For millions of disaster victims across South Asia, the danger is far from over. Even those who weren't injured face the threat of deadly infectious diseases, which can spread easily in the chaos caused by the earthquake and tsunamis.
As relief workers from around the world head toward the stricken coastal regions, experts say, the threat of epidemic grows daily among weakened, often homeless refugees.
Most disaster relief specialists agreed that officials should focus first on providing a steady supply of clean water to victims, who are most vulnerable to waterborne diseases such as cholera, typhoid, dysentery and other diarrheal illnesses.
"That's the No. 1 priority," said Dr. Ronald Waldman, an expert on disaster relief at Columbia University's Mailman School of Public Health.
Waldman spoke by cell phone from an airport in Sweden. He had cut short his vacation there and was on his way to Geneva to help the World Health Organization's relief effort. Within days, he will likely end up helping direct work in Indonesia, where tens of thousands were killed by the earthquake and waves.
Waldman said relief workers have a window of three to 10 days in which to prevent disease outbreaks among refugees. But given the scale of devastation, he was not optimistic.
"There's a high likelihood that waterborne diseases will break out," he said.
Waterborne illness is the most pressing problem, Waldman and others say, because the enormous waves contaminated sources of clean water, either by demolishing water filtration and sewage systems or by inundating wells and reservoirs with undrinkable salt water.
"Latrines and animal waste get mixed into the water," said Les Roberts, an expert on disaster and waterborne disease at the Johns Hopkins Bloomberg School of Public Health. "The chances of fecal-oral transmission become quite high."
In addition, many people are left homeless and have little opportunity to wash properly, increasing the chances of spreading disease.
Lack of clean water could be a special problem in South Asia, Waldman said, because it's needed to cook rice, a staple for many.
People displaced by natural disasters and living in cramped quarters without clean water become walking incubators for waterborne and insect-borne diseases. Especially in children, something as benign as a cold can turn into a deadly case of pneumonia.
"This becomes a very acute problem here," said Dr. Gilbert Burnham, co-director of Hopkins' Center for International Emergency, Disaster and Refugee Studies.
Diarrhea can cause severe dehydration which, under normal circumstances, would be easily treated with an infusion of fluids. But without food, shelter or water, already weakened victims - especially children and the elderly - are particularly vulnerable.
"I wouldn't be surprised if, in the next 24 hours, some of the more isolated areas are already dealing with outbreaks of diarrhea," Burnham said.
Epidemics often follow natural disasters. According to the WHO, a typhoon that hit the Trust Territory of the Pacific Islands in 1971 disrupted water sources. People drank ground water contaminated by pig feces, resulting in an outbreak of balantidiasis, a bacterial intestinal infection.
Such outbreaks can be deadly. In 1994, cholera broke out among a million Rwandan refugees who had taken refuge in Goma, Zaire. Within three weeks, 45,000 had died.
Public health officials have learned several lessons from that disaster, said Waldman, who was among the health workers who tried to stem the epidemic.
Clean water is most important. Officials have also learned to reach out to refugees instead of expecting them to come to clinics.
"They're shell-shocked. They don't know where to go," Waldman said. "You need to get out there and aggressively offer help."
Perhaps surprisingly, corpses are not the source of the most serious health problems.
"What we're really worried about more than anything else is big outbreaks of epidemic disease - unrelated to bodies," said Burnham. "You're just at the mercy of the microbes."
Airborne illnesses, including measles and bacterial pneumonia, can also break out after a natural disaster. The danger is particularly high when refugees are living in crowded shelters.
Diseases spread by mosquitoes pose a danger, too. Roberts noted that refugees often end up living outside, where they are more likely to be bitten, and develop malaria or dengue fever.
In 1991, an earthquake and subsequent flooding in Costa Rica led to a malaria outbreak. Though mosquitoes might initially be washed away by major floods, they can recolonize within weeks.
Water-related disasters also can lead to an increase in snakebites, Roberts said, because the reptiles are flushed from their normal habitat and slither into areas frequented by humans. And electrocutions are often a problem, as people inadvertently encounter downed live wires.
Waldman knows from experience just how difficult the problems are in South Asia.
"I think," he said as he boarded his plane to Geneva, "it's gonna be an enormous challenge."