Officials closed down a disaster shelter in the town after more than 20 people complained of diarrhoea and vomiting, though they later denied that dysentery was to blame.
The sight of 25,000 refugees from the flooding crammed into the Superdome sports arena in New Orleans, where the toilets had broken down in the immediate aftermath of the hurricane, had already raised concerns about potential epidemics.
But public concern far outpaces the frequency of serious outbreaks. In the first few weeks after the Asian tsunami there were concerns that waterborne epidemics could double the death toll, but a month after the disaster the World Health Organisation reported that even in Aceh - the Indonesian province most severely hit by the tsunami, - outbreaks had been prevented by a well-coordinated public health programme.
The 2000 floods in Mozambique made more than 500,000 people homeless in a country with high levels of endemic diseases and little infrastructure to cope with the effects of a major natural disaster. But only 2,200 people died of gastric disease as a result.
Basic hygiene rules are enough to prevent most waterborne diseases. Washing your hands with soap and clean water, drinking only bottled water, and cleaning all unpackaged food products in boiled water are enough to kill off most pathogens.
Such measures, however, become nigh on impossible following a major disaster in which water, electricity and gas supplies have been cut off and flooding is widespread - hence the US government's insistence that the New Orleans be evacuated.
With estimates of the death toll topping 10,000, there is also a great deal of public concern about the health impact of dead bodies still to be recovered.
Health experts say such concern is unnecessary. A few diseases - such as HIV and tuberculosis - can persist in a body after death, and they are only likely to infect doctors and recovery workers in close contact with the bodies. Few of the diseases associated with flooding carry an extra risk from dead bodies.
A greater risk of epidemics comes from pathogens such West Nile virus, which is highly already prevalent in the US, and would potentially thrive in the conditions left behind by Katrina.
On top of this are the often-ignored effects of stress caused by the displacement and chaos brought on by a major disaster.
"After an incident like this people get run down, their immune systems are compromised, they get gastric and respiratory infections, and particularly old people can go into a terminal decline," said Professor Sandy Cairncross of the London School of Hygiene and Tropical Medicine.
"A large number of the elderly people who have been bussed out of New Orleans after this storm will die of pneumonia in the coming year, but that won't get counted in the official disaster statistics," he said.
There are also significant mental health issues to be considered following an event on the scale of Hurricane Katrina. A 1998 paper in the New England Journal of Medicine found that suicide rates increase markedly following natural disasters.
In normal times, 11 people out of every 100,000 in the US commit suicide each year, but the researchers found that flooding leads to a 14% increase in the suicide rate and hurricanes to a 19% increase.
Much of this depression is caused by the stress of having to rebuild shattered lives - an aspect often shied away from by governments in their impact assessments.
Professor Cairncross says it is essential the problem is seriously addressed by politicians.
"In the Netherlands, flood insurance is provided by the public, not the private sector," he said. "The federal government in America, having skimped on the flood defences around New Orleans, should be helping people to rebuild."
The following is a summary of the principle health risks faced in Katrina's wake:
DYSENTERY
How do you get infected?
Most of the microbes that cause dysentery can be passed on via contaminated water. The most common bacterial infections are caused by E coli, shigella, and salmonella. Floodwaters can be tainted with faecal matter from overflowing sewers, and the microbes can be present in food exposed to infected water even after it is dried.
What does it do to you?
Dysentery describes any form of diarrhoea with blood in it. Infections can be relatively benign but often cause fevers, cramps, nausea and vomiting. Dehydration is a serious risk as sufferers often have difficulty holding down water.
How is it cured?
Antibiotics are effective in tackling most forms of dysentery. Sometimes injections are needed if a patient is vomiting antibiotic pills.
What is the level of risk?
High. Despite evacuation efforts, many people still remain in hurricane-effected areas where hygiene is poor. Overcrowding in relief centres can also result in poor hygiene, and the microbes causing dysentery are more common in the US than those linked with more severe gastric upsets.
WEST NILE VIRUS
How do you get infected?
A bite from an infected mosquito. The disease is often spread by birds, which can carry the virus in their bloodstreams and are bitten by mosquitoes.
What does it do to you?
Most people experience no symptoms at all, but one in five people develop fever that in rare cases can develop into a more severe disease attacking the brain and spinal cord.
How is it cured?
There is no vaccine, and treatment can only mediate the symptoms of the disease.
What is the level of risk?
High. West Nile virus is already a serious risk in the summer months in the US, and flooding increases the risk of mosquitoes breeding.
HEPATITIS
How do you get infected?
Ingesting viruses of the picornaviridae family, which can get into floodwaters in the same way as diarrhoea microbes, via contaminated sewage.
What does it do to you?
The disease attacks the liver and causes jaundice, fever and nausea.
How is it cured?
There is a vaccine, but if you have not received it the only treatment is rest and the avoidance of fatty foods and alcohol which could upset the liver.
What is the level of risk?
Medium to low. The disease is more commonly passed on through the handling of food by infected people, and there has not been a serious outbreak of waterborne Hepatitis A in the US since the 1980s.
WEIL'S DISEASE
How do you get infected?Exposure to water, soil or vegetation contaminated by rat urine containing the leptospirosis bacterium. Even skin contact is enough to cause infection.
What does it do to you?
In most cases, the infection results in flu-like symptoms, fever and jaundice. In more severe cases it can lead to liver and kidney damage, meningitis and death.
How is it cured?
Antibiotics should be given as soon after the infection as possible.
What is the level of risk?
Medium to low. The bacterium can only survive in fresh water, and most of the flooding along the US Gulf coast involves saltwater from coastal lakes and lagoons.
TYPHOID
How do you get infected?
By ingesting infected water and food products.
What does it do to you?
A very high fever, stomach pains, and skin rashes which can last up to a month and that lead to death in up to 30% of cases.
How is it cured?
A course of antibiotics brings the fever under control within a matter of days.
What is the level of risk?
Low. The disease needs to be prevalent in the local area to cause an epidemic, and typhoid is very rare in the US.
CHOLERA:
How do you get infected?
Drinking water or eating food contaminated with the vibrio cholerae bacterium, which gets into the water via infected faecal matter.
What does it do to you?
Symptoms are often mild, but in severe cases the disease can lead to acute diarrhoea and vomiting so serious that dehydration can lead to death within a matter of hours.
How is it cured?
The simplest treatment is to drink plenty of water and rehydration salts. The disease typically runs its course within a matter of days, though in severe cases a saline drip may be needed to replace body fluids. Antibiotics can shorten the attack.
What is the level of risk?
Extremely low. Like typhoid, cholera is extremely rare in the US and is unlikely to cause an epidemic.
