10/16/2014 01:36 EDT | Updated 12/16/2014 05:59 EST

Vaccinate gorillas against Ebola, Gorilla Doctors recommend

Veterinarians who care for wild gorillas want government permission to give the endangered animals an experimental Ebola vaccine in case of a nearby viral outbreak. 

Mike Cranfield, the Canadian co-director of the non-profit group Gorilla Doctors, says its member are "very, very concerned" about the risk to gorillas of Ebola.

The human outbreak centred in West Africa has killed nearly 4,500 people, the World Health Organization reported Wednesday.

But previous outbreaks have killed tens of thousands of gorillas and chimpanzees — a 2002 outbreak at Lossie Sanctuary in northwest Congo alone killed 5,000 gorillas, or93 per cent of the population at the sanctuary, at the time, a 2006 study reported.

"It's so devastating," said Cranfield. "Where people had gone in before and there was high numbers of great apes ... now they go in and it's completely silent. They can't find any."

Cranfield, who is originally from Peterborough, Ont., was speaking to ahead of the debut of Gorilla Doctors, a documentary about his group's work that airs tonight (Thursday) on CBC-TV's The Nature of Things.

There are only about 880 mountain gorillas left in the world, including 450 to 500 that are habituated to humans, and receive monitoring and medical care from Gorilla Doctors. The group also cares for orphaned baby gorillas.

Cranfield said if an Ebola outbreak threatens the gorillas under the groups' care, it will recommend to the governments of Rwanda and the Democratic Republic of Congo, where gorillas live, that the animals sbe given an experimental vaccine such as VSV-EBOV made by NewLink Genetics. The government's permission would be required to do that.

A number of experimental Ebola vaccines have been shown to be successful in monkeys, including VSV-EBOV which is undergoing its first human trials in the U.S. Another, called cAd3 and licensed to the pharmaceutical giant GSK is also in human trials, while an experimental Ebola vaccine developed by Johnson & Johnson's Crucell unit will start human trials in 2015. 

Cranfield acknowledged that the current human outbreak might make it hard to get a supply of vaccine for the gorillas.

"I'm not sure how available it's going to be now, whether they're holding it back for people."

Other human illnesses also pose a threat to gorillas, who are susceptible to many of our diseases because they share 98.5 per cent of our genes.

Respiratory disease a leading cause of death

While the leading cause of death for gorillas is trauma, usually inflicted by adult males on infants fathered by other males, the second leading cause is respiratory disease, Cranfield said.

He added that gorillas can get diseases from both other wildlife and from humans. But the "extreme ecotourism" around parks with mountain gorillas that span the border between Rwanda and the Democratic Republic of Congo results in a lot of human-gorilla interaction that can transmit diseases.

Gorilla Doctors treats such illnesses with antibiotics when a gorilla becomes so ill that he or she stops eating. The vets may also consider vaccinating gorillas against some respiratory diseases in the future if scientific evidence supports that, Cranfield said.

In the meantime, the group tries to ensure tourists who get within 20 metres of the gorillas wear masks, and the vets themselves wear protective clothing when handling the gorillas.

Cranfield says that if an Ebola outbreak does reach areas where the gorillas live, he recommends temporarily stopping human ecotours to see the gorillas.

The Gorilla Doctors' work has faced some controversy, as critics question the implications for "wild animals" that receive this amount of medical intervention and human contact.

Gorilla Doctors airs at 8 p.m. tonight on CBC-TV's The Nature of Things. During the broadcast, Jessica Burbridge, communications director for @GorillaDoctors, will take questions live on Twitter with @cbcdocs. The film was produced by 52 Media, Inc. and directed by Roberto Verdecchia and Michael Boland.