PORT-AU-PRINCE, Haiti — Duquesne Fils-Aimé, stripped to the waist, stepped gingerly into the canal, drawing stares of astonishment from the spectators above. When he ducked his head under the water — if one could call it that — an audible gasp rose from the crowd.

Plastic bottles and bags, shredded underwear, shoes and endless globs of unidentifiable black muck bobbed like a fetid tarp around Mr. Fils-Aimé and his colleagues as they started another shift — cleaning out the canal by hand.

On and on they worked in the drink, making little progress but at least a little cash in a Sisyphean battle against the squalor that chokes the canals and ditches passing as sewers, causes floods of wastewater and helps spread the cholera epidemic now gripping more than half the country.

“We do the bad,” Mr. Fils-Aimé, 41, said of his work, “and maybe people won’t get sick.”

At least there were no animal carcasses that day; the men have seen plenty of them — dogs, rats, goats. They swam a few strokes, black water slopping over them in a stench many layers thick. At one point, Mr. Fils-Aimé sat entirely supported on the filth as if shipwrecked, fishing out debris to the lucky crew member on dry land.

The job pays $112 a month, and the men are thankful for it, even though they say they sometimes go weeks without getting paid. Unemployment is so crushing here that for some, it is the first steady work they have ever had.

“I can’t tell you how long I was looking for a job, so when I found this I took it,” said Dieusov Étienne, 38, who has done the work for three years.

Garbage and filth overflow here, spilling from trash bins left unemptied for months and littering tent camps for earthquake refugees. When the rains come, as they did after Hurricane Tomas brushed the island on Nov. 5, the backed-up waterways spread over any vacant patch, creating an ideal home for cholera. Children splash and defecate in the water, people use it to rinse dishes and wash clothes, and some, with few options, even consume it.

In a matter of weeks, the disease has killed more than 1,000 people, hospitalized around 17,000 with choleralike symptoms and prompted violent protests against international peacekeepers, whom residents accuse of importing the illness from South Asia.

There is no sewage plant in Haiti; some hotels and private homes have their own septic systems, and entrepreneurs scour the city cleaning latrines, often dumping the waste in the most convenient canal or drainage ditch.

Even the work of cleaning the canals is a testament to the extreme difficulties of preventing cholera in a country where infrastructure was minimal long before the earthquake and where sanitation crews have to descend into the muck with hardly any tools, much less gloves or suits to protect them.

“Sometimes I get a fever and I thank the Lord I am O.K.,” Mr. Fils-Aimé said.

He is well aware that cholera is carried in water, filthy water that, judging by the excrement along the banks around him, is likely to contain the feces that spread the disease. But he needs the money and tries not to think much beyond that.

“I am not worried,” he said. “Whatever is going to come, is going to come.”

The workers wash after work, and given the trials of so many here, they carry a sense of resignation about the risks.

“I don’t care about cholera,” said Odvel Étienne, 24, fresh out of the water with bits of debris sticking to his body. “We are all going to die someday.”

He is the youngest of the crew of four, who are mostly middle-aged and had never worked a regular job before this.

His colleague, the elder Mr. Étienne, who is not related to Odvel, tells a typical story — of moving from farm work in the countryside to the city 15 years ago looking for better opportunities.

He moved in with relatives and depended on them. He has a wife, a 12-year-old daughter and three other relatives, and they live in an apartment that suffered little damage in the quake, making him one of Haiti’s fortunates.

He got this job as most people do, through connections. A friend heard of an opening and recommended him.

“I knew what it was, but I needed the job,” he said. It pays the $62 a month for private school for his daughter and supports the rest of his family.

Some, like Désiré Harry, 26, see the men in the muck and wish it were them.

“It should be my job, people my age,” he complained while watching Mr. Étienne clear a culvert.

The people who gathered to watch seemed appreciative — or awestruck — over the spectacle of men essentially swimming in a cesspool.

“They are the only ones brave enough to do this,” said Claude Ambroise, 44, who is also unemployed.

Brave, perhaps, does not quite capture it.

As the debris picked out of the canal grew, Élines Fedenaud, the lucky dry man, scooped it onto a pile to be picked up by a truck later, if it showed up. Often it does not, the men said, making their work that much more futile.

They have been working on the canal for a month but do not seem particularly discouraged that the garbage they have fished out continues piling up, without getting hauled away. What irked them were delays in getting paid; they sometimes went a month or more without a check.

As they worked, a passing truck blared campaign jingles to a Caribbean beat, advertisements for Jude Célestin, President René Préval’s choice in the Nov. 28 presidential election.

The younger Mr. Étienne did a little jig to the music, but he scoffed at all of the 19 candidates in the race.

“The money they do for that could be money for what I am doing here,” he said.

Into the putrid water they went, tossing debris out.