What is Cholera? Understanding this Severe Diarrheal Disease

Cholera is an acute diarrheal illness caused by infection of the intestine with Vibrio cholerae bacteria. Contracted from consuming contaminated food or water, cholera remains a significant global health concern, particularly in regions with inadequate sanitation and limited access to clean water. This easily preventable and treatable disease can become life-threatening within hours if left unaddressed, making swift intervention critical. Globally, it is estimated that cholera affects millions and causes tens of thousands of deaths annually, highlighting the urgent need for improved water, sanitation, and hygiene (WASH) infrastructure and access to effective treatments.

Cholera Overview: A Preventable Crisis

Cholera is more than just a severe case of diarrhea; it’s a stark indicator of global inequity and a lack of essential social and economic development. The disease thrives in environments where access to safe water and basic sanitation is compromised. While most individuals infected with cholera experience mild to moderate symptoms that can be effectively managed with oral rehydration solution (ORS), the infection can escalate rapidly. Prompt treatment is paramount to survival, especially for severe cases which require intravenous fluids, alongside ORS and antibiotics. Effective public health responses hinge on robust epidemiological and laboratory surveillance systems that can quickly detect, monitor, and guide interventions during outbreaks.

Recognizing Cholera Symptoms

The hallmark symptom of cholera is severe acute watery diarrhea, which can lead to critical dehydration and death if not promptly treated. While many people infected with V. cholerae remain asymptomatic, they can still shed the bacteria in their feces for up to 10 days, contributing to its spread. Symptoms typically manifest between 12 hours and 5 days after infection. Although the majority of cholera cases present with mild to moderate diarrhea, a subset of individuals develop dangerously severe dehydration requiring immediate medical attention.

A Brief History of Cholera

Cholera is not a new disease; it has been recognized for centuries. The 19th century marked the beginning of cholera’s global reach with the first recorded pandemic. Since then, six more pandemics have swept across the globe, tragically claiming millions of lives. The current, seventh pandemic, began in South Asia in 1961 and continues to impact populations worldwide, demonstrating cholera’s persistent threat.

Vibrio Cholerae Strains: Identifying the Culprits

Outbreaks of cholera are primarily attributed to two serogroups of Vibrio cholerae: O1 and O139. Recently, V. cholerae O1 has been the dominant cause of outbreaks globally. V. cholerae O139 was previously responsible for outbreaks in Asia, but now it is rarely identified, mostly in isolated cases. Importantly, the severity of illness caused by both serogroups is indistinguishable, meaning that regardless of the strain, cholera poses the same health risks.

Epidemiology, Risk Factors, and Global Burden of Cholera

Cholera is endemic in many countries, meaning outbreaks occur regularly. In other regions, outbreaks are sporadic, with years potentially separating incidents. The common thread linking cholera outbreaks is inadequate access to safe water, basic sanitation, and poor hygiene practices. These deficiencies can be exacerbated by conflict, population displacement, climate-related disasters such as cyclones, floods, and droughts, and insufficient investment in maintaining and improving WASH infrastructure and services.

Global cholera case reports to the WHO have been on an upward trend in recent years. In 2023, WHO received reports of over half a million cases and thousands of deaths from dozens of countries. However, these figures are likely a significant underestimation of the true burden of cholera. Researchers estimate the actual number of cases to be in the millions annually, with tens to over a hundred thousand deaths. This discrepancy is largely due to under-reporting stemming from weak surveillance systems and concerns about negative impacts on trade and tourism.

Cholera Prevention and Control Strategies

A multi-faceted approach is essential for effective cholera prevention and control. This includes strengthening disease surveillance, improving water, sanitation, and hygiene infrastructure, actively engaging communities through risk communication, ensuring access to timely and quality treatment, and implementing oral cholera vaccine (OCV) campaigns.

Cholera Surveillance: Early Detection is Key

Cholera surveillance must be integrated into broader disease surveillance systems. This requires prompt reporting, thorough data analysis, accurate interpretation, and efficient information sharing at all levels, from local communities to global health organizations. Rapid diagnostic tests (RDTs) are valuable tools for the early detection of potential cholera outbreaks, but laboratory confirmation through culture, seroagglutination, or polymerase chain reaction (PCR) remains crucial for definitive diagnosis. Countries vulnerable to or experiencing cholera outbreaks should prioritize strengthening their surveillance systems, following the revised guidelines of the Global Taskforce on Cholera Control (GTFCC), to ensure swift detection and effective response.

WASH Interventions: Long-Term Solutions

The sustainable solution to cholera control lies in long-term economic development and achieving universal access to safe drinking water, basic sanitation, and good hygiene practices. WASH interventions are not only crucial for preventing cholera but also for a wide range of waterborne diseases and contribute significantly to achieving the Sustainable Development Goals. During cholera outbreaks, targeted WASH activities are vital to curb transmission. These may include improving WASH facilities in healthcare settings, rigorous water quality monitoring, distributing WASH kits to affected communities, and promoting essential hygiene practices like handwashing.

Cholera Treatment: Effective and Accessible

Cholera is highly treatable. The majority of people with cholera can be effectively treated with the prompt administration of oral rehydration solution (ORS). Severely dehydrated patients are at high risk of death and require rapid intravenous fluid replacement in addition to ORS and antibiotics. Patients with pre-existing health conditions may need specialized care in dedicated treatment centers. The case fatality rate in treatment centers should ideally be maintained below 1%, indicating effective management. Ensuring community access to ORS is critical during cholera outbreaks. However, mass antibiotic administration (chemoprophylaxis) is not recommended for cholera prevention as it has not been proven effective in controlling spread and can contribute to antimicrobial resistance.

Community Engagement: Empowering Local Action

Meaningful community engagement is crucial for successful cholera control. This involves working collaboratively with local populations to design and implement programs that address their specific needs and cultural contexts. Respecting local customs, practices, and beliefs is essential for promoting protective behaviors such as consistent handwashing with soap and water, safe food and water preparation and storage, and proper disposal of feces. Even funeral practices for cholera victims may need to be adapted to minimize infection risks among mourners. Communities should be actively involved in decisions regarding the location of oral rehydration points (ORPs) and the implementation of other community-level cholera control measures. Effective risk communication is also a key component of community engagement, ensuring people understand cholera risks, symptoms, prevention methods, reporting procedures, and the importance of seeking immediate treatment when symptoms appear.

Oral Cholera Vaccines (OCV): A Powerful Tool

Currently, there are three WHO pre-qualified oral cholera vaccines (OCV) available: Dukoral®, Euvichol-Plus®, and Euvichol-S®. For adults, Dukoral® requires two doses plus a buffer solution, while Euvichol-Plus® and Euvichol-S® also require two doses for full protection but do not need a buffer. A single dose of Euvichol-Plus® or Euvichol-S® can provide good short-term protection. Euvichol-S®, the newest vaccine pre-qualified by WHO, is a simplified version of Euvichol-Plus®. Shanchol vaccine is no longer in production. Euvichol-Plus® and Euvichol-S® are the vaccines currently utilized for mass vaccination campaigns through the Global OCV Stockpile, supported by Gavi, the Vaccine Alliance. Due to a global vaccine shortage since October 2022, and with the guidance of the Strategic Advisory Group of Experts (SAGE), a single-dose vaccine regimen is being used in many situations. OCV is safe for use during pregnancy.

Cholera Kits: Essential Resources for Outbreak Response

WHO has developed six types of cholera kits to support cholera outbreak investigation, laboratory confirmation, and patient treatment: one kit for investigation, one for laboratory culture confirmation, three for treatment at different healthcare levels (community, peripheral, and central), and a support kit containing logistical materials like solar lamps and water storage. Each treatment kit contains enough supplies to treat 100 cholera patients.

The Global Task Force on Cholera Control (GTFCC): A United Front

The Global Task Force on Cholera Control (GTFCC) is a partnership uniting governmental and non-governmental organizations, UN agencies, and academic institutions dedicated to reducing the global burden of cholera. Hosted by WHO, the GTFCC works to: develop global strategies for cholera prevention and control, support countries in long-term cholera control and elimination through national cholera plans (NCPs), create and disseminate technical guidelines and operational manuals, support research into innovative cholera prevention and control approaches, and raise the visibility of cholera as a critical global public health challenge.

Ending Cholera: The 2030 Roadmap

In 2017, the GTFCC launched Ending Cholera: A Global Roadmap to 2030. This ambitious strategy aims to reduce cholera deaths by 90% and eliminate cholera in as many as 20 countries by 2030. The roadmap focuses on three strategic axes: 1) early detection and rapid multisectoral response to outbreaks; 2) targeted multisectoral interventions in cholera hotspots known as Priority Areas for Multisectoral Interventions (PAMIs); and 3) establishing effective coordination mechanisms for technical support, advocacy, resource mobilization, and partnerships at local and global levels. The strategy received endorsement at the Seventy-first World Health Assembly in 2018, solidifying global commitment to cholera elimination.

WHO’s Role in Cholera Control

The WHO cholera program plays a leading role in raising global awareness of cholera and advocating for its control. WHO provides direct support to Member States across all pillars of cholera control, including strengthening epidemiological surveillance, enhancing laboratory capacity, improving treatment access and quality, promoting WASH and IPC practices, fostering community engagement, and facilitating access to and implementation of OCV campaigns. WHO also supports research into new and improved cholera prevention and control strategies. Furthermore, WHO hosts the GTFCC Secretariat and is a key member of the International Coordinating Group (ICG) for emergency vaccine stockpile coordination.