The Devastating 2014-2016 Ebola Outbreak on Gorillas in West Africa

14

The village is like a thousand others in Africa. Its red-tinged mud huts huddle together under the shade of centuries-old jungle trees. Chickens cluck busily about pecking at the dust and children run around playing tag. It was early December 2013, and in the village of Meliandou in southern Guinea, two-year-old Emile Ouamouno had been playing with a free-tailed bat he’d found on the ground. Four days later, the toddler was dead. By the end of the month, his mother, elder sister, grandmother and the health care worker who’d tried in vain to help the family were all also dead. It was the start of the 2014-16 West African Ebola pandemic, and in the months that followed TV screens around the world were filled with images of international medical workers treating the dead and dying across a swathe of West Africa.


In June 2016, the WHO announced that Guinea was finally free of Ebola and in October of that year, I flew to Conakry, the capital of this little-known Francophone nation to find out what I could about the impact of Ebola. However, the already well-documented impact on humans wasn’t what I wanted to learn more about. Instead, I wanted to know about Ebola’s devastating impact on our closest cousins: the great apes of Africa.

Habitat loss is, most people assume, the biggest threat to chimpanzees, gorillas and bonobos, followed by the bush meat and exotic pet trade. Some scientists and conservationists though, suspect that right now, the single biggest threat to the continued survival of Africa’s apes is actually Ebola. Certainly, the virus, which causes severe haemorrhagic fever in both humans and apes, is even more deadly for the great apes than it is for humans. An estimated 77 per cent of chimpanzees that catch the virus die of it and, in certain areas, a staggering 95 per cent of gorillas succumb to the disease. For humans, the mortality rate stands at 50 per cent. Some conservationists have even, controversially, said that since the early 1990s a third of the planet’s wild chimpanzees and gorillas have been killed by the Ebola virus.

Guinea has the largest population of chimpanzees in West Africa. An estimated 20,000 chimps eke out an increasingly perilous existence here. This, combined with Guinea being the seeding ground of the worst outbreak of human Ebola the world has ever known, made Guinea seem the ideal place for me to start my investigation. I’d left Conakry, the sprawling, polluted capital, in a hired 4×4 with a driver. We’d soared across the flat, busy coastal plain, then followed a buckling and bending road up onto the edge of the cool and green Fouta Djalon highlands before descending again into hotter and drier countryside. Villages became ever more scarce until eventually, many hours later, we found ourselves driving through parched open woodland heading towards the Parc National du Haute-Niger where I had a meeting with a chimpanzee expert. Christelle Colin is a vet, and the executive director of the French-run ‘Centre de Conservation pour Chimpanzés’, which aims to re-introduce chimpanzees captured for the exotic pet trade back to a life in the wild. Many of the chimpanzees rescued by project staff are physically unwell and psychologically disturbed (the majority were ripped from their mothers’ arms as babies) and have forgotten how to live in the wild. It takes years, often around a decade, to re-equip the chimps with all the skills they’ll need to make it alone in the forest.

As Christelle and I sat under the shade of a drooping forest tree and talked about Ebola, four tiny chimpanzee babies played rumble-tumble games around us. ‘We know very little about how Ebola actually works in the wild because when it hits a population of apes normally, all we find is just the carcass of a chimp or gorilla,’ explained Christelle. ‘We think that the contamination is passed on from fruit bats [various species of bat are the host animal for the virus]. The bat takes a couple of mouthfuls of a piece of fruit and then a chimpanzee or gorilla comes along and eats the rest of the fruit and contracts the virus.’ When I asked how badly Guinea’s chimp population had been hit during the 2014-16 human outbreak, Christelle surprised me by saying that although chimps in Guinea often have no choice but to live in close proximity to villagers, Ebola hadn’t been detected. Even so, there were nervous moments throughout the outbreak. ‘There are bats all over the place here and so it was very stressful. Most of the chimps we have here were found with traffickers who were trying to smuggle them out to China and the Emirates for the pet trade, but we have one chimpanzee which we got from Liberia in 2014. There was a huge fear at the time that the chimps could spread Ebola and people wanted to kill this chimp.’ We talked more about chimpanzee conservation and biology before our conversation drifted onto the subject of bush meat, including the eating of chimpanzees and gorillas, which is one of the other major threats against Africa’s great apes. Christelle told me how in Guinea, a majority Muslim nation, people don’t eat much bush meat and certainly not chimpanzees but that it was common in Central Africa. She then paused, obviously thinking about how not to make her next statement sound flippant: ‘In a way Ebola was a good thing because people across Africa got scared about eating bush meat.’

There’s no shortage of rainforest in the Republic of Congo (the lesser-known, little sister of the massive and troubled, neighbouring Democratic Republic of Congo). About 60 per cent of the country consists of nothing but steamy lowland jungle that’s so pristine that the forests here are considered some of the richest and most biologically important on Earth. Landing in the capital, Brazzaville, I used a combination of buses, beaten-up bush taxis, dug-out canoes, and my own two feet to reach the far north of the country where the rainforest is at its most luxuriant. Here I met up with German biologist, Eva Luef, who was studying western lowland gorillas. She led me along narrow elephant and buffalo trails to a large, natural forest clearing, where we clambered up to a roughly built wooden viewing platform and gazed in awe across a vast swampy clearing busy with wildlife. In one sweeping glance, I counted two elephants, five or six forest buffalo, a solitary bongo antelope flirting with the shadows and then, calmly munching bundles of water weeds, some two-dozen western lowland gorillas. Talking quietly so as not to disturb any of the animals, Eva told me that it was just to the south of here that in 2004 Ebola had wiped out nearly 95 per cent of the 400-strong gorilla population of the Odzala forest area. Scientists working in the area at the time had reported that ‘hundreds, if not thousands, of additional gorillas living around this small population were also killed.’ Around the same time it’s also thought that at least another 5,000 gorillas had died of the virus elsewhere in Central Africa. According to an issue of the Gorilla Journal (a specialist publication aimed at scientists working with wild gorillas), Ebola outbreaks in 2001 and 2003 in Gabon and the Republic of Congo saw populations of gorillas in parts of those countries collapse by 50 per cent and the chimpanzee population fall by a terrifying 80 per cent. Furthermore, according to WWF, back in 1994, an outbreak in Minkébé in northern Gabon almost completely decimated what was once the world’s second-largest population of protected gorillas and chimpanzees. Today, thanks to deforestation, agriculture and urban development, many of Africa’s great apes live in ‘forest islands’ of varying size (this is particularly the case in West Africa) and this means that when Ebola strikes, it can wipe almost all the apes in that ‘island’ out.


So, it’s clear that Ebola poses a significant threat to the future of Africa’s great apes, but what can we do to stop it? While it’s very hard, if not impossible, to get rid of Ebola in the wild there could be some hope. Scientists have been working on an Ebola vaccine for chimpanzees and gorillas. The proto-vaccine they’ve come up with involves inserting a protein from the surface of the Ebola virus into an existing live rabies vaccine. When this was given to ten chimpanzees in a US lab it only took a month for all of the chimpanzees to develop high levels of Ebola antibodies. It was an encouraging sign and the team behind it, led by Dr Peter Walsh from the University of Cambridge, were confident that it could have a real positive effect in the fight against Ebola.

However, there are problems and they are such that the vaccine most likely will never actually be put into use in the wild. Firstly, there’s the issue of how to administer it to wild and very timid chimps and gorillas. Scientists working on the vaccine hoped that they might be able to lace a fruit bait with it, which would then be consumed by the chimps and gorillas. However, the apes often live in very remote areas that can be hard to access and, more importantly, it’s likely that other animals (pouched rats in particular) would get to the bait first.

The other, perhaps more terminal hurdle, is that in 2016, before Walsh and his team had finished conducting their tests, new US laws regarding biomedical research on chimpanzees came into effect. Although these new rules prevent captive apes being used for medical tests there is a clause which says that tests can go ahead if they are seen as being of benefit to wild populations, which of course in this case they most likely would. The problem is that no US animal sanctuary with chimpanzees applied for the necessary permits to conduct tests on their apes due, Walsh believes, to the fear of reaction from animal rights groups.

As Eva and I sat watching the gorillas finish off their water salad lunch and march back into the shade of the forest, I couldn’t help but ponder the irony of how these new, animal rights championed laws may, in fact, go a long way to spelling disaster for the wild chimps and gorillas of Guinea and Congo.

Source : Geographical Magazine