The United States will help fight Ebola over “the long haul,” the American ambassador to the United Nations said on a trip to the West African countries hit by the outbreak.

Samantha Power will be in Sierra Leone on Monday. She met Sunday with religious leaders in Guinea, where the Ebola outbreak was first identified in March.

“We are in this with you for the long haul,” she said. The outbreak has killed nearly 5,000 people, the vast majority of them in Guinea, Liberia and Sierra Leone. “We have got to overcome the fear and the stigma that are associated with Ebola.”

Many people hide in their homes rather than seek medical care because of fears that an Ebola diagnosis is an automatic death sentence and the social stigma attached to the disease, further fueling its spread. So far, more than 10,000 people are believed to have been infected.

The United Nations mission to combat Ebola laid out a plan last week to isolate at least 70 percent of cases — the level that experts say is necessary to slow the disease’s spread. The U.N. plan also includes safely burying at least 70 percent of victims by Dec. 1, and to have 100 percent of cases isolated and all the dead safely buried by Jan. 1.

There is no licensed treatment or vaccine for Ebola, so separating the sick from the healthy is the only way to stop Ebola’s transmission.

Health authorities are meant to rigorously track down everyone who has had contact with the sick and monitor or even isolate them during the disease’s incubation period, which can last up to 21 days. However, the disease spread for so long before it was identified in West Africa that tracing contacts has been difficult, if not impossible, in the worst-hit countries.

Other countries with one or only a handful of cases have been more successful. Ten people who had contact with a Spanish nursing assistant who survived Ebola were released Monday from a Madrid hospital after spending 21 days under observation and showing no symptoms, a hospital official said. She spoke on condition of anonymity in keeping with hospital policy.

Nursing assistant Teresa Romero was cleared of the virus last week but is being treated for after effects.

(AP)