Posted on behalf of Ian Redmond.

One afternoon of the Great Ape Health workshop, August 21-23, was spent discussing methods to vaccinate apes against such deadly natural diseases as Ebola, or against diseases that humans might bring, such as ‘flu.  Many captive gorillas, we were told, are given an annual ‘flu vaccine as a precautionary measure but this has not yet been done to wild gorillas.  

There is an ethical debate about whether this is an unacceptable level of intervention in a natural ecosystem, but the majority of those present seemed to agree that if human activities are causing the problem, humans should attempt to solve it.  And although Ebola might be natural, the repopulation of an area after an outbreak is more difficult since humans have fragmented the forest and in many places, bushmeat hunters will still kill any survivors.  

Paradoxically though, Ebola seems to have a greater impact where gorillas are not hunted, because densities are higher and this enables the disease to spread more easily.  But vaccination of gorilla populations at risk from the advancing Ebola wave is now a serious option thanks to Peter Walsh and colleagues in a project called Vaccinape (http://www.vaccinape.org/). 

They are working on oral vaccines for unhabituated gorillas (if they can find a bait that wild gorillas want to eat) and vaccines to be delivered by darts or so-called biobullets (biodegradable material with the vaccine inside) for gorillas who can be approached. Not only might this save whole populations of gorillas, it will greatly reduce the risk of Ebola outbreaks in humans – many of which have been traced back to someone handling or butchering an infected ape they found in the forest.  

As such, it would seem to me that the costs of Vaccinape should be shared by human health agencies, because as Richard Preston graphically described in The Hot Zone (http://www.richardpreston.net/books/hz.html) if one of these emerging diseases mutates to be better able to survive out of the host’s body, enabling it to spread by droplet infection, H1N1 would seem like a walk in the park in comparison…
 
The links between human and gorilla health is the focus of a relatively new NGO, Conservation Through Public Health (www.ctph.org), that recently won the Whitley Award (http://www.youtube.com/watch?v=8tDRbZ80OAY).  Founded by Uganda’s best know wildlife vet, Dr Gladys Kalema Zikusoka, it recognises that there is a three-way connection between human health, domestic livestock and wildlife. As people and their animals are increasingly living in close proximity to dwindling natural habitat, the health of the whole eco-system needs to be addressed. 

A recent study of E. coli bacteria in gorilla dung, for example, found strains showing resistance to antibiotics (available without prescription in Uganda) that can only have come from the local human population. Gladys and her team work to improve treatment of people and livestock around gorilla habitat as well as the wildlife in that habitat, and introduce health measures to minimise the risks of cross-contamination. 

After the workshop finished, Gladys and her husband Lawrence kindly hosted me for my last night in Kampala. Lawrence is a telecom specialist and is seeking to launch a new Gorilla Calling Card that would bring a sustainable source of revenue to expand this important work to other gorilla habitats.  We could have talked all night, but I had to finish reviewing Desmond Morris’s new book ‘Planet Ape’ for BBC Wildlife, and we all had an early start the next day.

Read Ian’s previous post here!

The risk of droplet infection with new viruses is of global concern with the spread of H1N1 swine ‘flu virus, so soon after the H5N1 bird ‘flu.  Measures already in place to minimise the risk of such transmission to habituated apes include refusing a visit to anyone showing symptoms, the ‘no closer than 7m rule’ and preventing tourists from leaving any foreign objects, litter or bodily fluids (unless buried deep) in the park.

Some sites have gone further and request that tourists wear surgical masks for the time spent near the apes.  We do not know the mortality rate that such viruses might cause if they were to spread through a gorilla group, and whilst any such loss would be a blow to a small population, it is likely that most infected animals would recover and there-after be immune to that strain of ‘flu. 

The ‘worst nightmare’ scenario for all involved with the Mountain Gorillas is the possibility of an Ebola outbreak in the Virungas or Bwindi; we know from Western Lowland Gorillas that Ebola kills ninety something per cent of those infected – approximately one third of the western gorilla population has been killed by Ebola in the past decade or so.  

The promising tourism site at Lossi in Congo Brazzaville suffered in this way when the habituated animals died of Ebola, and the evidence suggests that there is a front of outbreaks, moving northwards towards the region with the largest concentration of western gorillas (see animation by Peter Walsh, and YoG interview to follow). Ebola has not yet been reported in eastern gorilla populations, but during the Great Ape Health workshop in Uganda, August 21-23, I learned that there was a close call recently with the closely related Marburg virus.
 
A Dutch tourist fell ill a few days after returning from a holiday in Uganda last year, and sadly died. Tests in the Netherlands revealed that she had contracted Marburg, and when her itinerary was examined, virologists concluded that she had most likely picked up the virus whilst visiting the Python Cave in the Maramagambo Forest. 

This is a fantastic place for any naturalist – a collapsed lava tube with a roost of Rousette’s Tongue-clicking Fruit Bats and pythons that coil around the rocks on the cave wall to snatch bats out of the air as they pass. I have taken tours there myself, and then – just as this lady did – gone on to visit the gorillas in Bwindi.  The difference is that this poor unfortunate woman was unknowingly incubating Marburg haemorrhagic fever when she reportedly came within 5m of the gorillas (http://www.cdc.gov/eid/content/15/8/1171.htm).  

Neither Marburg nor Ebola can survive long out of the body, and fortunately, neither the gorillas nor any of the 130 or so people she came into contact with were infected. But this tragic case should act as a warning, and simple measures such as introducing disinfected boot dips and asking tour companies that plan to visit the caves, to do so after seeing the gorillas would further minimise the risk.

Cheers, Ian

Read Ian’s previous post here!

The idea of health care for wild gorillas might seem strange – especially in countries where human health care is so limited, and there are too few veterinarians for domestic livestock, let alone wildlife.  But ever since Dian Fossey asked the Morris Animal Foundation to help provide veterinary expertise for the mountain gorillas there has been a dedicated team of animal health professionals doing just that.

The Mountain Gorilla Veterinary Project has become a central part of the conservation efforts for the species, and since ebola became known as one of the major threats facing Western Lowland Gorillas and Central Chimpanzees, great ape health has risen up the agenda.

This is not as esoteric as it may sound to some people. Humans and the other great apes have such similar biochemistry that many pathogens can easily flourish in both. Diseases that we catch from other animals are known as zoonoses, and the list of zoonotic diseases seems to be growing.

Not only can we catch diseases from other apes, but with the rising number of tourists coming within coughing distance of habituated gorillas and chimpanzees, we pose a risk to them too. And with sanctuaries filling up with confiscated animals and seeking suitable release sites, the risk of sending diseases from captive animals into a wild population also needs to be considered, as does the risk faced by immunologically naïve ex-captives being released into forests full of pathogens against which they have little resistance.

To discuss these issues from a conservation perspective, the Great Ape Health Workshop was convened in Entebbe, Uganda from 21st to 14th August.   Part scientific symposium, part practical workshop, this was probably the biggest gathering of ape health experts and fieldworkers to date.   I had been asked to chair the afternoon session of the first day, and having studied gorilla parasites in the 1970s, was delighted to do so.

When thinking about biodiversity conservation, we should remember that protecting large animals also protects the many fascinating species that live in or on them – if there were no gorillas, the species specific gorilla lice, mites and worms would have no-where to go!  For four days, there were a lively exchanges of ideas and new technological developments, and much renewing of old friendships and building new ones.  It was also a great place to grab YoG Blog video interviews (though please bear I mind it might be a while before they appear on the site).

Cheers, Ian

Read Ian’s previous post here!