By Alexandra Sifferlin
March 16, 2015

The American health care worker with Ebola who is being treated by the National Institutes of Health (NIH) has gone from serious to critical condition, according to the agency.

The patient was infected while working Sierra Leone and then was flown to the NIH in Bethesda, Md. for treatment, arriving March 13.

The patient is the second to be treated for Ebola by the NIH. Dallas nurse Nina Pham was the first. She survived the disease after being infected by Thomas Eric Duncan, the first person with Ebola to be diagnosed in the U.S.

The NIH has not released additional details about the latest patient.

Twelve other workers from the NIH patient’s volunteer organization, Partners in Health, are coming to the U.S. for monitoring. One person being monitored in Nebraska was brought to Nebraska Medical Center on Monday after beginning to experience possible Ebola symptoms, the Associated Press reports.

MORE: American Health Worker With Ebola Heading to U.S. for Treatment

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