Patient possibly exposed to Ebola due at Nebraska hospital for observation...........

A U.S. health care worker who was possibly exposed to the Ebola virus in Sierra Leone was expected to arrive for observation on Sunday at a Nebraska facility that has treated three Ebola cases, hospital officials said.

The patient, who was not identified, was expected to arrive at the Biocontainment Unit at the University of Nebraska Medical Center in Omaha via private air ambulance around 2 p.m. CST for observation and possible treatment, the center said in a statement.

The patient "has been exposed to the virus but is not ill and is not contagious," said Dr. Phil Smith, the unit's medical director, adding "we will be taking all appropriate precautions."

It gave no details on how the possible exposure occurred.

The same team that cared for three previous Ebola patients at the facility, two of whom were successfully treated, would be working on the case, Smith said. A third patient who arrived gravely ill died a short time later.

The center will monitor for development of infection over the 21-day incubation period using observation and blood tests.

On Saturday, a London hospital said a British nurse being treated for Ebola was in critical condition after deteriorating over the last two days.

The Royal Free Hospital said Pauline Cafferkey, 39, the first person diagnosed with Ebola on British soil, had returned to Britain from Sierra Leone where she had been working for a charity.

Ebola, a hemorrhagic fever, has killed more than 8,000 people out of more than 20,000 cases in an outbreak that began in March. Most all of the cases have been in Liberia, Sierra Leone and Guinea.