6. Ebola The Ebola virus first emerged in 1976 in simultaneous outbreaks in Sudan and Zaire. It is known to be a zoonotic virus as it is currently devastating the populations of lowland gorillas in Central Africa.
Despite considerable effort by the World Health Organization, no animal reservoir capable of sustaining the virus between outbreaks has been identified.
However, it has been hypothesized that the most likely candidate is the fruit bat. Ebola hemorrhagic fever is potentially lethal and encompasses a range of symptoms including fever, vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding.