Most really deadly diseases are deadly because they are something else’s version of a cold that wrecks up everything else. For example, Bubonic Plague really wants to be in Central Asian ground squirrels and just goes completely nuts when in just about anything else.
When an outbreak like this happens the disease is happily chilling in whatever animal population it is “supposed” to be in just being passed back and forth and minding its own business. Then something happens, a parasite sucks it out and injects it in something else or the animal gets eaten without being properly cooked or there a fight and the comingling of blood or something. Now the disease is somewhere it’s not supposed to be and isn’t happy, all the stuff it normally does to reproduce and spread works different and wrong and instead of using the animal’s systems property it just wrecks the place. That person dies quickly between a few days and a few weeks and maybe something happens in that time that move it to a different person. Now you have an outbreak. If people keep on going about their normal days then it spreads in a community, people who travel normally spread it, and when things get bad people run… but they usually run after some of them are infected and that just spreads it even worse.
It’s very important in areas where these kinds of diseases are endemic to a wild animal population to respond quickly when someone is bitten by a wild animal or parasite and isolate them before it spreads to people who travel. There’s a world of difference between isolating a family and trying to isolate a village and trying to isolate tens of thousands of people spread across hundreds of square miles. But, we do it.
Each time we do it we do eliminate Ebola… but only the Ebola in humans, the wild animals for whom it’s just a flu are unaffected by our treatment and it’s only a matter of time before it happens all over again.