Ebola’s Other Victims: One-Third of the World’s Gorillas and Chimpanzees

image via (cc) flickr user mape_s

While the headlines, and accompanying panic, may have subsided for many of us, the Ebola outbreak of 2014 remains one of the most horrific viral epidemics in recent memory. A January 2015 report by the World Health Organization places the number of fatalities at 8,641, with nearly three times that reportedly infected across West Africa. The degree to which life in and around the affected areas has been seismically disrupted is hard to most of us to fathom. It is an outbreak—the most recent of many—that in both scale and severity feels more akin to a war than a disease. But alongside the catastrophic human toll of Ebola’s rampage across West Africa is an alarming trend affecting our nearest genetic cousins: Gorillas and chimpanzees, which have reportedly lost a full one-third of their global populations to Ebola since the 1990s.

In The Conversation, Meera Inglis, a PhD candidate in conservation policy at the University of Sheffield in the UK, goes so far as to name the Ebola virus “the single greatest threat to the survival of gorillas and chimpanzees.” She explains:

The virus is even more deadly for other great apes as it is for humans, with mortality rates approximately 95 percent for gorillas and 77 percent for chimpanzees (Pan troglodytes). Current estimates suggest a third of the world’s gorillas and chimpanzees have died from Ebola since the 1990s.

As with humans, these deaths tend to come in epidemics. In 1995, an outbreak is reported to have killed more than 90 percent of the gorillas in Minkébé Park in northern Gabon. In 2002-2003 a single outbreak of ZEBOV (the Zaire strain of Ebola) in the Democratic Republic of Congo killed an estimated 5,000 Western gorillas (Gorilla gorilla). It’s hard to accurately count such elusive creatures but the WWF estimates there are up to 100,000 left in the wild—so a single Ebola outbreak wiped out a considerable chunk of the world’s gorilla population.

While there are efforts to explore Ebola vaccination for great apes, Cath Lawson, an official from the World Wildlife Fund explained to The Independent that the dispersal of such a vaccine would, at best, only protect a small number of apes. Rather, Lawson explained, the WWF focuses on “natural barriers,” such as rivers and human construction, to prevent the spread of the virus amongst ape populations. It is, in part, a tactic Inglis seems to agree with, writing:

Conservation efforts aimed at restoring forest habitat could also help curb the spread of the virus, as larger forested areas would reduce the chances of infected animals coming into contact with one another

Of course the loss of ape life pales in comparison with the devastating effect Ebola has had on human communities. But, a 2014 article published by the Jane Goodall Institute of Canada suggests that, in some cases, the relationship between incidents of Ebola in apes and in humans are more than simply correlative—they’re causative. The article describes a series of human-based Ebola outbreaks in mid-to-late ‘90s, which were traced to the consumption of chimpanzee meat from an ape population that, while diagnosed only after the fact, had long been infected by the virus. “Contact with these infected animals,” the article concludes, “...had likely led to the three secondary epidemics in humans.”

All the more reason to work toward ending this horrific disease, once and for all.