Cholera killed 7,598 people in 2025, in fewer countries than two years before

WHO's thirty-third epidemiological update on the multi-country cholera outbreak, published January 27, closes the books on 2025 [s1]. Between January 1 and December 28, 2025, a cumulative 614,828 cholera cases and 7,598 deaths were reported from 33 countries across five WHO regions [s1].

Those are the two numbers to hold. The rest of this piece is about what they can and cannot be taken to mean.

The shape of the year

Cases were reported across five regions. The Eastern Mediterranean Region recorded the highest numbers, followed by the African Region, the South-East Asia Region, the Americas Region, and the Western Pacific Region [s1]. The European Region reported none [s1].

December brought a decline. In weeks 49 to 52, 17,327 new cholera and acute watery diarrhoea cases were reported from 16 countries across three WHO regions, alongside 137 cholera-related deaths [s1]. Both figures were lower than November's: cases fell 25 percent and deaths 16 percent month on month [s1].

A single month's decline is a data point, not a trend. Cholera transmission is seasonal in many settings and driven by rainfall, flooding, and displacement, so a December drop can reflect weather as readily as it reflects control.

The comparison that matters

WHO's cholera fact sheet records that in 2023, 535,321 cases and 4,007 deaths were reported to the organisation from 45 countries [s2].

Set the two years side by side. In 2023: 535,321 cases, 4,007 deaths, 45 countries [s2]. In 2025: 614,828 cases, 7,598 deaths, 33 countries [s1].

More cases and substantially more deaths, reported from fewer countries. That combination is the finding, and it admits more than one explanation. Transmission may have concentrated into a smaller number of severely affected countries. Surveillance may have weakened in places that stopped reporting. Case management may have deteriorated where health systems were under strain. The update does not adjudicate between these, and neither should a reader.

WHO's update does not report a case fatality rate for 2025 [s1].

Why the reported numbers are floors, not totals

This is the most important caveat and it comes from WHO itself. Researchers estimate that there are 1.3 to 4.0 million cholera cases and 21,000 to 143,000 deaths worldwide each year [s2]. Reported figures fall far below those estimates.

WHO attributes the discrepancy to limited surveillance systems and to cases going unrecorded out of fear of repercussions for trade and tourism [s2]. Cholera is a disease with an economic cost to declaring it.

There is a clinical reason for undercounting as well. Most people infected with Vibrio cholerae have mild or moderate diarrhoea and can be treated with oral rehydration solution; a minority develop severe acute watery diarrhoea and life-threatening dehydration [s2]. Mild cases are the ones least likely to reach a facility that tests and reports.

So the 614,828 figure should be read as a count of cases that entered a reporting system, not a count of cases that occurred.

What drives it

Cholera is an acute diarrhoeal infection caused by consuming food or water contaminated with Vibrio cholerae [s2]. Only two serogroups, O1 and O139, cause outbreaks, and O1 has caused all recent ones [s2].

WHO describes cholera as a global public health threat that indicates inequity and a lack of social and economic development [s2]. Outbreaks are linked to limited access to safe water, basic sanitation and hygiene — conditions produced by conflict, population displacement, climate events including cyclones, floods and drought, and underinvestment in water and sanitation infrastructure [s2].

The current, seventh cholera pandemic began in south Asia in 1961 and continues [s2].

What the disease does, and what stops it

Untreated, severe cholera can be fatal within hours [s2]. Symptoms appear 12 hours to five days after infection, and most infected people develop no symptoms while still shedding bacteria in their faeces for one to ten days [s2].

Treatment is unglamorous and effective: oral rehydration solution for most patients, and intravenous fluids plus ORS and antibiotics for severe cases [s2]. Speed matters more than sophistication, which is why case fatality tracks access to care rather than the virulence of a strain.

Prevention rests on water, sanitation and hygiene; the oral cholera vaccine can help prevent and control outbreaks [s2]. WHO also notes that countries need strong epidemiological and laboratory surveillance to detect and monitor outbreaks and guide responses [s2] — which is the same capacity whose apparent contraction the 2023-to-2025 comparison raises questions about.

What to watch

Whether the December decline continues into the first quarter of 2026, or reverses with seasonal rains.

Whether the number of countries reporting recovers. A count of affected countries that falls while cases rise is a surveillance question before it is an epidemiological one.

And whether deaths track cases. Cholera mortality is largely a function of how quickly rehydration reaches a patient, so a rising death count against a smaller geographic footprint points at treatment access rather than at the pathogen.

This article is informational and is not medical advice.