As global health authorities focus on containing the latest Ebola outbreak in the Democratic Republic of Congo, experts are highlighting the critical need to understand the virus's origins in wildlife. The current outbreak, caused by the Bundibugyo virus, has already led to over 1,250 cases and at least 362 deaths, underscoring the ongoing threat posed by these highly fatal pathogens.
The Bundibugyo virus, a relative of the more widely known Zaire Ebola virus responsible for the devastating West African pandemic from 2014 to 2016, presents with sudden symptoms including headaches, diarrhoea, kidney and liver malfunction, and sometimes internal and external bleeding. A grim aspect of the disease is its contagiousness even after death, posing a risk to family members during traditional funeral preparations.
While immediate efforts are dedicated to isolating patients and tracing contacts to curb the spread, virologists stress that once the current outbreak is under control, the focus must shift to fundamental questions: why did this outbreak occur, and where did the disease originate? The answers are considered indispensable for preventing or significantly mitigating future epidemics.
Despite Ebola viruses being high on lists of potential bio-terror agents, surprisingly little is known about their presence in the wild. Fruit bats are frequently cited as potential reservoir hosts, a theory supported by their known role in carrying the related Marburg virus. However, definitive proof that bats are viable incubators for all Ebola virus strains, including Bundibugyo, remains elusive. Historically, initial human cases in outbreaks have been linked to exposure to other mammals, such as forest antelopes, gorillas, and chimpanzees, suggesting a more varied host range.
The scientific challenge of identifying these wildlife reservoirs is immense. Researchers face difficulties in sampling wary wild animals in remote tropical forests and in politically unstable regions. Furthermore, the intermittent nature of outbreaks means capturing the virus 'red-handed' during a spillover event from wildlife to humans is exceedingly difficult. These complexities are compounded by reported cost-cutting in research and health funds by international donors, which could further deplete necessary infrastructure for such vital studies.
Despite these hurdles, the urgency for answers is growing. Before 2010, Ebola outbreaks rarely exceeded 300 cases. Since then, there have been three outbreaks with thousands of cases, indicating a clear trend towards larger and more frequent epidemics. Understanding the intricate workings of Ebola viruses in their natural environment is crucial for developing effective mitigation strategies, such as establishing wildland buffers or other measures to reduce human exposure.