Prior to the 2013-2016 Ebola pandemic, few people were aware of the Ebolavirus genus of viruses. However, just days after the announcement that the most recent outbreak in the Democratic Republic of Congo had ended, the government of Sierra Leone announced the discovery of a sixth species of ebolavirus.
What are the Ebolaviruses?
Ebolaviruses are a genus of viruses in the Filovirus family. There are five previously described species:
- Zaire ebolavirus
- Sudan ebolavirus
- Reston ebolavirus
- Taï Forest ebolavirus
- Bundibugyo ebolavirus
Out of these, only Zaire, Sudan, and Bundibugyo have caused deadly outbreaks. Taï Forest can infect humans, but Reston ebolavirus is only found in pigs and macaques. In outbreak pandemic situations, mortality can reach up to 90%, and there is no defined treatment or vaccine currently available. However a potential vaccine trialed during the end of the 2013 outbreak has shown promising results (which I will write a post about soon!). There is also another species of virus, Marburg virus, in the Filovirus family. Marburg virus causes a similar disease to ebola, and also is the cause of several outbreaks in Sub-Saharan Africa since its discovery in 1967.
The sixth and most recently discovered species of ebolavirus, named Bombali ebolavirus, was reported last week. Bombali ebolavirus was discovered in two species of bats in Sierra Leone, Mops condyrulus and Chaerephon pumilus. Bats are considered to be reservoirs of ebolaviruses, which can zoonotically transfer to humans through close contact with infected animals, such as eating bushmeat.
The glycoprotein of Bombali ebolavirus, which is used by the virus to enter host cells, was able to infect human cells in a laboratory setting. However, this experiment was under artifical conditions, and does not mean that Bombali ebolavirus will be pathogenic to humans, or cause disease.
There is expected to be a formal paper released soon, providing more details about Bombali ebolavirus, and its similarity to other known ebolaviruses.