Have we lost the chance to save our gorillas?

Scientists have completed a trial for the ebola vaccine on captive chimps, but could this be the last one?
14 March 2017

Interview with 

Peter Walsh, University of Cambridge


Ebola made the headlines in 2014 when there was major outbreak in West Africa. Thankfully, for the time being at least, the threat to humans was halted, but it’s still a massive problem for gorillas. Experts estimate that, over the last 30 years, a THIRD of gorillas have been wiped out by the virus. So how do you protect a wild animal from a disease? The same way you do with people: a vaccine! The results from a trial in chimpanzees for a new oral vaccine were published this week in Scientific reports, suggesting the vaccine would be effective, with no damaging side effects. But new legislation in America could prevent further trials of this kind, which could be devastating for future outbreaks of diseases in our endangered cousins. Georgia Mills spoke to Peter Walsh from the University of Cambridge, and Apes Incorporated, about the challenges of vaccinating a 450 pound wild gorilla!

Peter - With wild animals it’s more difficult to protect them. Some of the gorillas and chimpanzees are in tourism programmes or research programmes where they’re habituated to the presence of people. With those animals you can get up close, you can get a dart gun or a blow dart. We use a phtt and you can shoot them with a little dart that has the vaccine.

The other animals are very afraid of people and so it’s too difficult to try and track each one and shoot them with a dart. So what we’re working on is an oral vaccine where you put the vaccine in a little bait. We’re using a fruity bait that’s sweet and we’re testing that now Africa. You put the vaccine in there and then you can put that at areas where there’s high activity rates by gorillas and chimpanzees, and then they’ll eat the bait and then become immunised that way. We have a problem right now, we have gambian rats (pouch rats) and the rats come in at night and they eat all my bait and so I’m working on ways to get around that. But, in principle, we should have the ability to really precisely target who gets vaccinated.

Georgia - OK. I suppose you’ve got to test that this form works?

Peter - Exactly. So we need to go out and, preferably, in the species that we’re trying to vaccinate in the wild, we need to test in the captive animal or closely related species. So chimpanzees, gorillas, and humans also, are very closely related. The objective of testing this in a chimp is to see will it have a robust immune response and will it cause any kind of health complications, and so the trial we’ve just done did exactly that. We took ten chimpanzees: four of them we injected intramuscularly and six we gave an oral dose of the vaccine. Then we took blood samples every week for a month and what we found was, first of all, it didn’t cause any health complications, they didn’t get sick. And they didn’t show any kind of behavioural anomalies, they weren’t really stressed out.

And the other thing it showed is they had an immune response that was very similar to the immune response of monkeys who were vaccinated, and then challenged with ebola and survived. So we didn’t actually challenge the chimps with ebola, we just look at their immune response and health response, but their immune response was very similar to the responses of these monkeys that were actually challenged and survived challenge.

Georgia - Is it quite hard to test these things? I mean, there aren’t too many gorillas and chimps around - is it hard to get that testing process through?

Peter - Yes. It’s exceptionally hard because the United States is the last developed country that allowed biomedical testing on chimps and, as of last summer, they’ve now banned it. The rationale was that it was inhumane and that it was unproductive scientifically. I don’t want to get into a debate about whether or not it was productive for human health, that’s somebody else’s business. But what I can tell you absolutely is a) that it’s not unproductive for conservation reasons, and b) we actually did monitor the stress responses of the chimpanzees during the trial, and they don’t show the extreme health effects that the animal welfare advocates were claiming.  So now they’ve shut down these facilities and we really have no place where we can do the trial.

Now what critics say was: you can do this in a sanctuary, you could do this in a zoo. While the sanctuaries are all philosophically opposed to animal testing so they won’t do it, but zoos have facilities to do it safely. That’s the other issue as well - where can you do this safely? But they are terrified of a public backlash. So here we are, we have really no place where we can do these trials and consequently that’s a problem because in Africa, they say if you haven’t tested that vaccine in a captive ape, or any human, you're not going to use it on our endangered apes in the wild. So it’s a catch 22.

Georgia - Right. So in future when the next ebola comes it’s going to be more difficult to do what you’ve done here?

Peter - Exactly. This has happened before. Ebola goes away for a while and people say oh, it’s gone, it’s not a problem anymore, and then ‘boom’ it comes back and it kills a bunch of people. And all of a sudden it’s in the news and it’s like “Oh, we’re going to worry about it again,”. For once, for once, why don’t we think into the future and not react on a crisis basis but actually plan ahead and say you know a) we’re going to need to vaccinate for ebola again in the future, and b) there’s always other diseases. These animals are critically endangered. They’re in really bad shape and it’s incredibly frustrating because we have the ability to protect these animals but we’re not doing it for silly, foolish reasons.


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