Last Updated Mar 16, 2015 3:14 PM EDT
BETHESDA, Md. -- 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 Monday.
The agency said in a statement that the patient's status was changed from serious condition 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.
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.
The NIH hospital in Bethesda, Maryland, is equipped with special isolation facilities for treating patients with highly contagious diseases. It's same hospital where nurse Nina Pham was successfully treated after she contracted Ebola from a patient in Dallas last October.
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.
The Nebraska Medical Center in Omaha is monitoring four people who may have been exposed in Sierra Leone, and the hospital says one of them was moved into a biocontainment unit after developing symptoms on Sunday evening.
"At this point, this person has not tested positive for the Ebola virus," Phil Smith, M.D., medical director of the Biocontainment Unit at Nebraska Medicine, said in a press statement Monday. "However, because of a change in symptoms, we decided the most prudent course of action was to bring the individual to the Biocontainment Unit, where we can better monitor symptoms and safely perform testing."
Smith emphasized that the general public was not at risk because the person was separated from other patients and staff.
In addition to the people being monitored in Nebraska, three others arrived in the Washington area on Sunday to be near the NIH campus in Bethesda, and four were going to Atlanta to be near Emory University Hospital; one arrived Friday. Those workers have not tested positive for Ebola but may have been exposed.
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.
The World Health Organization reports more than 10,000 people have died of Ebola since the outbreak began in West Africa last year.