Many Americans have heard about cholera only from " The Oregon Trail ," the retro computer game in which players try to get their 1830s pioneers to the Oregon Territory. If your wagon train comes down with this highly contagious bacterial infection, the pioneers could die from diarrhea and dehydration before they get out of Nebraska.
Author
- Katrine L. Wallace
Assistant Professor of Epidemiology and Biostatistics, University of Illinois Chicago
In the 21st century, the U.S. records fewer than 20 cholera cases per year, nearly all of them in travelers who were infected abroad.
While cholera has nearly disappeared from wealthy countries, it remains one of the world's deadliest waterborne diseases in places where clean water and basic healthcare are unreliable.
The latest reminder came in the summer of 2026 in Sudan , where a long conflict has devastated hospitals and water systems, allowing cholera to spread rapidly.
As an epidemiology professor , I teach the story of John Snow , the London physician who traced an 1854 cholera outbreak to the contaminated Broad Street public water pump . His work not only helped establish modern epidemiology , it also illustrates a lesson that remains true today: Cholera spreads wherever safe water fails.
A worsening problem
Cholera has surged over the past five years: Reported cases rose about 175%, from 223,370 in 2021 , to 614,828 in 2025 . In fact, 2025 was the deadliest year for the disease in more than a decade, with almost 7,600 deaths across 33 countries. Over that period, there was an average of about 481,000 cases a year globally.
But the true burden is likely far higher, because many countries with the largest outbreaks lack the laboratory and surveillance systems needed to detect and report every case. The World Health Organization estimates the real figure is closer to 1.3 million to 4 million cases and 21,000 to 143,000 deaths each year.
The global cholera case fatality rate - that is, the proportion of people who die among everyone diagnosed with cholera - was roughly 1.2% in 2025 . A 1% case fatality rate is how the WHO measures adequate care.
Those cases and deaths are heavily concentrated: Africa accounted for about 70% of reported cholera deaths in 2025.
Easy to cure but hard to stop
What makes cholera so tragic from an epidemiological perspective is that it is one of the simplest diseases to treat. The bacterium Vibrio cholerae kills through dehydration - the watery diarrhea can drain a person to death within hours.
The remedy is oral rehydration solution, which is a mixture of clean water, sugar and salts. Most patients can recover from cholera with this solution alone. In severe cases, patients need intravenous fluids and antibiotics. In a functioning treatment center, fewer than 1% of the people who get cholera die from this infection, well within the WHO's global benchmark of adequate care.
The trouble is that the cause and the cure for cholera both come from water. Oral rehydration requires clean water, and cholera thrives where clean water is scarce among the roughly 2 billion people worldwide who still lack safe drinking water.
A problem of inequality
The countries hit hardest tend to share the same vulnerabilities : rapid urban growth that outpaces sanitation, climate-driven floods and droughts that contaminate or dry up safe water sources, and armed conflicts that push people into crowded camps and destroy the water and health systems meant to protect them.
An inexpensive and effective two-dose oral vaccine is also available, and its protection against infection lasts several years. Because demand has outstripped supply for so long, the global stockpile has been rationed in many areas to a single dose per person by the International Coordinating Group on Vaccine Provision - the WHO-led body that manages the global supply. One dose provides enough short-term protection that vaccinating twice as many people during an active outbreak saves more lives than giving two doses to half as many people.
The May 2026 outbreak in Sudan shows how quickly a steady situation can unravel. A vaccination campaign reaching millions of people had only just ended, and the country's last cholera outbreak was declared over in March 2026 . But just two months later another outbreak emerged , causing more than 1,330 confirmed cases and 114 deaths as of July 10.
The WHO reported an initial case fatality rate of 13.7% , reflecting the extent of the country's collapsed health services and the fact that early surveillance generally captures only patients with the most severe cholera symptoms.
Amid three years of war , the WHO reported in April 2026 that 37% of Sudan's health facilities were nonfunctional .
Sudan is one instance of a global pattern: In 2024 nearly a quarter of the world's cholera deaths occurred not in a health facility but in the community - at home, in a camp, on a road - among people who never reached care.
South Sudan's 2024-25 cholera outbreak illustrates the importance of timely treatment . The case fatality rate was 0.9% among patients treated in health facilities but 1.9% among all patients in the outbreak. Nearly half - 47% - of reported deaths occurred outside of a health facility.
Infrastructure saves lives
These cases of cholera are not inevitable. The WHO and its partners have set a goal of cutting cholera deaths by 90% by 2030 . The tools to do it - clean water, rehydration salts, vaccines - are proven and inexpensive. What is missing is the investment to put them where they are needed.
When I describe John Snow and the Broad Street pump to my students, I want them to see cholera not as a solved problem but as an unfinished one. This disease did not retreat because the bacterium weakened or because humanity outsmarted it. It retreated wherever people built the infrastructure and systems to keep water clean and treat the sick. It returns wherever those elements are absent or destroyed.
For many Americans, cholera survives only as a line on a screen in an old game. But for hundreds of millions of others, it is a disease of contaminated water, overwhelmed clinics and preventable deaths.
Katrine L. Wallace does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
