Ill health in wild apes is a major threat to their future survival. It’s true that everyone (us and our ape relatives) gets sick sometimes, but unfortunately the frequency and severity of disease experienced by wild apes is increasing because of our actions. And, as with humans, it is better to try to ensure that the apes remain fit and healthy than to have to cure ill health. Prevention is better than cure!
Habitat loss and hunting activities cause stress for apes and as a consequence make them more vulnerable to disease and infection. Disease can sometimes be transferred between different species. For example, it is suspected that the Ebola virus was transmitted from fruit bats to gorilla and chimp populations as a consequence of close encounters during feeding at the same fruiting trees. The restricted home range of western lowland gorillas (Republic of Congo, Cameroon and Gabon) has enabled Ebola to spread quickly through the population. Currently it is thought that 25% of the world’s gorilla population has died as a consequence of contracting Ebola; 90% of gorillas that contract Ebola die from heavy internal and external bleeding. Though chimpanzees also contract Ebola, the spread of the disease has been much slower as their populations are currently more widespread.
The similarity between us and our ape relatives means that we too can share diseases; transferred from us to them (anthroponosis) or from them to us (zoonosis). When the immune system recognises common diseases it can fight them. However for apes, greater exposure to people and their domestic livestock introduces a greater number and variety of diseases. Apes are not accustomed to many of these diseases and are therefore more susceptible to them. When apes are kept as pets or managed in rehabilitation centres they can sometimes contract tuberculosis and hepatitis from humans.
Hope!
As the impact of disease on ape conservation becomes more widely recognised, identification of what can be done to ‘prevent rather than cure’ diseases in these wild apes has been initiated. These efforts either aim to:
- improve the habitat of the apes through reinstating or creating natural boundaries to reduce the speed of spread or prevent further spread of disease; or
- reduce human-ape interactions to prevent transmission of disease. The most obvious and successful steps towards this goal have been taken in eco-tourism situations. In such situations proximity between apes and humans is reduced, increasing the risk of disease transfer. Increasingly tourists are provided with strict protocols to ensure they pose as low a risk as possible to the wild ape population they are viewing (e.g. you’re not allowed to visit if you have a ‘common cold’).
Our understanding of disease and its transmission has been improved greatly by leaps in veterinary medical science. In some unique circumstances veterinary treatment is being given to wild apes, though this presents a logistical, political and financial challenge.
