Scientists fear new Ebola outbreak may explain sudden gorilla disappearance

More than 20,000 Western lowland gorillas could die within months if outbreak confirmed

Scientists fear that emerging evidence may suggest a new outbreak of the Ebola virus, which, in addition to threatening human lives, would threaten tens of thousands of great apes – in this case gorillas and chimpanzees – in the Republic of Congo. The announcement was made by the International Primatological Society (IPS) and Great Ape Survival Project (GRASP) at the IPS’s 20th Congress, being held this week in Turin, Italy.

Congo’s Odzala National Park, a UNESCO Biosphere Reserve, contains an estimated 30,000 western lowland gorillas (Gorilla gorilla gorilla), the largest such population of the endangered species in the world. Until late last year, hundreds could regularly be spotted in Lokoue Bai, a natural clearing in the park where separate groups of the gorillas predictably congregated. But whereas 45 groups of gorillas (each with an average of eight individuals) were once normally observed there, the number since May has plummeted to only nine groups.

“We have not confirmed this as an outbreak of Ebola yet, but there are clear indications that we need to take that possibility seriously,” said Dr. Dieudonnè Ankara, GRASP Focal Point for Congo-Brazzaville, who confirmed these recent developments. “This situation demands serious attention, since another Ebola outbreak would have devastating effects not only for wildlife, but for my neighbors who call the area home.”

Fewer than 100,000 western lowland gorillas remain on Earth. A study published in the journal Nature last year suggested that when an ebola outbreak affects a given area, more than 80 percent of all great apes living in that area die of the disease.

Ebola outbreaks have already occurred in this general area. In the past two years, two reported cases were confirmed in Lossi Forest, approximately 50 kilometers south of Odzala. In both cases, more than 80 percent of all lowland gorillas and roughly 70 percent of all chimpanzees living there died.

Odzala National Park is also home to other threatened species, including the endangered chimpanzee (Pan troglodytes), the endangered African forest elephant (Loxodonta africana cyclotis), and the vulnerable lion (Panthera leo). The massive 13,600 square kilometer park sits in northeastern Congo, near the Gabonese border to the west and Cameroon to the north.

Scientists say multiple courses of action should be taken immediately: Field researchers already in the region, from groups including Ecofac, Wildlife Conservation Society and the University of Rennes, need greater human and financial resources to enhance monitoring in the park, in order to determine which species, if any, have been affected by Ebola, and in which part of the park they reside.

After affected regions have been identified, create geographical barriers, such as making rivers impassable, to decrease the likelihood of any further spread. Increase funding for Ebola vaccines for the great apes, which have already proven successful in monkeys and are showing greater promise in humans. If Ebola outbreak is confirmed, immediately warn all people living in the area to avoid handling dead animals. Ebola hemorrhagic fever is a severe, often-fatal disease that affects humans and non-human primates, such as monkeys, gorillas and chimpanzees. Researchers believe the disease, which first emerged in 1976, is zoonotic, or animal-borne. Many scientists believe it is spread through the butchering and handling of primate bushmeat. The disease has been confirmed only in six African nations: the Democratic Republic of Congo, the Republic of Congo, Gabon, Sudan, Côte d’Ivoire, and Uganda.

“This is clearly bad news, but it is not too late to act,” said Christophe Boesch, Professor at the Max Planck Institute in Leipzig, Germany. “Although it would be disastrous to the great apes if another outbreak of Ebola is confirmed, we still have it in our grasp to save a large number of these primates, man’s closest living relatives. The international community and non-governmental institutions must continue to commit resources to the Congo Basin, one of the last remaining tracts of wilderness in the world.”

Western lowland gorillas can grow to six feet tall when standing, and can weigh up to 450 pounds. They have a broad chest, a muscular neck, and strong hands and feet. Short, thin, grey-black to brown-black hair covers their entire body, except the face. Many bear a distinctive ginger-colored crown. In comparison to mountain gorillas, western lowland gorillas have wider and larger skulls. They are characterized as quiet, and peaceful animals that almost never attack unless provoked.

The relatively intact forests of Western Equatorial Africa are regarded as the last strongholds of African apes. Gabon and the Congo hold 80 percent of the world’s gorillas and most of the Central African chimpanzees. The population of apes in the Congo declined by more than half between 1983 and 2000.