Domestic worker Annita Symon fears for her children's health after seeing several friends fall seriously ill due to a cholera outbreak that has killed more than 1,600 people in Malawi over the last year.

Like many low-income families, she and her two children are forced to get their drinking water supplies from contaminated rivers that are spreading the disease in a country where about one in three households lacks access to safe drinking water.

"The water from (communal) taps doesn't come regularly but is also expensive. So sometimes we fetch from some streams or rivers and dams," said Symon, 27, who lives in Malawi's second-largest city Blantyre, one of the hotspots of the outbreak.

"We have been advised by the health workers to apply chlorine or boiling water before drinking," she said, adding she does not always treat water but was using chlorine handed out by health officials to help curb the current disease outbreak.

Cholera is mainly spread by contaminated food or water and can cause acute diarrhoea. While many people have mild symptoms, if untreated it can kill within hours. Children, especially those under age five, are particularly vulnerable.

Poor people are being especially hard hit by Malawi's deadliest ever outbreak of the disease, which comes amid an "exponential" rise in cases across Africa this year, according to the World Health Organization (WHO).

More than 50,000 people have been infected with cholera nationwide and more than 1,600 have died since March last year, according to health ministry data.

While the epidemic has brought fresh urgency to calls to improve water and sanitation access, they remain out of reach for many in Malawi, one of the world's poorest and least-developed nations.

About a third of households in the country of 18 million lack access to clean drinking water, according to the United Nations, while almost a quarter of all water points are not functional. Only 26% of the population have basic sanitation services.

Households that do not have water piped into their homes usually either use boreholes or buy supplies from kiosks.

A bucket of water costs just under 10 cents – a high sum for many in the southeast African nation, where about 70% of the population lives in extreme poverty, according to the World Bank.

In the southern district of Phalombe, Enifa Ngalawa, a 26-year-old sales agent, said they drink water from a shared tap fed by untreated water from a nearby mountain.

Her three-year-old daughter has had diarrhea dozens of times since last year.

"The water coming out from the tap is very dirty. My daughter has been having diarrhea almost every week to the extent that she stopped going to a nursery school last term," she said.

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Dirty Water

Adamson Muula, a professor of public health and epidemiology at Kamuzu University of Health Sciences, said the current cholera outbreak was concentrated in low-income areas.

"The wealthy do not draw water from shallow wells or in streams where sewage and water flow," he said.

The government declared the outbreak a public health emergency in December.

It has rolled out a national response plan in collaboration with the WHO, including oral vaccination campaigns, water quality tests in affected areas, and public education on water, sanitation and hygiene.

Volunteers will help identify communal water points for water quality testing and decontamination, provide purification chemicals to households, and support the construction of new toilets and handwashing facilities, Health Minister Khumbize Kandodo Chiponda said in a recent statement.

There are also particular challenges in tackling poor hygiene and disease in slums and other low-income urban areas, where clean water is sometimes unavailable.

A survey by the Society of Medical Doctors last year found some water kiosks in such areas had closed down, said its spokesperson Zaziwe Fatsani Gunda.

"The reason is that (local people) couldn't afford water from the kiosks, and some were closed because of debts with the water board and water association users," said Gunda.

"Many have been using untreated water, including from rivers and wells."

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Water Kiosks

Many households on the outskirts of urban areas rely on water kiosks operated by community-based Water User Associations (WUAs) under a government mandate.

The kiosks are intended to be affordable for low-income households, and their water supply tariff is heavily subsidised compared to standard household or commercial rates.

But their running costs - from kiosk operation bills to staff salaries - push up prices for customers, according to a 2016 Water Aid report.

"Low-income customers are paying more for water at kiosks than people with household connections," it said, adding that many of the poorest families ration water or turn to unsafe water sources.

Associations can also incur debts to the water boards that supply them if their sales income does not cover the cost of staff salaries, it said.

Poor construction of sanitary facilities and a widespread lack of awareness of health safety messages are exacerbating infection risks in poor urban districts, said George Jobe, executive director for Malawi Health Equity Network.

"Controlling behaviours and practices has proven to be difficult in high-density areas," he told the Thomson Reuters Foundation.

"For instance, it is not easy to control people when disposing waste ... especially in low income and high density areas where the facilities are either not available or the people don't follow the rules."

In Makhetha, a dense township on the outskirts of Blantyre, 30-year-old Flone Yobe frantically pushed herself into the queue of community members struggling to get water from a kiosk.

She said supplies could be erratic, and the vendor had run dry for almost the past two weeks.

"It's been difficult to get water and we've ended up going to the rivers," said Yobe, as water officials distributed extra supplies to families from a storage tank.

"Here at (this) kiosk, we haven't had water since last month and we're struggling. I fear for myself and my family."