Dr Martin Salia passed away from Ebola virus infection on Monday, despite receiving medication, a plasma transfusion, and the experimental drug ZMapp.

The chancellor of the hospital where he received treatment said that too much time had passed between the time Salia was infected and when he came to the United States for care.

Salia was a permanent resident of the US, but had returned to his native Sierra Leone to assist in the fight against the Ebola virus sweeping the country.

He first displayed symptoms on November 7, but a test for the virus was negative. According to Dr Phil Smith of the University of Nebraska Medical Center's (UNMC) biocontainment unit, a negative test is not uncommon in the disease's early stages, as there is not enough of the virus in the bloodstream to test positive.

When the symptoms did not subside, he took a second test on November 10, and was diagnosed with the deadly disease. Five days passed before Salia was flown to Omaha for treatment. By then, the surgeon had been infected for 13 days.

"In the very advanced stages, even the modern techniques we have at our disposal are not enough to help these patients once they reach a critical threshold," UNMC Chancellor Dr Jeffrey Gold told the Associated Press.

When Salia reached Omaha, his kidneys were nonfunctioning and he was having difficulty breathing. The 44-year-old was placed on dialysis and a respirator, and received an aggressive treatment regimen, but to no avail.

Dr Salia is survived by his wife, Isatu, and their two children, ages 12 and 20. In an April interview, he explained why he risked his health to serve others in Sierra Leone.

"I took this job not because I want to, but I firmly believe it was a calling and God wanted me to," he explained. "That's why I strongly believe it's God that brought me here to fix whatever comes my way.

"And I'm pretty sure, I'm confident, that I just need to lean on Him, trust Him for whatever comes in, because he sent me here. And that's my passion."