From the BBC, January 29, 2015
Scientists tracking the Ebola outbreak in Guinea say the virus has mutated.
Researchers at the Institut Pasteur in France, which first identified the outbreak last March, are investigating whether it could have become more contagious.
“We’ve now seen several cases that don’t have any symptoms at all, asymptomatic cases,” said Anavaj Sakuntabhai.
“These people may be the people who can spread the virus better, but we still don’t know that yet. A virus can change itself to less deadly, but more contagious and that’s something we are afraid of.”