The Ebola epidemic in Guinea, Liberia and Sierra Leone continues to spread despite country and international efforts to stop it in its tracks and make sure it never returns. As of October 1, 3,338 people have died and 7,178 are infected. More people have perished in this latest Ebola outbreak than in all previous outbreaks of the virus on the continent combined. In addition to the large number of people who have died, and the steady march of new infections, the three hardest-hit countries are also suffering heavy economic costs from trade and travel restrictions, food being in short supply, and other impacts. While health workers, international health agencies and charities work furiously to contain the outbreak, we must also think ahead so that we might avoid similar epidemics in the future. What might the first step be? Better understanding the animal origins of Ebola and other infectious diseases so that we can prevent an epidemic like this from ever happening again.
Ebola is a zoonotic disease, meaning that it is transmitted from animals to humans. In past outbreaks, this has occurred during the handling of wildlife – bats, gorillas, chimpanzees, monkeys, even porcupines. The running hypothesis for this outbreak is that it came from bats, though an early focus of consideration was on primates trafficked through capital cities. Regardless of the precise path of transmission, it is clear that we must examine human relationships with wildlife to ensure we protect against this and other future disease risks.
It may seem like a silly question. And of course I’m not proposing that we stock schools with bears and lions – that would probably keep students away. Nor am I suggesting that saving lions will solve the undersupply of education in developing countries. Rather, I am making a broader point about the links between different parts of ecosystems, which often have an indirect but underappreciated bearing on human development.
Habitat conversion and fragmentation, depletion of prey, and hunting have in many parts of the world reduced the ranges of wolves, lions, bears, tigers, sea otters, and other large carnivores to less than half of their original range. When their numbers nosedive, we not only lose iconic species. Ecosystems also lose the keystone species that eat smaller carnivores and herbivores. When fewer animals down the food chain get eaten, ecosystems change – and those changes affect us humans too. A recent article in Science Magazine casts a systematic light on the issue, and its lessons are important for development.
On land, large carnivores can help ensure functioning ecosystems. Consider the case of West Africa, where lions and leopard populations have dropped precipitously. Both species hunt olive baboons, which in turn like to eat the small antelopes, livestock, and food crops that humans also consume. Fewer lions and leopards have resulted in more baboons and more competition for food with humans. In some areas, baboon raids on fields have even forced families to keep children home from school so that they can protect the family crops. Also, since carnivores often go after sick prey, they reduce the prevalence of disease in their prey population. This can limit disease spillover between wild and domesticated animals, as well as cut related pastoralism and animal husbandry costs.