A US photojournalist said Tuesday he was grateful to be alive after the hospital treating him declared him now free of Ebola, in a minor victory over the virus that has killed more than 4,500 people.

Ashoka Mukpo, who was working as a freelance cameraman for NBC News in Monrovia, Liberia when he fell ill, will go home on Wednesday and also speak to the media.

"Recovering from Ebola is a truly humbling feeling," Mukpo, 33, said in a hospital statement.

"Too many are not as fortunate and lucky as I've been. I'm very happy to be alive."

The virus has killed more than 4,500 people in West Africa this year, and stoked fears that it could spread beyond the three worst-hit countries Liberia, Sierra Leone and Guinea, and become a global threat.

Eight people including Mukpo have or are being treated for Ebola in the United States, one of whom, a man from Liberia, has died.

Mukpo, who arrived at Nebraska Medical Center on October 6 and was able to walk off the plane that evacuated him from West Africa, added in the statement that he was not sure how he contracted the disease.

"I was around a lot of sick people the week before I got sick," he said. "I thought I was keeping a good distance and wish I knew exactly what went wrong."

A Centers for Disease Control and Prevention confirmed negative blood test showed that Mukpo no longer had the virus in his bloodstream, the Nebraska Medicine statement said.

No regrets

Mukpo spent a little more than two weeks inside a bio-containment unit, but said he had no regrets.

He had lived and worked in Liberia for a non-governmental organization for two years before returning to the United States initially in May, and desperately wanted to return to Africa a few months later, his parents have said, describing him as "crazy."

Mukpo went back to Liberia on September 4 and had begun freelancing for NBC News a day before he fell ill.

"I don't regret going to Liberia to cover the crisis," he said. "That country was a second home to me and I had to help raise the alarm."

There are growing fears in the United States about Ebola, for which there is no vaccine or any widely available cure.

New measures go into effect Wednesday in the United States tightening restrictions on travelers arriving from the three West African countries gripped by the Ebola outbreak, funneling them into five airports with extra health checks.

Mukpo was the second patient to be treated for the Ebola virus in Nebraska. Dr. Richard Sacra was declared virus-free when he left the biocontainment unit on September 25.

Dr. Phil Smith, medical director of the biocontainment unit at Nebraska Medicine-Nebraska Medical Center, said: "Our staff was confident it would be able to successfully care for another patient.

"We've learned first-hand that caring for a patient with the Ebola virus presents challenges you don't face in the regular hospital environment.

"But our years of training on protocol in the unit and gaining familiarity with all the personal protective equipment was certainly an advantage for us."