(AP) -- A surgeon who contracted Ebola in his native Sierra Leone died Monday while being treated in a biocontainment unit at a Nebraska hospital, the facility said.

Nebraska Medical Center said in a news release that Dr. Martin Salia died as a result of the disease. Hospital spokesman Taylor Wilson said Salia died shortly after 4 a.m. Monday.

"Dr. Salia was extremely critical when he arrived here, and unfortunately, despite our best efforts, we weren't able to save him," said Dr. Phil Smith, medical director of the biocontainment unit.

Salia arrived Saturday to be treated at the Omaha hospital, where two other Ebola patients have been successfully treated.

Salia had advanced symptoms when he arrived at the hospital Saturday, which included kidney and respiratory failure, the hospital said. He was placed on dialysis, a ventilator and given several medications to support his organ systems.

"We used every possible treatment available to give Dr. Salia every possible opportunity for survival," Smith said. "As we have learned, early treatment with these patients is essential. In Dr. Salia's case, his disease was already extremely advanced by the time he came here for treatment."

Salia's wife, Isatu Salia, said Monday that she and her family were grateful for the efforts made by her husband's medical team.

"We are so appreciate of the opportunity for my husband to be treated here and believe he was in the best place possible," Salia said.

Ebola has killed more than 5,000 people in West Africa, mostly in Liberia, Guinea and Sierra Leone. Five other doctors in Sierra Leone have contracted Ebola, and all have died.

The 44-year-old Salia had been working as a general surgeon at Kissy United Methodist Hospital in the Sierra Leone capital of Freetown. It's not clear whether he was involved in the care of Ebola patients. Kissy is not an Ebola treatment unit, but Salia worked in at least three other facilities, United Methodist News said, citing health ministry sources.

Salia, a Sierra Leone citizen who lived in Maryland, first showed Ebola symptoms on Nov. 6 but tested negative for the virus. He eventually tested positive on Nov. 10.

Isatu Salia said in a telephone interview over the weekend that when she spoke to her husband early Friday his voice sounded weak and shaky. But he told her "I love you" in a steady voice, she said.

They prayed together, she said, calling her husband "my everything."