Washington, Sep 29 (IANS): An American infected with the Ebola virus in West Africa has returned home and admitted to the US National Institutes of Health (NIH).

The physician, who has been working in an Ebola treatment unit in Sierra Leone, arrived at the NIH centre Sunday evening, Xinhua reported.

"The patient has been admitted to the NIH clinical centre's special studies unit that is specifically designed to provide high-level isolation capabilities and is staffed by infectious diseases and critical care specialists," an official said.

The institute has not disclosed the patient's identification.

Four American aid workers have already been airlifted back to the US from West Africa.

All but one have already been recovered and released from the hospital.

The current Ebola outbreak in West Africa has killed over 3,000 people and more than 6,500 people are believed to have been infected in the region, the World Health Organization said Friday.