American United Nations Ambassador Samantha Power is visiting Guinea, Liberia and Sierra Leone, countries stricken by the Ebola virus outbreak.

The outbreak has killed nearly 5,000 people in those countries, according to the World Health Organization, and over 10,000 have contracted the disease since the epidemic began in March.

Meeting religious leaders in Guinea on Sunday, Power told them, "We are in this with you for the long haul," reported The Associated Press.

The capital city Accra in Ghana is be used as the headquarters for the U.N. Mission for Ebola Emergency Response (UNMEER), operations were began there in September. Cuba has sent 165 doctors to Sierra Leone, and 91 more doctors and nurses are joining them. China has sent nearly 200 medical staff and humanitarian aid to the countries. Britain, France and the U.S. are helping in those countries they used to dominate during colonial times. France is focusing its efforts on Guinea, Britain on Sierra Leone and the United States on Liberia, according to The Associated Press.

U.N. Secretary-General Ban Ki-moon said last week the international response has been positive so far, but a "massive surge in assistance" is still needed in protective equipment, mobile laboratories, vehicles, helicopter and trained medical personal.

"They have asked for urgent help and the international community is answering the call with a totally unprecedented response," Ban told reporters.

On Friday, the governors of New Jersey and New York mandated a 21-day quarantine for people with any contact with Ebola patients and for medical workers returning from the West African countries. 

Their policy permits home confinement for medical workers who have had contact with Ebola patients if the workers show no symptoms, and they will receive twice-daily monitoring from health officials.

The measure was introduced after Dr. Craig Spencer, a doctor who had been in Guinea working with Doctors Without Borders, returned to New York and was admitted to Bellevue Hospital Center on Thursday to be treated for Ebola.

Before he was admitted, Dr. Spencer had ridden the subway, went bowling and ate at a restaurant. His girlfriend was also admitted to Bellevue, but has been since been released, and two of their friends were being monitored. Bellevue officials on Sunday said Dr. Spencer was in serious, but stable condition and has reacted to the plasma treatment well and looks better.

A nurse returning from Sierra Leone was forcibly quarantined in a New Jersey hospital isolation unit on Friday even though she said she had no symptoms and tested negative for Ebola. New Jersey officials said the nurse Kaci Hickox had been symptom-free for 24 hours and would be released and taken by private carrier to Maine. In a telephone interview with CNN, the nurse said her isolation at the hospital was "inhumane."

"We have to be very careful about letting politicians make health decisions," Hickox said.

The decision by Governor Andrew Cuomo and Chris Christie for the quarantine has sparked criticism from health officials. Dr. Anthony Fauci, of the National Institute of Allergy and Infectious Diseases, said the quarantines are unnecessary and might put off health workers from going to Guinea, Liberia and Sierra Leon to help stop the spread of Ebola.

"We're staying one step ahead," Cuomo told reporters Sunday night. "Some people say we're being too cautious. I'll take that criticism."

Illinois has announced they will introduce a quarantine as well.