Public health officials are still scrambling to find stranded people and treat the injured. In the immediate aftermath, aid workers are struggling to provide basic human needs: shelter, drinking water, food, clothing, and sanitation.
Also in short supply are the daily medicines needed by people with chronic illnesses such as diabetes and heart disease.
Disasters are humbling events. America is big, rich, and deep in resources. Yet the public health aftermath of Hurricane Katrina will continue for days, weeks, months, and years.
What can we expect as time goes by?
Floodwaters inevitably are contaminated with raw sewage. Even so, this water is not particularly dangerous unless a person drinks it or unless it gets into untreated wounds.
With water systems inoperative, sanitation becomes very difficult. Hand washing is the best way to prevent disease — but even hand washing is difficult in the absence of clean water. If available, alcohol-based hand sanitizers are very effective.
And water can be disinfected. This can be done by boiling water (a rolling boil for one minute) or, if boiling is impossible, by disinfection (1/8 teaspoon unscented chlorine bleach per gallon of clear water, 1/4 teaspoon per gallon of cloudy water; mix and let sit for 30 minutes).
One often overlooked source of contamination is bottled water from unsafe sources. If the source of bottled water is not known — especially if the seal on the bottle is not intact — it's a good idea to disinfect it.