Op-Ed: What We?re Afraid to Say About Ebola

[Shiloh]

Source: http://www.nytimes.com/2014/09/12/opinion/what-were-afraid-to-say-about-ebola.html?_r=0

The Opinion Pages | Op-Ed Contributor
What We?re Afraid to Say About Ebola
By MICHAEL T. OSTERHOLM
SEPT. 11, 2014


MINNEAPOLIS ? THE Ebola epidemic in West Africa has the potential to alter history as much as any plague has ever done.

There have been more than 4,300 cases and 2,300 deaths over the past six months. Last week, the World Health Organization warned that, by early October, there may be thousands of new cases per week in Liberia, Sierra Leone, Guinea and Nigeria. What is not getting said publicly, despite briefings and discussions in the inner circles of the world?s public health agencies, is that we are in totally uncharted waters and that Mother Nature is the only force in charge of the crisis at this time.

There are two possible future chapters to this story that should keep us up at night.

The first possibility is that the Ebola virus spreads from West Africa to megacities in other regions of the developing world. This outbreak is very different from the 19 that have occurred in Africa over the past 40 years. It is much easier to control Ebola infections in isolated villages. But there has been a 300 percent increase in Africa?s population over the last four decades, much of it in large city slums. What happens when an infected person yet to become ill travels by plane to Lagos, Nairobi, Kinshasa or Mogadishu ? or even Karachi, Jakarta, Mexico City or Dhaka?

The second possibility is one that virologists are loath to discuss openly but are definitely considering in private: that an Ebola virus could mutate to become transmissible through the air. You can now get Ebola only through direct contact with bodily fluids. But viruses like Ebola are notoriously sloppy in replicating, meaning the virus entering one person may be genetically different from the virus entering the next. The current Ebola virus?s hyper-evolution is unprecedented; there has been more human-to-human transmission in the past four months than most likely occurred in the last 500 to 1,000 years. Each new infection represents trillions of throws of the genetic dice...

 

[Nika]

Re: Op-Ed: What We?re Afraid to Say About Ebola

It was my understanding (am i wrong?) that seq. data shows no change across this outbreak. (If im confusing this w MERS-nCOV stability let me know)

 

[GardenSpider]

Re: Op-Ed: What We?re Afraid to Say About Ebola

It was my understanding (am i wrong?) that seq. data shows no change across this outbreak. (If im confusing this w MERS-nCOV stability let me know)

The point seems to be: The longer the virus circulates in the human population, the more mutations it accumulates. It is evolving into a human virus and that is worrisome.

http://www.nature.com/news/ebola-virus-mutating-rapidly-as-it-spreads-1.15777
...
The virus amassed 50 mutations during its first month, the researchers found. They say there is no sign that any of these mutations have contributed to the unprecedented size of the outbreak by changing the characteristics of the Ebola virus ? for instance, its ability to spread from person to person or to kill infected patients. But others are eager to examine these questions.

And such risks rise as the virus continues to spread. ?The longer we allow the outbreak to continue, the greater the opportunity the virus has to mutate, and it?s possible that it will mutate into a form that would be an even greater threat than it is right now,? says Charles Chiu, an infectious-disease physician at the University of California, San Francisco.
?

http://www.npr.org/blogs/goatsandso...dly-mutating-as-it-spreads-across-west-africa
...
"The more time you give a virus to mutate and the more human-to-human transmission you see," she says, "the more opportunities you give it to fall upon some [mutation] that could make it more easily transmissible or more pathogenic."
?

http://www.broadinstitute.org/news/6017
...
The team found more than 300 genetic changes that make the 2014 Ebola virus genomes distinct from the viral genomes tied to previous Ebola outbreaks. They also found sequence variations indicating that, from the samples sequenced, the EVD outbreak started from a single introduction into humans, subsequently spreading from person to person over many months.
...

 

[Pathfinder]

Re: Op-Ed: What We?re Afraid to Say About Ebola

More from the article provided by Shiloh:

So what must we do that we are not doing?

First, we need someone to take over the position of ?command and control.?The United Nations is the only international organization that can direct the immense amount of medical, public health and humanitarian aid that must come from many different countries and nongovernmental groups to smother this epidemic. Thus far it has played at best a collaborating role, and with everyone in charge, no one is in charge.

A Security Council resolution could give the United Nations total responsibility for controlling the outbreak, while respecting West African nations? sovereignty as much as possible. The United Nations could, for instance, secure aircraft and landing rights. Many private airlines are refusing to fly into the affected countries, making it very difficult to deploy critical supplies and personnel. The Group of 7 countries? military air and ground support must be brought in to ensure supply chains for medical and infection-control products, as well as food and water for quarantined areas.

The United Nations should provide whatever number of beds are needed; the World Health Organization has recommended 1,500, but we may need thousands more. It should also coordinate the recruitment and training around the world of medical and nursing staff, in particular by bringing in local residents who have survived Ebola, and are no longer at risk of infection. Many countries are pledging medical resources, but donations will not result in an effective treatment system if no single group is responsible for coordinating them.

 

[Nika]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Thnx GardenSpider! now have better grasp ... my next question (perhaps to myself) is : is this level of instability normal for EBOV or is this a relatively unique char of this outbreak. My knowledgebase skews more to influenza viruses then MERS then EBOV last

 

[Vibrant62]

Re: Op-Ed: What We?re Afraid to Say About Ebola

I think that in general:-

a) overall, ebola (as compared to influenza) is a relatively stable virus.

b) as the number of sequential passages through human hosts increases, the greater the natural selective pressure for genetic changes that increase adaptation to a human host.

In other words ebola is changing from a zoonotic virus to become a human virus; once it has fully adapted, we could probably expect the genome to stabilise again.

The worry here is what 'fully adapted' might mean for humankind.

 

[JJackson]

Re: Op-Ed: What We?re Afraid to Say About Ebola

I think that in general:-

a) overall, ebola (as compared to influenza) is a relatively stable virus.

b) as the number of sequential passages through human hosts increases, the greater the natural selective pressure for genetic changes that increase adaptation to a human host.

In other words ebola is changing from a zoonotic virus to become a human virus; once it has fully adapted, we could probably expect the genome to stabilise again.

The worry here is what 'fully adapted' might mean for humankind.

One other point to note Nika is that while both are -ssRNA viruses with similar numbers of nucleotides flu has 8 RNA strands where ebola has a single strand. It is the segmented nature of influenza that allows for recombination events which cause instant massive changes. This in not an evolutionary path available to Ebola.

 

[Nika]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Makes ebola rather more interesting then. I just need to go park myself at pub med and dig into the next 3 questions I have. Thnx for taking the time to share. Being a Scientist means I never end with my questions.

 

[Dallas]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Can I throw a question in here? How have they prevented the spread to Cote d'lvoire, Guinea-Bissau or Mali? As bad as it is it does not seem to be spreading geographically or is this just a matter of time?

 

[Vibrant62]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Under the IHR regulations, countries are obliged to report cases of notifiable diseases, but they ARE NOT obliged to give the WHO authorisation to make those cases public and report them in situation updates. In other words, just because we dont hear of cases in these (or other) countries, does not mean there aren't any. Countries retain the right to keep outbreaks secret.

IMHO spread to these adjacent countries will be inevitable, if they have not already occurred.

 

[Chris]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Ian Mackay has a post regarding this Op ed piece:

http://virologydownunder.blogspot.com.au/2014/09/the-wind-beneath-my-ebola-virus.html

 

[Pathfinder]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Ian Mackay has a post regarding this Op ed piece:

http://virologydownunder.blogspot.com.au/2014/09/the-wind-beneath-my-ebola-virus.html

Excerpt from this article:
...
"If the many thousands of people predicted to die from a virus that is killing 4 in 5 confirmed cases (see the Medicins Sans Frontieres tweet below) is not enough reason for stopping the spread of Ebola virus, then stopping this particular evolving variant before it does change into something worse or more ingrained to the communities all over Africa and beyond, really is. While it may not make the changes necessary for it to go airborne, it has shown signs of rapid adaptation and that was relatively early in what is going to be a very long chain of human-to-human-to-human-to-human... transmission. Each person allowing the virus to adapt further if that's what it needs to do

Such a long transmission chain, from 1 animal>human infection, has never been recorded before and so we are indeed in new territory when it comes to the ebolaviruses. For now at least, the Ebola virus in 5 countries in and around West Africa has the upper hand. This tiny self-assembling unthinking, thing is totally dependent on our cells to replicate itself - and we are not doing enough to starve it of those cells.

It clearly doesn't "need" to be airborne to spread efficiently."

 

[JJackson]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Ian Mackay is on the money.
Why Dr. Osterholm brought up air borne transmission had been confusing me too. Evolution is random at the genetic level and only gains an apparent direction through selection of beneficial adaptions. The problem with going from contact transmission to airborne is the intermediate steps which need to be viable also. There is no obvious and easy route between the two.
Mutations that caused, for example, projectile vomiting would have an obvious benefit, an increase in environmental longevity would have a benefit and could lead to droplet transmission and then onto air-borne transmission but while not impossible a leap to air-borne seems a rather unrealistic scenario.
Not that any of that is really need the virus is doing fine as it is.

 

[Vibrant62]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Norovirus spreads in much the same way, and is a highly successful virus.

Also many of the greatest plagues mankind has ever known were not airborne: e.g. smallpox

 

[Flari]

Re: Op-Ed: What We?re Afraid to Say About Ebola

What prevents the air transmission of the virus is its size / length of 1,000 nm or much more.
Already droplets of only 100 nm do not consider themselves in floating and sinking within ~ one meter to the ground as long as no strong wind prevented.
The minimal length of ~ 1000 nm applies to all Filoviridae.
A mutation that greatly reduced the size of a virus has never been observed in my eyes.

 

[Emily]

Re: Op-Ed: What We?re Afraid to Say About Ebola

I just posted this in the science library.

1976 Zaire strain outbreak study: Fewer haemorrhagic manifestations & fatalities during later stages of the epidemic after the virus had undergone several generations in man

 

[Vibrant62]

Re: Op-Ed: What We?re Afraid to Say About Ebola

Thanks Flari - good point.

A mutation that made ebola transmissible before the visible onset of clear symptoms (i.e during the early febrile strage) would be just as problematic as airborne transmission and make contact tracing very much more difficult.

I think this is a greater and more realistic concern for adaptation/ increased transmission risk.