U.S. Sen. Robert C. Byrd was admitted to a hospital Monday evening because of a high temperature, his spokesman said.

"He came into the office today, and he was a little sluggish," said Jesse Jacobs. After a vote at 5:30 p.m., Byrd went home, where his caregiver took his temperature, Jacobs said.

"I guess that was enough of a concern for her that she immediately called his doctor, who suggested he should be admitted to a hospital for observation," Jacobs said.

Jacobs did not know which hospital Byrd was taken to.

Byrd, 90, is the longest-serving senator in United States history. He was hospitalized last winter after a fall at home and then again a week later for a reaction to antibiotics.

U.S. Sen. Robert C. Byrd was admitted to a hospital Monday evening because of a high temperature, his spokesman said.

"He came into the office today, and he was a little sluggish," said Jesse Jacobs. After a vote at 5:30 p.m., Byrd went home, where his caregiver took his temperature, Jacobs said.

"I guess that was enough of a concern for her that she immediately called his doctor, who suggested he should be admitted to a hospital for observation," Jacobs said.

Jacobs did not know which hospital Byrd was taken to.

Byrd, 90, is the longest-serving senator in United States history. He was hospitalized last winter after a fall at home and then again a week later for a reaction to antibiotics.