Liberia’s Ebola outbreak largely traced to one source

Genetic analysis of third hard-hit country fills in gaps in virus’ spread and evolution

Ebola outbreak network map

BRANCHING OUT  In Liberia, a single lineage of Ebola virus (middle dot) split into subgroups as it passed from person to person and mutated. Each dot is a slightly different version of the virus within the subgroups. Dot size indicates how many people carried that version. Researchers tracked the virus as it spread from Liberia (blue) into Guinea (red) and Mali (yellow).

J.T. Ladner et al/Cell Host & Microbe 2015

A single introduction of the Ebola virus led to most cases of the deadly disease in Liberia, a new genetic study suggests.