Emerging evidence suggests a new outbreak of the Ebola virus in the Republic of Congo's Odzala National Park that may explain a sudden disappearance of hundreds of Western lowland gorillas, scientists said on Friday.
A confirmed outbreak of the deadly virus could potentially kill 20,000 gorillas within months and threaten people living near the park.
"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 with the Great Ape Survival Project (GRASP).
Odzala National Park contains an estimated 30,000 western lowland gorillas - the largest such population of the endangered species in the world.
Until late last year, hundreds could be spotted in Lokoue Bai, a natural clearing in the park where separate groups of the gorillas predictably congregated.
Gorillas are being driven to extinction by habitat loss, illegal hunting and the Ebola virus. (Photo courtesy UNEP)
Ankara says 45 groups of gorillas - each with an average of eight individuals - were once normally observed there.
But since May that number has fallen to only nine groups, Ankara said.
"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," Ankara said.
The 13,600 square kilometer park is situated in northeastern Congo, near the Gabonese border to the west and Cameroon to the north. It is home to other rare species, including the endangered chimpanzee and the endangered African forest elephant.
Ebola outbreaks have already occurred in this general area. Over the past two years, two reported cases were confirmed in Lossi Forest, some 50 kilometers (30 miles) south of Odzala.
In both cases, more than 80 percent of all lowland gorillas and roughly 70 percent of all chimpanzees living there lost their lives.
The new concern about an Ebola outbreak in Odzala was raised Friday at the International Primatological Society's (IPS) 20th Congress in Turin, Italy.
"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."
Boesch and his colleagues called on the international community and nongovernmental organizations to commit additional support to field researchers already in and around Odzala in order to determine if an Ebola outbreak has occurred.
The Ebola virus has been confirmed in six African nations - the Democratic Republic of Congo, the Republic of Congo, Gabon, Sudan, Côte d'Ivoire, and Uganda. (Photo courtesy World Health Organization)
If affected regions are found in the park, the scientists urge the creation of geographical barriers, such as making rivers impassable, to decrease the likelihood of any further spread. Individuals living nearby should be immediately warned to avoid handling dead animals, the scientists said.
They also want increased funding for Ebola vaccines for the great apes, which have already proven successful in monkeys and are showing promise in humans.
Ebola is one of the world's most virulent viral diseases, killing some 50 percent to 90 percent of all who are infected.
The virus was first identified in a western equatorial province of Sudan and in a nearby region of the Democratic Republic of Congo in 1976.
Contaminated bush meat has transferred the deadly virus from animals to people, but scientists are unsure how Ebola is transferred among apes and other animals.
The renewed concern comes on top of rising fears about the future of the world's great apes and the toll Ebola may be taking of the last remaining population.
A study published last year in the journal "Nature" warned that illegal hunting and Ebola are decimating gorilla and chimpanzee populations in Western Equatorial Africa.
That discovery alarmed conservationists because many believed ape populations in these densely forested, remote regions in Gabon and the Republic of Congo, were relatively stable.
Some 80 percent of wild gorillas and most wild chimpanzees are believed to live in this area of West Africa, but the "Nature" study found that these populations have dropped by at least 50 percent over the past 20 years.
Habitat destruction remains a major threat - the United Nations Environment Program predicts that less than 10 percent of the remaining wild ape habitat in West Africa will be intact by 2030 if the current level of forest development continues.
