By Dave Sherwood

PORTLAND Maine (Reuters) - A patient in Portland, Maine, is being held for observation for a potential case of Ebola at the request of the U.S. Centers for Disease Control and Prevention, health officials said.

No information about the patient, his condition or travels has been released by the hospital, and there is no confirmation of Ebola, according to Dr. August Valenti, an infectious disease specialist at Maine Medical Center. He said in a statement that the decision was a precautionary step.

"Maine Medical Center is using policies developed by the World Health Organization. Those policies exceed the policies of Center for Disease Control and represent the strictest of guidelines," Valenti said.

Hospitals across the United States are on high alert as authorities continue to investigate how a nurse in an isolation ward at a hospital in Texas contracted Ebola, the first instance of a person contracting the disease on U.S. soil.

Numerous other Ebola scares in the past week, including one in which passengers at Boston's Logan Airport were removed from an airplane that had arrived from Dubai, have turned out to be false alarms.

Portland hospital officials said health workers there are using a higher level of protective apparel than that recommended by the CDC.

The Maine hospital's response comes as medical experts, including CDC chief Dr. Thomas Frieden, have acknowledged a need to rethink how highly infectious diseases are handled in the United States.

The current Ebola outbreak, the worst on record, has killed some 4,447 people, mostly in Liberia, Sierra Leone and Guinea in West Africa.

(Editing by Scott Malone and Doina Chiacu)