When an outbreak of the deadly Ebola virus began in West Africa this spring, a Harvard researcher who studies how evolution shapes the genome sprang into action. A three-person team from Harvard and Tulane universities promptly departed for Sierra Leone to help instruct staff at a local hospital how to do a genetic test for the new, virulent strain of Ebola that has infected nearly 300 people so far.
The gulf between science and medicine in this case may seem impossibly wide: the science involves fascinating, though seemingly academic questions about the signatures of evolution left behind in our DNA, while the medical issues are urgent and real amid an unfolding public health crisis.
But for Pardis Sabeti, a genetics researcher at Harvard and the Broad Institute, the two threads are tightly woven together. Insights gained from each part of her work may prompt new research questions -- as well as possible public health strategies.
For years, Sabeti and her colleagues have studied the genome, searching for areas where natural selection had left its imprint. To her surprise, Sabeti found that one of the genes with the strongest signal of evolution’s handiwork was involved in Lassa fever infection.
“Lassa fever got called to my attention in 2007 because the top signal in the genome of evolutionary selection was a gene critical for the entry of the virus,” Sabeti said. “And I became interested in whether this was an ancient virus or widespread, because it had a signal that suggested humans have been fighting it for a long time.”
Based on her study of evolution in the human genome, Sabeti became more interested in the relatively obscure, but deadly hemorrhagic fever in West Africa that has been called an “emerging” disease. The disease that was only identified a few decades ago, but was likely to be thousands of years old. She began to collaborate with a hospital first in Nigeria and then one in Sierra Leone to try and study the virus and how it evolves, as well as to understand how people living in those areas may be exposed to and possibly develop resistance to the infection.
That work led to partnerships that meant that Sabeti and colleagues found themselves, in effect, helping build the infrastructure and training staff to respond rapidly to such infections -- by detecting them early and even monitoring people for signs of exposure.
Before 2008, when she and her team began to work with a hospital in Nigeria, she was told that a handful of health care workers died each year of Lassa fever. Ever since her team began to collaborate with them and help build a rapid diagnostic process, the hospital has had new technology and policies in place. They haven’t lost any staff members to Lassa fever in the years since, because the early detection means they can treat anyone who contracts the infection with a powerful antiviral medication right away.
When Ebola was detected in Guinea this spring, she and her collaborators were ready to expand those types of diagnostic capabilities to Ebola, using the relationships with local hospitals as both a public health and a research partnership. Samples of the virus are being sent to the Broad Institute, a genomics research center in Cambridge, to be sequenced and studied.
To continue their outreach and efforts to build on-the-ground expertise, 20 African scientists from Sierra Leone and Senegal will be spending eight weeks at the Broad and Harvard this summer to learn and do scientific research.
“We’re just really focused on building capacity there and having them do everything,” Sabeti said. “They are the ones seeing the cases all the time.”Carolyn Y. Johnson can be reached at firstname.lastname@example.org. Follow her on Twitter @carolynyjohnson.