Ebola is one of the most lethal diseases known to man. It turns your insides to mush in days and only a small percentage of those exposed live. Several outbreaks have taken place in Africa, and more than one hard science fiction thriller has featured an outbreak of the disease as a mutation makes it possible to spread with a sneeze, instead of the far more difficult more of transmission (generally through close contact with diseased tissue or blood or spit).
This hasn't taken place, but scientists have discovered that African fruit bats in areas where there have been Ebola outbreaks in the past can act as carriers of the deadly disease, without getting sick themselves. Thus, eating a dead bat, or perhaps even handling one, could cause the initial infection that leads to the infection of an entire village.
The only reason to have some measure of comfort that an Ebola outbreak will not be the next pandemic that kills millions is that it is so lethal. Unlike HIV, which has a dormancy period of years, allowing it to be spread widely before it actually harms its host, Ebola kills quickly, leaving little time for infected people to spread the disease.