Disease

Ebola Outbreak Declared Over in West Africa

West Africa is now free of Ebola, marking an end to the devastating epidemic that plagued the region for two years.

The three hardest-hit countries — Guinea, Liberia and Sierra Leone — have not had any new Ebola cases for at least 42 days, according to a statement from the World Health Organization released today (Jan. 14). Health officials typically wait 42 days to declare a country Ebola-free, because this is twice as long as the 21-day incubation period of the virus (the time it takes for a person infected with the virus to show symptoms).

Liberia was the most recent of the three countries to be declared Ebola-free — today marks 42 days since the last person to have Ebola there was cured of the disease, according to WHO. Liberia was previously declared Ebola-free twice during 2015, but each time the country subsequently experienced small "flare-ups" of the disease. Sierra Leone's Ebola outbreak was declared over in early November 2015, and Guinea was declared free of Ebola in late December.

However, officials warn that new cases of Ebola could still appear in the region, and that efforts are needed to prevent and respond to any new outbreaks.