Bats Mistakenly Accused in Search for Ebola Origin
For more than a decade, virologists have speculated that Ebola outbreaks would be traced to bats. And sensational media headlines have turned speculation into “fact.” Governments have invested billions of dollars searching for the origin1, mostly focused on bats.
Contrary to the evidence, the index case for the 2013-2014 outbreak was first attributed to fruit bats2, then to insect-eating bats3. However, early investigations implicated primates4. Ebola antibodies were discovered in the feces of 10% of wild gorillas5 and 18.7% of pygmies6, suggesting a potential primate reservoir status that was largely ignored. By 2016, Leendertz7 pointed out that the preponderance of evidence pointed to sources other than bats and urged a broader search. Again, most virologists remained inexplicably focused on bats. And prominent news media continued to blame bats8.
When the recent Guinea outbreak was traced to a human who had carried the virus for five years without detectable symptoms9, the origins of previous outbreaks had to be reexamined. On closer scrutiny, it was discovered that early assumptions of a bat origin had prevented an adequate investigation. The “index” case, a two-year-old boy, had slept and eaten with an apparently infected grandmother who likely carried Ebola with symptoms that were not yet understood10.
Outbreaks long assumed to be spillovers from wildlife (namely bats) are now better explained as reemergence’s from latency in people with asymptomatic infections. Last April, Fairhead et al.10 concluded that Ebola has been endemic in humans over long periods of time, possibly across generations. Such evidence has been ignored repeatedly in a rush to prove, instead of test, the bat origin hypothesis.
This has been costly. Enormous amounts of public health funding appear to have been misdirected. The credibility of science has been compromised. Human lives have been lost needlessly, and decades of conservation progress have been reversed. Sadly, this embarrassing, but key discovery remains seriously unreported.
- Holmes, E.C., Rambaut, A., and Andersen, K.G. (2018). Pandemics: Spend on surveillance, not prediction. Nature 558, 180–182.
- Leendertz, S.A.J., Gogarten, J.F., Düx, A., Calvignac-Spencer, S., and Leendertz, F.H. (2016). Assessing the Evidence Supporting Fruit Bats as the Primary Reservoirs for Ebola Viruses. Ecohealth 13, 18.
- A. M. Saez et al. EMBO Molecular Medicine. Vol.7:1(2015):17-23.
- Ryan, S.J., and Walsh, P.D. (2011). Consequences of Non-Intervention for Infectious Disease in African Great Apes. PLOS ONE 6, e29030.
- Reed, P.E., Mulangu, S., Cameron, K.N., Ondzie, A.U., Joly, D., Bermejo, M., Rouquet, P., Fabozzi, G., Bailey, M., Shen, Z., et al. (2014). A New Approach for Monitoring Ebolavirus in Wild Great Apes. PLOS Neglected Tropical Diseases 8, e3143.
- Mulangu, S., Borchert, M., Paweska, J., Tshomba, A., Afounde, A., Kulidri, A., Swanepoel, R., Muyembe-Tamfum, J.-J., and van der Stuyft, P. (2016). High prevalence of IgG antibodies to Ebola virus in the Efé pygmy population in the Watsa region, Democratic Republic of the Congo.
- Aina, S., Leendertz, J., and Kuhn, J.H. (2016). Testing New Hypotheses Regarding Ebolavirus Reservoirs. Viruses 2016, Vol. 8, Page 30 8, 30.
- Ebola In The Skies? How The Virus Made It To West Africa : Goats and Soda : NPR https://www.npr.org/sections/goatsandsoda/2014/08/19/341468027/ebola-in-the-skies-how-the-virus-made-it-to-west-africa.
- Kupferschmidt, K. (2021). Ebola virus may lurk in survivors for many years. Science 371, 1188.
- Fairhead, J., Leach, M., and Millimouno, D. (2021). Spillover or endemic? Reconsidering the origins of Ebola virus disease outbreaks by revisiting local accounts in light of new evidence from Guinea. BMJ Global Health 6.