New York City health officials said Wednesday that they are now monitoring 357 people for signs of Ebola -- including medical volunteers who returned from Africa in the past three weeks as well as hospital personnel involved in treating the infected doctor in Manhattan.

Officials also said that the second of three associates who came in contact with Dr. Craig Spencer before his diagnosis was being released from government-ordered quarantine.

The friend, who has not been publicly identified, is now subject to "direct active monitoring" instead -- a determination made "after additional physician review," officials said.

"The individual poses no public health threat and is showing no symptoms," the city said in a statement. "This person's daily movements in New York City will no longer be restricted, and the individual will be assessed twice each day by Health Department staff."

Officials provided no specifics about what changed about the friend's status to warrant the release from quarantine. The friend will now be subject to regular assessment by health officials.

Spencer's fiancee, Morgan Dixon, remains under quarantine.

The 357 people "are being monitored out of an abundance of caution, and none are showing any symptoms," city officials said.

"The vast majority of these individuals are travelers arriving in New York City within the past 21 days from the three Ebola-affected countries," officials said.

There were 117 people being actively monitored as of Oct. 30, and the number will continue to fluctuate as people finish the 21-day Ebola incubation window and others are added to the list of those being monitored.

Ebola can only spread through direct contact with bodily fluids.

Spencer, an emergency doctor who went to West Africa to volunteer in the disease-ravaged region, was diagnosed late last month with Ebola and is being treated at Bellevue Hospital Center. He is in stable condition and is improving, the city said.