How does the Ebola virus work?

Genetic sequencing can help track the spread and adaptation of viral outbreaks such as Ebola and Lassa Fever, and ultimately guide development of treatments and vaccines. Dr Pardis Sabeti, Associate Professor at the Center for Systems Biology at Harvard University and a speaker at the World Economic Forum’s Annual Meeting of the New Champions 2014, explains how her team in Sierra Leone and the US mapped genomes from the blood of some of the first reported Ebola patients in the current outbreak.

Here are some quotes from the clip, and you can watch the full video at the top of this page:

On the origins of the current Ebola outbreak

Each virus has a genome. You can create a ‘family tree’ of all of different outbreaks’ genomes and how they’re related to each other. We don’t know who the mother and the father is. We know there’s a root but we don’t know exactly what came from whom. But the belief is that the 1976 strain (previously the largest Ebola outbreak, with 318 cases) at some point broke off … and it looks like this outbreak separated away from other strains some time around 2004. Where was it since then? We don’t know. Unlike some viruses, we don’t know what the natural reservoir is for Ebola. A lot of people think it’s bats, but it’s still very controversial; it could have been circulating in insects, in an environment or in individuals.

On what genome sequencing can show

The Ebola genome has 20,000 letters. In comparison, the human genome has 3 billion. We have 20,000 genes, Ebola has just seven – seven main proteins that make up its mass.

You can see mutations happening across the genome … and you can see mutations happening in real time in an individual. The value of all these mutations is you can really get a sense of how this thing is changing over time. We can even see transmission chains. We can see who infects who, and we’ve been able to trace infections happening across the country.

On the need to track virus genomes in real time

All of the different things that we use to intervene with these viruses are based on the sequence of the genome of the virus itself. The diagnostics are based on finding the markers that target the genome and pull it out, so you have to know what you’re targeting in order to figure out if the virus is there.

The vaccines are mimicking the virus and its protein sequence, which is based on the genome sequence, and even some of the therapies, like the monoclonal antibody ZMapp, that was famously used for the two Americans, is also based on the protein sequence of the virus, which again is based on the genome underneath it. So, it’s super-important to be able to analyse that genome in real time because it’s changing.

There are hundreds of mutations, and many of them have already hit the diagnostics being used, and we have to be able to move and change with the virus.

On the need for collaboration

The headlines tell you what an important event and what a frightening event this is for humanity – the biggest outbreak of all time.

One of the important things we did was immediately made our data publicly available on the web. That’s something we’ve been told is an unusual thing to do, but in an outbreak scenario, we want every single best mind in the world working as fast as possible to figure out what it does.

This is an extraordinary devastation and I hope that we can all work together to find solutions and to make sure that this is the last great outbreak in our history.

Author: Dr. Pardis Sabeti is an Associate Professor at the Center for Systems Biology at Harvard University and a World Economic Forum Young Global Leader.

Image: Laboratory technicans of the company Icon Genetics prepare proteines from Tobacco plants (Nicotiana benthamiana) for weighing in a laboratory in Halle, August 14, 2014. REUTERS/Axel Schmidt