Maryland House Speaker Michael Busch (D-Anne Arundel) speaks at a news conference in Annapolis in March. (Brian Witte/AP)

Maryland House Speaker Michael E. Busch, who underwent a liver transplant last month, is recuperating at home and doctors are pleased with his progress, according to an aide.

Busch (D-Anne Arundel), 70, was diagnosed with nonalcoholic steatohepatitis, a liver disease, and doctors recommended a transplant after growing concerned that his condition was worsening. His sister donated a portion of her liver through the living-donor program at the University of Maryland Medical Center.

Alexandra Hughes, Busch’s chief of staff, said Busch, the ­longest-serving House speaker in state history, is continuing to stay involved in legislative duties during his recovery. But he is not expected to return to the State House until some time next month.

“He continues to be engaged with the operation of the House of Delegates by phone and receives mail and memos from staff regularly,” Hughes said.

Busch recently made an unexpected appearance at the State House and tried to greet workers and others before he was whisked away by his staff, according to two people who spoke on the condition of anonymity because they were not authorized to speak publicly. Transplant patients have weakened immune systems and are encouraged to avoid contact with crowds.

According to the University of Maryland living-donor program, it takes about two months for livers to regrow to their original size in a transplant recipient and in the donor.

Busch’s staff posted a video on his Facebook page about a week after his operation to thank those who sent messages to Busch, whom they referred to as “#IronMike.” The video starts with a photo of Busch, wearing a black baseball cap and a hospital gown, giving two thumbs up.

Hughes said on social media last month that Busch, who filed for reelection in May, looks forward to his continued recovery and returning to his work.

Busch posted a picture of supporters holding a Busch campaign sign on his Facebook page last week. The post said that he had missed the Fourth of July parade in Annapolis for the first time in his political career. He also wrote that he wanted to thank his friends for their support and that he “can’t wait to start knocking on doors with them in the fall.”