What makes controlling Ebola virus challenging

Controlling the Ebola virus poses significant challenges due to several factors. The Democratic Republic of Congo (DRC), currently experiencing its deadliest outbreak in history, has seen the current epidemic surpass the 2014-2016 outbreak in terms of severity. The World Health Organization (WHO) declared this outbreak a public health emergency on May 17, but it likely began at least three months prior to detection.

Identifying the natural reservoir of Ebola viruses is a complex task. The first mysterious cases of Bundibugyo virus were reported in Uganda's Bundibugyo district in November 2007. This discovery marked the 5th species of ebolavirus, with each genus of different Ebola virus species showing a 30-40% divergence. This diversity reflects the varying ecological niches and evolutionary histories of these viruses.

Despite extensive research, the precise reservoir host of ebolaviruses remains unknown, with bats hypothesized as the most probable host.

Transmission of Ebola viruses is complicated by their complex pathways. In Bundibugyo, communities live near national parks, increasing the likelihood of contact with monkeys, baboons, fruit bats, and other primates. Recent studies using cameras in bat-infested caves have observed various wildlife preying on bats, complicating the transmission chain. Additionally, tourist visits to these caves, often without protective measures, further complicate tracing the virus's origin.

Genetic clues can aid in tracking the spread of the Ebola virus. Two teams of scientists from DRC and Uganda published three genome sequences online, which will help in understanding how the virus is spreading. However, combating the Bundibugyo virus is challenging due to limited outbreaks, lack of approved vaccines and treatments, and a severe shortage of diagnostic tools and protocols.

Furthermore, large-scale deforestation for mining activities in Africa is recognized as a risk factor for zoonotic spillover events, potentially increasing the likelihood of Ebola virus transmission.