A Liberian who was the first person diagnosed with Ebola outside of Africa has died in a Texas hospital, officials said Wednesday.

“It is with profound sadness and heartfelt disappointment that we must inform you of the death of Thomas Eric Duncan this morning at 7:51 am (1251 GMT),” said the statement from Texas Health Presbyterian Hospital Dallas spokesman Wendell Watson.

“Mr. Duncan succumbed to an insidious disease, Ebola. He fought courageously in this battle.”

Thomas Eric Duncan: Dies in Texas

Meanwhile, US media reported that airports were to begin tougher screening of passengers arriving from the West African nations where Ebola has killed more than 3,400 people since the beginning of the year.

Quoting a federal official, the Washington Post reported that travellers from West Africa would be subjected to Ebola screening at five US airports — Atlanta, Chicago’s O’Hare, New York’s JFK and Newark airports and Dulles in Washington — as early as this weekend.

CNN, also citing anonymous sources, said temperatures would be taken of travelers from a so-called “Ebola zone,” including Guinea, Sierra Leone, Liberia and Nigeria.

NBC News added that travellers would be asked to fill out questionnaires as well

Duncan flew from Liberia to Texas to visit family, arriving in Dallas on September 20. He began feeling sick four days later, but was not hospitalized until September 28.

The Texas health care system came under heavy criticism for initially turning Duncan away when he first sought care on September 25.

Duncan was sent home even after he reported Ebola-like symptoms and said he had recently traveled from Liberia, the hardest-hit nation in the current outbreak.

Jesse Jackson, Weeks and Duncan’s son at a vigil Tuesday for Eric Duncan

“The past week has been an enormous test of our health system, but for one family it has been far more personal. Today they lost a dear member of their family,” said Texas health commissioner David Lakey.

“They have our sincere condolences, and we are keeping them in our thoughts.”

Lakey said that the medical team in Texas has “provided excellent and compassionate care, but Ebola is a disease that attacks the body in many ways.”

Duncan’s condition worsened from serious to critical over the weekend. On Saturday, he began receiving an experimental treatment called brincidofovir.

On Monday, doctors said his liver function had declined, and that he was on a ventilator and was receiving kidney dialysis.

Health officials are monitoring dozens of people who may have come in contact with Duncan, including about 10 who are considered at high risk of contracting Ebola.

The virus is spread through close contact with the bodily fluids of an infected person, or by touching the corpse of a person who has died of Ebola, experts say.

US hospitals in Nebraska and Georgia have successfully treated and released three American missionaries who were infected with Ebola in West Africa.

A fourth US doctor was treated at Emory University Hospital after becoming infected with Ebola in Sierra Leone. His name and condition were never released by officials.

Another US national who worked as a freelance cameraman for NBC News, Ashoka Mukpo, arrived in Nebraska this week for treatment after catching Ebola in Liberia.

The first known US citizen to come down with Ebola, dual American-Liberian national Patrick Sawyer, died in July after traveling by plane from Liberia to Nigeria.