The evacuation of survivors from storm stricken New Orleans is not justified by the risk of disease from stagnant water, say health experts.
Medical access is a problem
They say the threat of outbreaks of diseases such as cholera from the water is low.
However, the poor living conditions and difficulty in getting medical care to any who fall sick are reason enough for people to be moved from the area.
The city's mayor ordered the forced evacuation of the 5,000-10,000 residents thought still to be living in New Orleans despite the lasting effects of Hurricane Katrina.
Mayor Ray Nagin said all citizens except those involved in the rescue effort should leave immediately.
"There are toxins in the water, gas leaks... We are fighting at least four fires... It is not safe," he said.
There have been fears water contaminated by dead bodies, raw sewage and debris could pose a health risk.
Three people are also known to have died from contaminated flood water, in the aftermath of Hurricane Katrina.
However, experts say the threat of serious disease is generally low.
Dead bodies actually carry a low risk of the disease - it is the living who pollute water supplies, leading to the spread of diarrhoea type diseases.
There have been reports that up to 200 New Orleans citizens staying in the Houston Astrodome are suffering from gastro-intestinal illnesses. Other US reports have suggested several people have died from a disease similar to cholera following Hurricane Katrina.
However outbreaks of diseases such as cholera and typhoid are not likely, because the microbes which carry them are virtually non-existent in the US.
Experts say the cause of the New Orleans deaths cannot be confirmed until laboratory tests have been carried out.
But there are other disease risks.
Dr Louis Minsky, the director of Metropolitan Medical Response in the state capital of Louisiana, Baton Rouge, told ABC Good Morning America that all the stagnant water was the perfect breeding ground for mosquitoes, which carry the potentially deadly West Nile virus.
However Dr Jean Luc Poncelet, head of the World Health Organization's emergency preparedness and disaster relief programme in the US, stressed that the risk of serious disease was still relatively low.
"Gastrointestinal illnesses are absolutely normal in these circumstances.
"Frequently, with the fear, panic and anxiety people jump to names like typhoid and we have to bear that in mind.
"Everything that we are seeing now corresponds with what we have seen in previous disasters and is nothing that could completely overwhelm capacity.
"Illnesses are probably not justification for an evacuation, but the conditions in which people are living in are certainly much more reason."
Returning to normality
He said it would be difficult to provide health services to the residents who remained, which was another good reason for moving people out.
"It's more the absence of services. It's the capacity for dealing with the normal health problems too in those situations."
He pointed out that people were still just as likely to need medical attention for classic ailments, such as heart disease, at these times.
"The most important thing is re-establishing health services."
Dr Donna Johnson from the American Red Cross agreed.
She said there were still pockets of people who required the most basic of care - food, water and shelter.
But she said there had been no big disease outbreaks as some had feared.
"We have had some sporadic calls about diarrhoea and we will watch that carefully."
She said efforts were also being focused on moving those most at risk of ill health, such as the elderly and those with existing medical conditions, to places where they could get the healthcare they needed.
Dr Poncelet said it was important for people to get back to some kind of normality as soon as possible.
"The next few weeks will be really tough. People will be really tired of not having the normal structure to life."
He said experiences from tsunami that hit the Indian Ocean on Boxing Day 2004 showed that the sooner people were able to re-establish typical activity, such as going back to work or school, the faster they recovered from the trauma.