Comparing sociocultural features of cholera in three endemic African settings

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.

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Key Words

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

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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

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Grants

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

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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

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Antibacterial carbonic anhydrase inhibitors targeting Vibrio cholerae enzymes

INTRODUCTION

Cholera is a bacterial diarrheal disease caused by pathogen bacteria Vibrio cholerae, which produces the cholera toxin (CT). In addition to improving water sanitation, oral cholera vaccines have been developed to control infection. Besides, rehydration and antibiotic therapy are complementary treatment strategies for cholera. ToxT regulatory protein activates transcription of CT gene, which is enhanced by bicarbonate (HCO3-).

AREAS COVERED

This review delves into the genomic blueprint of V. cholerae, which encodes for α-, β-, and γ- carbonic anhydrases (CAs). We explore how the CAs contribute to the pathogenicity of V. cholerae and discuss the potential of CA inhibitors in mitigating the disease's impact.

EXPERT OPINION

CA inhibitors can reduce the virulence of bacteria and control cholera. Here, we reviewed all reported CA inhibitors, noting that α-CA from V. cholerae (VchCAα) was the most effective inhibited enzyme compared to the β- and γ-CA families (VchCAβ and VchCAγ). Among the CA inhibitors, acyl selenobenzenesulfonamidenamides and simple/heteroaromatic sulfonamides were the best VchCA inhibitors in the nM range. It was noted that some antibacterial compounds show good inhibitory effects on all three bacterial CAs. CA inhibitors belonging to other classes may be synthesized and tested on VchCAs to harness cholera.

Public and health professional epidemic risk perceptions in countries that are highly vulnerable to epidemics: a systematic review

Background

Risk communication interventions during epidemics aim to modify risk perceptions to achieve rapid shifts in population health behaviours. Exposure to frequent and often concurrent epidemics may influence how the public and health professionals perceive and respond to epidemic risks. This review aimed to systematically examine the evidence on risk perceptions of epidemic-prone diseases in countries highly vulnerable to epidemics.

Methods

We conducted a systematic review using PRISMA standards. We included peer-reviewed studies describing or measuring risk perceptions of epidemic-prone diseases among the general adult population or health professionals in 62 countries considered highly vulnerable to epidemics. We searched seven bibliographic databases and applied a four-stage screening and selection process, followed by quality appraisal. We conducted a narrative meta-synthesis and descriptive summary of the evidence, guided by the Social Amplification of Risk Framework.

Results

Fifty-six studies were eligible for the final review. They were conducted in eighteen countries and addressed thirteen epidemic-prone diseases. Forty-five studies were quantitative, six qualitative and five used mixed methods. Forty-one studies described epidemic risk perceptions in the general public and nineteen among health professionals. Perceived severity of epidemic-prone diseases appeared high across public and health professional populations. However, perceived likelihood of acquiring disease varied from low to moderate to high among the general public, and appeared consistently high amongst health professionals. Other occupational groups with high exposure to specific diseases, such as bushmeat handlers, reported even lower perceived likelihood than the general population. Among health professionals, the safety and effectiveness of the work environment and of the broader health system response influenced perceptions. Among the general population, disease severity, familiarity and controllability of diseases were influential factors. However, the evidence on how epidemic risk perceptions are formed or modified in these populations is limited.

Conclusions

The evidence affords some insights into patterns of epidemic risk perception and influencing factors, but inadequately explores what underlies perceptions and their variability, particularly among diseases, populations and over time. Approaches to defining and measuring epidemic risk perceptions are relatively underdeveloped.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-021-00927-z.

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.

Prevalence and diversity of enteric pathogens among cholera treatment centre patients with acute diarrhea in Uvira, Democratic Republic of Congo

BACKGROUND

Cholera remains a major global health challenge. Uvira, in the Democratic Republic of the Congo (DRC), has had endemic cholera since the 1970's and has been implicated as a possible point of origin for national outbreaks. A previous study among this population, reported a case confirmation rate of 40% by rapid diagnostic test (RDT) among patients at the Uvira Cholera Treatment Centre (CTC). This study considers the prevalence and diversity of 15 enteric pathogens in suspected cholera cases seeking treatment at the Uvira CTC.

METHODS

We used the Luminex xTAG® multiplex PCR to test for 15 enteric pathogens, including toxigenic strains of V. cholerae in rectal swabs preserved on Whatman FTA Elute cards. Results were interpreted on MAGPIX® and analyzed on the xTAG® Data Analysis Software. Prevalence of enteric pathogens were calculated and pathogen diversity was modelled with a Poisson regression.

RESULTS

Among 269 enrolled CTC patients, PCR detected the presence of toxigenic Vibrio cholerae in 38% (103/269) of the patients, which were considered to be cholera cases. These strains were detected as the sole pathogen in 36% (37/103) of these cases. Almost half (45%) of all study participants carried multiple enteric pathogens (two or more). Enterotoxigenic Escherichia coli (36%) and Cryptosporidium (28%) were the other most common pathogens identified amongst all participants. No pathogen was detected in 16.4% of study participants. Mean number of pathogens was highest amongst boys and girls aged 1-15 years and lowest in women aged 16-81 years. Ninety-three percent of toxigenic V. cholerae strains detected by PCR were found in patients having tested positive for V. cholerae O1 by RDT.

CONCLUSIONS

Our study supports previous results from DRC and other cholera endemic areas in sub-Sahara Africa with less than half of CTC admissions positive for cholera by PCR. More research is required to determine the causes of severe acute diarrhea in these low-resource, endemic areas to optimize treatment measures.

TRIAL REGISTRATION

This study is part of the impact evaluation study entitled: "Impact Evaluation of Urban Water Supply Improvements on Cholera and Other Diarrheal Diseases in Uvira, Democratic Republic of Congo" registered on 10 October 2016 at clinicaltrials.gov Identification number: NCT02928341 .

A protracted cholera outbreak among residents in an urban setting, Nairobi county, Kenya, 2015

Introduction

in 2015, a cholera outbreak was confirmed in Nairobi county, Kenya, which we investigated to identify risk factors for infection and recommend control measures.

Methods

we analyzed national cholera surveillance data to describe epidemiological patterns and carried out a case-control study to find reasons for the Nairobi county outbreak. Suspected cholera cases were Nairobi residents aged >2 years with acute watery diarrhea (>4 stools/≤12 hours) and illness onset 1-14 May 2015. Confirmed cases had Vibrio cholerae isolated from stool. Case-patients were frequency-matched to persons without diarrhea (1:2 by age group, residence), interviewed using standardized questionaires. Logistic regression identified factors associated with case status. Household water was analyzed for fecal coliforms and Escherichia coli.

Results

during December 2014-June 2015, 4,218 cholera cases including 282 (6.7%) confirmed cases and 79 deaths (case-fatality rate [CFR] 1.9%) were reported from 14 of 47 Kenyan counties. Nairobi county reported 781 (19.0 %) cases (attack rate, 18/100,000 persons), including 607 (78%) hospitalisations, 20 deaths (CFR 2.6%) and 55 laboratory-confirmed cases (7.0%). Seven (70%) of 10 water samples from communal water points had coliforms; one had Escherichia coli. Factors associated with cholera in Nairobi were drinking untreated water (adjusted odds ratio [aOR] 6.5, 95% confidence interval [CI] 2.3-18.8), lacking health education (aOR 2.4, CI 1.1-7.9) and eating food outside home (aOR 2.4, 95% CI 1.2-5.7).

Conclusion

we recommend safe water, health education, avoiding eating foods prepared outside home and improved sanitation in Nairobi county. Adherence to these practices could have prevented this protacted cholera outbreak.

Enhanced sensitivity to cholera toxin in female ADP-ribosylarginine hydrolase (ARH1)-deficient mice

Cholera toxin, an 84-kDa multimeric protein and a major virulence factor of Vibrio cholerae, uses the ADP-ribosyltransferase activity of its A subunit to intoxicate host cells. ADP-ribosylation is a posttranslational modification of proteins, in which the ADP-ribose moiety of NAD⁺ is transferred to an acceptor. In mammalian cells, ADP-ribosylation of acceptors appears to be reversible. ADP-ribosyltransferases (ARTs) catalyze the modification of acceptor proteins, and ADP-ribose-acceptor hydrolases (ARHs) cleave the ADP-ribose-acceptor bond. ARH1 specifically cleaves the ADP-ribose-arginine bond. We previously demonstrated a role for endogenous ARH1 in regulating the extent of cholera toxin-mediated fluid and electrolyte abnormalities in a mouse model of intoxication. Murine ARH1-knockout (KO) cells and ARH1-KO mice exhibited increased sensitivity to cholera toxin compared to their wild-type (WT) counterparts. In the current report, we examined the sensitivity to cholera toxin of male and female ARH1-KO and WT mice. Intestinal loops derived from female ARH1-KO mice when injected with cholera toxin showed increased fluid accumulation compared to male ARH1-KO mice. WT mice did not show gender differences in fluid accumulation, ADP-ribosylarginine content, and ADP-ribosyl Gαs levels. Injection of 8-Bromo-cAMP into the intestinal loops also increased fluid accumulation, however, there was no significant difference between female and male mice or in WT and KO mice. Female ARH1-KO mice showed greater amounts of ADP-ribosylated Gαs protein and increased ADP-ribosylarginine content both in whole intestine and in epithelial cells than did male ARH1-KO mice. These results demonstrate that female ARH1-KO mice are more sensitive to cholera toxin than male mice. Loss of ARH1 confers gender sensitivity to the effects of cholera toxin but not of cyclic AMP. These observations may in part explain the finding noted in some clinical reports of enhanced symptoms of cholera and/or diarrhea in women than men.

An outbreak of cholera in western Kenya, 2015: a case control study

Introduction

in February 2015, an outbreak of acute watery diarrhea was reported in two sub counties in western Kenya. Vibrio cholerae 01 serotype Ogawa was isolated from 26 cases and from water samples collected from a river mainly used by residents of the two sub-counties for domestic purposes. We carried out an investigation to determine factors associated with the outbreak.

Methods

we conducted a frequency matched case control study in the community. We defined cases as episodes of watery diarrhea (at least three motions in 24 hours) in persons ≥ 2 years who were residents of Rongo or Ndhiwa sub-counties from January 23-February 25, 2015. Cases were systematically recruited from a cholera line list and matched to two controls (persons without diarrhea since January 23, 2015) by age category and residence. A structured questionnaire was administered to evaluate exposures in cases and controls and multivariable logistic regression done to determine independent factors associated with the outbreak.

Results

we recruited 52 cases and 104 controls. Females constituted 61% (95/156) of all participants. Overall latrine coverage was 58% (90/156). Latrine coverage was 44% (23/52) for cases and 64% (67/104) for controls. Having no latrine at home (aOR = 10.9; 95% CI: 3.02-39.21), practicing communal hand washing in a basin (aOR = 6.5; 95% CI: 2.30-18.11) and vending of food as an occupation (aOR = 3.4; 95% CI: 1.06-10.74) were independently associated with the outbreak.

Conclusion

poor latrine coverage and personal hygiene practices were identified as the main drivers of the outbreak. We recommended improved public health education on latrine usage and promotion of hand washing with soap and water in the community.

Environmental Surveillance of Vibrio cholerae O1/O139 in the Five African Great Lakes and Other Major Surface Water Sources in Uganda

Cholera is a major public health problem in the African Great Lakes basin. Two hypotheses might explain this observation, namely the lakes are reservoirs of toxigenic Vibrio cholerae O1 and O139 bacteria, or cholera outbreaks are a result of repeated pathogen introduction from the neighboring communities/countries but the lakes facilitate the introductions. A prospective study was conducted in Uganda between February 2015 and January 2016 in which 28 selected surface water sources were tested for the presence of V. cholerae species using cholera rapid test and multiplex polymerase chain reaction. Of 322 water samples tested, 35 (10.8%) were positive for V. cholerae non O1/non O139 and two samples tested positive for non-toxigenic atypical V. cholerae O139. None of the samples tested had toxigenic V. cholerae O1 or O139 that are responsible for cholera epidemics. The Lake Albert region registered the highest number of positive tests for V. cholerae non O1/non O139 at 47% (9/19). The peak period for V. cholerae non O1/non O139 positive tests was in March–July 2015 which coincided with the first rainy season in Uganda. This study showed that the surface water sources, including the African Great Lakes in Uganda, are less likely to be reservoirs for the observed V. cholerae O1 or O139 epidemics, though they are natural habitats for V. cholerae non O1/non O139 and atypical non-toxigenic V. cholerae O139. Further studies by WGS tests of non-toxigenic atypical V. cholerae O139 and physicochemical tests of surface water sources that supports V. cholerae should be done to provide more information. Since V. cholerae non O1/non O139 may cause other human infections, their continued surveillance is needed to understand their potential pathogenicity.

Vibrio spp. infections

Vibrio is a genus of ubiquitous bacteria found in a wide variety of aquatic and marine habitats; of the >100 described Vibrio spp., ~12 cause infections in humans. Vibrio cholerae can cause cholera, a severe diarrhoeal disease that can be quickly fatal if untreated and is typically transmitted via contaminated water and person-to-person contact. Non-cholera Vibrio spp. (for example, Vibrio parahaemolyticus, Vibrio alginolyticus and Vibrio vulnificus) cause vibriosis - infections normally acquired through exposure to sea water or through consumption of raw or undercooked contaminated seafood. Non-cholera bacteria can lead to several clinical manifestations, most commonly mild, self-limiting gastroenteritis, with the exception of V. vulnificus, an opportunistic pathogen with a high mortality that causes wound infections that can rapidly lead to septicaemia. Treatment for Vibrio spp. infection largely depends on the causative pathogen: for example, rehydration therapy for V. cholerae infection and debridement of infected tissues for V. vulnificus-associated wound infections, with antibiotic therapy for severe cholera and systemic infections. Although cholera is preventable and effective oral cholera vaccines are available, outbreaks can be triggered by natural or man-made events that contaminate drinking water or compromise access to safe water and sanitation. The incidence of vibriosis is rising, perhaps owing in part to the spread of Vibrio spp. favoured by climate change and rising sea water temperature.

Sociocultural determinants of anticipated oral cholera vaccine acceptance in three African settings: a meta-analytic approach

BACKGROUND

Controlling cholera remains a significant challenge in Sub-Saharan Africa. In areas where access to safe water and sanitation are limited, oral cholera vaccine (OCV) can save lives. Establishment of a global stockpile for OCV reflects increasing priority for use of cholera vaccines in endemic settings. Community acceptance of vaccines, however, is critical and sociocultural features of acceptance require attention for effective implementation. This study identifies and compares sociocultural determinants of anticipated OCV acceptance across populations in Southeastern Democratic Republic of Congo, Western Kenya and Zanzibar.

METHODS

Cross-sectional studies were conducted using similar but locally-adapted semistructured interviews among 1095 respondents in three African settings. Logistic regression models identified sociocultural determinants of OCV acceptance from these studies in endemic areas of Southeastern Democratic Republic of Congo (SE-DRC), Western Kenya (W-Kenya) and Zanzibar. Meta-analytic techniques highlighted common and distinctive determinants in the three settings.

RESULTS

Anticipated OCV acceptance was high in all settings. More than 93% of community respondents overall indicated interest in a no-cost vaccine. Higher anticipated acceptance was observed in areas with less access to public health facilities. In all settings awareness of cholera prevention methods (safe food consumption and garbage disposal) and relating ingestion to cholera causation were associated with greater acceptance. Higher age, larger households, lack of education, social vulnerability and knowledge of oral rehydration solution for self-treatment were negatively associated with anticipated OCV acceptance. Setting-specific determinants of acceptance included reporting a reliable income (W-Kenya and Zanzibar, not SE-DRC). In SE-DRC, intention to purchase an OCV appeared unrelated to ability to pay. Rural residents were less likely than urban counterparts to accept an OCV in W-Kenya, but more likely in Zanzibar. Prayer as a form of self-treatment was associated with vaccine acceptance in SE-DRC and W-Kenya, but not in Zanzibar.

CONCLUSIONS

These cholera-endemic African communities are especially interested in no-cost OCVs. Health education and attention to local social and cultural features of cholera and vaccines would likely increase vaccine coverage. High demand and absence of insurmountable sociocultural barriers to vaccination with OCVs indicate potential for mass vaccination in planning for comprehensive control or elimination.

The effects of utility evaluations, biomedical knowledge and modernization on intention to exclusively use biomedical health facilities among rural households in Mozambique

In resource-limited settings, the choice between utilizing biomedical health services and/or traditional healers is critical to the success of the public health mission. In the literature, this choice has been predicted to be influenced by three major factors: knowledge about biomedical etiologies; cultural modernization; and rational choice. The current study investigated all three of these predicted determinants, applying data from a general household survey conducted in 2010 in Zambézia Province of Mozambique involving 1045 randomly sampled rural households. Overall, more respondents (N = 802) intended to continue to supplement their biomedical healthcare with traditional healer services in comparison with those intending to utilize biomedical care exclusively (N = 243). The findings strongly supported the predicted association between rational utility (measured as satisfaction with the quality of service and results from past care) with the future intention to continue to supplement or utilize biomedical care exclusively. Odds of moving away from supplementation increase by a factor of 2.5 if the respondent reported seeing their condition improve under government/private biomedical care. Odds of staying with supplementation increase by a factor 3.1 if the respondent was satisfied with traditional care and a factor of 16 if the condition had improved under traditional care. Modernization variables (education, income, religion, and Portuguese language skills) were relevant and provided a significant component of the best scientific model. Amount of biomedical knowledge was not a significant predictor of choice. There was a small effect on choice from knowing the limitations of biomedical care. The findings have implications for public healthcare promotion activities in areas where biomedical care is introduced as an alternative to traditional healing.