Fears of an Ebola outbreak in New York City were heightened on Monday when a man who recently returned from West Africa was treated at a Manhattan hospital for symptoms of the deadly disease.

The unidentified patient, complaining of high fever and gastrointestinal distress, was placed in “strict isolation” at Mount Sinai Hospital while he underwent a battery of tests for the virus.

The hospital expects to receive the results Tuesday or Wednesday.

Neighbors of the Upper East Side hospital were on edge as news circulated of the potential Ebola patient.

“It’s scary — very, very scary,” said Lily Ayala, 58, who lives across the street from the medical center.

“It’s contagious, and people out here don’t know about it. It’s bad because everyone just sits in the ER together. If you’re going to get it, you’re going to get it right there.”

But by Monday evening, officials said it was “unlikely” that the patient harbored the often-fatal virus.

“It’s much more likely that it’s a much more common condition, and we’re ruling those things out as well,” said Mount Sinai’s chief medical officer, Jeremy Boal.

Patients who were in the waiting room with the man will not have to undergo testing, but the hospital is advising his family on how they can screen themselves.

Symptoms of the disease — which has a fatality rate of about 60 percent — include fever, red eyes, severe diarrhea, vomiting and internal bleeding, according to the World Health Organization. The virus spreads through bodily fluids.

Dr. John Wolff, a physician for infectious diseases at Mount Sinai, didn’t know the specifics of this particular case, but is familiar with the disease and said hospitals are not going to “panic.”

“We want to keep alert, but at the same time we’re not going to panic,” he told The Post. “We expect that people now are going to be more aware of their symptoms than before.”

Another patient was isolated at Bellevue Hospital last week after arriving from a trip to West Africa with symptoms. He was screened at John F. Kennedy International Airport and taken to the hospital.

But his fever cleared up within a day — and it was determined that he had not caught Ebola.

Experts have said that an Ebola outbreak in the US is very unlikely, but the feds are still looking out for international travelers exhibiting flu-like symptoms.

So far, three nations have borne the brunt of the worst outbreak in recorded history: Sierra Leone, Liberia and Guinea.

Nigerian authorities said Monday they confirmed a second case of Ebola — a doctor in Lagos who treated a Liberian victim.

The Ebola outbreak death toll has reached a staggering 887, according to the World Health Organization. More than 1,600 people have been infected with the disease since it emerged in Guinea earlier this year.

Additional reporting by Antonio Antenucci and Danika Fears