COVID-19 isn’t merely a human disease—animals can catch it too. Species infected so far include domestic cats, lions, tigers, mink, and dogs. In January, three gorillas at the San Diego Zoo Safari Park tested positive, the first such cases in any non-human primate.
The gorillas—which were likely infected by an asymptomatic keeper—recovered, in part with medical help. Winston, the troop’s 49-year-old leader, who has an underlying heart condition, developed pneumonia and was given antibiotics, heart medication, and monoclonal antibody therapy.
That great apes are susceptible to the coronavirus doesn’t surprise researchers, given the similarity between humans and primates, including gorillas, chimpanzees, and orangutans. The worry now is that these animals could be exposed to COVID-19 in the wild.
A new study published in the scientific journal People and Nature shows that this is a real risk.
To get a sense of how close tourists get to wild mountain gorillas in the three countries where the endangered primates live—Uganda, Rwanda, and the Democratic Republic of Congo—a team of scientists analyzed tourist selfies taken with animals before the pandemic took hold. They found that most people posting these photos got closer to gorillas than is allowed, often close enough to spread diseases such as the coronavirus.
“What we’ve seen is that regulations are not always followed, and that the average distance between tourists and gorillas has become shorter and shorter over the last seven years,” says Magdalena Svensson, a lecturer at Oxford Brookes University, in the U.K., and co-author of the People and Nature study.
The International Union for Conservation of Nature (IUCN), which monitors the status of wildlife species, publishes best-practice guidelines for great ape tourism, which recommend keeping a distance of at least 23 feet (seven meters) from the animals and wearing face masks. Uganda, Rwanda, and DRC all had adopted the seven-meter rule before the pandemic; only DRC had required face masks.
Gorilla tourism is operating now, although at limited capacity and with stricter safe guards in place than before the pandemic. But Svensson warns that the animals will be at significant risk of catching COVID-19 if the rules aren’t strengthened and enforced going forward.
“We don’t want to stop gorilla tourism or stop people from seeing these amazing animals, but we do want to make it as safe as possible for everyone,” she says.
Open to infection
Tourism is a huge boon to primate conservation, bringing in essential funds that support protection efforts and local economies. Tourism also helps to keep poachers away by bringing visitors and rangers into areas where the animals are found and showing local people the value of keeping great apes alive and healthy.
But because of our genetic similarity to the apes, humans regularly transmit a number of maladies to them, from E. coli to scabies and Giardia to pneumonia.
Respiratory illnesses are a particular scourge. Several pathogens that generally cause only cold-like symptoms in humans can be fatal for great apes—such viruses are the leading cause of death for some populations. In 2016 and 2017, for example, an outbreak of human respiratory illness in chimps in Kibale National Park, in Uganda, killed 25 animals in a single group and infected 44 percent of the group’s 205 members.
The San Diego Zoo’s gorillas are the first primates known to have been infected with COVID-19 outside a laboratory setting. Experimentally, scientists have confirmed that African green monkeys, rhesus macaques, and cynomolgus macaques can contract the virus and show serious symptoms.
“All apes and many monkeys are almost certainly susceptible to COVID-19 infection and disease,” says Tony Goldberg, an epidemiologist at the University of Wisconsin, Madison.
If wild gorillas become infected with COVID-19, the virus would almost certainly be more severe than in the captive animals at the San Diego Zoo, which had “excellent veterinary care,” Goldberg adds. “It would probably spread very rapidly within gorilla families, which spend all their time together.”
Svensson and her colleagues were interested in seeing how closely the IUCN’s rules have been followed by people attempting to see gorillas. Given current travel limitations, they looked to Instagram for insight into how tourists behave in the field. “We’re trying to be creative and do research that could help primate conservation, even [remotely],” Svensson says.
A search using the hashtags #gorillatrekking and #gorillatracking revealed 858 selfies with mountain gorillas posted from 2013 to 2019. Svensson and a colleague separately estimated the distance between the gorilla and the human in each photo. If their approximations differed significantly, they asked a third colleague to judge the distance.
The results don’t present a full picture of how all tourists behave in the field around the roughly 1,000 mountain gorillas surviving in the wild today, but they do suggest that significant numbers of people aren’t following the rules. Of the 858 selfies, 86 percent were taken within 13 feet (four meters) of a gorilla. Only three percent of photos, on the other hand, were taken at least 23 feet away, as required. In 25 photos, people were even touching the animals.
Tourists seem to have been creeping closer to the great apes: Over the six-year study period, the average distance between people and gorillas decreased by about three feet.
The researchers also examined the use of face masks in the selfies. In DRC, where masks are required, they found that 65 percent of people wore them. In Uganda and Rwanda, where masks aren’t mandatory, no selfie-takers wore one. With field research and wildlife tourism slowly opening back up, both Rwanda and Uganda now require face masks and have increased the safe distance from 23 feet to 32 feet. It’s unclear if these changes will be permanent. (National Geographic Expeditions that take visitors to see great apes follow the health and safety protocols set forth by government wildlife authorities.)
“The authors of this paper should be congratulated for recognizing selfies as an underutilized data source,” says Goldberg, who was not involved in the research. “It’s very hard to get accurate data about encounters with wild apes from interviews with tourists or guides, and photos can reveal different aspects of the tourism experience that might not be apparent otherwise.”
A chance to change
The problems revealed in the selfie study aren’t unique to gorillas, Goldberg adds. Darcey Glasser, a graduate student at the City University of New York with whom Goldberg collaborated, joined 101 chimpanzee-viewing excursions in Uganda and observed more than 900 instances of tourists engaging in bodily functions in chimp areas that could spread disease—coughing, sneezing, urinating, spitting. As described in the study, published in January 2021, Glasser also observed thousands of moments when tourists touched tree trunks and branches that chimps could come into contact with. While touching trees doesn’t violate any current rule, it’s one of many possible modes of disease transmission that could be lessened with more stringent measures, Glasser concludes.
Svensson says she hopes the coronavirus pandemic will help improve primate tourism regulations and enforcement. Face masks, she says, are now the norm and could easily be included as mandatory accessories for all primate viewing.
Gladys Kalema-Zikusoka, a veterinarian and founder of Conservation Through Public Health, a Uganda-based nonprofit that promotes coexistence of people, gorillas, and other wildlife, also hopes COVID-19 will provide impetus for positive change.
“The results from this research will be useful for creating a culture of responsible tourism for gorillas, chimpanzees, and orangutans, and can also be adapted for other primates,” she says.