Sources inside the secretive country told tour operators the ban will come into effect on FridayNorth Korea will bar entry to foreigners on tourist trips from Friday, because of worries over the spread of the deadly Ebola virus, according to operators of tours to the isolated country.At least 4,877 people have died in the worlds worst recorded outbreak of Ebola, the World Health Organization (WHO) estimates, with nearly 10,000 cases recorded by 19 October, though the true toll could be three times as much.