In what could trigger a fresh wave of panic, a man admitted to a hospital in New York City is being tested for Ebola, according to CBS News.
The man arrived at the emergency room of Mount Sinai hospital early Monday with "high fever and gastrointestinal symptoms".
He told doctors that he had recently travelled to a west African country where, he said, Ebola had broken out.
"All necessary steps are being taken to ensure the safety of all patients, visitors and staff," a hospital spokesperson said in a statement.
Around 1,000 people have died in the recent outbreak of Ebola in the African nations of Guinea, Liberia, Sierra Leone, and Nigeria.
Second American boards flight home
Meanwhile, the second American missionary to contract Ebola in West Africa left Liberia early Tuesday en route to the United States, authorities said.
Nancy Writebol will be treated at Emory University Hospital in Atlanta, where her colleague Dr Kent Brantly is also a patient, and said to be improving.
Before leaving Liberia, Writebol received a second dose of an experimental serum. Although still seriously ill, she was able to walk with assistance and has regained her appetite, sources said.