"This is the largest public health crisis to face this country in nearly a hundred years," said Shelley Hearne, executive director for the Trust For America's Health. "If [HHS] does its job well, what you actually do is you prevent hundreds of thousands of people from getting sick."

It could also - to some degree - help restore credibility to an administration that has been derided for its delayed and bungled hurricane response, which culminated in the unceremonious departure this week of Federal Emergency Management Director Michael Brown and the president's concession Tuesday that mistakes may have been made.

Leavitt, the former three-term Utah governor, and HHS have largely escaped the type of scorn that was heaped upon Brown, the Department of Homeland Security and President Bush.

"You don't hear those stories because Secretary Leavitt and HHS are doing what they need to be doing," said Bob Wood, who was chief of staff to Leavitt's predecessor at HHS, Tommy ThompÂson. "Unfortunately in these times of crisis the finger-pointing is only at what has gone wrong and not at what has gone right. And I think at HHS the reason you don't hear the outcry is because they've done a lot of things right."

It's unlikely that Leavitt and his department will be able to make significant repairs to the public-relations damage the administration has suffered in recent days.

"You can help, but the credibility is not going to come from HHS," said Norm Ornstein, a political scientist at the American Enterprise Institute. "Some of it could come from [Homeland Security] and FEMA, but a lot of it has to come from the president himself."

Leavitt was in Louisiana on Tuesday and travels to Mississippi and Alabama today, visiting with evacuees and medical teams and promoting the department's efforts to make it easier for evacuees to get medical care. It was Leavitt's third trip to the region in just more than a week.

As the hurricane approached, Leavitt was in Salt Lake City visiting his first grandson, but the trip was cut short as Katrina bore down on the Gulf Coast and Leavitt returned to Washington on Aug. 27, and put his department on alert.

In the wake of the storm, Leavitt designated a public health emergency in the Gulf Coast region, expediting construction of temporary clinics and delivery of medical reÂsources. By the weekend, he was on television, offering the dire prediction that thousands likely perished in the hurricane and flooding.

The delivery of health care was not without problems. For example, FEMA initially kept emergency medical teams away from the New Orleans convention center and the Superdome.

"It was more difficult to establish a foothold at the convention center and the Superdome because of the security issues that have been widely reported, but, ultimately, health care was provided in those areas," Leavitt told reporters last week. On the whole, "people received remarkable care under the circumstances."

David Satcher, former surgeon general and an assistant secretary at HHS under President Clinton, said in an interview the FEMA-led response was "mishandled in a lot of ways," but the action taken by HHS appears to have been solid.

"I think the overall response was deplorable in terms of the timing and there's plenty of blame go around, but I think the overall public health response was heroic," said Georges Benjamin, executive director of the American Public Health Association.

Initial efforts focused on caring for the thousands of sick, injured and displaced residents, including treating those in urgent need of medication for conditions such as heart disease or diabetes.

Now the focus is shifting to preventing outbreaks of disease.

"This is quite the toxic jambalaya that is being cooked down there," said Hearne.

The water that flooded New Orleans is tainted with an unknown mixture of toxins, some of which naturally suppress an immune system. Add the stress put on evacuees and responders, which can further undermine the ability to fight disease, and the "barrage of pathogens" in the close quarters in which evacuees live and conditions are ripe for illnesses to spread, Hearne said.

Thus far, there have been reports of some intestinal illness among evacuees, and other communicable illnesses. But HHS spokesman Bill Hall said that there have not been the type of widespread ailments that were feared.

Officials are vaccinating evacuees in the temporary shelters and crews are planning to spray areas with standing water to prevent mosquitoes from spreading illness among the survivors. A public education effort also is cautioning residents of potential contamination in food or water supplies, encouraging cleanliness and warning against actions that could cause fire, electrocution or carbon monoxide poisoning.

This week, the department announced $2.3 million in grants to help establish 26 health centers in areas impacted.

There also will be needs in the longer term, particularly providing mental health services for evacuees and rescuers traumatized by what they have gone through, said Satcher.

"I think the history is such that we underestimate the mental health problems," said Satcher, now interim president at Morehouse School of Medicine in Atlanta. "As people see what they consider sort of a hopeless situation - bodies floating on the water, the scene like they saw in the Superdome - people are not ready for that. They are not prepared to deal with it."

Indeed, said Wood, the role of Leavitt's department in the region will not be diminishing anytime soon.

"There's going to be a lot more asked of Health and Human Services in the months and, unfortunately, maybe years ahead."

Leavitt's journey

A native of Cedar City, Mike Leavitt was elected Utah's 14th governor in 1992. He went on to win election twice more. In 2003, he stepped down to join the Bush administration as head of the Environmental Protection Agency. In January, he landed a Cabinet job, overseeing the much larger Department of Health and Human Services.