Public health officials said the death of a man in Dallas from Ebola — a virus that has now claimed more than 4,000 lives worldwide — should be a warning to the medical community about the epidemic’s lethal reach.

“There are a number of lessons here,” Dr. Anita Barry, director of the Infectious Disease Bureau at the Boston Public Health Commission, said. “The importance of being aware of what exactly is a risk factor and what is not, and how you identify a key risk factor, what you do with that information, how you move forward, you need to know what your hospital’s plan is for providing care to that person who may be ill.”

Others said travelers from West Africa seeking help in ERs must be scrutinized.

“The biggest lesson is that travel history is extremely important when a person first presents to the emergency department,” said Dr. Amesh A. Adalja, infectious disease specialist with the University of Pittsburgh.

Barry said even that can be tricky.

“Someone who comes from West Africa with a fever is more likely to have malaria or typhoid,” she said. “I think it’s important when you think about the possibility of someone having Ebola, to have the correct details in the questions they ask.”

The World Health Organization announced yesterday that deaths from Ebola have hit 4,033. One of those victims was Thomas Eric Duncan, 42, who had been visiting Dallas.

Duncan’s temperature spiked to 103 degrees during the hours of his initial visit to an emergency room — a fever that was flagged with an exclamation point in the hospital’s record-keeping system, his medical records provided to The Associated Press show.

Despite telling a nurse that he had recently been in Africa and displaying other symptoms that could indicate Ebola, Duncan underwent a battery of tests and was eventually sent home.

His family provided his medical records to the AP — more than 1,400 pages in all. They encompass his time in the ER, his urgent return to the hospital two days later and chronicle his steep decline as his organs began to fail.

Duncan carried the deadly virus with him from his home in Liberia, though he showed no symptoms when he left for the United States. He arrived in Dallas Sept. 20 and fell ill four days later.

When he first showed up at Texas Health Presbyterian Hospital Sept. 25, he complained of abdominal pain, dizziness, a headache and decreased urination, his health records reveal. He reported severe pain — rating it an eight on a scale of 10. Doctors gave him CT scans to rule out appendicitis, stroke and numerous other serious ailments, and he was prescribed antibiotics and told to take Tylenol, before returning to the apartment where he was staying with a Dallas woman and three other people, the records state. He died on Wednesday.

Herald wire services contributed to this report.