ArticlePDF Available

Notes from the Field: Chlorination Strategies for Drinking Water During a Cholera Epidemic — Tanzania, 2016

DOI:10.15585/mmwr.mm6541a6
Authors:
Alice Wang
Alice Wang
Alice Wang
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Colleen Mone Hardy at Centers for Disease Control and Prevention
Colleen Mone Hardy
Anu Rajasingham at U.S. Department of Health and Human Services
Anu Rajasingham
Andrea Martinsen
Andrea Martinsen
Andrea Martinsen
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Show all 15 authorsHide
Download full-text PDF
Read full-text
Download citation

Abstract

The bulk chlorination strategy in Dar es Salaam targeted water tanks of private vendors. These vendors sell to households where piped water supplies are limited. Vendors received a supply of 8.68-g sodium dichloroisocyanurate (NaDCC) tablets that disinfect up to 5,000-L volumes as well as instructions on proper use (4). In February 2016, this strategy was piloted in the Manzese Ward, one of 27 wards in the Kinondoni District, in Dar es Salaam. Ward health officers were given test kits and trained to monitor free chlorine residual in water tanks each week. Activities included mapping of vendor locations, distribution of a 3-month supply of NaDCC tablets, and weekly free chlorine residual monitoring of storage tanks. The pilot in Manzese Ward was successful, and the strategy was then expanded to four additional cholera-affected wards in Kinondoni District. As of June 9, 2016, a total of 430 vendors, representing the majority of water vendors, have been mapped and 313 vendors in Kinondoni received tablets. Because of encouraging results, this program was subsequently expanded to two other districts in Dar es Salaam, as well as to parts of Morogoro and Zanzibar. An evaluation of the program will be completed in October 2016.
Content uploaded by Colleen Mone Hardy
Author content
All content in this area was uploaded by Colleen Mone Hardy on Jan 17, 2017
Content may be subject to copyright.
Morbidity and Mortality Weekly Report
1150 MMWR / October 21, 2016 / Vol. 65 / No. 41 US Department of Health and Human Services/Centers for Disease Control and Prevention
Notes from the Field
Chlorination Strategies for Drinking Water During
a Cholera Epidemic — Tanzania, 2016
Alice Wang, PhD1,2; Colleen Hardy, MPH3; Anangu Rajasingham,
MPH3; Andrea Martinsen, MPH3; Lindsay Templin, MPH3; Stanislaus
Kamwaga, MSc4; Kiwe Sebunya, MSc4; Brenda Jhuthi, MPH5; Michael
Habtu, MSc 6; Stephen Kiberiti, MD7; Khalid Massa, MD7; Rob Quick,
MD8; Jane Mulungu3,9; Rachel Eidex, PhD3,9; Thomas Handzel, PhD3
Since August 2015, the Ministry of Health, Community
Development, Gender, Elderly and Children (MoHCDGEC)
of Tanzania has been leading the response to a widespread
cholera outbreak. As of June 9, 2016, cholera had affected 23
of 25 regions in Tanzania, with 21,750 cumulative cases and
341 deaths reported (Ally Nyanga, MoHCDGEC Emergency
Operations Center, personal communication, June 2016).
Approximately one fourth of all cases occurred in the Dar es
Salaam region on the east coast. Regions surrounding Lake
Victoria, in the north, also reported high case counts, including
Mwanza with 9% (Ally Nyanga, MoHCDGEC Emergency
Operations Center, personal communication, June 2016).
Since the start of the outbreak, MoHCDGEC and the Ministry
of Water (MOW) have collaborated with the Tanzania Red
Cross Society, United Nations Children’s Fund (UNICEF),
World Health Organization (WHO), and CDC to enhance
the water, sanitation, and hygiene (WASH) response to prevent
the further spread of cholera.
Access to safe drinking water is critical and prevents cholera
transmission (1). Chlorination effectively and affordably dis-
infects water and protects against recontamination. Because
water quality might deteriorate after chlorination (2), dur-
ing cholera outbreaks WHO recommends a minimum free
chlorine residual of 2.0 mg/L at the point-of-filling for tanker
trucks, 1.0 mg/L for standpipes and wells, and 0.2-0.5 mg/L
at point-of-use (3). To ensure adequate free chlorine residual
in drinking water, MoHCDGEC and MOW have encouraged
municipal water authorities to increase chlorination of piped
water to WHO-recommended free chlorine residual levels, and,
because of the variety of water delivery mechanisms, developed
two additional strategies in collaboration with WASH partners,
including a bulk chlorination strategy in Dar es Salaam and a
household water treatment strategy in Mwanza.
The bulk chlorination strategy in Dar es Salaam targeted
water tanks of private vendors. These vendors sell to households
where piped water supplies are limited. Vendors received a sup-
ply of 8.68-g sodium dichloroisocyanurate (NaDCC) tablets
that disinfect up to 5,000-L volumes as well as instructions
on proper use (4). In February 2016, this strategy was piloted
in the Manzese Ward, one of 27 wards in the Kinondoni
District, in Dar es Salaam. Ward health officers were given
test kits and trained to monitor free chlorine residual in water
tanks each week. Activities included mapping of vendor loca-
tions, distribution of a 3-month supply of NaDCC tablets,
and weekly free chlorine residual monitoring of storage tanks.
The pilot in Manzese Ward was successful, and the strategy
was then expanded to four additional cholera-affected wards in
Kinondoni District. As of June 9, 2016, a total of 430 vendors,
representing the majority of water vendors, have been mapped
and 313 vendors in Kinondoni received tablets. Because of
encouraging results, this program was subsequently expanded
to two other districts in Dar es Salaam, as well as to parts of
Morogoro and Zanzibar. An evaluation of the program will
be completed in October 2016.
To increase access to safe drinking water at the household
level, especially for communities that rely on untreated lake
water for drinking, WASH partners developed a strategy for
distribution of 67-mg NaDCC tablets that treat 20-L volumes.
Cholera-affected communities in four regions of Tanzania
were identified based on case counts, case-fatality rates, and
recent cholera cases as reported by local Tanzania Red Cross
volunteers. With support from UNICEF, the Tanzania Red
Cross Society distributed a 1-month supply of NaDCC tablets
and provided cholera prevention education to households in
communities in the Mwanza region; distribution to three
other regions followed. CDC provided 9 million tablets for
this campaign, including 6 million tablets for distribution to
cholera-affected regions and 3 million tablets as a reserve supply
for future outbreaks. Distribution of NaDCC tablets to priority
communities in Mwanza has been completed. WASH partners
are committed to providing continued support in implementa-
tion and monitoring to improve access to safe drinking water
during the cholera epidemic and beyond.
Acknowledgments
Tanzania regional and district health teams; National Water
Quality Laboratory, Mwanza, Tanzania; International Federation of
Red Cross; Tanzania Red Cross Society; United Nations Children’s
Fund; World Health Organization; Tanzania; CDC–Tanzania, Dar
es Salaam, Tanzania; National Center for Emerging and Zoonotic
Infectious Diseases, CDC; Global Disease Detection Operations
Center, Division of Global Health Protection, Center for Global
Health, CDC; Global Rapid Response Team, Emergency Response
and Recovery Branch, Division of Global Health Protection, Center
for Global Health, CDC.
Morbidity and Mortality Weekly Report
MMWR / October 21, 2016 / Vol. 65 / No. 41 1151
US Department of Health and Human Services/Centers for Disease Control and Prevention
1Epidemic Intelligence Service, CDC; 2Division of Environmental Hazards
and Health Effects, National Center for Environmental Health, CDC; 3Division
of Global Health Protection, Center for Global Health, CDC; 4United Nations
Children’s Fund; 5International Federation of Red Cross; 6World Health
Organization; 7Tanzanian Ministry of Health, Community Development,
Gender, Elderly and Children, Dar es Salaam, Tanzania; 8Division of
Foodborne, Waterborne, and Environmental Disease, National Center for
Emerging and Zoonotic Infectious Diseases, CDC; 9Division of Global Health
Protection, Center for Global Health, CDC Country Office–Tanzania.
Corresponding author: Alice Wang, ilm1@cdc.gov, 770-488-3411.
References
1. Waldman RJ, Mintz ED, Papowitz HE. The cure for cholera—improving
access to safe water and sanitation. N Engl J Med 2013;368:592–4. http://
dx.doi.org/10.1056/NEJMp1214179
2. World Health Organization. Guidelines for drinking-water quality, 4th
ed. Geneva, Switzerland: World Health Organization; 2016. http://apps.
who.int/iris/bitstream/10665/44584/1/9789241548151_eng.pdf
3. World Health Organization. Chlorine monitoring at point sources and
in piped distribution systems. Fact Sheet 2.30. Geneva, Switzerland: World
Health Organization; 2016. http://www.who.int/water_sanitation_health/
hygiene/emergencies/fs2_30.pdf
4. Clasen T, Edmondson P. Sodium dichloroisocyanurate (NaDCC) tablets
as an alternative to sodium hypochlorite for the routine treatment of
drinking water at the household level. Int J Hyg Environ Health
2006;209:173–81. http://dx.doi.org/10.1016/j.ijheh.2005.11.004
... Finally, when it comes to good practice, 44.8% of ppl have not and will not chlorinate their water supply. Chlorination of water supply is one of the recommended policies in the awareness campaign of the Ministry of Public Health of Lebanon, which is also supported by clinical data showing reduced cholera burden after chlorination during acute outbreaks [27][28][29] . Crowding has no association with any KAP subset. ...
Lebanese Population Knowledge, Attitudes, and Practice Regarding Cholera Disease and their Knowledge and Attitude Regarding the Cholera Vaccine Following an Outbreak in Lebanon
Preprint
Full-text available
  • Jan 2023
The objective was to evaluate the knowledge, attitudes, and practices of the Lebanese population towards cholera and its vaccination. A cross-sectional study was conducted using a self-administered questionnaire among a sample of Lebanese residents. The questionnaire consisted of questions about the participants' demographics, knowledge, attitudes, and practice towards cholera and vaccination. The final sample size was 691 respondents. The proportion of female and male participants was 68.7% and 31.3%, respectively. The results showed that the majority had a good knowledge of cholera, with 97.4% identifying severe diarrhea as the main symptom. Young age, different governorate of residence, and higher education were associated with better knowledge. Most participants had positive attitude, which was correlated with being female and having children under the age of 5 in the same household. Regarding practices, the majority reported engaging in some form of cholera prevention, such as always cooking (90.8%) and washing (88.3%) food. Being older, female, and homemaker was associated with better practice. Most participants expressed good knowledge and a positive attitude towards the vaccine, with 55.5% indicating that they would surely be willing to be vaccinated if freely available. However, 14.2% participants rejected and expressed concerns about the vaccine. Higher cholera knowledge was significantly predictive of vaccination willingness (B = 0.091). In conclusion, this study has provided insights into the knowledge, attitudes, and practices of the Lebanese population towards cholera and its vaccination. The findings can be used to inform the development of public health interventions aimed at improving cholera prevention and control in Lebanon.
View
... Besides, case-area targeted interventions have been frequently conducted against cholera epidemics, and are supported by the observed increase of cholera risk for neighbors living within a few dozen meters of cases during days following their presentation [28,29]. However, feedback from the field has been scarce and scattered, reported activities have usually been implemented at a local level, during short time periods, and described with few details [30][31][32]26,[33][34][35][36][37][38]7,8,[39][40][41][42][43]. ...
The national alert-response strategy against cholera in Haiti: a four-year assessment of its implementation
Preprint
Full-text available
  • Feb 2018
Background A massive cholera epidemic struck Haiti on October 2010. As part of the national cholera elimination plan, the Haitian government, UNICEF and other international partners launched a nationwide alert-response strategy from July 2013. This strategy established a coordinated methodology to rapidly target cholera-affected communities with WaSH (water sanitation and hygiene) response interventions conducted by field mobile teams. An innovative red-orange-green alert system was established, based on routine surveillance data, to weekly monitor the epidemic. Methodology/Principal findings We used cholera consolidated surveillance databases, alert records and details of 31,306 response interventions notified by WaSH mobile teams to describe and assess the implementation of this approach between July 2013 and June 2017. Response to red and orange alerts was heterogeneous across the country, but significantly improved throughout the study period so that 75% of red and orange alerts were responded within the same epidemiological week during the 1 st semester of 2017. Numbers of persons educated about cholera, houses decontaminated by chlorine spraying, households which received water chlorination tablets and water sources that were chlorinated during the same week as cholera alerts significantly increased. Alerts appeared to be an interesting and simple indicator to monitor the dynamic of the epidemic and assess the implementation of response activities. Conclusions/Significance The implementation of a nationwide alert-response strategy against cholera in Haiti was feasible albeit with certain obstacles. Its cost was less than USD 8 million per year. Continuing this strategy seems essential to eventually defeat cholera in Haiti while ambitious long-term water and sanitation projects are conducted in vulnerable areas. It constitutes a core element of the current national plan for cholera elimination of the Haitian Government.
View
... Because the long history of failure of adapting large expensive centralized systems that require more water, more funding and more government capacity than is available, new approaches are needed for collecting, disinfecting and distributing water that are specifically designed to function in the water-, capital-and governance-constrained contexts where risk of cholera and other waterborne diseases is greatest. Such approaches are likely to operate on a smaller scale than traditional municipal networks [91,92]; rigorous evaluation of these decentralized approaches can provide valuable sector guidance. In addition, developing and testing approaches to prevent or mitigate the effects of intermittent water supply service could reduce risk. ...
Broad approaches to cholera control in Asia: Water, sanitation and handwashing
Article
Full-text available
  • Aug 2019
Cholera has been eliminated as a public health problem in high-income countries that have implemented sanitation system separating the community's fecal waste from their drinking water and food supply. These expensive, highly-engineered systems, first developed in London over 150 years ago, have not reached low-income high-risk communities across Asia. Barriers to their implementation in communities at highest risk for cholera include the high capital and operating costs for this technological approach, limited capacity and perverse incentives of local governments, and a decreasing availability of water. Interim solutions including household level water treatment, constructing latrines and handwashing promotion have only marginally reduced the risk of cholera and other fecally transmitted diseases. Increased research to develop and policy flexibility to implement a new generation of solutions that are designed specifically to address the physical, financial and political constraints of low-income communities offers the best prospect for reducing the burden of cholera across Asia.
View
... Thailand was the only country outside of Africa that reported cholera in refugee camps. Tanzania had the most documented cases, at 3,620, 97% of which were reported from three camps in 2015 in conjunction with a massive countrywide epidemic [40]. Kenya had the second-highest number of cases (2,908), followed by Thailand (645) and the Republic of the Congo (628). ...
View
... Promising results led to expansion of the program. 15 The emergency bulk chlorination program was a collaborative project between the U.N. Children's Fund (UNICEF), Tanzania, the MoHCDGEC of Tanzania, and the US Centers for Disease Control and Prevention (CDC). MoHCDGEC and UNICEF implemented the program, and the CDC set up the monitoring and evaluation system. ...
Evaluation of an Emergency Bulk Chlorination Project Targeting Drinking Water Vendors in Cholera-Affected Wards of Dar es Salaam and Morogoro, Tanzania
Article
Full-text available
  • Apr 2019
In August 2015, an outbreak of cholera was reported in Tanzania. In cholera-affected areas of urban Dar es Salaam and Morogoro, many households obtained drinking water from vendors, who sold water from tanks ranging in volume from 1,000 to 20,000 L. Water supplied by vendors was not adequately chlorinated. The Tanzanian Ministry of Health, Community Development, Gender, Elderly and Children and the U.N. Children's Fund, Tanzania, collaborated to enroll and train vendors to treat their water with 8.68-g sodium dichloroisocyanurate tablets (Medentech, Ireland). The Centers for Disease Control and Prevention (CDC) provided monitoring and evaluation support. Vendors were provided a 3-month supply of chlorine tablets. A baseline assessment and routine monitoring were conducted by ward environmental health officers. Approximately 3 months after chlorine tablet distribution, an evaluation of the program was conducted. The evaluation included a full enumeration of all vendors, an in-depth survey with half of the vendors enumerated, and focus group discussions. In total, 797 (88.9%) vendors were included in the full enumeration and 392 in the in-depth survey. Free residual chlorine (FRC) was detected in 12.0% of tanks at baseline and 69.6% of tanks during the evaluation; however, only 17.4% of these tanks had FRC ≥ 0.5 mg/L. The results suggest high acceptability and use of the chlorine tablets by water vendors. However, given variation in the water source used and longer storage times, dosing could be increased in future programming. Bulk chlorination using chlorine tablets offers an efficient community-level approach to treating water closer to the point of use.
View
... However, feedback from the field has been scarce. Reported activities have usually been implemented at a local level, during short time periods, and described with few details [7,8,29,[34][35][36][37][38][39][40][41][42][43][44][45][46][47]. ...
The case-area targeted rapid response strategy to control cholera in Haiti: a four-year implementation study
Article
Full-text available
Background In October 2010, Haiti was struck by a large-scale cholera epidemic. The Haitian government, UNICEF and other international partners launched an unprecedented nationwide alert-response strategy in July 2013. Coordinated NGOs recruited local rapid response mobile teams to conduct case-area targeted interventions (CATIs), including education sessions, household decontamination by chlorine spraying, and distribution of chlorine tablets. An innovative red-orange-green alert system was also established to monitor the epidemic at the communal scale on a weekly basis. Our study aimed to describe and evaluate the exhaustiveness, intensity and quality of the CATIs in response to cholera alerts in Haiti between July 2013 and June 2017. Methodology/principal findings We analyzed the response to 7,856 weekly cholera alerts using routine surveillance data and severity criteria, which was based on the details of 31,306 notified CATIs. The odds of CATI response during the same week (exhaustiveness) and the number of complete CATIs in responded alerts (intensity and quality) were estimated using multivariate generalized linear mixed models and several covariates. CATIs were carried out significantly more often in response to red alerts (adjusted odds ratio (aOR) [95%-confidence interval, 95%-CI], 2.52 [2.22–2.87]) compared with orange alerts. Significantly more complete CATIs were carried out in response to red alerts compared with orange alerts (adjusted incidence ratio (aIR), 1.85 [1.73–1.99]). Over the course of the eight-semester study, we observed a significant improvement in the exhaustiveness (aOR, 1.43 [1.38–1.48] per semester) as well as the intensity and quality (aIR, 1.23 [1.2–1.25] per semester) of CATI responses, independently of funds available for the strategy. The odds of launching a CATI response significantly decreased with increased rainfall (aOR, 0.99 [0.97–1] per each accumulated cm). Response interventions were significantly heterogeneous between NGOs, communes and departments. Conclusions/significance The implementation of a nationwide case-area targeted rapid response strategy to control cholera in Haiti was feasible albeit with certain obstacles. Such feedback from the field and ongoing impact studies will be very informative for actors and international donors involved in cholera control and elimination in Haiti and in other affected countries.
View
... A recent and novel intervention in Tanzania during a cholera outbreak in 2015 attempted to bypass challenges with household-level chlorination by chlorinating water in large tanks operated by private vendors [123]. A similar approach, using emergency public water storage tanks, was recently successfully used in Zambia [124]. ...
Cholera
Article
  • Jul 2018
Purpose of Review This review describes the basic epidemiologic, clinical, and microbiologic aspects of cholera, highlights new developments within these areas, and presents strategies for applying currently available tools and knowledge more effectively. Recent Findings From 1990 to 2016, the reported global burden of cholera fluctuated between 74,000 and 595,000 cases per year; however, modeling estimates suggest the real burden is between 1.3 and 4.0 million cases and 95,000 deaths yearly. In 2018, the World Health Assembly endorsed a new initiative to reduce cholera deaths by 90% and eliminate local cholera transmission in 20 countries by 2030. New tools, including localized GIS mapping, climate modeling, whole genome sequencing, oral vaccines, rapid diagnostic tests, and new applications of water, sanitation, and hygiene interventions, could support this goal. Challenges include a high proportion of fragile states among cholera-endemic countries, urbanization, climate change, and the need for cholera treatment guidelines for pregnant women and malnourished children. Summary Reducing cholera morbidity and mortality depends on real-time surveillance, outbreak detection and response; timely access to appropriate case management and cholera vaccines; and provision of safe water, sanitation, and hygiene.
View
View
Public Water Supply and Sanitation Authorities for Strategic Sustainable Domestic Water Management. A Case of Iringa Region In Tanzania
Article
Full-text available
  • Oct 2019
Water supply is a mandatory service for the majority from respective legal public water utilities, and their sustainability reflects implementations of best management strategies at a local level. The objectives of this study were (i) to assess current approaches used in water quality and quantity management (ii) propose a sustainable domestic water management strategy. This was achieved through secondary water data trends, on-site water quality assessments, visits of water supply and sanitation authorities, and assessment of their performances. It was observed that water supplied in rural-based authorities was quite different from that supplied in an urban setting as far as quality and quantity are concerned, urban-based supplies are affordable to users over rural ones. A new strategy on water management is presented for sustainable water supply; it is based on controlling groundwater abstractions and preference of surface water in public water supplies. Rural water supply management must learn several practices realized at urban supplies for the betterment of services for the majority of the users.
View
Public Water Supply and Sanitation Authorities: A Sustainable Domestic Water Management Strategy in Tanzania
Preprint
Full-text available
  • Jun 2019
Water supply is a mandatory service for Tanzanians from respective legal public water utilities, and their sustainability reflects implementations of best management strategies at a local level. The objective of this study was to assess current approaches used in water quality and quantity management in Tanzania. This was achieved through secondary water data tends, on-site water quality assessments, visits of respective water supply and sanitation authorities, and assessment of their performances. It was observed that water supplied in rural-based authorities was quite different from that supplied in an urban setting as far as quality and quantity is concerned, urban-based supplies being of assistance to users over rural ones. A new strategy on water management is presented for sustainable water supply in Tanzania; it is based on controlling groundwater abstractions and preference of surface water in public water supplies. Rural water supply management must learn several practices realized at urban supplies for the betterment of respective majority water users.
View
The Cure for Cholera - Improving Access to Safe Water and Sanitation
Article
Whenever epidemics of cholera occur, the global public health community is energized. Experts meet, guidelines for control are reviewed and reissued, and new and modified interventions are proposed and promoted. In the past two decades, these things happened after cholera appeared in Latin America in 1991, in the wake of the Rwandan genocide and the ensuing refugee crisis in Zaire (now Democratic Republic of Congo) in 1994, in Zimbabwe in 2008, and in October 2010, at the onset of the ongoing epidemic in Haiti (see article by Barzilay et al.). But even when it is not covered in the news . . .
View
WHO, Guidelines for Drinking-Water Quality, World Health Organization, Geneva, 1993
Article
  • Jan 1993
Edición revisada de: International standards for driking-water y de European standard for driking-water Incluye bibliografía e índice v. 1. Recommendations -- v. 2. Health criteria and other supporting information -- v. 3. Drinking-water quality control in small-community supplies
View
Sodium dichloroisocynnurate (NaDCC) tablets as an alternative to Sodium hypochlorite for the routine treatment of drinking water at the household level
Article
Household water treatment using sodium hypochlorite (NaOCl) has been recognized as a cost-effective means of reducing the heavy burden of diarrhea and other waterborne diseases, especially among populations without access to improved water supplies. Sodium dichloroisocyanurate (NaDCC), which is widely used in emergencies, is an alternative source of chlorine that may present certain advantages over NaOCl for household-based interventions in development settings. We summarize the basic chemistry and possible benefits of NaDCC, and review the available literature concerning its safety and regulatory treatment and microbiological effectiveness. We review the evidence concerning NaDCC in field studies, including microbiological performance and health outcomes. Finally, we examine studies and data to compare NaDCC with NaOCl in terms of compliance, acceptability, affordability and sustainability, and suggest areas for further research.
View