The Ebola virus behind the current West African outbreak is not mutating as quickly as some scientists had feared, according to a new report appearing in Science.
The deadliness and spread of the current Ebola epidemic in West Africa sparked concerns that the virus was mutating faster than other strains of the virus. A report published over the summer had indicated that the strain could be mutating twice as fast as other Ebola viruses, though that report examined a relatively small timeframe, the New York Times says.
An international team of researchers now says the outbreak strain mutates at about the same rate as other Ebola viruses.
Using samples from Mali collected in October and November and earlier ones from taken from Guinea in March and Sierra Leone in June, the team calculated a nucleotide substitution rate of 9.6 × 10–4 substitutions per site per year for the outbreak virus, which largely matches the previously reported nucleotide substitution rates of between 6.2 × 10–4 and 9.5 × 10–4 for other Ebola viruses. It's also similar, LiveScience notes, to the mutation rate of other RNA viruses, including the one that causes the common cold.
"It hasn't become increasingly lethal or increasingly virulent," study author David Safronetz from the National Institute of Allergy and Infectious Diseases tells the New York Times. "The virus — it's doing what it's always done."
Instead, the scale of the epidemic appears to be due its outbreak "at the intersection of three vulnerable countries," the Times says.