The death toll in the world's worst Ebola epidemic has risen to 5,689 out of 15,935 cases reported in eight countries by the end of November 23, and the number of cases in Sierra Leone is set to overtake that of Liberia, which had been the hardest-hit country, the U.N. health agency said Wednesday. Almost all cases and all but 15 deaths have been in Liberia, Sierra Leone, and Guinea, and the three West African countries reported 600 new cases in the past week, the World Health Organization (WHO) said in its latest update. "The total number of cases reported in Sierra Leone since the outbreak began will soon eclipse the number reported from Liberia," the U.N. agency said. Sierra Lone has reported nearly 6,600 cases, while Liberia has reported more than 7,150. Transmission of the deadly virus remains intense in Sierra Leone, excluding the country's southeast, with the capital, Freetown, still the worst affected area, the WHO said. "Liberia and Sierra Leone report that fewer than 70 percent of patients are isolated," it said. Health experts say West Africa's Ebola epidemic could worsen further before abating, but new infections should begin to decline in all affected countries by the end of this year.