NEW ORLEANS — Authorities said Monday that some of Hurricane Katrina's evacuees have contracted a bacterial disease that is considered a more benign cousin of cholera, but is potentially fatal in people whose immune systems have been compromised.
Officials at the Centers for Disease Control and Prevention in Atlanta said the bacterium, vibrio vulnificus, might have been picked up by people with open wounds who were forced to wade through polluted floodwaters for a long time.
Von Roebuck, a CDC spokesman, said officials had detected the disease among some storm evacuees and stragglers but had not been able to determine how many cases there were. It does not appear that anyone has died from the disease, Roebuck said.
Since flooding began, authorities have predicted that New Orleans could be stricken with a host of diseases, particularly as unretrieved bodies remained in the water. This appears to be the first confirmation of illness caused by the storm and the flood.
New Orleans Mayor C. Ray Nagin said Monday that the possibility of epidemics was a critical concern.
"The water quality in the streets continues to deteriorate," Nagin said. "There is some really nasty looking stuff out there. I worry about it every day. The more time that passes, there are more dead bodies left floating, and more mosquitoes breeding and hatching. They bite people who are dead."
Nagin said he was concerned about a widespread outbreak of the potentially fatal West Nile virus. For two days, he has called upon the federal government to provide crop dusters that can coat the city with chemicals to kill mosquitoes breeding in the floodwaters. That had not occurred by Monday evening.
He said he was also concerned about airborne toxic hazards and natural gas in the area.
Those health threats are why every resident must leave the city -- even those living on dry land, Nagin said, adding that they "will be able to come back."
Vibrio vulnificus belongs to the same family as cholera -- and those stricken with the bacterium were discovered, officials said, only because tests were done amid false reports that cholera had been discovered among evacuees.
Among healthy people, vibrio vulnificus causes vomiting, diarrhea and abdominal pain but is generally not life-threatening. It can be readily cured with antibiotics such as doxycycline or cephalosporins, with no long-term effects.
It is substantially more serious in people with chronic liver disease or people who have compromised immune systems, such as those taking transplant drugs. In those cases, the bacterium escapes into the bloodstream, where it causes fever and chills, septic shock -- characterized by sharply decreased blood pressure -- and blistering skin lesions.
About half of those who contract bloodstream infections die, according to the CDC.
There is no evidence that the bacterium spreads from human to human.
The bacterium can also cause skin infections if people have open wounds, which can lead to skin breakdown and ulceration.
About 45 hospitalizations and 15 deaths are reported each year in the Gulf Coast states, but many experts think the actual number of cases is far higher. Most cases occur from May to October, when the ocean is warmer.
In New Orleans' 9th Ward, O'Neil Broyard, 67, said Monday that he was not concerned about the threat of disease, although several feet of increasingly fetid water stands just behind his business, the Saturn Bar.
Broyard has been mucking around in the water for days. During the height of the flooding, 2 feet of water was in the bar and he spent three days cleaning it out. He said he took precautions every time he slogged through the water.
"I washed up good," Broyard said. "I got that antibacterial soap and I just put it on my feet."
Like thousands of others left in town, Broyard rejected the mayor's call to evacuate. Instead, he said he was intent on guarding his bar, a small, strange gem in the east of the city that has acquired a cult following over the years for its collection of surreal, comic paintings by a local artist and its earthy, no-nonsense management.
Times staff writers Richard Fausset and Thomas Maugh II contributed to this report.