The Origin of Human Outbreaks
Field investigations have revealed direct connections between wildlife and human infections.
- All human Ebola virus outbreaks during 2001-2003 in the forest zone between Gabon and the Republic of Congo resulted from handling infected wild animal carcasses.
- 5 human outbreaks occurred from October 2001 to December 2003, with 313 cases and 264 deaths.
- After the first outbreak, an Animal Mortality Monitoring Network was created to predict and possibly prevent human Ebola outbreaks.
A Devastating Impact on the Species
The impact was so massive that the Western Lowland Gorilla population (Gorilla gorilla gorilla) was drastically reduced. Investigations confirmed that the lethal strain Zaire ebolavirus wiped out entire clans, profoundly affecting vital protected areas like Odzala National Park and the Lossi Gorilla Sanctuary.
Congo basin forest covered in mist.
The forest ecosystem proved to be a complex setting for virus propagation. This extraordinary mortality was a determining factor for the International Union for Conservation of Nature (IUCN) to reclassify the species as "Critically Endangered" (CR).
- Since August 2001, the network recovered 98 wild animal carcasses, including 65 great apes.
- Of the recovered great apes, 50 were gorillas and 15 were chimpanzees.
- Laboratory analyses found that 10 gorillas, 3 chimpanzees, and 1 duiker tested positive for the Ebola virus.
- The population density of lowland gorillas in this region is ≤ 10 gorillas/km².
- Wildlife outbreaks began before each of the 5 documented human outbreaks.