In the hard-hit town of Jeremie, dozens of cases have already been reported.
The storm left at least 372 dead in the impoverished Caribbean nation, with the toll likely to rise sharply as rescue workers reach previously inaccessible areas.
Some towns were nearly entirely erased from the map, stressed the UN Secretary General Ban Ki-moon adding that these numbers and needs are rising as more isolated regions are affected by the hurricane.
Vince DeGennaro, a Port-au-Prince-based doctor who is the medical director for the country's only medical emergency helicopter program, has been flying medical relief flights since Thursday into towns along Haiti's devastated southwest coast in the aftermath of the storm.
Haiti's biggest banana growing region, Arcahaie, saw about 80 percent of its banana crops destroyed by winds and flooding, according to the Miami Herald.
"The houses we built are saving lives, because they are sheltering other people", he said. In June and July of this year alone, the agency responded to more than 1,000 cholera alerts in all 10 departments of the country, benefiting about 8,000 households.
A medical vehicle attached to the 24th Marine Expeditionary Unit (24th MEU), drives aboard the amphibious assault ship USS Iwo Jima (LHD 7) during an onload of more than 500 Marines from the 24th Marine Expeditionary Unit and almost 300 pallets of supplies.
"Some communities are still without access by land and there are rivers between them; several roads are severely damaged", civil society leader Colette Lespinasse told Anadolu Agency.
The UN's World Food Programme tapped into food stocks previously set aside for schools to feed hundreds of desperate families, spokesman Alexis Masciarelli said. The UN estimates that 1.4 million people are in need of immediate assistance.
One of the problems caused by the lack of communications is that the residents of Sud province are finding it next to impossible to collect the money sent them by family members, principally from the United States and Canada. Three of nine U.S. helicopters had arrived in Jeremie by Sunday, bringing rice and cooking oil, among other things.
Honduras, which maintains a force of 60 troops in Haiti as part of a United Nations peacekeeping mission, was sending a planeload of aid on Tuesday, along with 50 military officers to help the victims, President Juan Orlando Hernandez said. Most are submerged in flood waters and many houses have lost their walls and roofs. "We have the capacity at our headquarters to produce 1,200 gallons of chlorine every 24 hours", Horan said, adding that his group is also planning to fly community-scale chlorine makers to some of the hardest-hit areas. He also warned of food insecurity and the spread of communicable diseases, especially cholera. A cholera outbreak followed the heartbreaking natural disaster which struck the country in 2010.
"Haiti's southernmost departments of Grande Anse and the South were the worst hit, with 198 and 78 fatalities, respectively, " it said.
"We hope that God gives us the possibility to rebuild the Church and help the victims here in this area", he said, before the music seized him, and he slowly joined in the chant, closing his eyes and turning his palms up toward the sky.
While evaluation teams were working to get a precise picture of the health situation, medical supplies were being brought in, Poncelet said.
Dony St Germain, an official with El Shaddai Ministries International, said young men in villages off the road between the southern city of Les Cayes and Jeremie were starting to put up blockades of rocks and broken branches to halt the convoys.
"We must think about developing a plan, to coordinate support and deliver it where it's most needed and not where it's easiest to access", Wahba said.