The 2008 cholera epidemic in Zimbabwe: experience of the icddr,b team in the field

Influences of community engagement and health system strengthening for cholera control in cholera reporting countries

The 2030 Global Task Force on Cholera Control Roadmap hinges on strengthening the implementation of multistranded cholera interventions, including community engagement and health system strengthening. However, a composite picture of specific facilitators and barriers for these interventions and any overlapping factors existing between the two, is lacking. Therefore, this study aims to address this shortcoming, focusing on cholera-reporting countries, which are disproportionately affected by cholera and may be cholera endemic. A scoping methodology was chosen to allow for iterative mapping, synthesis of the available research and to pinpoint research activity for global and local cholera policy-makers and shareholders. Using the Arksey and O'Malley framework for scoping reviews, we searched PubMed, Web of Science and CINAHL. Inclusion criteria included publication in English between 1990 and 2021 and cholera as the primary document focus in an epidemic or endemic setting. Data charting was completed through narrative descriptive and thematic analysis. Forty-four documents were included, with half relating to sub-Saharan African countries, 68% (30/44) to cholera endemic settings and 21% (9/44) to insecure settings. We identified four themes of facilitators and barriers to health systems strengthening: health system cooperation and agreement with external actors; maintaining functional capacity in the face of change; good governance, focused political will and sociopolitical influences on the cholera response and insecurity and targeted destruction. Community engagement had two themes: trust building in the health system and growing social cohesion. Insecurity and the community; cooperation and agreement; and sociopolitical influences on trust building were themes of factors acting at the interface between community engagement and health system. Given the decisive role of the community-health system interface for both sustained health system strengthening and community engagement, there is a need to advocate for conflict resolution, trust building and good governance for long-term cholera prevention and control in cholera reporting countries.

Antibiotic-Resistant Vibrio cholerae O1 and Its SXT Elements Associated with Two Cholera Epidemics in Kenya in 2007 to 2010 and 2015 to 2016

Multidrug-resistant Vibrio cholerae O1 strains have long been observed in Africa, and strains exhibiting new resistance phenotypes have emerged during recent epidemics in Kenya. This study aimed to determine the epidemiological aspects, drug resistance patterns, and genetic elements of V. cholerae O1 strains isolated from two cholera epidemics in Kenya between 2007 and 2010 and between 2015 and 2016. A total of 228 V. cholerae O1 strains, including 226 clinical strains isolated from 13 counties in Kenya during the 2007-2010 and 2015-2016 cholera epidemics and two environmental isolates (from shallow well water and spring water isolates) isolated from Pokot and Kwale Counties, respectively, in 2010 were subjected to biotyping, serotyping, and antimicrobial susceptibility testing, including the detection of antibiotic resistance genes and mobile genetic elements. All V. cholerae isolates were identified as El Tor biotypes and susceptible to ceftriaxone, gentamicin, and ciprofloxacin. The majority of isolates were resistant to trimethoprim-sulfamethoxazole (94.6%), streptomycin (92.8%), and nalidixic acid (64.5%), while lower resistance was observed against ampicillin (3.6%), amoxicillin (4.2%), chloramphenicol (3.0%), and doxycycline (1.8%). Concurrently, the integrating conjugative (SXT) element was found in 95.5% of the V. cholerae isolates; conversely, class 1, 2, and 3 integrons were absent. Additionally, 64.5% of the isolates exhibited multidrug resistance patterns. Antibiotic-resistant gene clusters suggest that environmental bacteria may act as cassette reservoirs that favor resistant pathogens. On the other hand, the 2015-2016 epidemic strains were found susceptible to most antibiotics except nalidixic acid. This revealed the replacement of multidrug-resistant strains exhibiting new resistance phenotypes that emerged after Kenya's 2007-2010 epidemic. IMPORTANCE Kenya is a country where cholera is endemic; it has experienced three substantial epidemics over the past few decades, but there are limited data on the drug resistance patterns of V. cholerae at the national level. To the best of our knowledge, this is the first study to investigate the antimicrobial susceptibility profiles of V. cholerae O1 strains isolated from two consecutive epidemics and to examine their associated antimicrobial genetic determinants. Our study results revealed two distinct antibiotic resistance trends in two separate epidemics, particularly trends for multidrug-associated mobile genetic elements and chromosomal mutation-oriented resistant strains from the 2007-2010 epidemic. In contrast, only nalidixic acid-associated chromosomal mutated strains were isolated from the 2015-2016 epidemic. This study also found similar patterns of antibiotic resistance in environmental and clinical strains. Continuous monitoring is needed to control emerging multidrug-resistant isolates in the future.

When silence goes viral, Africa sneezes! A perspective on Africa's subdued research response to COVID-19 and a call for local scientific evidence

By mid-September 2020, over 1.33 million confirmed COVID-19 cases and 32 thousand deaths had been reported in Africa. Global research on COVID-19 went 'viral' with a record 3487 research contributions comprising of 2062 journal papers and 1425 preprints published within the first three months following the outbreak of COVID-19. Surprisingly, the silence of the African research community has been unprecedented - contributing a paltry 0.6% (22 contributions), a figure nearly matched by Colombia (18 publications). Until now, a comprehensive perspective on the reasons for this subdued research response, and COVID-19 themes critical to Africa has been missing. We posit that while a milieu of factors accounts for this silence, unprecedented research opportunities exist to support COVID-19 decision and policy formulation in Africa. The subdued response reflects weak research systems, characterized by deep-rooted challenges, including severe lack of research expertise, funding, and infrastructure, coupled with poor working conditions. Hence, Africa's contribution to research on infectious diseases, including COVID-19, remains weak. Perceptions and attitudes among researchers and policy-makers on COVID-19, and the role of science in decision and policy-making also exist. Moreover, COVID-19 and earlier severe acute respiratory syndromes are considered as 'imported diseases' originating from outside Africa. Thus, notions may exist that the control methods will come from outside Africa through 'technology-transfer' or 'capacity-building'. Yet local COVID-19 research is needed to address knowledge gaps, including; (1) potential novel transmission of SARS-CoV-2, (2) adaption of generic COVID-19 control measures to suit African settings, (3) occurrence and persistence of SARS-CoV-2 in solid waste, wastewaters, on-site sanitation systems, and drinking water, and (4) the 'human factor' including the role of gender, perceptions, myths, attitudes, and religious beliefs in the transmission and control of COVID-19. Therefore, there is a need to: (1) strengthen local research capacity and evaluation systems, (2) consider biosafety and ethical issues, (3) initiate cross-disciplinary research and global collaboration on COVID-19, and (4) integrate science communication in COVID-19 programs.

Leaving no stone unturned in light of the COVID-19 faecal-oral hypothesis? A water, sanitation and hygiene (WASH) perspective targeting low-income countries

The human coronavirus disease (COVID-19) is now a global pandemic. Social distancing, hand hygiene and the use of personal protective equipment dominate the current fight against COVID-19. In developing countries, the need for clean water provision, sanitation and hygiene has only received limited attention. The current perspective examines the latest evidence on the occurrence, persistence and faecal-oral transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the etiological agent causing COVID-19. Evidence shows that SARS-CoV-2 proliferate in the human gastrointestinal system, and is shed via faeces. SARS-CoV-2 can survive and remain viable for up to 6 to 9 days on surfaces. Recent wastewater-based epidemiological studies from several countries also detected SARS-CoV-2 RNA in raw wastewaters. Shell disorder analysis shows that SARS-CoV-2 has a rigid outer shell conferring resilience, and a low shell disorder conferring moderate potential for faecal-oral transmission. Taken together, these findings point to potential faecal-oral transmission of SARS-CoV-2, which may partly explain its rapid transmission. Three potential mechanisms may account for SARS-CoV-2 faecal-oral transmission: (1) untreated contaminated drinking water, (2) raw and poorly cooked marine and aquatic foods from contaminated sources, (3) raw wastewater-based vegetatble production systems (e.g., salads) and aquaculture, and (4) vector-mediated transmission from faecal sources to foods, particularly those from open markets and street vending. SARS-CoV-2 faecal-oral transmission could be particularly high in developing countries due to several risk factors, including; (1) poor drinking water, wastewater and sanitation infrastructure, (2) poor hygiene and food handling practices, (3) unhygienic and rudimentary funeral practices, including home burials close to drinking water sources, and (4) poor social security and health care systems with low capacity to cope with disease outbreaks. Hence, clean drinking water provision, proper sanitation, food safety and hygiene could be critical in the current fight against COVID-19. Future research directions on COVID-19 faecal-oral transmission are highlighted.

Lessons Learned from Enhancing Sentinel Surveillance for Cholera in Post-Earthquake Nepal in 2016

A major earthquake in 2015 that struck Nepal created a favorable environment for the rapid spread of infectious diseases. In anticipation of a cholera outbreak in 2016, UNICEF, Johns Hopkins University, and the Group for Technical Assistance, Nepal, collaborated to assist the government of Nepal to strengthen early warning surveillance, laboratory-based diagnosis, and field investigation. This article outlines the challenges and lessons learned in cholera prevention and control based on the authors’ experiences in 2016. Priorities for the future plan should include sustaining the enhanced surveillance system for acute gastroenteritis and cholera, rolling out a rapid diagnostic test, and ensuring rapid and systematic epidemiological investigation and environmental testing.

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.

Cholera epidemic in Yemen, 2016-18: an analysis of surveillance data

Background

In war-torn Yemen, reports of confirmed cholera started in late September, 2016. The disease continues to plague Yemen today in what has become the largest documented cholera epidemic of modern times. We aimed to describe the key epidemiological features of this epidemic, including the drivers of cholera transmission during the outbreak.

Methods

The Yemen Health Authorities set up a national cholera surveillance system to collect information on suspected cholera cases presenting at health facilities. Individual variables included symptom onset date, age, severity of dehydration, and rapid diagnostic test result. Suspected cholera cases were confirmed by culture, and a subset of samples had additional phenotypic and genotypic analysis. We first conducted descriptive analyses at national and governorate levels. We divided the epidemic into three time periods: the first wave (Sept 28, 2016, to April 23, 2017), the increasing phase of the second wave (April 24, 2017, to July 2, 2017), and the decreasing phase of the second wave (July 3, 2017, to March 12, 2018). We reconstructed the changes in cholera transmission over time by estimating the instantaneous reproduction number, R_t. Finally, we estimated the association between rainfall and the daily cholera incidence during the increasing phase of the second epidemic wave by fitting a spatiotemporal regression model.

Findings

From Sept 28, 2016, to March 12, 2018, 1 103 683 suspected cholera cases (attack rate 3·69%) and 2385 deaths (case fatality risk 0·22%) were reported countrywide. The epidemic consisted of two distinct waves with a surge in transmission in May, 2017, corresponding to a median R_t of more than 2 in 13 of 23 governorates. Microbiological analyses suggested that the same Vibrio cholerae O1 Ogawa strain circulated in both waves. We found a positive, non-linear, association between weekly rainfall and suspected cholera incidence in the following 10 days; the relative risk of cholera after a weekly rainfall of 25 mm was 1·42 (95% CI 1·31–1·55) compared with a week without rain.

Interpretation

Our analysis suggests that the small first cholera epidemic wave seeded cholera across Yemen during the dry season. When the rains returned in April, 2017, they triggered widespread cholera transmission that led to the large second wave. These results suggest that cholera could resurge during the ongoing 2018 rainy season if transmission remains active. Therefore, health authorities and partners should immediately enhance current control efforts to mitigate the risk of a new cholera epidemic wave in Yemen.

Funding

Health Authorities of Yemen, WHO, and Médecins Sans Frontières.

Sensitivity, Specificity, and Public-Health Utility of Clinical Case Definitions Based on the Signs and Symptoms of Cholera in Africa

During 2014, Africa reported more than half of the global suspected cholera cases. Based on the data collected from seven countries in the African Cholera Surveillance Network (Africhol), we assessed the sensitivity, specificity, and positive and negative predictive values of clinical cholera case definitions, including that recommended by the World Health Organization (WHO) using culture confirmation as the gold standard. The study was designed to assess results in real-world field situations in settings with recent cholera outbreaks or endemicity. From June 2011 to July 2015, a total of 5,084 persons with suspected cholera were tested for Vibrio cholerae in seven different countries of which 35.7% had culture confirmation. For all countries combined, the WHO case definition had a sensitivity = 92.7%, specificity = 8.1%, positive predictive value = 36.1%, and negative predictive value = 66.6%. Adding dehydration, vomiting, or rice water stools to the case definition could increase the specificity without a substantial decrease in sensitivity. Future studies could further refine our findings primarily by using more sensitive methods for cholera confirmation.

The Cholera Epidemic in Zimbabwe, 2008-2009: A Review and Critique of the Evidence

The 2008-2009 Zimbabwe cholera epidemic resulted in 98,585 reported cases and caused more than 4,000 deaths. In this study, we used a mixed-methods approach that combined primary qualitative data from a 2008 Physicians for Human Rights-led investigation with a systematic review and content analysis of the scientific literature. Our initial investigation included semi-structured interviews of 92 key informants, which we supplemented with reviews of the social science and human rights literature, as well as international news reports. Our systematic review of the scientific literature retrieved 59 unique citations, of which 30 met criteria for inclusion in the content analysis: 14 of the 30 (46.7%) articles mentioned the political dimension of the epidemic, while 7 (23.3%) referenced Mugabe or his political party (ZANU-PF). Our investigation revealed that the 2008-2009 Zimbabwean cholera epidemic was exacerbated by a series of human rights abuses, including the politicization of water, health care, aid, and information. The failure of the scientific community to directly address the political determinants of the epidemic exposes challenges to maintaining scientific integrity in the setting of humanitarian responses to complex health and human rights crises. While the period of the cholera epidemic and the health care system collapse is now nearly a decade in the past, the findings of this work remain highly relevant for Zimbabwe and other countries, as complex health and rights interactions remain widespread, and governance concerns continue to limit improvements in human health.

Retrospective Analysis of Serotype Switching of Vibrio cholerae O1 in a Cholera Endemic Region Shows It Is a Non-random Process

Genomic data generated from clinical Vibrio cholerae O1 isolates collected over a five year period in an area of Kolkata, India with seasonal cholera outbreaks allowed a detailed genetic analysis of serotype switching that occurred from Ogawa to Inaba and back to Ogawa. The change from Ogawa to Inaba resulted from mutational disruption of the methyltransferase encoded by the wbeT gene. Re-emergence of the Ogawa serotype was found to result either from expansion of an already existing Ogawa clade or reversion of the mutation in an Inaba clade. Our data suggests that such transitions are not random events but rather driven by as yet unidentified selection mechanisms based on differences in the structure of the O1 antigen or in the serotype-determining wbeT gene.

Cholera is a major health problem in many parts of the world causing seasonal outbreaks in endemic areas. Essentially only the O1 serogroup of Vibrio cholerae causes epidemic cholera. This serogroup has two immunologically distinguishable serotype variants called Ogawa and Inaba. The Inaba serotype is a consequence of a mutation in a single gene, wbeT, that in its intact form encodes for an enzyme that methylates the terminal perosamine sugar of the lipopolysaccharide side chain thus resulting in the Ogawa serotype. By careful examination over a five-year period of the genetic lineages of bacteria causing cholera in an endemic area we show data indicating that serotype switching is not a random process but is driven by selection pressures that have yet to be identified.

Cholera outbreaks in Africa

During the current seventh cholera pandemic, Africa bore the major brunt of global disease burden. More than 40 years after its resurgence in Africa in 1970, cholera remains a grave public health problem, characterized by large disease burden, frequent outbreaks, persistent endemicity, and high CFRs, particularly in the region of the central African Great Lakes which might act as reservoirs for cholera. There, cases occur year round with a rise in incidence during the rainy season. Elsewhere in sub-Saharan Africa, cholera occurs mostly in outbreaks of varying size with a constant threat of widespread epidemics. Between 1970 and 2011, African countries reported 3,221,050 suspected cholera cases to the World Health Organization, representing 46 % of all cases reported globally. Excluding the Haitian epidemic, sub-Saharan Africa accounted for 86 % of reported cases and 99 % of deaths worldwide in 2011. The number of cholera cases is possibly much higher than what is reported to the WHO due to the variation in modalities, completeness, and case definition of national cholera data. One source on country specific incidence rates for Africa, adjusting for underreporting, estimates 1,341,080 cases and 160,930 deaths (52.6 % of 2,548,227 estimated cases and 79.6 % of 209,216 estimated deaths worldwide). Another estimates 1,411,453 cases and 53,632 deaths per year, respectively (50 % of 2,836,669 estimated cases and 58.6 % of 91,490 estimated deaths worldwide). Within Africa, half of all cases between 1970 and 2011 were notified from only seven countries: Angola, Democratic Republic of the Congo, Mozambique, Nigeria, Somalia, Tanzania, and South Africa. In contrast to a global trend of decreasing case fatality ratios (CFRs), CFRs have remained stable in Africa at approximately 2 %. Early propagation of cholera outbreaks depends largely on the extent of individual bacterial shedding, host and organism characteristics, the likelihood of people coming into contact with an infectious dose of Vibrio cholerae and on the virulence of the implicated strain. Cholera transmission can then be amplified by several factors including contamination of human water- or food sources; climate and extreme weather events; political and economic crises; high population density combined with poor quality informal housing and poor hygiene practices; spread beyond a local community through human travel and animals, e.g., water birds. At an individual level, cholera risk may increase with decreasing immunity and hypochlorhydria, such as that induced by Helicobacter pylori infection, which is endemic in much of Africa, and may increase individual susceptibility and cholera incidence. Since contaminated water is the main vehicle for the spread of cholera, the obvious long-term solution to eradicate the disease is the provision of safe water to all African populations. This requires considerable human and financial resources and time. In the short and medium term, vaccination may help to prevent and control the spread of cholera outbreaks. Regardless of the intervention, further understanding of cholera biology and epidemiology is essential to identify populations and areas at increased risk and thus ensure the most efficient use of scarce resources for the prevention and control of cholera.

High case fatality cholera outbreak in Western Kenya, August 2010

Introduction

Cholera is a disease caused by the bacterium Vibrio cholera and has been an important public health problem since its first pandemic in 1817. Kenya has had numerous outbreaks of cholera ever since it was first detected there during 1971. In August 2010 an outbreak of cholera occurred in Kuria West District spreading to the neighboring Migori District. We conducted an investigation in order to determine the magnitude of the problem and institute control measures.

Methods

In order to update the line lists we reviewed records in Migori and Kuria district hospitals and conducted active case search in the community between 30th August and 6th September 2010. Data was analyzed using Epi-Info 3.5.2.

Results

A total of 114 cases and with 10 deaths (Case Fatality Rate = 9%) were documented. The index case was an 80 years old woman from Mabera Division who had hosted a cultural marriage ceremony a day before the outbreak. The mean age of case patients was 34.5 years (Standard Deviation=23.4) with a range 5 to 80 years. Females accounted for 61.4% of cases; people aged 10-39 years accounted 46.9%, those 40-69 years accounted for 29.2% and those above 70 years accounted for 9.7% of the cases. Sixty percent of deaths occurred among patients aged 50 years and over, case fatality rate was highest in this age group (16.7%) followed by those aged 40-49 years (12.5%), 20-29 years (10%) and 10-19 years (4.8%). The outbreak was confirmed within 2 weeks of onset after one (16.7%) of the six samples taken tested positive for V. cholera (serotype Inaba).

Conclusion

High case fatality rate and late laboratory confirmation was noted in this outbreak. There was urgent need to capacity build the districts on cholera case management, outbreak management, and equip the Migori District Hospital laboratory to allow prompt confirmation.