Broad approaches to cholera control in Asia: Water, sanitation and handwashing

Outbreak of cholera due to contaminated pond water utilisation in a rural area of West Bengal, India, 2021

BACKGROUND

On March 31, 2021, an outbreak of diarrhoeal disease was reported in Dangapara village of Purba Bardhaman district, West Bengal, India. The outbreak was investigated to estimate the magnitude, identify aetiological agents and source of infection, and guide prevention control measures.

METHODS

We did an active search for case patients at Dangapara village. We excluded children under five years of age from the epidemiological analysis. We described the outbreak by time, place, and person. We conducted a case control study with 133 controls and 65 cases. Water samples from different sources and rectal swabs from case patients were collected and sent for laboratory investigations.

RESULTS

We identified 95 case patients among 330 residents of Dangapara village (attack rate 29 %). Three stool samples were positive for Vibrio cholerae, and two pond water samples were contaminated with coliform organisms. Washing utensils [adjusted odds ratio (AOR): 69.8, (95% confidence interval (CI) 6.5-749.5)] and taking a bath in pond water [AOR: 3.4, (95% CI 1.2-9)] were associated with increased risk of illness. About 97% of cases were attributed to washing utensils in pond water. Washing hands before taking food was associated with a lower risk of developing disease with AOR: 0.1 (95% CI 0.03-0.33).

CONCLUSION

A cholera outbreak occurred among residents of Dangapara village due to theuse of contaminated pond water for washing utensils and bathing. Prompt management of cases and immediate discontinuation of pond water use stopped the outbreak.

Social histories of public health misinformation and infodemics: case studies of four pandemics

Recognition of misinformation as a public health threat and interest in infodemics, defined as an inundation of information accompanying an epidemic or acute health event, have increased worldwide. However, scientists have no consensus on how to best define and identify misinformation and other essential characteristics of infodemics. We conducted a narrative review of secondary historical sources to examine previous infodemics in relation to four infectious diseases associated with pandemics (ie, smallpox, cholera, 1918 influenza, and HIV) and challenge the assumption that misinformation is a new phenomenon associated with increased use of social media or with the COVID-19 pandemic. On the contrary, we found that the spread of health misinformation has always been a public health challenge that has necessitated innovative solutions from medical and public health communities. We suggest expanding beyond the narrow scope of addressing misinformation to manage information ecosystems, defined as how people consume, produce, interact with, and behave around information, which include factors such as trust, stigma, and scientific literacy. Although misinformation can spread on a global scale, this holistic approach advocates for community-level interventions that improve relationships and trust between medical or public health entities and local populations.

Mask-Wearing and Handwashing Behaviors of Chinese Rural Residents during the Pandemic of COVID-19: A Cross-Sectional Survey

OBJECTIVE

To understand mask-wearing and handwashing behaviors of Chinese rural residents during the COVID-19 pandemic and to analyze the associated factors.

METHODS

This study used a multi-stage random sampling method to conduct a cross-sectional questionnaire survey during the period of July to December of 2021, in six counties located in Shandong, Shanxi, and Yunnan provinces representing the eastern, central, and western regions of China, respectively. A total of 3864 villagers were surveyed with a questionnaire, and 3832 valid questionnaires were finally analyzed. Descriptive statistics and logistic regression analysis were used for statistical analysis.

RESULTS

Around ninety-four percent (93.6%) of rural residents reported mask-wearing during the COVID-19 pandemic, but only 44.5% of them could replace masks in time. Multivariate logistic regression analysis showed that those who were female, aged 15-59, had an education level of high school and above, were divorced/widowed, worked as farmers (workers), or were rural residents in Shandong Province were more likely to wear masks. Furthermore, those who were female, aged 15-59, had an education level of high school and above, were unmarried and married, were business and service workers, or were rural residents in Shandong and Shanxi Province replaced masks more timely. Around seventy percent (69.7%) of rural residents reported using soap when washing their hands, but only 38.0% of rural residents could wash their hands properly. Multivariate logistic regression analysis showed that rural residents who were aged 35-59, had an education of high school and above, or lived in Shandong Province and Shanxi Province were more likely to wash their hands with soap. Those who were aged 15-59, had an education of high school and above, worked as farmers (workers), were employees of governmental departments and retirees, were business and service workers, or were students had higher proper handwashing rates.

CONCLUSION

During the COVID-19 pandemic, the proportion of Chinese rural residents wearing masks reached 93.6%, but only 44.5% were able to replace masks in time, gender, age, education level, marital status, occupation, and living place had an impact on mask-wearing. The proportion of Chinese rural residents who could wash hands with soap reached 69.7%, but only 38.0% could wash their hands properly. Age and education level were influencing factors for both washing-hand with soap and proper handwashing.

Are better existing WASH practices in urban slums associated with a lower long-term risk of severe cholera? A prospective cohort study with 4 years of follow-up in Mirpur, Bangladesh

OBJECTIVE

To investigate the association between existing household water quality, sanitation and hygiene (WASH) practices and severe cholera risk in a dense urban slum where cholera is highly endemic.

DESIGN, SETTING AND PARTICIPANTS

We assembled a large prospective cohort within a cluster randomised trial evaluating the effectiveness of oral cholera vaccine. Our dynamic cohort population (n=193 576) comprised individuals living in the 'non-intervention' clusters of the trial, and were followed over 4 years. This study was conducted in a dense urban slum community of Dhaka, Bangladesh and cholera surveillance was undertaken in 12 hospitals serving the study area.

PRIMARY OUTCOME MEASURE

First severe cholera episode detected during follow-up period.

METHODS

We applied a machine learning algorithm on a training subpopulation (n=96 943) to develop a binary ('better', 'not better') composite WASH variable predictive of severe cholera. The WASH rule was evaluated for performance in a separate validation subpopulation (n=96 633). Afterwards, we used Cox regression models to evaluate the association between 'better' WASH households and severe cholera risk over 4 years in the entire study population.

RESULTS

The 'better' WASH rule found that water quality and access were the most significant factors associated with severe cholera risk. Members of 'better' WASH households, constituting one-third of the population, had a 47% reduced risk of severe cholera (95% CI: 29 to 69; p<0.001), after adjusting for covariates. The protective association between living in a 'better' WASH household and severe cholera persisted in all age groups.

CONCLUSIONS

Salutary existing household WASH practices were associated with a significantly reduced long-term risk of severe cholera in an urban slum of Dhaka. These findings suggest that WASH adaptations already practised in the community may be important for developing and implementing effective and sustainable cholera control programmes in similar settings.

TRIAL REGISTRATION NUMBER

This article is a re-analysis of data from a cluster randomized trial; can be found on ClinicalTrials.gov NCT01339845.

Diagnosis, Management, and Future Control of Cholera

Cholera, caused by Vibrio cholerae, persists in developing countries due to inadequate access to safe water, sanitation, and hygiene. There are approximately 4 million cases and 143,000 deaths each year due to cholera. The disease is transmitted fecally-orally via contaminated food or water. Severe dehydrating cholera can progress to hypovolemic shock due to the rapid loss of fluids and electrolytes, which requires a rapid infusion of intravenous (i.v.) fluids. The case fatality rate exceeds 50% without proper clinical management but can be less than 1% with prompt rehydration and antibiotics. Oral cholera vaccines (OCVs) serve as a major component of an integrated control package during outbreaks or within zones of endemicity. Water, sanitation, and hygiene (WaSH); health education; and prophylactic antibiotic treatment are additional components of the prevention and control of cholera. The World Health Organization (WHO) and the Global Task Force for Cholera Control (GTFCC) have set an ambitious goal of eliminating cholera by 2030 in high-risk areas.

How does handwashing behaviour change in response to a cholera outbreak? A qualitative case study in the Democratic Republic of the Congo

Background

Handwashing with soap has the potential to curb cholera transmission. This research explores how populations experienced and responded to the 2017 cholera outbreak in the Democratic Republic of the Congo and how this affected their handwashing behaviour.

Methods

Cholera cases were identified through local cholera treatment centre records. Comparison individuals were recruited from the same neighbourhoods by identifying households with no recent confirmed or suspected cholera cases. Multiple qualitative methods were employed to understand hand hygiene practices and their determinants, including unstructured observations, interviews and focus group discussions. The data collection tools and analysis were informed by the Behaviour Centred Design Framework. Comparisons were made between the experiences and practices of people from case households and participants from comparison households.

Results

Cholera was well understood by the population and viewed as a persistent and common health challenge. Handwashing with soap was generally observed to be rare during the outbreak despite self-reported increases in behaviour. Across case and comparison groups, individuals were unable to prioritise handwashing due to competing food-scarcity and livelihood challenges and there was little in the physical or social environments to cue handwashing or make it a convenient, rewarding or desirable to practice. The ability of people from case households to practice handwashing was further constrained by their exposure to cholera which in addition to illness, caused profound non-health impacts to household income, productivity, social status, and their sense of control.

Conclusions

Even though cholera outbreaks can cause disruptions to many determinants of behaviour, these shifts do not automatically facilitate an increase in preventative behaviours like handwashing with soap. Hygiene programmes targeting outbreaks within complex crises could be strengthened by acknowledging the emic experiences of the disease and adopting sustainable solutions which build upon local disease coping mechanisms.

Assessment of current status and geospatial analysis of compliance to bacteriological parameters: Tools to ensure access to safe water in Sri Lanka

Compliance of drinking-water to bacteriological parameters serves as a surrogate measure of the risk of water-borne diseases. Understanding the risk of water-borne diseases could help promote healthy behaviors such as household water treatment and safe water storage practices and advocacy to increase access to centrally-managed piped water. The objective of this research was to assess the current status of compliance and to geospatially analyze the probability of compliance to bacteriological parameters in the Western Province of Sri Lanka. A drinking-water quality survey was conducted among 4508 households representing four water-source types: National Water Supply and Drainage Board (NWSDB), dug wells, Community Water Supply (CWS), and tube wells, and other sources. Besides, a detailed assessment of selected NWSDB and CWS supplies was done. Water samples were tested for the total coliform count, thermotolerant coliform count, and free residual chlorine levels against the Sri Lanka Standards. Indicator kriging was performed using the geospatial analyst tool of ArcGIS version 10.6 for different water source types to interpolate the probability of compliance for both total coliform count and thermotolerant coliform count. The bacteriological compliance decreased from NWSDB to tube wells and other sources to CWS to dug wells. The interpolation maps confirm the relatively higher compliance of NWSDB for bacteriological parameters compared to other sources. Areas with a high probability of compliance for both parameters show considerable overlap with urban areas with a supply of centrally managed water from the NWSDB. It is recommended to expand the coverage of NWSDB water, strengthen the drinking-water quality surveillance system and water safety plans, and promote household water treatment and safe storage practices in the Western Province of Sri Lanka.

A genomic snapshot of Salmonella enterica serovar Typhi in Colombia

Little is known about the genetic diversity of Salmonella enterica serovar Typhi (S. Typhi) circulating in Latin America. It has been observed that typhoid fever is still endemic in this part of the world; however, a lack of standardized blood culture surveillance across Latin American makes estimating the true disease burden problematic. The Colombian National Health Service established a surveillance system for tracking bacterial pathogens, including S. Typhi, in 2006. Here, we characterized 77 representative Colombian S. Typhi isolates collected between 1997 and 2018 using pulse field gel electrophoresis (PFGE; the accepted genotyping method in Latin America) and whole genome sequencing (WGS). We found that the main S. Typhi clades circulating in Colombia were clades 2.5 and 3.5. Notably, the sequenced S. Typhi isolates from Colombia were closely related in a global phylogeny. Consequently, these data suggest that these are endemic clades circulating in Colombia. We found that AMR in S. Typhi in Colombia was uncommon, with a small subset of organisms exhibiting mutations associated with reduced susceptibility to fluoroquinolones. This is the first time that S. Typhi isolated from Colombia have been characterized by WGS, and after comparing these data with those generated using PFGE, we conclude that PFGE is unsuitable for tracking S. Typhi clones and mapping transmission. The genetic diversity of pathogens such as S. Typhi is limited in Latin America and should be targeted for future surveillance studies incorporating WGS.

Anti-diarrheal therapeutic potential of diminazene aceturate stimulation of the ACE II/Ang-(1-7)/Mas receptor axis in mice: A trial study

The angiotensin (Ang) II converting enzyme (ACE II) pathway has recently been shown to be associated with several beneficial effects on the body, especially on the cardiac system and gastrointestinal tract. ACE II is responsible for converting Ang II into the active peptide Ang-(1-7), which in turn binds to a metabotropic receptor, the Mas receptor (MasR). Recent studies have demonstrated that Diminazene Aceturate (DIZE), a trypanosomicide used in animals, activates the ACE II pathway. In this study, we aimed to evaluate the antidiarrheal effects promoted by the administration of DIZE to activate the ACE II/Ang-(1-7)/MasR axis in induced diarrhea mice models. The results show that activation of the ACE II pathway exerts antidiarrheal effects that reduce total diarrheal stools and enteropooling. In addition, it increases Na⁺/K⁺-ATPase activity and reduces gastrointestinal transit and thus inhibits contractions of intestinal smooth muscle; decreases transepithelial electrical resistance, epithelial permeability, PGE2-induced diarrhea, and proinflammatory cytokines; and increases anti-inflammatory cytokines. Enzyme-linked immunosorbent assay (ELISA) demonstrated that DIZE, when activating the ACE II/Ang-(1-7)/MasR axis, can still interact with GM1 receptors, which reduces cholera toxin-induced diarrhea. Therefore, activation of the ACE II/Ang-(1-7)/MasR axis can be an important pharmacological target for the treatment of diarrheal diseases.

Prevention and control of cholera with household and community water, sanitation and hygiene (WASH) interventions: A scoping review of current international guidelines

Introduction

Cholera remains a frequent cause of outbreaks globally, particularly in areas with inadequate water, sanitation and hygiene (WASH) services. Cholera is spread through faecal-oral routes, and studies demonstrate that ingestion of Vibrio cholerae occurs from consuming contaminated food and water, contact with cholera cases and transmission from contaminated environmental point sources. WASH guidelines recommending interventions for the prevention and control of cholera are numerous and vary considerably in their recommendations. To date, there has been no review of practice guidelines used in cholera prevention and control programmes.

Methods

We systematically searched international agency websites to identify WASH intervention guidelines used in cholera programmes in endemic and epidemic settings. Recommendations listed in the guidelines were extracted, categorised and analysed. Analysis was based on consistency, concordance and recommendations were classified on the basis of whether the interventions targeted within-household or community-level transmission.

Results

Eight international guidelines were included in this review: three by non-governmental organisations (NGOs), one from a non-profit organisation (NPO), three from multilateral organisations and one from a research institution. There were 95 distinct recommendations identified, and concordance among guidelines was poor to fair. All categories of WASH interventions were featured in the guidelines. The majority of recommendations targeted community-level transmission (45%), 35% targeted within-household transmission and 20% both.

Conclusions

Recent evidence suggests that interventions for effective cholera control and response to epidemics should focus on case-centred approaches and within-household transmission. Guidelines did consistently propose interventions targeting transmission within households. However, the majority of recommendations listed in guidelines targeted community-level transmission and tended to be more focused on preventing contamination of the environment by cases or recurrent outbreaks, and the level of service required to interrupt community-level transmission was often not specified. The guidelines in current use were varied and interpretation may be difficult when conflicting recommendations are provided. Future editions of guidelines should reflect on the inclusion of evidence-based approaches, cholera transmission models and resource-efficient strategies.