The notorious Ebola virus (EVD) is not a new disease, so why have many people only heard of it recently? Described in 1976 by Belgian scientist Peter Piot, EVD became a Neglected Tropical Disease (NTDs). NTDs are communicable diseases affecting tropical and sub-tropical regions. They are therefore not accorded the same priorities from governments and big pharma as those that affect developed countries. While there have been previous outbreaks of EVD, the recent epidemic in West Africa was the most widespread and devastating. Of 28,616 cases, 11,310 were fatal, which is a greater mortality count than all previous outbreaks combined.
Earlier incidents of EVD have been small and short-lived, begging the question – what was different about the 2014-2015 outbreak? Researchers at the University of Massachusetts and University of Nottingham have analysed the genome of around 2000 samples of the virus to search for a genetic answer.
The biomedical researchers found a mutation that arose about 3-4 months into the outbreak, coinciding with a dramatic increase in the number of EVD cases. While it would be almost impossible to determine conclusively that the mutation caused the unprecedented severity of the epidemic, there does appear to be a correlation. The mutation in question affects a glycoprotein expressed on the virus which made it ‘stickier’ to human cells, making adhesion easier. It is thought that this increased the infectivity of the virus, leading to wider spread and increased lethality of the disease. It was found that the mutation did not increase infectivity in other mammals, only in humans.
While it would be difficult to pinpoint the many mutations of disease and their effects on infectivity and virulence, it is vitally important to study these evolutions so that prevention and control of future outbreaks can be improved.