An American health care worker who contracted Ebola while volunteering in a Sierra Leone treatment unit has been downgraded to critical condition at the National Institutes of Health , doctors said on Monday . The patient 's status was changed from serious to critical condition , meaning the person 's condition has apparently worsened . The patient is being treated at the National Institutes of Health 's hospital near Washington , D.C . The patient was flown in isolation from Sierra Leone on a chartered plane last week and arrived early on Friday morning . The patient 's name , age and gender have not been released . Scroll down for video . A health care worker prepares a colleague 's Ebola virus protective gear at a clinic operated by the International Medical Corps in Makeni , Sierra Leone . Five people in the U.S. are now being monitored after being exposed to Ebola . The person is a clinician working with Partners in Health , a Boston-based nonprofit organization . The group has been treating patients in Liberia and Sierra Leone since November . This came as a second American health care worker who was possibly exposed to Ebola has been moved to Nebraska Medicine 's biocontainment unit after a change in symptoms , the hospital said on Monday . The worker was one of four monitored in Nebraska after exposure to another American who tested positive for Ebola . The person who was moved has not tested positive for the virus , the hospital said . None of the patients has been identified . The hospital said it would receive a fifth person who was part of the initial exposure in Sierra Leone later on Monday . The latest NIH patient is the 11th person with Ebola to be treated in the U.S. Two patients in the U.S. have died : a man treated in Dallas after contracting the virus in Africa and a doctor evacuated from Africa to Nebraska when he was already critically ill . The man in Dallas had contracted the virus in his native Liberia . He transmitted the disease to two nurses , resulting in widespread concern in the U.S. , with questions raised about emergency department screening of patients , monitoring of ill travelers from Africa and even disputes over the disposal of potentially infectious waste from hospitals . The World Health Organization has estimated 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 . While deaths have slowed dramatically in recent months , the virus appears stubbornly entrenched in parts of Guinea and Sierra Leone . A Centers for Disease Control and Prevention spokesman said that besides the patient at NIH , there are 11 other Partners in Health workers being brought to the United States for monitoring . That includes four going to Atlanta to be near Emory University Hospital ; one arrived Friday . On Saturday , four health care workers arrived at the Nebraska Medical Center in Omaha , and three arrived in the Washington area on Sunday to be near the NIH campus in Bethesda . One of those being monitored in Nebraska has developed symptoms of Ebola and was being moved to a biocontainment unit , hospital officials said in a news release on Monday . However , none of those being monitored has tested positive for Ebola . The National Institutes of Health said it has no other pending admissions of additional patients with the Ebola virus or who have been exposed to Ebola . CDC workers in Sierra Leone are involved in investigating the illness of the first patient , including looking for other people the person was in contact with . It 's possible other people will be transported to the United States for monitoring , said the spokesman , Tom Skinner.= . A U.S. healthcare worker , who had been caring for Ebola patients in Sierra Leone , has been downgraded to critical condition at the National Institutes of Health in DC ( pictured )
Ebola patient has been downgraded from serious to critical at Nebraska Medicine 's in DC . Second American who was possibly exposed to Ebola moved to the National Institutes of Health biocontainment unit after change in symptoms .