New Yorkers seemed to take news of the city's first case of Ebola in stride Friday by going about business as usual.
The infected patient, Dr. Craig Spencer, is known to have traveled on at least three subway lines after returning from West Africa, where he treated Ebola patients as a volunteer with Doctors Without Borders.
Friday morning, subway ridership was at normal levels, the Metropolitan Transportation Authority told CNBC. The system handles an average 5.8 million riders a day. Traffic on Metro-North lines, which shuttle about 280,000 commuters daily into the city from upstate and Connecticut, also remained normal.
"The MTA New York City Subway system is safe to ride. The person diagnosed with Ebola in New York City rode the subway several times since returning from abroad, but the state and city health commissioners agree there was no risk to any other subway customers or any MTA employees," the MTA said in a statement.
Ebola cannot be spread by casual contact and is not contagious until symptoms appear, health officials say.
The authority noted that the virus cannot live for more than a few hours on hard surfaces. It also said it had issued protective gloves to employees and instructed staff to use 10 percent bleach solution to disinfect trains and double bag any potential infectious waste.
Spencer also rode in a hired car that he booked through ride-sharing service Uber on Wednesday evening. Uber, which is known for tracking ridership in real time, did not respond to multiple requests for comment on whether ridership on its New York City network had dipped.
In a statement Thursday, the company said the New York City Department of Health and Mental Hygiene determined that the driver of Spencer's car and subsequent passengers were not at risk.
During a press conference Thursday, Mayor Bill de Blasio stressed that the case was under control and that the lone known infection should not keep city residents from going about their business.
"There is no cause for alarm. New Yorkers need to understand that the situation is being handled and handled well," de Blasio said. "There is no reason for New Yorkers to change their daily routine in any way."
The mayor rode the subway on Friday to show it was safe to take public transportation.
Tevi Troy, former deputy secretary of the U.S. Department of Health and Human Services, told CNBC's "Squawk Box" it was no surprise that a case of Ebola showed up in New York City, given its position as an international gateway.
"Obviously New York is the most likely city where Ebola would have appeared given how much traffic goes through New York," Troy said. "It sounds like New York is mostly prepared. The hospital that Dr. Spencer is at is one of the hospitals that is ready to deal with this."
The case has raised questions over whether health-care professionals who work with Ebola patients in West Africa should not just monitor themselves for symptoms, but enter self-quarantine.
While Spencer reported to Doctors Without Borders after becoming symptomatic, he has faced criticism for taking public transportation and going bowling in Brooklyn shortly after returning to New York City.
Dr. Scott Gottlieb, a fellow at the American Enterprise Institute, told "Squawk Box" the Centers for Disease Control and Prevention should actively monitor people who return from Ebola-stricken areas of West Africa by checking in via telephone. But he said asking health professionals, who are capable of self-monitoring, to enter quarantine would have adverse effects.
"If we impose a system where you quarantine people for up to a month after they arrive back, that's going to discourage health care workers from going over there," Gottlieb said.