Responding rapidly to the deadly outbreak of Ebola virus disease (EVD) in West Africa, a team of researchers from the Broad Institute and Harvard University, working with the Sierra Leone Ministry of Health and Sanitation and researchers elsewhere, has sequenced and analyzed many Ebola virus genomes. Their findings could have important implications for rapid field diagnostic tests.

The researchers hope their results will speed up scientific understanding of the epidemic and assist global efforts to contain it.

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The researchers sequenced 99 Ebola virus genomes collected from 78 Ebola patients in Sierra Leone during the first 24 days of the outbreak. (Some patients contributed samples more than once, allowing researchers a clearer view into how the virus can change in a single individual over the course of infection.) The team found more than 300 genetic changes that make the 2014 Ebola virus genomes distinct from the viral genomes tied to previous outbreaks. They also found sequence variations indicating that the present outbreak started from a single introduction into humans, subsequently spreading from person to person over many months.

The variations they identified were frequently in parts of the genome that encode proteins. Some of the variation detected may affect the primers, or starting points for DNA synthesis, used in polymerase chain reaction (PCR)-based diagnostic tests, emphasizing the importance of genomic surveillance and the need for vigilance. The researchers reported their results online today in the journal Science.

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, making the data available to the global scientific community.

“By making the data immediately available to the community, we hope to accelerate response efforts,” said co-senior author Pardis Sabeti, a senior associate member at the Broad Institute and an associate professor at Harvard University. “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.”

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