The current Ebola outbreak in West Africa has claimed over 8,500 lives, with over 21,000 cases confirmed. With no cure, experimental drugs and vaccines are being developed to tackle the disease. These therapies target specific sequences in the viral genome. However, the virus is rapidly mutating through a process called genetic drift.
According to Dr Gustavo Palacios, director of USAMRIID and lead author on the current study, this could affect how potent the new drugs are: 'We wanted to highlight an area where genomic drift, the natural process of evolution on this RNA virus genome, could affect the development of therapeutic countermeasures.'
Dr Palacios' team worked with research groups from Harvard University and the Massachusetts Institute of Technology and compared the current strain of Ebola with two previous strains that caused outbreaks in 1976 and 1995 in the Democratic Republic of Congo (formerly Zaire). In each comparison, they found more than 600 mutations to the Ebola genetic code.
Of these 600 mutations, the team found ten that could interfere with genetic sequences targeted by the experimental drugs. Seven of these mutations occurred between 1976 and 1995. The remaining three mutations occurred after December 2013, during the current outbreak.
'The virus has not only changed since these therapies were designed, but it's continuing to change,' lead author Dr Jeffrey Kugelman, a viral geneticist at USAMRIID and captain with the US Army, said. 'Ebola researchers need to assess drug efficacy in a timely manner to make sure that valuable resources are not spent developing therapies that no longer work.'
The findings were published in American Society for Microbiology journal mBio.