Rapid sequencing and analysis of 99 genomes have enabled researchers to identify more than 300 genetic changes in the Ebola virus genome, according to results published in Science.
With collaboration with the Sierra Leone Ministry of Health and Sanitation, Pardis Sabeti, MD, DPhil, of the Broad Institute and Harvard University, and colleagues sequenced Ebola virus genomes collected from 78 patients with the virus in Sierra Leone during the first 24 days of the outbreak. Along with the mutations, which make the 2014 Ebola virus distinct from the viral genomes tied to previous Ebola outbreaks, the researchers found sequence variations indicating that the outbreak started from a single introduction into humans.
To accelerate response efforts, the research team released the full-length sequences on the National Center for Biotechnology Information’s DNA sequence database in advance of publication.
“By making the data immediately available to the community, we hope to accelerate response efforts,” Sabeti said in a press release. “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. We were honored and encouraged. A spirit of international and multidisciplinary collaboration is needed to quickly shed light on the ongoing outbreak.”
The variations identified through deep sequencing were frequently in regions of the genome-encoding proteins. Some of the genetic variations detected may affect the primers used in PCR-based diagnostic tests.
The transmission path and evolutionary relationships of the samples were also outlined, revealing that the lineage responsible for the current outbreak diverged from the Middle African version of the virus within the past 10 years and spread from Guinea to Sierra Leone by 12 people who had attended the same funeral.
The sequencing identified 395 mutations, more than 340 of which distinguish the current outbreak from previous ones. The researchers said they hope that their findings may serve as a starting point for further research.
“We’ve uncovered more than 300 genetic clues about what sets this outbreak apart from previous outbreaks,” Stephen Gire, of the Broad Institute and Harvard University, said in a press release. “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.”
As of Aug. 22, there have been 2,615 cases of Ebola and 1,427 deaths throughout Liberia, Guinea, Sierra Leone and Nigeria, according to the CDC. It is the largest recorded Ebola outbreak.
Disclosure: The researchers report no relevant financial disclosures.