It has been just a few months since Africa was declared completely Ebola free. The last Ebola outbreak was the largest in recorded history; and in fact, it was bigger than all the other Ebola outbreaks in history combined.
Research suggests that during the 2014/2015 Ebola outbreak, Ebola adapted to infect human tissues with greater ease. Two studies published in the journal Cell found a mutation on the Ebola virus that increased the ability of the virus to infect human cells fourfold.
The genetic code of nearly 2,000 Ebola virus samples were analysed by researchers at the University of Nottingham and the University of Massachusetts; they both documented a change on the surface of the Ebola virus that enabled it to lock more easily on human cells.
Prof Jeremy Luban one of the scientists that conducted the study from the University of Massachusetts Medical School, spoke to the BBC World Service’s Science in Action and told them that “The mutation makes the virus more infectious.”
Pofessor Jonathan Ball, from the University of Nottingham, added that an increase as great as fourfold was “not trivial”. He told the BBC news website; “When a virus is introduced into a new environment, a new niche, it will try to adapt to that new environment … That just happened to coincide with widescale spread of the virus – this was a mutation that appeared when the virus took off.”
The study adds another facet to the current explanation on why the spread of the virus was much greater. The reason that has been given for the high incidence of the Ebola outbreak was that the virus managed to get into dense urban cities such as Monrovia in Liberia. Prof Luban however discussed another possibility of that explosive spread stating;
“One possibility is this mutation, which has never been seen before, in some way contributed to the severity of the outbreak and answering that question conclusively is probably something we cannot do … [But] it is hard to imagine the mutation was not relevant.”
The research also provided some other insights such as the fact that as the virus adapted to more readily infected people it became less able to infect its likely natural host species (fruit bats). The researchers also said that people who were infected by the mutant form of the virus were more likely to die than people infected with the original form.