西アフリカではエボラが大流行した。って英語でなんて言うの？

If an infectious disease starts spreading to large numbers of people, it is known as an 'epidemic'. If the numbers of people become great, or involving a whole population seriously, then it may be referred to as a 'pandemic'.

When we describe something as 'terrible' it implies that that thing was very bad.
An 'epidemic' is when a disease or illness spreads quickly among a population. In West Africa the disease spread quickly, and far and wide. People in the USA and Europe were being diagnosed with the illness.
The disease was mainly active in Guinea, Liberia and Sierra Leone.

The word "recently" talks about the latest outbreak of Ebola. The phrase "large scale" emphasizes just how big the outbreak was.

I hope that this helps :)

"There was an outbreak of Ebola in West Africa."
Saying there was an outbreak means a large scale sickness. You are saying that it was in West Africa so it gives a place.

When you want to explain that there was an Ebola outbreak in West Africa, then you can say:
-In West Africa, there was a large outbreak of Ebola
-There was a large outbreak of Ebola in West Africa

When an infectious disease spreads widely across a country or region then it is referred to as an 'epidemic' you can also use the word 'outbreak' this means the same thing