everyone,

I am writing to our scientific discussion community to share new 
evidence that just came to my attention: Some of the Ebola genetic 
variants circulating in Liberia may result in *higher serum viral 
titers* than previously observed for species Zaire ebolavirus.

Note: I am using the term 'Ebola-2014' to refer to all Zaire ebolavirus 
variants circulating during the West African outbreak of 2014. All 
variants sequenced so far in the outbreak share approximately 97% 
homology with the Mayinga-76 consensus sequence, and have fall into 
approximately four phylogenetic sub-clades (GN, SL1, SL2, and SL3) (Gire 
et al, 2014).

We have all been asking the question of 'What's different this time?' 
regarding the outbreak since our first community call.

During last weeks discussion , we discussed the fact that Ebola-2014 
genetic variants had already acquired significant genetic diversity from 
Feb 2014 to June 2014.  However, as of last week, there had been no 
evidence that Ebola-2014 mutations had impacted the viral phenotype.

That may have changed.  We will need to await formal confirmation and 
write up of the following findings, but the following anecdotal reports 
could end up to be very important.

===

To quote Dr. Jahrling at NIH/NIAID, "If [what we observe is] true, 
[Ebola 2014] is a very different bug."

Case reports have just come to light suggesting that Ebola-2014, 
particularly the genetic variants circulating in Liberia, have been 
resulting in significantly _higher serum viral titers_ as compared to 
previous outbreaks of Zaire ebolavirus.

The reports come from the field lab of Dr. Peter Jahrling (Chief 
Scientist, Emerging Viral Pathogens, NIH/NIAID), who has a team on the 
ground in Monrovia, Liberia.

According to WHO reports distributed on ProMED, Monrovia is one of the 
key areas where the Ebola outbreak is growing rapidly.

=====

Dr. Jahrling stated the following in a recent interview...

'We are using tests now that weren't using in the past, but there seems 
to be a belief that the [Ebola] virus load is higher in these patients 
[today] than what we have seen before. If true, that's a very different 
bug.'

'I have a field team in Monrovia. They are running [tests]. They are 
telling me that viral loads are coming up very quickly and really high, 
higher than they are used to seeing.'

'It may be that the virus burns hotter and quicker.' -Dr. Peter 
Jahrling, Oct 13th, 2014

====

Dr. Jahrling is highly credible. He was a co-discover of the Reston 
ebolavirus species.

If confirmed, his team's observation could have a number of 
interpretations and implications. For example, we know there are an 
increasing number of distinct Ebola-2014 viral lineages, which are 
growing as a function of the number of people infected (Gire, 2014).

Some of the Ebola-2014 genetic variants found in current outbreak may be 
responsible for changes in EVD etiology, such as the increased viral 
shedding claimed by Dr. Jahrling.

The anecdotal reports from Dr. Jahrling's field lab are the first 
credible claims that Ebola-2014 genetic changes are having an observable 
phenotypic impact on EVD.  If Dr. Jahrling's anecdotal field 
observations hold up to scientific scrutiny, it may imply that 
Ebola-2014 has acquired at least one fitness adaptation which allows it 
to replicate and amplify to higher viral loads.

If this discovery is true and not an error, then the fact that one or 
more Ebola-2014 genetic variants are resulting in an altered phenotype 
might be evidence for a new Ebola 'strain' (Kuhn, 2012) within the 
species Zaire ebolavirus.

The ability for an Ebola-2014 genetic variant to achieve higher viral 
loads could potentially make the virus more contagious (increasing R0). 
. . Higher viral titers could increase overall viral shedding.  On a 
more speculative note, higher viral titers might alter ratios of 
circulating Ebola PFU/mL relative to levels of circulating cytokines 
like IL-6, perhaps providing a theoretical basis for 'asymptomatic 
transmission'.

====
From Vox Interview Article...

Peter Jahrling, one of the country's top scientists, has dedicated his 
life to studying some of the most dangerous viruses on the planet. 
Twenty-five years ago, he cut his teeth on Lassa hemorrhagic fever, 
hunting for Ebola's viral cousin in Liberia. In 1989, he helped discover 
Reston, a new Ebola strain, in his Virginia lab.

Jahrling now serves as a chief scientist at the National Institute of 
Allergy and Infectious Diseases, where he runs the emerging viral 
pathogens section. He has been watching this Ebola epidemic with a 
mixture of horror, concern and scientific curiosity. And there's one 
thing he's found particularly worrisome: the mutations of the virus that 
are circulating now look to be more contagious than the ones that have 
turned up in the past.

When his team has run tests on patients in Liberia, they seem to carry a 
much higher "viral load." In other words, Ebola victims today have more 
of the virus in their blood — and that could make them more contagious.

====

The anecdotal reports from Dr. Jahrling's team will need to be confirmed 
by follow-up research.

I wanted to make everyone aware of this development as perhaps something 
to follow up on in the future, perhaps as a subject for expert 
evaluation by others.

Genetic changes to the virus could prove problematic (given the high 
mutation rate), and will need to be monitored closely.

====

sources:

http://www.vox.com/2014/10/13/6959087/ebola-outbreak-virus-mutated-airborne

http://www.dailymail.co.uk/news/article-2798086/mutant-ebola-warning-leading-u-s-scientist-warns-deadly-virus-changing-contagious.html


Sincerely,
Alex