Public Health: Cholera Response and Epidemic Management

Cholera is an acute diarrhoeal disease that can kill within hours if left untreated. There are many ways to prevent and control the spread of cholera, which requires actions both inside the health sector and beyond, including access to safe water, sanitation and good hygiene practices (WASH). As cholera is a feco-oral disease, sanitation plays a key role in preventing and reducing transmission. Although the focus here will be mainly on cholera in emergencies it is important to recognise that where possible, efforts to control cholera should seek to build long-term systems and consider the longer-term prevention beyond reactive approaches.

Key Actions

• In closed environments (e.g. displaced persons/refugee camps or urban areas, particularly slums), where the risk of transmission is particularly high, the aim should be to reduce this risk by ensuring that minimum sanitary standards are met and by eliminating open defecationOpen DefecationPractice of defecating outside in the open environment.:
• • at least install single pit latrines with a temporary superstructureSuperstructureThe above ground walls and roof built around a toilet or bathing facility to provide privacy and protection to the user. - provided that the minimum distances (vertical and lateral) between the pits and water sources are respected.
  • If possible, try to prioritise neighbourhoods from which the cases originate and those with poor excretaExcretaRefers to human excrements consisting of urine and faeces. management. This requires both the capacity to monitor cases in real time (mapping) in coordination with response teams and health partners, and appropriate diagnostic tools so that response teams can assess the status of sanitation in these neighbourhoods.
• In flood-prone areas, rocky areas where it is difficult to dig or areas with a shallow aquifer close to the surface, alternative sanitation systems can be used to prevent pits overflowing or infiltrating directly into the aquiferAquiferAn underground layer of permeable rock or sediment (usually gravel or sand) that holds or transmits groundwater.:
• • Use of raised latrines with excretaExcretaRefers to human excrements consisting of urine and faeces. collection in watertight tanks. Appropriate and safe emptying, transport and disposal of excretaExcretaRefers to human excrements consisting of urine and faeces. must be provided for.
  • Waterproofing of pits (brickwork and waterproof rendering or use of containers). It is also necessary to plan for emptying, transport and unloading operations.
• All new and/or rehabilitated sanitation facilities must include an adequate hand-washing station with soap and water.
• in camps and densely populated areas, it is vital to maintain and clean the sanitation infrastructure. It is therefore essential to build latrines with surfaces that are easy to clean and disinfect. During epidemics, cleaning teams trained to follow disinfectionDisinfectionThe elimination of (pathogenic) microorganisms by inactivation (using chemical agents, radiation or heat) or by physical separation processes (e.g. membranes). protocols must be employed with a frequency proportional to the use of the sanitary facilities. Latrines should be disinfected regularly with a chlorine solution. They also need to ensure that soap and water are available in the hand-washing facilities. The use of these teams must be anticipated in financial and logistical terms.
• DesludgingDesludgingThe process of removing the accumulated sludge from a storage or treatment facility. and treatment: safe emptying and unloading operations should be planned, particularly during epidemic periods. Special precautions must be taken when emptying waste to limit the risks (personal protective equipmentPersonal Protective EquipmentProtective clothing including boots, masks, gloves, apron, etc. or other garments or equipment designed to protect the wearer's body from injury or infection from sanitation products., mechanical emptying whenever possible, disinfectionDisinfectionThe elimination of (pathogenic) microorganisms by inactivation (using chemical agents, radiation or heat) or by physical separation processes (e.g. membranes). protocol for this equipment, the truck, and the collection site), particularly for operators (see health and safety of sanitation workers). In addition to conventional treatments, it is possible to carry out emergency lime treatment using available protocols (taking into account the potential impact of adding limeLimeThe common name for calcium oxide (quicklime, CaO) or calcium hydroxide (slaked or hydrated lime, Ca(OH)2). It is a white, caustic and alkaline powder produced by heating limestone. Slaked lime is less caustic than quicklime and is widely used in water/wastewater treatment and… on the rest of the sanitation chain). For non-emptying latrines, after liming and disinfecting the superstructureSuperstructureThe above ground walls and roof built around a toilet or bathing facility to provide privacy and protection to the user., the pit should be closed, and the superstructureSuperstructureThe above ground walls and roof built around a toilet or bathing facility to provide privacy and protection to the user. removed. In Haiti, where limeLimeThe common name for calcium oxide (quicklime, CaO) or calcium hydroxide (slaked or hydrated lime, Ca(OH)2). It is a white, caustic and alkaline powder produced by heating limestone. Slaked lime is less caustic than quicklime and is widely used in water/wastewater treatment and… treatment of sludgeSludgeMixture of solids and liquids, containing mostly excreta and water, in combination with sand, grit, metals, trash and/or various chemical compounds. A distinction can be made between faecal sludge and wastewater sludge. Faecal sludge comes from on-site sanitation technologies,… from cholera treatment centers (CTC) was deemed unsuitable, other options were tested: the first system used coagulationCoagulationThe destabilisation of particles in water by adding chemicals (e.g. aluminium sulphate or ferric chloride) so that they can aggregate and form larger flocs./flocculationFlocculationThe process by which the size of particles increases as a result of particle collision. Particles form aggregates or flocs from finely divided particles and from chemically destabilised particles and can then be removed by settling or filtration. and disinfectionDisinfectionThe elimination of (pathogenic) microorganisms by inactivation (using chemical agents, radiation or heat) or by physical separation processes (e.g. membranes). with hydrated (slaked) limeLimeThe common name for calcium oxide (quicklime, CaO) or calcium hydroxide (slaked or hydrated lime, Ca(OH)2). It is a white, caustic and alkaline powder produced by heating limestone. Slaked lime is less caustic than quicklime and is widely used in water/wastewater treatment and…, the second system the addition of hydrochloric acid, followed by pHpHThe measure of acidity or alkalinity of a substance. A pH value below 7 indicates that it is acidic, a pH value above 7 indicates that it is basic (alkaline). neutralization and coagulationCoagulationThe destabilisation of particles in water by adding chemicals (e.g. aluminium sulphate or ferric chloride) so that they can aggregate and form larger flocs./ flocculationFlocculationThe process by which the size of particles increases as a result of particle collision. Particles form aggregates or flocs from finely divided particles and from chemically destabilised particles and can then be removed by settling or filtration. of suspended solids using aluminum sulfate (Sozzi, Fabre et al. 2015). Both systems use pHpHThe measure of acidity or alkalinity of a substance. A pH value below 7 indicates that it is acidic, a pH value above 7 indicates that it is basic (alkaline). changes with the intent to inactivate the cholera bacteriaBacteriaSimple, single cell organisms that are found everywhere on earth. They are essential for maintaining life and performing essential “services”, such as composting, aerobic degradation of waste, and digesting food in human intestines. Some types, however, can be pathogenic and…. Removal rates in large scale (30,000 Liter) tanks in actual CTC situations were similar for both systems. It is unknown if the removal rate of thermotolerant coliforms would reduce transmission of cholera from the waste, but the risk of transmission would be reduced
• WastewaterWastewaterUsed water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff/stormwater, and any sewer inflow/infiltration. disposal: preventing cross-contamination in wastewaterWastewaterUsed water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff/stormwater, and any sewer inflow/infiltration. networks, ensuring the cleanliness of drainageDrainageDrainage refers to the process of removing excess water from an area and its transport to another location. systems, promoting, and supporting the repair of damaged sewerSewerAn open channel or closed pipe used to convey sewage. pipes and wastewaterWastewaterUsed water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff/stormwater, and any sewer inflow/infiltration. treatment plants.
• Key points to monitor during interventions:
• • The toiletToiletA sanitation facility (or ‘user interface’) used for urination and defecation. Often interchangeably referred to as latrine. slabs must be disinfected in proportion to use.
  • Daily: Toilets must be safely and easily accessible to all people. Open defecationOpen DefecationPractice of defecating outside in the open environment. in densely populated areas must be eliminated, particularly near water sources or tapping points.
  • Weekly: the level of filling of pits and their emptying according to protocols.
  • Regularly in the form of discussions and surveys with the population: presence of functional hand-washing facilities.
• Provision of sanitation systems and services to health facilities treating cholera cases. This includes toilets accessible to patients, separate for men, women, children and health staff, management of patient faecesFaecesRefers to (semi-solid) excrement that is not mixed with urine or water. Depending on diet, each person produces approximately 50–150 kg per year of faecal matter of which about 80 % is water and the remaining solid fraction is mostly composed of organic material. Of the total… and vomit, waste management (sharp, soft and organic), wastewaterWastewaterUsed water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff/stormwater, and any sewer inflow/infiltration. management and vectorVectorAn organism (most commonly an insect) that transmits a disease to a host. For example, flies are vectors as they can carry and transmit pathogens from faeces to humans. control. The provision of cleaning equipment and the human and financial resources dedicated to maintaining a clean and hygienic environment should also be considered. To assess sanitation needs in cholera treatment centre, use the WHO WASH Facility Improvement Tool.
• Protection of workers: It is important to ensure that the people in charge of sanitation activities with a high risk of contact with the bacteriaBacteriaSimple, single cell organisms that are found everywhere on earth. They are essential for maintaining life and performing essential “services”, such as composting, aerobic degradation of waste, and digesting food in human intestines. Some types, however, can be pathogenic and…, and in particular those in charge of desludgingDesludgingThe process of removing the accumulated sludge from a storage or treatment facility., are properly equipped with personal protective equipmentPersonal Protective EquipmentProtective clothing including boots, masks, gloves, apron, etc. or other garments or equipment designed to protect the wearer's body from injury or infection from sanitation products. (boots, gloves, apron and above all systematic hand-washing equipment, mask, sprayer for cleaning equipment, chlorine) and adequately trained in the risks of exposure.

Relevance/Importance

Every year, cholera affects a large proportion of the world's population. The true global burden is largely unknown, as most cases go unreported. However, previous studies estimate that there are between 1.3 and 4 million cases and that it causes between 21,000 and 143,000 deaths - and although sub-Saharan Africa is disproportionately affected, the disease has a global footprint. (Ali et al, 2015). Almost every developing country faces the threat of cholera, and many have experienced – or are currently experiencing – outbreaks. In order to control cholera sustainably, water and sanitation service levels need to be improved, particularly in hotspots (areas heavily affected by the disease).

Overview

Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. (WHO, 2022). Therefore, universal access to safe drinking water and improved sanitationImproved SanitationSanitation facilities that ensure hygienic separation of human excreta from human contact. is key in the fight against cholera. The global roadmap to end cholera consists of (1) early detection and rapid response to contain outbreaks, (2) a targeted approach to improve prevention through WASH programmes and vaccines, and (3) coordination of human, technical and financial resources. A multifaceted approach is key to achieve this road map. A combination of various strategical pillars are used, including: (1) leadership and coordination, (2) surveillance, (3) water, sanitation, and hygiene, (4) community engagementCommunity EngagementConnects the community and other stakeholders so that people affected by crisis can participate and have more control over the response and its impact on them., (5) health care system strengthening, and (6) oral cholera vaccines.

Long-term strategy: Sanitation for sustainable cholera elimination is primarily about achieving the associated Sustainable Development Goals (and in particular Goal 6.2 on improved sanitationImproved SanitationSanitation facilities that ensure hygienic separation of human excreta from human contact.). This is no different from traditional sanitation development issues except that sanitation is targeted to cholera hotspots - or Priority Areas for Multisectoral Interventions (PAMIS).

The main focus here is on sanitation interventions during outbreaks. However, sanitation practitioners working in countries where cholera is endemic and where a prioritisation exercise has been conducted to identify key hotspots or PAMIS are strongly encouraged to focus their interventions over the long term and advocate for sufficient investment in these areas. In addition, data collected by emergency WASH actors during outbreaks can contribute to the identification of priority areas.

Evidence: In systematic reviews in 2017, there were few sanitation intervention evaluations identified. In a review of response outbreaks, only two evaluations were identified. In a review on emergency responses, more evaluations were identified but they all focused on latrineLatrineA sanitation facility used for urination and defecation including a 'user interface' and an 'onsite storage pit'. Often interchangeably referred to as toilet. construction and latrineLatrineA sanitation facility used for urination and defecation including a 'user interface' and an 'onsite storage pit'. Often interchangeably referred to as toilet. alternatives. More recently, there has been increased interest in the management of faecal sludgeSludgeMixture of solids and liquids, containing mostly excreta and water, in combination with sand, grit, metals, trash and/or various chemical compounds. A distinction can be made between faecal sludge and wastewater sludge. Faecal sludge comes from on-site sanitation technologies,… and the treatment of human waste, with evaluations coming out: “Four systematic reviews found that WASH interventions can reduce disease transmission if they are context-appropriate (Taylor et al., 2015; Lantagne and Yates, 2018; Wolfe et al., 2018; Yates et al., 2017), with success factors including being appropriately timed, simple to use, community-driven, and the population having previous exposure with, and receiving trainings on, the intervention. (Ricau et al, 2023).”However, across the whole sanitation in outbreaks sector, there is a lack of data.

The current common practice for sanitation in most humanitarian emergencies is to collect, desludge, and then discharge untreated sludgeSludgeMixture of solids and liquids, containing mostly excreta and water, in combination with sand, grit, metals, trash and/or various chemical compounds. A distinction can be made between faecal sludge and wastewater sludge. Faecal sludge comes from on-site sanitation technologies,… into the environment, which causes public health risks. Guidelines for WASH in cholera include long-term improvement of fecal sludgeSludgeMixture of solids and liquids, containing mostly excreta and water, in combination with sand, grit, metals, trash and/or various chemical compounds. A distinction can be made between faecal sludge and wastewater sludge. Faecal sludge comes from on-site sanitation technologies,… management but lack interventions for outbreak response. Guidelines exist on managing cholera-infected fecal sludgeSludgeMixture of solids and liquids, containing mostly excreta and water, in combination with sand, grit, metals, trash and/or various chemical compounds. A distinction can be made between faecal sludge and wastewater sludge. Faecal sludge comes from on-site sanitation technologies,… in health and cholera centers, but they are not readily transferable to general population settings. Primary review showed that using limeLimeThe common name for calcium oxide (quicklime, CaO) or calcium hydroxide (slaked or hydrated lime, Ca(OH)2). It is a white, caustic and alkaline powder produced by heating limestone. Slaked lime is less caustic than quicklime and is widely used in water/wastewater treatment and… may be the most appropriate.

Key principles: During epidemics, excretaExcretaRefers to human excrements consisting of urine and faeces. control must be adapted and targeted according to the context and operational constraints. Six key contexts of transmission have been identified during an epidemic: (1) in the homes of patients and their neighbours, (2) in institutions and public places, (3) during population gatherings, (4) through environmental contamination, (5) during burials and funerals and (6) in cholera treatment facilities.

Sanitation interventions, which aim to isolate faecal matter from the environment, and treat waste to prevent ongoing transmission, can play a key role in breaking transmission routes for most of these transmission contexts (particularly at household level, in institutions and public places, in cholera treatment facilities, and to limit environmental contamination).

In most cases, this involves setting up temporary communal latrines, taking precautions against the risk of contamination of water sources and the spread of disease due to poor maintenance. More generally, any intervention to introduce, improve or expand the coverage of facilities for the safe management, disposal and treatment of excretaExcretaRefers to human excrements consisting of urine and faeces., i.e. to reduce direct and indirect contact with human faecesFaecesRefers to (semi-solid) excrement that is not mixed with urine or water. Depending on diet, each person produces approximately 50–150 kg per year of faecal matter of which about 80 % is water and the remaining solid fraction is mostly composed of organic material. Of the total…: e.g. latrineLatrineA sanitation facility used for urination and defecation including a 'user interface' and an 'onsite storage pit'. Often interchangeably referred to as toilet. construction, pour flush or water sealed flush toilet, compostingCompostingThe process by which biodegradable components are biologically decomposed by microorganisms (mainly bacteria and fungi) under controlled aerobic conditions. toiletToiletA sanitation facility (or ‘user interface’) used for urination and defecation. Often interchangeably referred to as latrine., piped sewer system, septic tank, simple pit latrines, VIP latrine, defecation trenches or use of a potty or scoop for the disposal of child faeces (D'Mello Guyett et al, 2020).

The Sphere Standards for excretaExcretaRefers to human excrements consisting of urine and faeces. management and the sanitation quality standards for emergency situations of the Technical Working Group (TWG) on Faecal SludgeSludgeMixture of solids and liquids, containing mostly excreta and water, in combination with sand, grit, metals, trash and/or various chemical compounds. A distinction can be made between faecal sludge and wastewater sludge. Faecal sludge comes from on-site sanitation technologies,… Management (FSM) are applicable.

Due to the faeco-oral mode of transmission, existing sanitation systems must be studied in terms of risk analysis during epidemics, using sanitary surveys or any other relevant tool to understand the existing contamination risks throughout the water supply chain (based on soil characteristics, type, condition and functionality of water supply and sanitation systems, or reciprocal location of water supply and sanitation systems).

It is important to note that very few cholera control interventions focus solely on sanitation and that many guidelines do not prioritise sanitation interventions as a direct means of reducing cholera during epidemics.

Some specific contexts, such as heavily populated areas (camps, urban and peri-urban areas, areas prone to flooding, areas with sensitive groundwater conditions, or areas with rocky ground, need to be carefully analysed in terms of existing sanitation services because they are more likely to be exposed to increased risks of transmission in the event of a low level of service and because their characteristics increase the operational constraints when it comes to sanitation interventions.

As in any other intervention context, cross-cutting needs related to sanitation must be considered when implementing solutions. In particular, the risks associated with protection and gender-based violence must be analysed and mitigated.

Similarly, community engagement must be consistently maintained in sanitation interventions during epidemics and must make it possible to analyse and draw on communityCommunityA group of people sharing something in common. perceptions and practices to develop response strategies and adapt to existing knowledge and capacities.