A trial Ebola vaccine was found to be safe and effective in producing an immune response in chimpanzees; but the treatment was tested on captive chimps. 

These "orphan" vaccines that never undergo expensive licensing processes to be used in humans could aid in primate conservation, a University of Cambridge news release reported. 

In order to pay back moral debts to chimpanzees used for captive testing, the researchers hope to provide wild chimps at risk of tourist-transmitted disease with these vaccines. 

"The ape conservation community has long been non-interventionist, taking a 'Garden of Eden' approach to modern medicine for wild animals, but we ended Eden by destroying habitats and spreading disease," Dr Peter Walsh, the senior author on the study from the Division of Biological Anthropology, University of Cambridge, who conducted the trial at the New Iberia Research Centre in the US with researchers from the Centre, as well as the US Army, the University of Louisiana and the conservation charity Apes Incorporated (ApesInc.org), said in the news release. "Half of deaths among chimps and gorillas that live in proximity to humans are from our respiratory viruses. For us it's a sore throat - for them it's death."

Vaccinations could make a huge difference in this death rate. 

"We need to be pragmatic about saving these animals now before they are wiped out forever, and vaccination could be a turning point. But park managers are adamant - and rightly so at this stage - that all vaccines are tested on captive apes before deployment in the wild. This means access to captive chimpanzees for vaccine trials," Walsh said. 

These contagious respiratory infections impose as high on a risk to the populations of African primates as poaching and other common dangers. Vaccines could be the answer to these problems but testing them out on captive monkeys is a necessity. 

The United States is currently the only country to perform biomedical testing on captive chimpanzees. 

To test an Ebola vaccine researchers injected captive chimpanzees with a "virus-like particle." The vaccine proved to greatly increase the immune response in the animals. 

"We've demonstrated that it's feasible for very modestly funded ape conservationists to adapt these orphan vaccines into conservation tools, but the ability to trial vaccines on captive chimps is vital. Ours is the first conservation-related vaccine trial on captive chimpanzees - and it may be the last," the author wrote, the news release reported.