"When you get a complete collapse of a city like this, with virtually no infrastructure, with already poor infrastructure before the collapse, and no infrastructure afterwards and no services, you can imagine everybody feels like they are kind of on their own."
Doctor' McCormick specializes in infectious diseases. He once ran the high security laboratory at the Centers for Disease Control. He says the biggest risk in Haiti right now is all of those injuries becoming infected if not attended to quickly.
"So people with broken bones and cuts, a lot of these are going to result in infection. The other thing is that with breathing in all of the dust from the collapsed buildings is also set up for spread of pulmonary infections, particularly viral infections and bacterial."
Dr. McCormick says another problem is the lack of clean water and fresh food.
"If enough help doesn't arrive and people start to drink dirty water and eat spoiled food."
He says even more people will get sick.