A woman caresses her child who has cholera symptoms at a cholera treatment center in Mirebalais, Haiti. A recent spike in cholera cases has been reported in the country following heavy rains. (Eduardo Verdugo/Associated Press)

A deadly cholera outbreak that swept the country last fall has returned, fuelled by weeks of heavy rains that have helped spread the waterborne bacteria that has flouirshed in rivers and rice fields.

The treatment centre in Mirebalais, a town lying about an hour's drive north of the capital, Port-au-Prince, is again seeing dozens of new patients a day, many arriving at the edge of death from dehydration.

The centre saw a fivefold jump from April to May and it hasn't let up since, said Louise Ivers, senior health and policy adviser to the U.S.-based Partners in Health, which runs the clinic in association with the Health Ministry.

"When people come here, they're in critical condition, ready to die," said Francole Adonis, who registers the new arrivals at the centre. "They're collapsing in the yard. The situation is horrible."

Cases tripled in 3 months

The number of new cases each day spiked to 1,700 a day in mid-June, three times as many as sought treatment in March, according to the Health Ministry. The daily average dropped back down to about 1,000 a day by the end of June but could surge again as the rainy season develops.

The epidemic began in rural Haiti last fall, likely brought by U.N. peacekeepers from Nepal. It swept through the countryside of an impoverished nation already overwhelmed by a January 2010 earthquake that left hundreds of thousands homeless and by political instability following disputed elections.

Cholera has sickened at least 370,000 people and killed more than 5,500 since the outbreak started in October, according to the Health Ministry. The exact total is unknown since many Haitians live in remote areas with no access to health care. The disease is relatively easy to treat if people can get help in time. 

When the outbreak began, foreign volunteers descended on Haiti to staff rural clinics and help provide access to clean drinking water.

Many feared it would devastate Port-au-Prince, where hundreds of thousands of people were living in densely packed refugee camps. But people in the capital had access to latrines and potable water, thanks to the huge international aid effort, and it was spared the worst of the disease.

Health-worker fatigue

The disease faded in winter and spring, when rain is less frequent, and many aid workers moved on. U.N. troops in Haiti turned their attention to the country's many other pressing problems.

Now there is a fear among aid workers who remain that there won't be enough resources if the latest surge gets worse.

"If the cases continue on the same path we could see a lot of health-worker fatigue," said Cate Oswald, a Partners in Health co-ordinator. "The health care force is already stretched thin."

Oswald recalled how volunteers were everywhere during the first response to the outbreak, providing supplies such as bleach, which is sprayed on shoes and throughout the centres to prevent the spread of cholera.

"At one point we were worrying about too much duplication of efforts," Oswald said. "Then the rains started coming. And cholera was still here."