This is scientific American 60 second science. I'm Christopher and Tariata.

Ebola outbreaks before the most recent one have been fairly contained,

geographically limited, and just a couple hundred cases.

The latest outbreak, though, which started in late 2013 and lasted more than two years, was

entirely different.

There were almost 30,000 cases.

Jeremy Lubin, a virologist at the University of Massachusetts Medical School.

You could argue this is the first actual epidemic.

Lubin and his colleagues studied publicly available data on the evolutionary family tree of the Ebola

virus during the latest outbreak, how the strains mutated and changed over time.

And one in particular caught our attention. It arose early in the epidemic and it's the only form of the virus that persisted beyond that point.

This mutant strain was armed with an alteration in the protein it uses to enter. beyond that

the point. This mutant strain was armed with an alteration in the protein it uses to enter cells.

And what Lubin's team found was that the modified protein

actually made the strain more infectious to the cells of humans and

other primates, but not to other mammals.

The study is in the journal's cell.

Lubin says it's unclear whether this increased infectivity helped drive the outbreak to

epidemic proportions, or whether the length and size of the epidemic simply allowed for more virulent strains like this one to appear.

Still, he says studying these strains helps us understand how the virus infects and how it replicates.

That may help us treat infections in the future to develop therapies or to develop vaccines to block infection.

In other words, know thy enemy.

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