Colorado health officials scrambled to determine whether a man who recently worked with sick people in eastern Congo and became ill Sunday in Denver had contracted the deadly Ebola virus — and doctors also isolated an ambulance crew for testing and were looking for another person in metro Denver who may have had contact with the man.

Denver Health and Hospitals officials Sunday night were waiting for test results from a state health lab but said that, based on an initial test in a special isolated unit, they do not believe the man has Ebola. A Colorado Department of Public Health and Environment (CDPHE) bulletin late Sunday said testing “is negative for Ebola.”

The man had been working with sick and dead people in an area of eastern Congo where a recent outbreak of Ebola had largely dissipated with no new Ebola cases reported over the past 45 days. On Sunday morning, he reported sudden severe symptoms at his residence in Denver, Denver Health chief medical officer Connie Price said.

“We felt that, if he had Ebola, then he could be very communicable … We had no wiggle room to be wrong,” Price said.

The man “became ill very suddenly this morning,” she said, declining to specify his exact symptoms but saying they could mimic illnesses including flu and appendicitis. “He is getting better, so that is good.”

Three members of the ambulance crew that picked up the man — two of them paramedics, one a student — also were being held in isolation, and Denver public health officials were looking for a “significant other” who may have had contact with the man warranting testing as a precaution.

Denver public health officials were “working through” how to handle the man’s residence before confirmatory testing for Ebola was complete, Price said Sunday afternoon outside the hospital. “We don’t think we’re going to have to do anything with his house because we don’t think he is going to be confirmed.”

Denver Health officials temporarily diverted ambulances away from the city’s main public health hospital but said they resumed normal operations by noon.

Denver officials were coordinating with federal Centers for Disease Control (CDC) and CDPHE officials in assessing risks.

The man told health officials he felt ill Sunday morning, reported having worked recently as medical missionary in eastern Congo, and arrived at the hospital at about 8:30 a.m. by ambulance. Doctors set up a special isolation unit and were assessing his condition.

“The patient’s symptoms could represent a variety of common illnesses,” Denver Health spokeswoman Jennifer Hillmann said. “The patient in question had reported being in an area of the Congo on a medical missionary trip, but he was in a location where the Ebola outbreak had been officially declared over, with no cases reported for 45 days, according to the CDC.”

He was listed in fair condition Sunday night.

Hospital officials said they were “on normal operations” and that “there is no threat or concern for patient, staff or visitor safety.” Denver Department of Public Health and Environment officials couldn’t be reached late Sunday.

Denver Health is on normal operations and there is no threat or concern for patient, staff or visitor safety. pic.twitter.com/lPvqkBaLDm — Denver Health (@DenverHealthMed) July 29, 2018

Denver Health staffers are trained and equipped to deal with situations involving infectious diseases. And the CDC has designated Denver’s hospital as one of 10 around the nation prepared to treat patients with Ebola.

At the hospital Sunday afternoon, staffers called the situation “under control.”

Ebola is a rare but serious viral disease that often causes fevers, headaches, diarrhea, vomiting, stomach pain, weakness, muscle pain and unexplained bleeding or bruising. There have been no outbreaks of Ebola in the United States.

The viruses that cause Ebola are located mainly in sub-Saharan Africa, according to the CDC. People can get Ebola through direct contact with an infected animal or a sick or dead person infected with the virus.

There’s no approved vaccine or treatment. The latest research on Ebola aims to find natural hosts for the virus, develop vaccines to protect at-risk populations and discover therapies to improve treatment.

Congo’s latest outbreak of Ebola virus is over, health ministry officials announced Tuesday, hailing a relatively speedy international response that apparently contained its spread to remote rural areas. An Ebola outbreak in West Africa, detected by the World Health Organization in 2014, ended with more than 28,600 cases and 11,325 deaths.