Ebola
It is now generally agreed that Ebola is responsible for a massive decline in the numbers of great apes in certain regions of Gabon and northern Congo, with some estimates suggesting that populations have decreased by as much as 90% in some areas.
The additional threat posed by the commercial trade in bushmeat means that small post-ebola populations of great apes that may have recovered in the past to repopulate an area, are at high risk of being extirpatedbefore their numbers are able to recover. Ebola hemorrhagic fever is a severe, often-fatal disease in humans and nonhuman primates (monkeys, gorillas, and chimpanzees) that has appeared sporadically since its initial recognition in 1976. The disease is caused by infection with Ebola virus, named after a river in the Democratic Republic of the Congo (formerly Zaire) in Africa, where it was first recognized. The virus is one of two members of a family of RNA viruses called the Filoviridae . There are four identified subtypes of Ebola virus. Three of the four have caused disease in humans: Ebola-Zaire, Ebola-Sudan, and Ebola-Ivory Coast. The fourth, Ebola-Reston, has caused disease in nonhuman primates, but not in humans.
The exact origin, locations, and natural habitat (known as the "natural reservoir") of the Ebola virus remain unknown. However, on the basis of available evidence and the nature of similar viruses, researchers believe that the virus is zoonotic (animal-borne), and is normally resident within a host species. Recent scientific findings point towards a large fruit bat as the likely reservoir. Outbreaks seem to emerge when the virus is transmitted from this host to another animal, such as a gorilla or other primate. Recent human outbreaks in Northern Congo and Gabon have all been traced back to humans handling infected ape meat.