American doctor Rick Sacra, a 51-year-old Christian missionary who was infected with Ebola in Liberia, has recovered and was released from the hospital on Thursday.

"I am so happy to be here with all of you today on the occasion of my release from the hospital," he told reporters.

"The CDC has declared me safe and free of virus," said Sacra, thanking God, his medical team and those who prayed for him while he was ill.

The obstetrician was infected on August 29 and flown on September 5 to Nebraska Medical Center, where he was given an experimental drug called TKM-Ebola.

He was also given a blood transfusion from another American doctor, Kent Brantly, who recovered from the virus earlier this year.

When Brantly was sickened with Ebola in Monrovia, he also received blood from a child who had recovered from the hemorrhagic virus, as well as a different experimental drug called ZMapp.

Earlier this month, global health experts in Geneva agreed that blood therapies and convalescent serums could be used to fight Ebola immediately, while safety trials begin for potential vaccines.

There is no drug or vaccine on the market to treat Ebola.

The world's worst-ever Ebola epidemic has now infected nearly 6,300 people in West Africa and killed nearly half of them, according to the World Health Organization.

In its latest update, the UN health agency said a total of 6,263 people had been infected across five west African countries -- 44 percent of them over the past three weeks -- and that 2,917 had died.