In the shadow of the latest Ebola outbreak in the Democratic Republic of the Congo, a crucial question looms large: How can we prevent the next big outbreak? While the immediate focus is on containing the current crisis, which has claimed over 360 lives and infected more than 1,250 people, the long-term solution lies in understanding the origins of the virus and the intricate dance between humans, wildlife, and the environment. This is not merely a scientific inquiry but a call to action, one that demands our attention and a reevaluation of our approach to disease prevention and management.
The Bundibugyo virus, the culprit behind the current outbreak, is a relative of the infamous Zaire Ebola virus, which has caused sporadic outbreaks in remote African rainforests since the 1970s. What makes this particular virus particularly terrifying is its high fatality rate and the fact that it remains contagious even after death. This means that family members and loved ones of the deceased can be exposed when they wash and clothe the body in preparation for the funeral, exacerbating the spread of the disease.
The priority right now is to dedicate resources to fight the outbreak. Without a proven 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 to these questions are critical to preventing or mitigating the next outbreak. The virus is a relative of the more infamous Zaire Ebola virus, which 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.
One of the key challenges in understanding the origins of Ebola outbreaks is the elusive nature of the virus in wildlife. Fruit bats, which are widespread, abundant, large, and conspicuous animals, have been blamed as a source for each Ebola virus outbreak. However, 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.
Historically, the first human cases in Ebola virus outbreaks were linked to exposure to other mammal species: forest antelopes, gorillas, and chimpanzees. Experimentally infected pigs can shed infectious Ebola viruses and can infect primates. So it appears that Ebola viruses have a varied approach when it comes to host animals. It’s also possible the virus can hide away in the same host for years before recrudescing, a mechanism that could explain the long periods when Ebola viruses seem to vanish without trace.
Determining Bundibugyo virus transmission patterns in tropical forests is a complex task. How do you convince a group of wary canopy-dwelling monkeys to provide samples? Capture them? Shoot them? Analyze their feces? Or should you target herds of bush pigs? Or giant fruit bats? Or all of the above? And if this disease is rare, and outbreaks in humans occur after the disease has spilled from wildlife, then how on earth do you capture the virus red-handed?
These issues make muddy waters for understanding how diseases emerge; just look at the controversies surrounding the origins of COVID-19. And now imagine attempting this kind of scientific research in an area of political unrest, and in the face of ruthless cost-cutting of research and health funds by the US and UK and the consequent evaporation of infrastructure.
Yet these questions need to be answered. Before 2010, the largest Ebola virus outbreaks rarely exceeded 300 cases, but since then there have been three outbreaks where cases are counted in the thousands. The trend is indubitably one of larger epidemics. If we knew how Ebola viruses worked, we could mitigate against them by reducing human exposure, whether it be using wildland buffers or discouraging consumption of wild animals. Or we could adopt integrated surveillance programs that look for signs of disease spread among wildlife, livestock, and humans.
The problem is, if we don’t know the source, not only do humans remain at risk but local wildlife can also suffer needlessly via retaliations against perceived wildlife culprits, like the bat-killing sprees in the aftermath of COVID-19: in Cuba, people set fire to roosts; in Rwanda, government workers aimed water cannon at bats; and in many other countries bat roosts were attacked and destroyed. This kind of action will achieve nothing for human health if the species is unrelated to the pathogen’s transmission, and disturbing or culling wildlife populations can unintentionally exacerbate disease spread, whether it’s Marburg virus, rabies, or bovine tuberculosis.
The links between humans, wildlife, and the environment are at the crux of the so-called "one health" approach, which explicitly recognizes the connections and how that might affect the health of all three components. Optimizing health for one element can simultaneously boost health in another. This is not a concept limited to Bundibugyo; it can be locally applied anywhere: chicken farms and wild swimming in the Wye or bovine tuberculosis in badgers and cows.
The burning question is whether this outbreak might provide the incentive to act to try to prevent future epidemics. Personally, I think that the answer lies in a more holistic and integrated approach to disease prevention and management. We need to invest in scientific research, strengthen healthcare infrastructure, and foster international cooperation to better understand and combat these deadly diseases. Only then can we hope to prevent the next big outbreak and protect the health of both humans and wildlife.
In my opinion, the key to preventing future epidemics lies in recognizing the interconnectedness of human, animal, and environmental health. By embracing the "one health" approach, we can work towards a more sustainable and resilient future, where disease outbreaks are minimized, and the health of all living beings is optimized.
