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2.1 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 defecation:
    • at least install single pit latrines with a temporary superstructure – 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 excreta 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 aquifer:
    • Use of raised latrines with excreta collection in watertight tanks. Appropriate and safe emptying, transport and disposal of excreta 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 disinfection 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.
  • Desludging 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 equipment, mechanical emptying whenever possible, disinfection 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 lime on the rest of the sanitation chain). For non-emptying latrines, after liming and disinfecting the superstructure, the pit should be closed, and the superstructure removed. In Haiti, where lime treatment of sludge from cholera treatment centers (CTC) was deemed unsuitable, other options were tested: the first system used coagulation/flocculation and disinfection with hydrated (slaked) lime, the second system the addition of hydrochloric acid, followed by pH neutralization and coagulation/ flocculation of suspended solids using aluminum sulfate (Sozzi, Fabre et al. 2015). Both systems use pH changes with the intent to inactivate the cholera bacteria. 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
  • Wastewater disposal: preventing cross-contamination in wastewater networks, ensuring the cleanliness of drainage systems, promoting, and supporting the repair of damaged sewer pipes and wastewater treatment plants.
  • Key points to monitor during interventions:
    • The toilet slabs must be disinfected in proportion to use.
    • Daily: Toilets must be safely and easily accessible to all people. Open defecation 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 faeces and vomit, waste management (sharp, soft and organic), wastewater management and vector 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 bacteria, and in particular those in charge of desludging, are properly equipped with personal protective equipment (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 sanitation 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 engagement, (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 sanitation). 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 latrine construction and latrine alternatives. More recently, there has been increased interest in the management of faecal sludge 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 sludge into the environment, which causes public health risks. Guidelines for WASH in cholera include long-term improvement of fecal sludge management but lack interventions for outbreak response. Guidelines exist on managing cholera-infected fecal sludge in health and cholera centers, but they are not readily transferable to general population settings. Primary review showed that using lime may be the most appropriate.

Key principles: During epidemics, excreta 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 excreta, i.e. to reduce direct and indirect contact with human faeces: e.g. latrine construction, pour flush or water sealed flush toilet, composting toilet, 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 excreta management and the sanitation quality standards for emergency situations of the Technical Working Group (TWG) on Faecal Sludge 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 community perceptions and practices to develop response strategies and adapt to existing knowledge and capacities.

Author(s) (1)
Baptiste Lecuyot
Solidarité International (SI)
Reviewer(s) / Contributor(s) (3)
Daniele Lantagne
Tufts University
Marine Ricau
Tufts University
Laurent Sax
Global Task Force on Cholera Control (GTFCC)

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