A doctor who recently returned from Guinea has tested positive for Ebola - the first case of the deadly virus in New York City.
Here is a timeline of Craig Spencer's movements since he got back from the West African nation:
When did he return from Guinea?
Spencer came back to the United States last week after treating Ebola patients in Guinea, where he worked for Doctors Without Borders.
He completed his work in Guinea on October 12 and left the country two days later via Brussels.
He arrived at John F. Kennedy International Airport on October 17, but he exhibited no symptoms of the virus until Thursday morning, said Dr. Mary Travis Bassett, New York City's health commissioner.
The physician, who works at Columbia Presbyterian Hospital, was checking his temperature twice a day. He has not seen any patients since his return.
Did he have any symptoms?
The 33-year-old did not have any symptoms after his return, but developed a fever, nausea, pain and fatigue Thursday morning. He began feeling sluggish a couple of days ago, and his fever spiked to 100.3 degrees Thursday, authorities said.
How many people has he been in contact with?
Spencer was in contact with four people after he started exhibiting symptoms, authorities said. Ebola isn't contagious until someone has symptoms.
Three people - his fiancĂ©e and two friends - are being placed on quarantine and monitored, health officials said. The fourth person is a car service driver who had no direct contact with him and is not considered at risk.
Spencer also went for a three-mile jog and visited a bowling alley in Brooklyn prior to feeling symptomatic, according to Bassett.
The bowling alley closed Thursday as a precaution, but it said in a statement that health officials have determined there are no risks to customers.
He also traveled on three subway lines. "At the time that the doctor was on the subway he did not have fever ... he was not symptomatic," Bassett said.
See more on this developing story on CNN.com