I first visited mountain gorillas in the wild in 1986, in what was then eastern Zaire (now Democratic Republic of Congo). Even then, on arrival, we were asked by local gorilla experts if anyone had a cold or felt sick, and if so, please don’t visit the gorillas since the infection could potentially be passed to them. If they had no resistance, that could wipe out the entire critically endangered subspecies.

We have known for a long time that gorillas and other great apes are susceptible to pathogens from humans.

Fast forward 20 years and those of us going into the forest to visit wild lowland gorillas in the Republic of Congo had to wear face masks and stay at least 25 feet away from them, again to ensure that we didn’t transmit any illness. So we have known for a long time that gorillas and other great apes are susceptible to pathogens from humans.

The current pandemic has made us acutely aware that so-called zoonotic diseases can pass between wild species and humans. This is especially true when we bring wild animals into markets in areas of high human density, as was probably the case with COVID-19. The exact route of transmission has not yet been confirmed, but one likely route was from bats to pangolins to humans. These species are not closely related to each other or to us, yet it is at least theoretically possible that the virus could transfer between them.

So what about when we humans go into places where significant populations of our closest wild relatives, great apes, occur? It would be extremely surprising if a coronavirus was not transmissible between ourselves and any of the seven species of great apes.

Of those seven species, two are Endangered and five Critically Endangered. Habitat loss and hunting have been the primary cause of their declines, and infusion of a potentially lethal disease could be the final straw for these amazing species. Forests where gorillas, chimpanzees, bonobos or orangutans live are visited by humans for a variety of reasons – including local communities hunting and gathering forest products for their own subsistence.

That does not necessarily bring humans into close proximity to the apes, and restricting them from entering forests outside protected areas would be both ethically and practically challenging. Enforcement patrols to protect the great apes and other threatened species in the protected areas against encroachment and poaching also bring people into the forest, and are essential to their survival. While the risks of disease transmission are clearly there, these patrols do not generally come into close proximity to the apes.

African apes are capable of extraordinary behaviours, but these do not include social distancing.

But there are two circumstances in which people deliberately do approach much closer to apes: (1) to conduct research into the lives of these animals and how best to conserve them; and (2) via ecotourism, whereby tourists are led by guides to forest locations where they are likely to encounter great apes. This brings invaluable revenue and jobs to often very rural poor communities, as well as raising awareness and support for the species’ conservation.

As a result of the coronavirus responsible for COVID-19, these activities now pose very serious risks to the survival of great apes. Gorillas are probably the most at risk; unlike the other great apes, they spend by far the majority of their time on the ground where we humans walk, making them the focus of the most developed tourist operations.

But all of the great ape species do come to the ground on occasion, and all are visited by tourists, so they are all potentially at risk. Apart from the more solitary orangutans, all species of great apes are highly sociable, living in close-knit social groups with physical interactions between them such as grooming and play occurring throughout large parts of every day. Transmission of any disease would thus be rapid. African apes are capable of extraordinary behaviours, but these do not include social distancing.

On 15 March 2020, the world’s leading relevant experts, the IUCN Species Survival Commission’s Specialist Groups on Primates (Section on Great Apes) and on Wildlife Health, issued a statement highlighting the risk that the SARS-CoV-2 coronavirus – the virus that causes COVID-19 in humans – poses to great apes. They call for any visits to great apes by humans to be reduced to the minimum needed to ensure the apes’ safety and health monitoring. Even those essential staff should stay at least 30 feet away from the animals, and nobody who is ill, or has been in contact with anyone ill in the past 14 days, should be allowed to visit the areas.

Out of concern for the animals, western lowland gorilla sites were very quick to close tourism. The first was the Nouablé-Ndoki National Park in Congo, with Gabon, other Congo sites, and Central African Republic following rapidly behind. The larger great ape tourism operators in East Africa have subsequently also closed their operations.

The risk of disease transmission between ourselves and other species, in both directions, is ever increasing. COVID-19 is the latest and most devastating example of this.

Human activities have brought wild species into closer proximity to us through legal and illegal wildlife trade in towns and cities. At the same time, we have come into closer proximity to wild species through moving into the last great wild areas of the world. As a result, the risk of disease transmission between ourselves and other species, in both directions, is also ever increasing. COVID-19 is the latest, and most devastating, example of this.

We all need to change our entire outlook and behaviour moving forward. Closing wildlife markets for human consumption and protecting our closest wild relatives are critical steps towards ensuring healthy futures for all. 

Dr. Elizabeth Bennett is Vice President for Species Conservation at WCS (Wildlife Conservation Society).