The U.S. freelance photographer who contracted Ebola while working in Liberia arrived in Nebraska on Monday to receive treatment for the disease.

Ashoka Mukpo was working as a freelancer for NBC in Liberia when he became sick, according to a report from ABC News. He was flown from Liberia in a plane equipped to handle Ebola patients.

After landing in Omaha, Nebraska, Mukpo was taken to the Nebraska Medical Center by ambulance and placed in the hospital's Biocontainment Unit. Mukpo is the second person to be treated in that unit, after Dr. Richard Sacra was treated there last month.

The Nebraska Medical Center is one of just four biocontainment units in the U.S. The others are at the U.S. Army Medical Research Institute of Infectious Diseases at Fort Detrick, Maryland; Missoula, Montana; and Emory University Hospital in Atlanta, at which the first two Americans to catch the disease were treated.

Mukpo is the fifth American to return to the United States for treatment since the start of the recent Ebola outbreak, which the World Health Organization says has killed more than 3,400 people, Fox News reported.

Mukpo previously spent two years working for a Liberian NGO before returning to the U.S. in the summer, his mother told the press. He returned to Liberia as Ebola began ravaging the country, which has been hardest hit by the virus.

"He feels a tremendous commitment to the Liberian people and the Liberian culture, and when he heard about the Ebola outbreak he felt compelled to go back ... much to the anxiety of his parents and family, obviously," Diana Mukpo said.

Mukpo contributed to various media reports while working in Liberia before he got sick and he also updated friends via Facebook.

In one post he wrote, "Man oh man I have seen some bad things in the last two weeks of my life. How unpredictable and fraught with danger life can be. How in some parts of the world, basic levels of help and assistance that we take for granted completely don't exist for many people."