The Ebola outbreak is raising new questions about whether ordering quarantines is an effective way to fight deadly disease in the U.S. Health experts say putting people into quarantine can be appropriate on a case-by-case basis. Experts have criticized Govs. Andrew Cuomo of New York and Chris Christie of New Jersey for announcing quarantines for health workers returning from West Africa, where the Ebola virus is raging. The Centers for Disease Control and Prevention has announced less restrictive guidelines with different recommendations aimed at different groups. Meanwhile, the Pentagon announced plans to go further than the CDC guidelines and put troops returning from Ebola response missions in West Africa in quarantine for 21 days — the incubation period for Ebola.

A look at the top Ebola developments worldwide Thursday:

THE LATEST

Nurse Kaci Hickox has left her home again. She followed through on her promise to defy Maine’s voluntary quarantine for health care workers who treated Ebola patients by going on a bike ride Thursday. Hickox, 33, and her boyfriend rode away on bicycles, followed by state police who were monitoring her movements and public interactions. Police couldn’t detain her without a court order signed by a judge. It was the second time in two days Hickox broke quarantine. She left her home Wednesday evening briefly to speak to reporters. Her actions indicate she has no intention of remaining in isolation for the remainder of the 21-day incubation period for Ebola that ends on Nov. 10.

NORTH KOREA TO QUARANTINE FOREIGNERS OVER EBOLA

North Korea is always on guard against outside influences, but now that it perceives the Ebola virus to be a threat, its anxiety has reached a new level. North Korean officials say they will quarantine foreigners for 21 days over fears of the spread of the deadly disease. An announcement distributed Thursday to foreign diplomatic missions in Pyongyang said that, regardless of country or region of origin, all foreigners will be quarantined under medical observation.

MEANWHILE IN WEST AFRICA

Top anti-Ebola officials say Liberia is making some progress in containing the outbreak while the crisis in Sierra Leone is going to get worse. The people of both countries must redouble efforts to stop the disease, which has infected more than 13,000 people and killed nearly 5,000, the officials said Thursday. The World Health Organization has said the rate of Ebola infections in Liberia appears to be declining, perhaps by as much by 25 percent week over week. Liberia is the hardest hit country in the Ebola outbreak sweeping West Africa that has also ravaged Guinea and Sierra Leone.

EBOLA FEARS INFECT LOUISIANA MEDICAL CONFERENCE

Louisiana state health officials are telling thousands of doctors planning to attend a tropical diseases meeting this weekend in New Orleans to stay away if they have been to certain African countries or have had contact with an Ebola patient in the last 21 days. The order came in a letter Wednesday to the American Society of Tropical Medicine and Hygiene, which made clear it did not agree with the decision. The tropical medicine group noted that the state’s stance goes beyond CDC guidelines.

EBOLA EXPERT SAYS CHINA AT RISK

A scientist who helped to discover the Ebola virus says he is concerned that the disease could spread to China. Peter Piot, who is director of the London School of Hygiene and Tropical Medicine, said Thursday the disease could spread, given the large numbers of Chinese workers traveling to and from Africa. More than 8,600 people have entered China’s southern Guangdong province from Ebola-affected areas since August, and there are dozens of flights a month. Piot is appealing to Japan for humanitarian assistance. Japan has pledged $40 million so far to help combat the Ebola outbreak, but Piot said more is needed.