The revolving-door leadership of the nation’s top public health agency took another potential turn on Wednesday, as Dr. Erica Schwartz’s nomination came before a U.S. Senate committee.Schwartz, 54, is up for director of the Atlanta-based Centers for Disease Control and Prevention, which is charged with protecting Americans from preventable health threats.Her career has largely been spent in military uniform, including in a leadership position at the U.S. Coast Guard where she oversaw the organization’s system of 41 clinics and 150 sick bays — as well as policies promoting vaccinations of service members. She later served as deputy surgeon general, where she helped lead uniformed medical and health professionals posted at the CDC and government health agencies that serve the general public.The CDC long enjoyed a sterling international reputation but has been in turmoil since Trump returned to office last year. Largely due to layoffs and resignations, the agency has lost more than 3,000 employees, or more than a quarter of its workforce. Morale has plummeted as a succession of mostly temporary leaders have come and gone — the front office filled with political appointees, many of them with little or no training in medicine or public health.“There’s still really good people who work there (at the CDC). They are doing their best to navigate choppy waters,” said Dr. David Margolius, director of Cleveland’s health department and a leader in a U.S. coalition of big city health departments. But CDC no longer seems to the authoritative and communicative lead that it was on outbreaks and other public health emergencies. “Basically everybody’s got to kind of choose their own adventure, as opposed to being led by a national public health department,” Margolius said.