An American healthcare worker who contracted Ebola while volunteering in Africa has arrived safely at the National Institutes of Health research hospital in Maryland , the agency announced Friday . The patient 's condition was still being evaluated after being flown in isolation from Sierra Leone on a chartered plane and was admitted at 4.44a.m . The patient 's name , age and gender were not released . Scroll down for video . Treatment : An American who contracted Ebola was expected to arrive Friday at the NIH research hospital in Bethesda after being transported to the United States in isolation on a chartered plane ( file photo ) The patient is the 10th person with Ebola to be treated in the U.S. and the second admitted to the NIH Clinical Center , which has one of the few containment facilities nationwide set up to treat Ebola patients . The patient had been volunteering at an Ebola treatment center in Sierra Leone , but the NIH did not release any further details about the patient . Previously , an American nurse was treated there after she contracted Ebola while caring for a Liberian man , Thomas Duncan , who died at Texas Health Presbyterian Hospital Dallas . The nurse , Nina Pham , survived and is Ebola-free . 'The NIH Clinical Center also admitted two individuals who experienced high-risk exposures to the Ebola virus while working on the Ebola response in West Africa , but who were ultimately found not to be infected , ' the agency said in its statement . Care : American nurse Nina Pham was treated at the Bethesda hospital after she contracted Ebola while caring for a Liberian man who died at a Dallas hospital . She survived and is Ebola-free ( October 2014 file photo ) Spread : The current Ebola outbreak is the largest ever for the disease . The center 's Special Clinical Studies Unit is staffed by specialists in infectious disease and critical care and is designed to prevent the spread of highly contagious viruses , including Ebola . The World Health Organization estimated Thursday that the virus has killed more than 10,000 people , mostly in the West African nations of Guinea , Liberia and Sierra Leone . The current outbreak is the largest ever for the disease , however , as deaths have slowed dramatically in recent months , the virus appears stubbornly entrenched in parts of Guinea and Sierra Leone .
Patient arrived Friday morning at NIH research hospital in Bethesda . Patient 's condition was still being evaluated after being flown in isolation . NIH did not release any further details about the patient . Sierra Leone was previously treated for Ebola at the hospital , survived and is now free of the virus .