U.S. health officials say the physical condition of most of the people evacuated from New Orleans after Hurricane Katrina is good. They are taking steps to keep it that way and prevent a wave of infections from breaking out in crowded shelters around the southeastern United States.

Officials of the U.S. Health and Human Services Department have returned from a tour of emergency shelters in Louisiana, Mississippi, and Texas and say that local communities have done a remarkable job providing temporary care for the hundreds of thousands of people forced to flee New Orleans and other regional sites devastated by Hurricane Katrina.

The department's chief, Michael Leavitt, says the local response was massive and good.

"I would judge it to have been strong and high quality, but predictably imperfect," said Mr. Leavitt.  "It has drained resources from local service providers. They have responded in a remarkable way. We walked through medical shelters that were staffed by the heads of departments of major hospitals working alongside medical students."

But the technical sophistication varies greatly. Mr. Leavitt says Houston, Texas, and Baton Rouge, Louisiana, for example, have shelters equipped like operating rooms in major hospitals.  At other places, such as the New Orleans airport, service is more basic, consisting of cots and first aid.

The top U.S. public health official, Surgeon General Richard Carmona, says communities quickly established shelters for health care and social services in what just days earlier had been convention centers, auditoriums, and other public facilities. He credits the quick reaction for preventing a public health disaster and restoring a sense of stability to evacuees' lives.

"It should be pointed out that we are a week out, and so far, so good," said Mr. Carmona.

The national government has established a command center in a New Orleans hospital, combining health, environmental, emergency preparedness and military experts. It has also dispatched public health teams from its Centers for Disease Control (CDC) in Atlanta and is coordinating help from health professionals across the country to back up the local shelters and hospitals, which are overwhelmed by the evacuee influx. The city of Baton Rouge, for example, has swelled from 500,000 people to 850,000. Health Secretary Michael Leavitt says 200 hospitals are sending personnel to cities in need and about 8,000 professionally qualified volunteers have registered to help via a toll-free telephone number.

Surgeon-General Carmona says the biggest challenge ahead is maintaining the ability to care for chronic illnesses the evacuees had before the hurricane.

"We have to help these folks through their acute challenges, but we realize we're going to have to be there in the long haul," he added.  "These hospitals need to be sustained, but the care is changing from acute to chronic, and behind it all are the public health needs that will be ongoing."

The U.S. health officials say among the public health threats they are watching for are outbreaks of infectious diseases that could erupt in the crowded shelters, particularly diarrhea and respiratory illnesses like influenza.

The head of the Centers for Disease Control, Julie Gerberding, compares the hurricane disaster health care effort to that after the Indian Ocean tsunami last December.

"When you think about the tsunami, the fact was that people got in early, they set up the systems to try to prevent these infectious diseases, and ultimately were remarkably successful in mitigating what could have been a second wave of infectious diseases in that context," she noted.  "That's exactly what we're working to do here in this country in the context of the shelters and certainly in the city of New Orleans."

Dr. Gerberding says the many dead bodies floating on or still submerged in New Orleans floodwaters do not present a health threat, since microbes cannot live in them.