A case-control study to assess risk factors related to cholera outbreak in Addis Ababa, Ethiopia, July 2016

Cholera outbreak and associated risk factors in Dollo Ado district, Ethiopia: un-matched case-control study, 2023

Background

Cholera is a highly contagious bacterial disease that causes severe watery diarrhea. It spreads mainly through contaminated food or water containing Vibrio cholerae O139 and remains a major global public health threat. We investigated an outbreak to identify its cause, source, and risk factors and to develop control measures.

Method

A suspected case was classified as the occurrence of acute watery diarrhea in a Dollo Ado District resident aged 2 or older between February 2, 2023 and March 15, 2023. A confirmed case was a suspected case with Vibrio cholerae detected in the patient's stool sample. An investigation of the outbreak was conducted; cases were described and the environment, where contamination may take place assessed and an unmatched case-control study conducted in Suftu Kebele, which served as the epi center of the outbreak. Logistic regression was used to identify risk factors for cholera infection.

Results

A total of 92 cases were identified, including 66 males and 26 females, with four deaths (4.3% fatality rate). Males had a higher attack rate (2.4 per 1,000 people) than females (1.6 per 1,000 people). Suftu village was the hardest-hit area (attack rate: 41 per 1,000 people). The outbreak began after a person suspected of having cholera returned from mandera, kenya, on February 2, 2023. Five days later, cases emerged in suftu village. Many residents practiced open defecation and used the dawa river for bathing, washing clothes, and drinking. Using untreated river water significantly increased the risk of infection (AOR = 20, 95% CI: 5.2-73).

Conclusion

The outbreak likely started at a funeral of a suspected cholera case, spreading through contaminated river water. It was contained within a week by restricting river water use and preventing further contamination.

Cholera Outbreaks in Low- and Middle-Income Countries in the Last Decade: A Systematic Review and Meta-Analysis

Cholera is linked to penury, making low- and middle-income countries (LMICs) particularly vulnerable to outbreaks. In this systematic review, we analyzed the drivers contributing to these outbreaks, focusing on the epidemiology of cholera in LMICs. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in PROSPERO (ID: CRD42024591613). We searched PubMed, Scopus, Web of Science, and Google Scholar to include studies on cholera outbreaks that occurred in LMICs from 1 January 2014 to 21 September 2024. Studies on outbreaks outside LMICs and focusing on sporadic cases were excluded. The risk of bias among included studies was assessed using a modified Downes et al. appraisal tool. Thematic analysis was used to synthesize the qualitative data, and meta-analyses to estimate the pooled prevalence. From 1662 records, 95 studies met inclusion criteria, primarily documenting outbreaks in Africa (74%) and Asia (26%). Contaminated water was the main route of disease transmission. The pooled fatality prevalence was 1.3% (95% CI: 1.1-1.6), and the detection rate among suspected cases was 57.8% (95% CI: 49.2-66.4). Vibrio cholerae O1 was the dominant serogroup while Ogawa was the dominant serotype. All studies reporting biotypes indicated El Tor. Although the isolates were 100% susceptible to ofloxacin, levofloxacin, norfloxacin, cefuroxime, and doxycycline, they were also fully resistant to amikacin, sulfamethoxazole, trimethoprim, and furazolidone. The persistence of cholera outbreaks in destitute areas with limited access to clean water and sanitation emphasizes the need for socioeconomic improvements, infrastructure development, and ongoing surveillance to support timely responses and achieve long-term prevention.

Identifying clustering of cholera cases using geospatial analysis in Kolkata and surrounding districts: data from patients at tertiary care referral hospitals

Background

Cholera cases have increased globally across the Eastern Mediterranean, Africa, Southeast Asia, and parts of Europe since early 2024. This study aims to identify cholera hotspots and understand the spatial distribution of cholera in Kolkata and surrounding regions, a key cholera reservoir. Additionally, we examine sociodemographic factors and aspects related to water, sanitation, and hygiene (WASH).

Methods

Cholera clusters were detected using kernel density estimation and spatial autocorrelation through Global Moran's-I statistics, with local cluster patterns examined using Local Moran's-I statistics. Cholera cases from August 2021 to December 2023, treated at two tertiary care facilities in Kolkata: Infectious Diseases and Beleghata General Hospital and Dr. B C Roy Post Graduate Institute of Paediatric Sciences Hospital were included. Additionally, through a case-control study, 196 culture-confirmed cholera cases and 764 age/sex-matched neighborhood controls were enrolled, to investigate cholera risk factors.

Findings

Spatial analysis revealed a concentration of 196 cholera cases in Kolkata and its surrounding regions of Howrah, Hooghly, and North and South 24 Parganas. Hotspot analysis showed significant clustering in several Kolkata wards (31, 33, 56, 46, 57, 58, 59, 61, 66, 71, and 107), particularly in the northern, central, and east Kolkata wetlands areas (Global Moran's I statistic = 0.14, p < 0.001). These clusters had proximity between cases, with a median distance of 187.7 m, and 25.5% of cases as close as 73.9 m apart, suggesting localized transmission. Hotspots were identified with an average distance of 1600 m between them. Local Moran's I analysis found dense "high-high" clusters in these areas (p < 0.01), with a mean Moran's I index of 0.3, (range 0.1-4.6). The case-control study revealed that males were more likely to contract cholera, with an adjusted odds ratio of 2.4 (p < 0.01). There was no significant association found between cholera infection and sociodemographic factors or various WASH practices.

Interpretation

The findings emphasize the importance of targeted interventions, especially in identified hotspots, to mitigate cholera transmission. Addressing Socio-economic, and environmental factors especially improvement in WASH practices may further enhance prevention effects.

Funding

The author KK, received funding from the program of the Japan Initiative for Global Research Network on Infectious Diseases, (grant id: JP23wm0125004), from the Ministry of Education, Culture, Sports, Science and Technology in Japan, and Japan Agency for Medical Research and Development.

Healthcare Seeking Behavior and Disease Perception Toward Cholera and Acute Diarrhea Among Populations Living in Cholera High-Priority Hotspots in Shashemene, Ethiopia

BACKGROUND

Healthcare seeking behavior (HSB) and community perception on cholera can influence its management. We conducted a cross-sectional survey to generate evidence on cholera associated HSB and disease perception in populations living in cholera hotspots in Ethiopia.

METHODS

A total of 870 randomly selected households (HHs) in Shashemene Town (ST) and Shashemene Woreda (SW) participated in our survey in January 2022.

RESULTS

Predominant HHs (91.0%; 792/870) responded "primary health center" as the nearest healthcare facility (HCF). Around 57.4% (247/430) of ST HHs traveled <30 minutes to the nearest HCF. In SW, 60.2% (265/440) of HHs travelled over 30 minutes and 25.9% (114/440) over 4 km. Two-thirds of all HHs paid

CONCLUSIONS

Variations in cholera prevention practices between rural and urban residents were shown. Addressing differences in HSB per age groups is needed for community engagement for early case detection and case management; critical in reducing cholera deaths and transmission.

Collapse

Key Words

• Ethiopia
• access to healthcare
• cholera
• disease perception
• healthcare seeking behavior

Collapse

MESH Headings

• Humans
• Cholera/epidemiology
• Ethiopia/epidemiology
• Cross-Sectional Studies
• Adult
• Female
• Male
• Patient Acceptance of Health Care/statistics & numerical data
• Diarrhea/epidemiology
• Adolescent
• Young Adult
• Middle Aged
• Health Knowledge, Attitudes, Practice
• Child
• Child, Preschool
• Infant
• Surveys and Questionnaires

Collapse

Grants

• Korea Support Committee
• CHMTD05083-010 International Vaccine Institute
• CHMTD05083-020 LG Electronics
• CHMTD05083-030 Community Chest of Korea

Collapse

Affiliation(s)

Tomas Getahun Clinical Trials Directorate, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
Dejene Hailu Clinical, Assessment, Regulatory, Evaluation (CARE) Unit, International Vaccine Institute, Seoul, Republic of Korea School of Public Health, Hawassa University, Hawassa, Ethiopia
Ondari D Mogeni Clinical, Assessment, Regulatory, Evaluation (CARE) Unit, International Vaccine Institute, Seoul, Republic of Korea
Edlawit Mesfin Getachew Clinical Trials Directorate, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
Biruk Yeshitela Bacterial and Viral Disease Research Directorate, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
Yeonji Jeon Clinical, Assessment, Regulatory, Evaluation (CARE) Unit, International Vaccine Institute, Seoul, Republic of Korea
Abel Gedefaw Clinical, Assessment, Regulatory, Evaluation (CARE) Unit, International Vaccine Institute, Seoul, Republic of Korea College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia
Samuyel Ayele Abebe Statistics and Data Management Department, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
Ermiyas Hundito Clinical Trials Directorate, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
David Mukasa Biostatistics and Data Management (BDM) Department, International Vaccine Institute, Seoul, Republic of Korea
Geun Hyeog Jang Biostatistics and Data Management (BDM) Department, International Vaccine Institute, Seoul, Republic of Korea
Gi Deok Pak Biostatistics and Data Management (BDM) Department, International Vaccine Institute, Seoul, Republic of Korea
Deok Ryun Kim Biostatistics and Data Management (BDM) Department, International Vaccine Institute, Seoul, Republic of Korea
Yeshambel Worku Demlie Public Health Emergency Management, Ethiopia Public Health Institute, Addis Ababa, Ethiopia
Mukemil Hussen Public Health Emergency Management, Ethiopia Public Health Institute, Addis Ababa, Ethiopia
Mekonnen Teferi Clinical Trials Directorate, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
Se Eun Park Clinical, Assessment, Regulatory, Evaluation (CARE) Unit, International Vaccine Institute, Seoul, Republic of Korea Department of Global Health and Disease Control, Yonsei University Graduate School of Public Health, Seoul, Republic of Korea

Collapse

Collaborators Collapse

Early use of oral cholera vaccines as a prime control measure during outbreaks: Necessary but not sufficient

INTRODUCTION

Despite being a preventable and treatable disease, cholera remains a public health problem in Sudan. The objective of the outbreak investigation was to identify associated risk factors that would help institute appropriate control measures.

MATERIAL AND METHODS

A case control study design was chosen to identify the risk factors for cholera in Gadarif State.

RESULTS

Multi-variate analysis of identified two risk factors and three preventive factors for cholera in Gadarif City.

RISK FACTORS

Buying foods or drinks from street vendors (OR = 71.36), 95 % CI: 16.58-307.14), living in an urban setting (Gadarif City) (OR = 5.38), 95 % CI: 2.10-13.81); and the preventive factors were: Washing hands with water after defecation but without soap (OR = 0.16), 95 % CI: 0.04-0.63) or with soap (OR = 0.01), 95 % CI: 0.00-0.03), washing hands before eating (OR = 0.15), 95 % CI: 0.05-0.51) and taking Oral Cholera Vaccine (OCV) (OR = 0.19, 95 % CI: 0.08-0.44). The effectiveness of OCV (VE) was (Unadjusted VE: 80 %, 95 % CI: 69 %-87 %) or (Adjusted VE = 81.0 %, 95 % CI: 56.0 %-92.0 %).

DISCUSSION

Cholera outbreaks, especially in the setting of a complex humanitarian crises, can spread rapidly, resulting in many deaths, and quickly become a public health crisis. Implementation of a community-wide vaccination campaign using OCV as early as possible during the outbreak while implementing other control measures to target hotspots and at-risk populations would expedite halting outbreaks of cholera and save lives.

Spatiotemporal dynamics of cholera epidemics in Ethiopia: 2015-2021

Since the onset of the seventh cholera pandemic, Ethiopia has been affected by recurrent epidemics. However, the epidemiology of cholera in this country remains poorly understood. This study aimed to describe cholera outbreak characteristics in Ethiopia from 2015 to 2021. During this period, Ethiopia experienced four epidemic waves. The first wave involved nationwide outbreaks during the second half of 2016 followed by outbreaks predominantly affecting Somali Region in 2017. The second wave primarily affected Tigray and Afar Regions. During the third wave, multiple smaller-scale outbreaks occurred during 2019. The fourth wave was limited to Bale Zone (Oromia Region) in 2021. Overall, a north to south shift was observed over the course of the study period. Major cholera transmission factors included limited access to safe water and sanitation facilities. Severe weather events (drought and flooding) appear to aggravate cholera diffusion. Cholera transmission between Ethiopia and nearby countries (Kenya and Somalia), likely plays a major role in regional cholera dynamics. Overall, this study provides the first understanding of recent spatiotemporal cholera dynamics in Ethiopia to inform cholera control and elimination strategies.

Determining factors associated with cholera disease in Ethiopia using Bayesian hierarchical modeling

Background

Cholera is a diarrheal disease caused by infection of the intestine with the gram-negative bacteria Vibrio cholera. It is caused by the ingestion of food or water and infected all age groups. This study aimed at identifying risk factors associated with cholera disease in Ethiopia using the Bayesian hierarchical model.

Methods

The study was conducted in Ethiopia across regions and this study used secondary data obtained from the Ethiopian public health institute. Latent Gaussian models were used in this study; which is a group of models that contains most statistical models used in practice. The posterior marginal distribution of the Latent Gaussian models with different priors is determined by R-Integrated Nested Laplace Approximation.

Results

There were 2790 cholera patients in Ethiopia across the regions. There were 81.61% of patients are survived from cholera outbreak disease and the rest 18.39% have died. There was 39% variation across the region in Ethiopia. Latent Gaussian models including random and fixed effects with standard priors were the best model to fit the data based on deviance. The odds of surviving from cholera outbreak disease for inpatient status are 0.609 times less than the outpatient status.

Conclusions

The authors conclude that the fitted latent Gaussian models indicate the predictor variables; admission status, aged between 15 and 44, another sick person in a family, dehydration status, oral rehydration salt, intravenous, and antibiotics were significantly associated with cholera outbreak disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14153-1.

Epidemiology of Cholera Outbreak and Summary of the Preparedness and Response Activities in Addis Ababa, Ethiopia, 2016

Background

Cholera is a major public health problem in Ethiopia. This study aimed to generate evidence to better understand the epidemiology of cholera as well as chronicle the city administration's emergency management efforts during the Addis Ababa cholera outbreak in 2016.

Method

A descriptive analysis was performed using the cholera outbreak data collected from June 8 to October 31, 2016. A case was defined as a patient aged 5 years or older who develops acute watery diarrhea with or without vomiting. Administrative and laboratory finding reports were also used, as well as documented situational updates.

Result

A total of 8,083 cases (AR of 0.24 percent) with 15 deaths (CFR of 0.18 percent) were reported. Males in unskilled manual occupations and housewives accounted for 2,198 (27.2%) and 1,195 (14.8%), respectively, of the total. A total of 6,908 cases (85.46 percent) sought medical attention within two days of the onset of the condition. The presence of the Kolfie river as well as the relatively confined living conditions of the residents aided in the emergence and rapid spread of the disease. The increased in-and-out movement of people, combined with the city administration's deficient development infrastructure of water, hygiene, and sanitation, contributes to higher morbidity and a longer duration of the outbreak. Multiple command posts established in various locations as well as a lack of collaboration among relevant stakeholders resulted in inefficient information and resource management. Furthermore, there is a lack of risk factor surveillance for the early detection of cholera-causing agents. Conclusion and Recommendations. This outbreak caused significant morbidity and mortality. Prioritizing early risk detection, implementing preventive measures, and developing positive working relationships with relevant parties are all critical. A well-established community-based surveillance system and incident management system (IMS) will be required for future emergency management. It is recommended that the city administration make critical adjustments to its developmental infrastructures related to water, sanitation, and hygiene and implement risk factor surveillance from sewerage lines for the early detection of agents that cause cholera.

Inadequate Hand Washing, Lack of Clean Drinking Water and Latrines as Major Determinants of Cholera Outbreak in Somali Region, Ethiopia in 2019

Introduction

Cholera remains a serious public health problem characterized by a large disease burden, frequent outbreaks, persistent endemicity, and high mortality, particularly in tropical and subtropical low-income countries including Ethiopia. The recent cholera outbreak in the Somali region began on 4 September to 1 November 2019. Cholera may spread rapidly through a population so that an early detection and reporting of the cases is mandatory. This study aimed to identify determinants of cholera infection among >5 years of age population in Somali region, Ethiopia.

Methods

A community-based unmatched case-control study was conducted among 228 (76 cases and 152 controls, 1:2 ratio) systematically selected population. Data were collected using a structured questionnaire administered by an interviewer and a record review. Descriptive statistics and multivariable logistic regression analysis was used to identify the determinants of the risk factors of cholera infection with a 95% confidence interval and statistical significance was declared a tap-value < 0.05.

Results

A total of 228 participants (33.3% cases and 66.7% controls) were enrolled in this study. The majority of the cases were in the range of 20–49 years of age (69.7%). The odds of acquiring cholera infection increased significantly by drinking unsafe pipe water (AOR 4.3, 95% CI 1.65–11.2), not having a household level toilet/latrine (AOR 3.25, 95% CI 1.57–6.76), hand washing only sometimes after the toilet (AOR 3.04, 95% CI 1.58–5.86) and not using water purification methods (AOR 2.3, 95% CI 1.13–4.54).

Conclusion

Major risk factors for cholera infection were related to drinking water and latrine hygiene. Improvement in awareness creation about cholera prevention and control methods, including water treatment, hygiene and sanitation were crucial in combating this cholera outbreak. Primary public health actions are ensuring clean drinking water, delivery of water purification tablets, soap and hand sanitizers and provision of health care and outbreak response. Long term goals in cholera affected areas include comprehensive water and sanitation strategies. Overall, the strategic role of a multi-sectoral approach in the design and implementation of public health interventions aimed at preventing and controlling cholera are essential to avert cholera outbreaks. Preparedness should be highlighted in cholera prone areas like Somali region especially after drought periods.

The nexus between improved water supply and water-borne diseases in urban areas in Africa: a scoping review

Background: The sub-Saharan Africa has the fastest rate of urbanisation in the world. However, infrastructure growth in the region is slower than urbanisation rates, leading to inadequate provision and access to basic services such as piped safe drinking water. Lack of sufficient access to safe water has the potential to increase the burden of waterborne diseases among these urbanising populations. This scoping review assesses how the relationship between waterborne diseases and water sufficiency in Africa has been studied. Methods: In April 2020, we searched the Web of Science, PubMed, Embase and Google Scholar databases for studies of African cities that examined the effect of insufficient piped water supply on selected waterborne disease and syndromes (cholera, typhoid, diarrhea, amoebiasis, dysentery, gastroneteritis, cryptosporidium, cyclosporiasis, giardiasis, rotavirus). Only studies conducted in cities that had more than half a million residents in 2014 were included. Results: A total of 32 studies in 24 cities from 17 countries were included in the study. Most studies used case-control, cross-sectional individual or ecological level study designs. Proportion of the study population with access to piped water was the common water availability metrics measured while amounts consumed per capita or water interruptions were seldom used in assessing sufficient water supply. Diarrhea, cholera and typhoid were the major diseases or syndromes used to understand the association between health and water sufficiency in urban areas. There was weak correlation between the study designs used and the association with health outcomes and water sufficiency metrics. Very few studies looked at change in health outcomes and water sufficiency over time. Conclusion: Surveillance of health outcomes and the trends in piped water quantity and mode of access should be prioritised in urban areas in Africa in order to implement interventions towards reducing the burden associated with waterborne diseases and syndromes.