AUSTIN, Texas - 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.

Former President George H.W. Bush smiles as he listens to Republican presidential candidate Mitt Romney speak as he met with Bush to pick up his formal endorsement in Houston in this March 29, 2012 file photo. [Photo/Agencies]

"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 at Methodist continue to be cautiously optimistic about the current course of treatment."

The 88-year-old was admitted to the hospital on Nov 23 for bronchitis.

A hospital spokesman said in mid-December that the former president was expected to be home from the hospital in time for Christmas, but that spokesman later said doctors felt that the former president should build up his energy before going home.

Bush has lower body parkinsonism, which causes a loss of balance, and has used wheelchairs for more than a year, McGrath said in an email on Wednesday.

Bush, the 41st US president and a Republican, took office in 1989 and served one term in the White House. The father of former President George W. Bush, he also served as a congressman, ambassador to the United Nations, envoy to China, CIA director and vice-president for two terms under Ronald Reagan.