It's named after the ebola river, which is one of the locations it was first identified in 1976. These things happen in warm tropical climates as they are the perfect breeding grounds, i.e. you can't catch a cold at the poles.. too cold, ironically.
It also doesn't help that some people eat monkeys that have found dead.
When there is a famine and no food to go around, a dead monkey would be considered a bonus.