"The mothers, the parents, are saying 'Help my baby, help my baby,' and it's too late," said Dr. Koji Nakashima. "You do everything you can. There's no explaining that."
More than 250 people are dead and 3,000 are sick as the outbreak spreads from Saint-Marc to the capital of Port-au-Prince. In an effort to contain the outbreak, the Dominican Republic closed its border with Haiti.
This acute infection can dehydrate the body in hours.
One patient has enough water in her body to sweat. Tears and sweat are a sign that doctors look at - and look for - to see if a person is very dehydrated. The fact she has some sweat is a very good sign.
Health officials believe the Artibonite River, Haiti's largest, may be the source of the cholera.
A massive information campaign is under way telling Haitians to use only treated water and to wash their hands thoroughly. Aid groups are racing to distribute clean water and filtration systems, and the CDC is working closely with Haitian authorities to track the outbreak.
While more than $10 billion has been pledged since the earthquake, there's been little progress rebuilding the housing and sanitation infrastructure needed to prevent this fast-moving disease.
"One of the mothers said, 'I left two of our kids dead at home. This is the one that's alive. Do what you can. Please save him,'" said Dr. Nakashima. "As a physician and as a person it's obviously a lot of pressure. But this is what we do."
That child is doing well tonight. Officials say the death rate has slowed. But it's still early in the epidemic, and this disease is unpredictable.