A woman sweeps the ground near her tent at a camp on the Port-au-Prince golf club set up for people left homeless by the earthquake.
Aid agencies are rolling out an ambitious vaccine program in and around Port-au-Prince in an effort to stem what health experts fear is an impending public-health crisis.
Little by little, the biggest health challenge facing the millions of people displaced by the earthquake is becoming less about treatment for their injuries or even obtaining food and water.
Hundreds of thousands of people are living in an estimated 591 settlements in the Port-au-Prince area. As aid agencies struggle to find a better solution to the strung-together sheets under which people are taking shelter, tent-city denizens are taking matters into their own hands, building more permanent shelters out of scraps of wood and corrugated iron salvaged from the ruins.
Aid workers say they're trying to teach people the importance of washing their hands and food before meals, of drinking only clean water and ensuring the purified water they receive stays that way.
But such directives seem absurd to some. A lack of clean water - and, for that matter, a lack of soap, of buckets in which to hold the water, or proper spouts so that dirty cups don't contaminate precious potable water when dipped inside whatever container is holding it - makes proper hygiene virtually impossible.
The Champ de Mars is perhaps the city's largest and most notorious tent city - a sea of flapping coloured cloth in front of the crumpled wreckage of the National Palace. It reeks of rotting garbage and human waste and the smell of too many desperate people crowded too closely together. Lined with vendors, dotted with wooden shacks and wreathed with smoke from cooking fires, it is becoming an increasingly permanent village within a destroyed city.
Overwhelmed medical clinics are seeing their first cases of children's dysentery, parasites and diarrhea. Doctors warn that's only the beginning, as a displaced population settles in for a long wait.
This week, a multimillion-person vaccination program will attempt to ward off the looming health crisis, targeting younger children most susceptible to potentially fatal diarrhea, pneumonia and dysentery.
The program, funded primarily by Unicef and the World Health Organization's Latin American arm, will in theory make tetanus shots available to all injury or trauma cases and conduct emergency vaccination in all temporary settlements, targeting 500,000 children under 7 with measles, rubella, diphtheria and pertussis shots. Some two million children 8 and older will get tetanus and diphtheria shots.
Haitians have abysmally low vaccination rates to begin with: Only 53 per cent have their basic tetanus shot - far lower than just about any country.
The idea is to prioritize vaccines for which there's longer coverage and diseases with greater risk, said WHO spokeswoman Olivia Law-Davies. Tetanus, diphtheria and pertussis, associated with pneumonia, are all notorious for wreaking havoc in post-earthquake situations.
At the Champ de Mars camp, Dieubon Avriné is taking matters into his own hands - building a shack from discarded wood and nails.
"It's better than a tent," he said. "I don't want to sleep in the rain."