Former President George H.W. Bush is in the intensive care unit of a Houston hospital and is in "guarded condition," family spokesman Jim McGrath said Wednesday.

"The president is alert and conversing with medical staff, and is surrounded by family," McGrath said in a statement reported by Reuters.

"Following a series of setbacks including a persistent fever, President Bush was admitted to the intensive care unit at Methodist Hospital on Sunday where he remains in guarded condition," McGrath said.

Doctors "continue to be cautiously optimistic about the current course of treatment," he added.

Bush has been in intensive care with a fever since Sunday.

"It's an elevated fever, so it's actually gone up in the last day or two," McGrath said. "It's a stubborn fever that won't go away."

Bush spent Christmas in Methodist Hospital, surrounded by loved ones after suffering for more than a month from a “lingering, bronchitis-like cough,” the Associated Press reported. The former Republican president had his wife, Barbara, and other relatives with him for a special holiday meal.

The 41st president of the United States has been hospitalized since Nov. 23 due to a throat condition. It was originally anticipated that Bush would be released and able to spend the Christmas holiday with his family at home, but McGrath said those plans were nixed when the 88-year-old developed a fever.

McGrath noted that Bush's son, Neil, and his wife were by his side on Tuesday, along with one of his grandsons.

The spokesman said that the hospital setting was a dramatic change from the usual Bush family dinner for Christmas, which is typically held at Gigi's Asian Bistro in Houston's Galleria neighborhood. Family members had intended to get food to go from the high-end Asian restaurant, he said.