Ebola is mutating; could evade current treatment

Researchers over at US Army Medical Research Institute of Infectious Diseases (USAMRIID) have found that the Ebola strain as we currently know it is mutating and several identified mutations will interfere with effectiveness of drugs and vaccines against the deadly virus.

Jeffrey Kugelman, the lead author of the study titled “Evaluation of the Potential Impact of Ebola Virus Genomic Drift on the Efficacy of Sequence-Based Candidate Therapeutics” published in mBio, said that the “The (Ebola) virus mutates rapidly and it`s an ongoing concern.”

In the study researchers have described the “genomic drift” or natural evolution of the virus and how it could interrupt the action of potential therapies designed to target the virus’ genetic sequence.

The researchers analysed three types of genetic sequence-based treatments currently evaluated for Ebola including monoclonal antibody; small-interfering RNA; and phosphorodiamidate morpholino oligomer drugs. All these three treatments have been developed using Ebola virus strains from two smaller outbreaks that occurred in 1976 and 1995.

USAMRIID team collaborated with investigators from Harvard University and the Massachusetts Institute of Technology to compared the current Ebola strain known as EBOV/Mak, with the two previous strains that caused outbreaks in 1976 and 1995. Researchers found more than 600 genetic mutations, which account for about three percent of the genome.

Researchers found 10 new mutations that might interfere with the mechanisms of the sequence-based drugs currently being tested and that three of these mutations appeared during the current West African outbreak.

“Ten of the observed mutations modify the sequence of the binding sites of monoclonal antibody (MAb) 13F6, MAb 1H3, MAb 6D8, MAb 13C6, and siRNA EK-1, VP24, and VP35 targets and might influence the binding efficacy of the sequence-based therapeutics, suggesting that their efficacy should be reevaluated against the currently circulating strain”, the study abstract notes.

“The virus has not only changed since these therapies were designed, but it`s continuing to change,” Kugelman 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.”

So far, there have been more than 21,000 Ebola cases with more than 8,300 deaths since the outbreak began last year in Liberia, Sierra Leone and Guinea, according to the WHO.