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The Ebola storm: apes in the firing line

  • Written by  Stuart Butler
  • Published in Wildlife
The Ebola storm: apes in the firing line
29 Dec
While it was the impact on civilian populations that generated most of the headlines during the 2014-2016 outbreak in West Africa, humans weren’t the only species devastated by Ebola – the region’s ape colonies are desperately struggling to recover

Meliandou in southern Guinea is a village like a thousand others in Africa. Its red-tinged mud huts huddle together under the shade of centuries-old trees. Chickens busily peck at the dust while children run around playing tag. Early in December 2013, 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, grand-mother and a 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 last year, the World Health Organization announced that Guinea was finally free of Ebola. The virus had claimed over 2,500 human victims in the country and more than 11,000 across western Africa. But aside from the well-documented impact on humans, the virus also had a less well-known, yet no less devastating impact on our closest cousins: the great apes of Africa.



Guinea has the largest population of chimpanzees in West Africa. An estimated 20,000 eke out an increasingly perilous existence here. Habitat loss is, most people assume, the biggest threat to chimps, gorillas and bonobos, followed by the bush meat and exotic pet trade. However, some scientists and conservationists suspect that right now the single biggest threat to the continued survival of Africa’s apes is actually Ebola.

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 (numbers in excess of 5,000) 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 all wild chimpanzees and gorillas have been killed by Ebola. Most recent estimates put the number of gorillas left in the wild at around 100,000.

Some 200 miles east of Guinea’s sprawling, polluted capital of Conakry, sits the Parc National du Haute-Niger, a 1,200 square kilometre national park. To reach it requires hours of driving across flat, busy coastal plains, followed by buckling and bending roads up to the edge of the cool and green Fouta Djalon highlands before descending again into hotter and drier countryside. Villages become ever more scarce until eventually you found yourself driving through parched open woodland heading towards one of the country’s most important protected spaces and base of operations to chimpanzee expert, Christelle Colin, the executive director of the French-run Centre de Conservation pour Chimpanzés.

The centre aims to re-introduce chimpanzees captured for the exotic pet trade back to a life in the wild. Many of the chimps 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 Colin sits under the shade of a drooping forest tree and talks about Ebola, four tiny chimpanzee babies play rumble-tumble games around her.

‘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,’ she explains. ‘We think that the contamination is passed on from fruit bats. 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.’

Colin goes on to explain that although chimps in Guinea often have no choice but to live in close proximity to villagers, during the 2014-16 human outbreak of Ebola, the virus hadn’t actually been detected in the animals. Even so, there were nervous moments throughout. ‘There are bats all over the place here and so it was very stressful,’ she recalls. ‘Most of the chimps we have here [at the Centre] are found with traffickers trying to smuggle them out to China and the Emirates for the pet trade. But there is one that we obtained from Liberia in 2014. At the time of the outbreak, there was a huge fear that the chimps could spread Ebola so people wanted to kill it.’

Bush meat remains one of the other major threats to Africa’s great apes. However, explains Colin, Guinea is a majority Muslim nation meaning that people here don’t eat much bush meat and certainly not chimpanzees, despite it being a common practice in Central Africa. ‘In a way,’ she suggests carefully so as not to sound flippant, ‘Ebola had an upside because people across Africa got scared about eating bush meat.’

ebola ape2



To really understand how badly Ebola hit apes, you have to venture to the heart of Africa and into the dank forests of the Congo Basin. 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 the forests here are considered some of the richest and most biologically important on the entire planet.

From the capital of Brazzaville, it takes a combination of buses, beaten up bush taxis, dug-out canoes, and walking to reach the far north of the country where the rainforest is at its most luxuriant. German biologist Eva Luef studies western lowland gorillas here in the massive Nouabalé-Ndoki National Park, a 1,500 square mile tropical rainforest that is devoid of human habitation, but said to contain the largest concentration of wildlife per square mile anywhere in Africa.

Narrow elephant and buffalo trails through the park lead to a large, natural forest clearing and a roughly built wooden viewing platform from where it is possible to gaze across a vast swampy clearing busy with wildlife. In one sweeping glance Luef counts a pair of elephants, five or six forest buffalo, a solitary bongo antelope flirting with the shadows and, calmly munching bundles of water weeds, some two dozen western lowland gorillas.

Talking quietly so as not to disturb any of the animals, Luef says that it was just to the south of here that, in 2004, Ebola wiped out nearly 95 per cent of the 400-strong gorilla population of the Odzala forest. Scientists working in the area at the time reported that ‘hundreds, if not thousands, of additional gorillas living around this small population were also killed.’ It’s also thought that at least another 5,000 gorillas died of the virus during the same period elsewhere in Central Africa.

According to 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, while the chimpanzee population fell by a terrifying 80 per cent. Furthermore, according to WWF, back in 1994, an outbreak in Minkébé in northern Gabon almost completely eradicated 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) meaning that when Ebola strikes, it can wipe almost all the apes in an ‘island’ out in one fell swoop.


‘It’s very hard, if not impossible, to get rid of Ebola in the wild but there could be some hope’



It’s clear that Ebola poses a significant threat to the future of Africa’s great apes, but what can be done to stop it? While it’s very hard, if not impossible, to completely eradicate Ebola in the wild, there could be some hope. Scientists from the University of Cambridge have been working on an Ebola vaccine specifically for chimpanzees and gorillas. This proto-vaccine involves inserting a protein from the surface of the Ebola virus into an existing live rabies vaccine.

When given to ten chimpanzees in a US laboratory, 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, a lecturer in Primate Quantitative Ecology, is confident it could have a 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 hoped they might be able to lace a fruit bait with it, one that would then be consumed by the chimps and gorillas. However, the apes often live in very remote areas that can be hard to access. More importantly, it’s likely that other animals (pouched rats in particular) would get to the bait first.

While that’s a challenging obstacle, it’s not an insurmountable one (indeed, the team behind the vaccine is already working on ways around it). Another, 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 states that tests can go ahead if they are seen as being of benefit to wild populations, which 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. Walsh believes this was due to the fear of reaction from animal rights groups and the sheer cost now associated with obtaining the correct permits.

Scientists are mixed in their views on the halting of these tests. Having dedicated much of her adult life to rescuing orphaned and captive chimps, Christelle Colin is understandably adamant in her views against the lab testing of chimps. ‘It would be like asking me if it is okay to use, for example, orphan kids to test a vaccine that could potentially kill them in order to save my own child,’ she describes.

But away from the morals of the testing, Colin is also sceptical of the logistics of administering the vaccines: ‘Nobody knows how we could efficiently administrate such a vaccine to wild great apes.’

Not all scientists wanted to see the project dropped though. Professor Adam Hart is an author, broadcaster and Professor of Science Communication at the University of Gloucestershire with a strong opposing view. ‘Let’s be clear,’ he says, ‘medical testing on captive apes is no one’s favoured option, but the loss of wild apes through a disease that it is potentially within our power to prevent would be a terrible crime against the natural world. To commit that crime under the cover of “animal rights” is, to my mind, environmentally irresponsible.’

Back in the Congo, as Eva Luef sits watching the gorillas finish off their water salad lunch before marching back into the shade of the forest, it’s hard not to 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 that would most benefit from the tests they’re preventing.

This was published in the September 2017 edition of Geographical magazine.

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