The Ebola virus, deadly as it is, is not showing any evidence of mutations that could lead to even more dangerous "supervirus" strains, a study indicates.
Despite early reports of rapid mutations, researchers say a comparison of virus samples from the beginning of the outbreak with more recent samples revealed genetic sequences that were almost identical.
This suggests there is little chance of the Ebola virus morphing into a more infectious or more deadly form, the researchers say in their study published in the journal Science.
"We do not see any evidence that the virus is mutating any more rapidly than has been reported in previous outbreaks," says study researcher Thomas Hoenen, a postdoctoral fellow in virology at the National Institutes of Health.
That means the virus is not likely to mutate into an airborne strain or one that becomes resistant to vaccines, tests and treatments currently being developed to battle the disease, the scientists say.
Any such discoveries should therefore remain effective against Ebola for some time to come, allowing researchers to stay ahead of it, experts say.
Presently, a healthy person must have direct contact with a sick person or their bodily fluids to be infected with Ebola, making it much harder to catch than other viruses like smallpox, influenza or measles, they say.
"There's this fear about, 'Suppose it becomes airborne?' This paper indicated that doesn't seem to be the case at all," says Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases (NIAID.)
The current outbreak has infected nearly 25,000 people in Guinea, Sierra Leone and Liberia and has claimed more than 10,000 lives. Researchers compared viral samples collected from patients who were infected in Guinea in March 2014, Sierra Leone in June 2014 and Mali in November 2014.
Viruses are constantly mutating, but almost all of the mutations fail to survive, and while the Ebola virus has been seen to mutate somewhat, that has not affected how the virus interacts with the human body, the researchers said.
"We need to stay vigilant and make sure that the virus isn't changing, but at the moment I don't think there's much of a fear this is occurring anytime soon," says study co-author Dr. Heinz Feldmann, chief of the Laboratory of Virology at NIAID.
The study findings are reassuring, suggesting the public health measures put into place in West Africa are and will remain effective, he says.
In the same issue of Science that carried the mutation study, researchers at the University of Wisconsin, Madison, have reported positive result in clinical trials using monkeys to test a new Ebola vaccine.
The vaccine was used with two groups of monkeys; one received one vaccination, the other group was given two.
The vaccine protected both groups against exposures to lethal doses of the Ebola virus, the researchers reported.
