With hospitals and clinics severely damaged, Haiti will also face risks of secondary infections. People seeking medical attention for broken bones and other injuries may not be able to get the help they need and may develop complications.
Dead bodies piled on the streets typically don't pose a public health risk. But for a country wracked by violence, seeing the dead will exact a psychological toll.
An American aid worker was trapped for about 10 hours under the rubble of her mission house before she was rescued by her husband, who told CBS' "Early Show" that he drove 100 miles (160 kilometers) to Port-au-Prince to find her. Frank Thorp said he dug for more than an hour to free his wife, Jillian, and a co-worker, from under about a foot of concrete.
An estimated 40,000-45,000 Americans live in Haiti, and the U.S. Embassy had no confirmed reports of deaths among its citizens. All but one American employed by the embassy have been accounted for, State Department officials said.
Even relatively wealthy neighborhoods were devastated.
An AP videographer saw a wrecked hospital where people screamed for help in Petionville, a hillside district that is home to many diplomats and wealthy Haitians as well as the poor.
At a destroyed four-story apartment building, a girl of about 16 stood atop a car, trying to see inside while several men pulled at a foot sticking from rubble. She said her family was inside.
"A school near here collapsed totally," Petionville resident Ken Michel said after surveying the damage. "We don't know if there were any children inside." He said many seemingly sturdy homes nearby were split apart.
The U.N.'s 9,000 peacekeepers in Haiti, many of whom are from Brazil, were distracted from aid efforts by their own tragedy: Many spent the night hunting for survivors in the ruins of their headquarters.