On September 20, 2014, Annie Jacobsen explains (in Biological War), a Liberian man named Thomas Eric Duncan arrived at the Dallas–Fort Worth International Airport — unaware that he was infected with Ebola hemorrhagic fever virus:
Feeling ill after his arrival in Dallas, Duncan went to the Texas Health Presbyterian Hospital emergency room, where he was misdiagnosed with a sinus infection, prescribed antibiotics (which do nothing to kill a virus), and told to take Tylenol. After four hours in the busy emergency room setting, he was discharged.
His condition worsened. Days later, Duncan was taken by ambulance back to the same Dallas hospital that had not admitted him when he first came in, a visitor from West Africa with early Ebola symptoms. By this time, he was displaying late-stage symptoms of Ebola, which include bleeding from the eyes, symptoms that are almost impossible to misdiagnose.
It is not as if the Ebola crisis was unknown to the medical establishment and ordinary American citizens alike in 2014. When Duncan arrived at the Dallas–Fort Worth International Airport, the Ebola epidemic in West Africa already had killed 3,000 people. There had been more than 100 front-page American news stories about the Ebola outbreak happening on the other side of the world. “A substantial portion of the American public [was] concerned about being infected with Ebola virus disease (EVD)” at the time, according to a prominent study on media attention.
It is not as if the Ebola crisis was unknown to the medical establishment and ordinary American citizens alike in 2014. When Duncan arrived at the Dallas–Fort Worth International Airport, the Ebola epidemic in West Africa already had killed 3,000 people. There had been more than 100 front-page American news stories about the Ebola outbreak happening on the other side of the world. “A substantial portion of the American public [was] concerned about being infected with Ebola virus disease (EVD)” at the time, according to a prominent study on media attention.
[…]
60 to 92 percent of Ebola victims bleed to death, with blood pouring out of the eyes, ears, nose, and skin.
[…]
At the time of his travel, Liberia accounted for roughly 45 percent of Ebola deaths. That no government officials, in either Belgium or the United States, asked Duncan if he’d been in the Ebola Hot Zone before they granted him entry may seem implausible, in hindsight. But this is what happened.
Because Ebola is not airborne, none of the other passengers on the flights Duncan traveled on, or at the airports he visited, became infected with Ebola. But he did infect two healthcare workers at the Texas Health Presbyterian Hospital in Dallas, where he ended up in the ICU before dying a horrific death.
[…]
In 2014, diagnostics were such that Ebola could not be detected in the bloodstream until symptoms emerged. Because Nurse Vinson had been caring for an Ebola patient in the hospital’s ICU, she consulted the CDC about her airplane travel plans, asking if she should get on her flight.
The CDC advised her to take her temperature.
When she reported she had a slight fever of 99.5 degrees Fahrenheit (37.5 degrees Celsius), a CDC official noted that its threshold for fever is 100.4 degrees Fahrenheit (38 degrees Celsius) and cleared Nurse Vinson to fly on a commercial aircraft. Upon returning from her trip to Ohio, Amber Joy Vinson tested positive for Ebola.
