NYC Isolates Ebola Doctor's Fiancee, Friends

America's biggest city is facing an enormous challenge: how to track down people who came into contact with an Ebola-infected doctor who traveled on three subway lines, jogged for miles, and even went bowling the day before he reported symptoms. Epidemiologists in New York City are using information from the Craig Spencer's MetroCard and credit cards to help trace his movements, reports the Guardian. More:

• Health authorities have now isolated Spencer's fiancee, as well as two friends he spent time with this week, reports the New York Times. The city plans to provide case managers for every person in quarantine.

• Mayor Bill de Blasio says the city has followed "clear and strong" protocols in handling Spencer, who returned from West Africa 11 days ago, the AP reports. "We want to state at the outset that New Yorkers have no reason to be alarmed," he said last night. "New Yorkers who have not been exposed are not at all at risk."
• The city's health commissioner says the chances of Spencer's subway rides posing a risk are "close to nil," and his visit to a Brooklyn bowling alley Wednesday probably doesn't pose much risk either, according to New York Times science reporter Donald McNeil. It would be possible to get Ebola from a bowling ball if someone "left blood, vomit, or feces on a bowling ball, and the next person to touch it did not even notice, and then put his fingers into his eyes, nose, or mouth," he writes, but mucus and saliva aren't highly infectious until a patient is much too ill to even consider bowling.
• New York-Presbyterian Hospital/Columbia University Medical Center, where Spencer is employed, describes him as "a dedicated humanitarian" who went to "an area of medical crisis to help a desperately underserved population," CNN reports. The hospital says the doctor has not been to work since he returned from the Doctors Without Borders mission to Guinea.

(More Ebola stories.)