Liberia put a group of patients under observation on Friday at a hospital in the capital Monrovia after they had contact with a woman infected with the deadly Ebola virus.
Deputy health minister Tolbert Nyensuah said the SD Cooper Hospital in Sinkor, an administrative district housing the United Nations, was remaining open and no one was being held against their will.
"The hospital has not been closed. No one is under quarantine. What we have done is that we have disinfected the hospital and we are doing contact tracing on several persons," he told AFP.
He did not say how many people were involved but local media reported 30 were being watched for signs of infection over 21 days.
Health authorities say a woman who knew she had Ebola entered the hospital seeking treatment for her symptoms without being screened for infection or declaring her illness.
She was seen by nurses and also reportedly had contact with "several" patients.
Ebola, one of the deadliest pathogens known to man, is spread through direct contact with the bodily fluids of an infected person showing symptoms such as fever or vomiting.
As of February 15, WHO said 23,253 people had been infected and 9,380 had died, almost all in Guinea, Sierra Leone and Liberia.
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