Confronting cholera and drought in Zambia

An example of a clean water access point in a peri-urban settlement of Lusaka, Zambia. Photo: PATH/Gareth Bentley

When we consider the link between extreme weather and diarrheal disease, flooding is often the first thing we think of. It’s easy to see the connection: when flooding overwhelms sanitation and sewage systems, safe water sources can become contaminated and spread waterborne diseases like cholera.

While floods are a major risk factor, sometimes the link between extreme weather and diarrheal disease is more complex.

“Crops can’t survive, but cholera can”

Emily Rand, who leads UNICEF’s water, sanitation, and hygiene (WASH) work in Zambia, described a convergence of multiple factors that contributed to the largest cholera outbreak ever recorded in Zambia in 2024. A few heavy rainfalls during the start of the worst drought in forty years caused flooding. Drains backed up and overflowed, contaminating shallow wells and resulting in more than 20,000 recorded cholera cases, many in dense urban areas like the city of Lusaka.

There were so many cases that the national sports stadium, called Heroes Stadium, was turned into a cholera treatment center overnight. “There were so many heroes at Heroes Stadium,” Emily said. “Some were volunteers who lost their lives trying to end the outbreak.” Eventually 71 out of 116 districts across all 10 provinces had cholera cases, with transmission documented in 61 districts. While the floods were enough to spread cholera, they weren’t enough for crops to grow.   

“Crops can’t survive, but cholera can,” Emily said. As the drought continued, many farmers witnessed a second and third crop harvest fail, exacerbating malnutrition.

The drought forced people to travel farther to find safe water and rely on shallow wells, which are more likely to be contaminated.  At the same time, the drought jeopardized Zambia’s power supply, 83 percent of which comes from hydroelectric sources. Without consistent hydropower, even in urban areas, water utilities could no longer pump safe water to residents on a reliable basis. When water did arrive, it was often only for an hour in the middle of the night.

A multipronged approach to cholera control and drought response

In Zambia, UNICEF worked closely with the Ministry of Health, the Ministry of Water Supply and Sanitation, the Red Cross, and other members of the Global WASH Cluster to respond to multiple crises.

Emily described a “multipronged approach” to chlorinate the water supply that involved adding chlorine to water at treatment facilities, at the point of collection, and at the point of use. UNICEF supported community-based volunteers to take chlorine door-to-door in directly affected areas, shifting to a cluster approach when the cases became too high. UNICEF also distributed supplies and discharge kits to health care facilities. Delivering supplies at clinics that were treating cholera patients proved to be a powerful intervention, according to Emily: “When you discharge kids, you give the families a bucket with soap and chlorine—and they use it and promote use to others.”  To address the longer-term safe water issues, UNICEF repaired boreholes—shafts drilled into the ground to access groundwater—that had dried up or needed new parts, and worked to improve WASH facilities in health care facilities and cholera treatment centers.

Prioritizing resilient water systems

The cholera outbreak in Zambia is a stark reminder that extreme weather, diarrheal disease, malnutrition, and energy supply are not siloed issues. While droughts put a strain on water supplies, they can affect not only access to WASH, but also agriculture and power.

These challenges are not unique to Zambia: from Hurricane Helene, which caused 4.7 million power outages across the Southeastern United States last fall, to heavy rainfall and flooding in countries like Spain and India, extreme weather patterns are a global phenomenon. To adapt to rising global temperatures and protect against diseases like cholera, policymakers must prioritize resiliency into all industries that involve water—not just water, sanitation, and hygiene (WASH) systems, but also hydropower, agriculture, and manufacturing.

Water security, public health, and energy supply are deeply interconnected. By investing in both long-term solutions like WASH infrastructure and short-term interventions like oral cholera vaccine, we can protect against waterborne diseases in the face of extreme weather.