Study: Ebola virus mutated more slowly than thought

Jun 17, 2015, 10:48 PM EDT
A health worker prepares a vaccination on March 10, 2015 at a health center in Conakry during the first clinical trials of the VSV-EBOV vaccine against the Ebola virus.

The devastating outbreak of Ebola in West Africa over the past year has been found to not have mutated as quickly as previously thought. A recent study contradicted previous evidence that demonstrated that the virus mutated at twice the rate previously seen. Reuters reports:

"The results are good news for the scientists working to develop long-term solutions for Ebola, such as vaccines and treatments, as it means these... should still work against the mutated strains of the virus," said Miles Carroll, head of research microbiology services at Public Health England (PHE), the laboratory leading the work.
Ebola has killed more than 11,000 people in Guinea, Sierra Leone and Liberia in an unprecedented epidemic that began more than a year ago. New cases have declined sharply in the past few months, but the outbreak is not yet over.
Dwindling numbers of new infections have, however, made work on trials designed to test and validate potential vaccines and treatments almost impossible.
For their study, Carroll and researchers across Europe and in affected West African countries had access to data on the virus covering almost a year.
They analyzed 179 patient samples obtained by the European Mobile Laboratory, which was deployed to the epicenter of the outbreak in Guinea, to find how the Ebola virus mutated and spread.
Doctors at Médecins Sans Frontières in Guéckédou, a town in southern Guinea near the borders of Sierra Leone and Liberia, sent the first samples of what turned out to be Ebola to labs in Hamburg and Lyon in March 2014. The labs confirmed the identity of the virus and alerted the WHO, which dispatched a rapid response unit called the European Mobile Laboratory to the scene. Tens of scientists travelled with diagnostic equipment to Guinea’s capital, Conakry, and onwards in four-by-fours to Guéckédou. The unit they set up ensured patients with Ebola were not sent to the main hospital, where the infection would easily spread to health workers and patients.
For the latest study, the scientists analysed about 15 Ebola samples taken each month of the outbreak from March 2014 to January 2015. Because the virus mutates over time, the DNA can reveal how the infection spread from one place to another.
According to the study in Nature, the initial outbreak grew around Guéckédou, Macenta and Kissidougou in Guinea in March 2014. By the end of May a new strain of the virus had been carried to Sierra Leone, and also into Liberia. The virus spread rapidly in those countries, before being carried back into Guinea from June 2014 onwards. This second wave was far worse than the first outbreak. In the autumn, the virus crossed twice from Guinea into Mali, from Beyla district in October and from the Siguiri district one month later.