Understanding Ebola’s wildlife origins is crucial to preventing next big outbreak

Staff carry a coffin at a hospital in Mongbwalu, Ituri. The outbreak has so far resulted in 254 deaths. Photograph: Dieudonne Dirole/EPA View image in fullscreen Staff carry a coffin at a hospital in Mongbwalu, Ituri. The outbreak has so far resulted in 254 deaths. Photograph: Dieudonne Dirole/EPA Analysis Understanding Ebola’s wildlife origins is crucial to preventing next big outbreak Dan Salkeld If we don’t know the source, not only do humans remain at risk but wildlife can suffer needlessly via retaliation While virologists and public health departments were palpitating over the news of an Andes virus infectious disease outbreak on a cruise ship (13 cases, three deaths), in the Democratic Republic of the Congo the Bundibugyo virus, the root of the current Ebola outbreak (currently more than 1,250 cases and at least 362 deaths), was smouldering under the radar. Bundibugyo virus is a horrifying, highly fatal pathogen. Symptom onset is sudden and includes headaches, diarrhoea, malfunctioning kidneys and liver, and, less frequently, internal and external bleeding (hence the term “haemorrhagic disease”). Grimly, contagiousness remains after death, meaning the family and loved ones of the deceased can be exposed when they wash and clothe the body in preparation for the funeral. The priority right now is to dedicate resources to fight the outbreak. Without a proven established vaccine, health workers will have to combat disease spread by isolating patients and tracing contacts who may have been exposed. But when the outbreak is controlled, it will be time to ask two questions: why did this outbreak happen? And where did the disease come from? The answers are critical to try to prevent or mitigate the next outbreak. View image in fullscreen Bundibugyo virus is a relative of the more infamous Zaire Ebola virus, which has caused outbreaks in remote African rainforests since the 1970s. Photograph: Bsip Sa/Alamy The virus is a relative of the more infamous Zaire Ebola virus that has sporadically caused outbreaks of Ebola virus disease in remote African rainforests since the 1970s, but exploded spectacularly to cause a pandemic in west Africa from 2014 to 2016. Terrifyingly, even though Ebola viruses are highly ranked on lists of bio-terror agents, we know very little about these viruses in the wild. Marburg virus, a more distantly related haemorrhagic fever virus, is known to persist in large fruit bats, and this has generated the reasonable but unproven assumption that bats are the reservoir hosts for the rest of the Ebola virus family. Fruit bats are widespread, abundant, large and conspicuous animals and are easily blamed as a source for each Ebola virus outbreak. Yet proof that bats are viable incubators of the Zaire Ebola virus remains frustratingly elusive. Arguing that bats are the source of Bundibugyo virus is currently just conjecture. Having a distant cousin who wears a kilt doesn’t make you Scottish. In fact, historically, the first human case