Experts in the US say a study into a past Ebola outbreak found 71% of people who had close contact with a victim and tested positive never fell illAnother showed 46% who came into close contact and did not get sick had evidence of infection with the Ebola virusTeam at universities of Texas and Florida believe the virus is silently immunising a significant portion of the West African populationIf they can be identified it could be vital in helping stop the spread of diseaseThey could be recruited as health workers to care for the sick Natural immunity could mean...
