Freetown, November 20 (RHC-AP) -— The spread of Ebola remains "intense" in most of Sierra Leone, even as things have improved somewhat in the two other countries hardest hit, the World Health Organization says.

Some 168 new confirmed cases emerged in a single week in Sierra Leone's capital of Freetown recently, according to a WHO report.

"The numbers are still rising and the transmission is persistent and widespread," said Amadu Kamara, the U.N.'s Ebola crisis manager in Sierra Leone. "Rapid and coordinated response are needed to overcome the spread of the Ebola disease."

The WHO report released late Wednesday indicated that Sierra Leone had the lowest percentage of Ebola patients who had been isolated — only 13 percent. By comparison, that figure was 72 percent in Guinea.

The disease is spread through direct physical contact with the bodily fluids of sick people and bodies, making it crucial that those who are contagious are placed into isolation.

Health officials are aiming to isolate at least 70 percent of the sick, a target Kamara acknowledged was still far out of reach.

WHO has said that at least 1,250 people have died in Sierra Leone since the outbreak there began earlier this year.

Ebola is blamed for more than 5,400 deaths in Sierra Leone, Liberia and Guinea.