Haitian children with cholera receive medical treatment in a provisional clinic run by medical humanitarian organization Doctors Without Borders in Port-au-Prince on Tuesday. (Eduardo Munoz/Reuters)

Haitians are preparing to head to the polls Sunday, despite calls by some to delay the election as health workers struggle to contain a deadly cholera outbreak that has killed at least 1,400 people.

Haitians will choose René Préval's replacement, along with a number of senators and deputies.

At least four of the 19 approved presidential candidates had called for a delay, but election officials and the majority of the candidates said the elections should go ahead as planned.

Edmond Mulet, the chief of the UN mission in Haiti, said Thursday elections should be held without delay despite worries about security issues and the cholera epidemic, Reuters reported.

Dr. John Andrus, the deputy director of the Pan-American Health Organization said in a statement Thursday that "the kind of movement and congregating you see with people going to vote is not the kind of movement that creates an increased risk of cholera transmission."

“Close contact does not put people at greater risk of cholera the way it would, for example, for flu," he said.

Cholera, an intestinal infection caused by the bacterium Vibrio cholerae, is spread by drinking contaminated water or eating contaminated food. It causes vomiting, diarrhea and dehydration, and can kill people within hours if left untreated.

A child with cholera symptoms is checked as she arrives to receive treatment at a clinic set up by the International Red Cross in Port-au-Prince on Wednesday. (Kena Betancur/Reuters)

Aid agencies are working with government officials to try and slow the spread of the disease, but top officials have said that much more needs to be done.

Valerie Amos, United Nations under-secretary for humanitarian aid, said Wednesday that Haiti desperately needs more doctors, nurses and supplies to help slow the epidemic.

"We need more treatment centres," she said. "We need more doctors and nurses, and I will be calling on our partners — not just other governments but also NGO partners [and] UN agencies — to make sure that we get more resources."

Health officials and relief workers are also trying to educate people about how to prevent cholera, using posters, text messages and radio broadcasts to spread the word.

Some non-governmental organizations are mounting loudspeakers and driving through neighbourhoods to spread the message of cholera prevention and treatment, the CBC's David Common said from Port-au-Prince.

Elouisel Luismin, a woman who sells pig ears and pork sausages at a Port-au-Prince market, told CBC's Connie Watson that she's not afraid of cholera because she knows what to do – and because nobody has it in her neighbourhood.

"You have to boil the water, drink treated water, only eat cooked vegetables," she said through a translator.

PAHO said Thursday that the Haitian Ministry of Health has confirmed that cholera has spread to all 10 of Haiti's administrative regions, known as departments.