Tracking genetic changes in the ebola virus is vital because diagnostic tests and prospective treatments rely heavily on understanding the viral genome. The work will hopefully aid the development of drugs and allow diagnostic tests to keep up with the rapidly mutating virus, the researchers say.
The team has made the sequence data publicly available since they began processing the samples, allowing other research teams to 'quickly shed light on the ongoing outbreak'. Dr Pardis Sabeti from Harvard University, who led the research, said: 'Upon releasing our first batch of ebola sequences in June, some of the world's leading epidemic specialists contacted us, and many of them are now also actively working on the data'.
Seventy-eight ebola patients in Sierra Leone were studied as part of the ongoing research. The current outbreak of the virus likely stemmed from one animal-to-human transmission, and began to spread quickly following a funeral in Guinea at which 12 people contracted the disease, the analysis has determined.
'We've uncovered more than 300 genetic clues about what sets this outbreak apart from previous outbreaks', said Stephen Gire, one of the study authors. 'Although we don't know whether these differences are related to the severity of the current outbreak, by sharing these data with the research community, we hope to speed up our understanding of this epidemic and support global efforts to contain it'.
Diagnostic tests for ebola involve checking for the viral genes, but the research has found that the mutations affect parts of the genome that the diagnostic tests focus on. Dr Sabeti told The Scientist: 'Already we've seen that the virus has mutated away from currently used diagnostics, [which] is likely to have some effect on the sensitivity of those assays'.
One of the drugs currently being tested, TKM-ebola, targets ebola genes using small sections of genetic material called short interfering RNAs. TKM-ebola has recently received approval to begin testing in humans, and a similar drug, TKM-Marburg, has been shown to cure an ebola-like virus in rhesus monkeys several days after infection.
Five of the paper's co-authors, who were healthcare workers at Kenema Government Hospital in Sierra Leone, died after contracting ebola. To date, over 1,500 people have died of the virus, with this outbreak carrying a 52 percent mortality rate.
Jason Ladner, from the US Army Medical Research Institute of Infectious Diseases, told The Scientist: 'These sequences have provided the first look into how the virus has been changing since the start of the outbreak. Such genetic changes are important to account for in the design and testing of medical countermeasures'.