They're standing in basements in shoulder-high water swirling with slime and sewage.
They're wading in muddy rivers and fields polluted with fertilizer and animal and human wastes.And they're going without water in their taps and toilets.
Across the drenched Midwest, tens of thousands of flood victims trying to salvage their homes, their businesses and their futures face an even more pressing priority: their health.
"We're walking around in waters in a contaminated environment," said Loren Will, an Iowa State University public health specialist and extension veterinarian. "We have, in a sense, a large cesspool. It's diluted, but that's what it is."
A team of federal public health officials, some from the Centers for Disease Control and Prevention, has been reviewing conditions in Iowa, and they so say so far, so good.
"We're not seeing any outbreak at this time," said Scott Lillibridge, a CDC epidemiologist. "We're not finding any serious infectious disease, no major injuries."
People are flushing toilets with rain water or using portable toilets, cleaning their hands with store-bought moistened towels and drinking bottled water. The two largest hospitals report no increase in emergency room visits.
Health officials say many problems can be avoided with common sense and precautions - boil water, wear protective footwear, keep children out of the water and get tetanus shots, if needed. Tetanus, a sometimes fatal disease of the central nervous system, is caused by bacteria entering open wounds.
Iowa officials have distributed 30,000 doses of the vaccine. The Minnesota Health Department has sent out about 2,000 test kits to be given to homeowners who suspect their wells are contaminated.
In Missouri, the Health Department has become a flood victim. High waters entered an air conditioner at the agency's main laboratory in Jefferson City and forced it to close.
Medical experts warn that health dangers will rise even as river levels fall and people should keep their guard up to avoid intestinal and viral illnesses.
"There will be a temptation after the next week, week and a half goes by to say `I'm bulletproof or waterproof,' " said Dr. Frank Young, director of the U.S. Public Health Service's Office of Emergency Preparedness. "That's not the time to take a risk."
In the flood aftermath, a second wave of health hazards will threaten, caused by mosquitoes, rancid food and animal carcasses.
But Young said minor injuries, such as cuts, open wounds and sprained backs, are the most immediate concern.
Poor sanitation, ingesting floodwaters and eating contaminated food pose a risk of skin and viral infections, such as hepatitis A, and numerous intestinal illnesses, including diarrhea, dysentery, salmonella, giardiasis and shigellosis.
The flood "has moved the river and the river environment to us," said Dr. Richard Wenzel, a University of Iowa professor of internal medicine. "The consequences are infection, increased mosquitoes and other insects and diseases transmitted from those. People shouldn't be playing in this stuff.