Predictors of disease severity in patients admitted to a cholera treatment center in urban Haiti

Clinical Characteristics and Factors Associated With Severe Outcomes of 1891 Pediatric Patients Admitted to the Referral Cholera Treatment Centers in Lusaka, Zambia, December 2023-March 2024

Background

Zambia declared a cholera outbreak on 18 October 2023 and, as of 31 June 2024, had recorded 23 381 cases and 740 deaths. Of the patients seen at the 2 main cholera treatment centers in the capital Lusaka, a third of them were children aged 0 to 15 years. Despite the significant pediatric cholera burden, risk factors for mortality and prolonged hospitalization remain unknown.

Methods

A retrospective data review was conducted by examining the clinical characteristics of patients aged 0 to 15 years hospitalized at the 2 cholera treatment centers between 15 October 2023 and 31 March 2024. Descriptive analysis was conducted for patient characteristics, and penalized logistic regression (PLR) was used to analyze risk factors for the outcomes.

Results

A total of 1891 patients were identified, among which 1.4% (18/1253) had fatal outcomes and 47.9% (399/833) had hospitalization >2 days. By the PLR, the following factors were independently correlated with hospitalization >2 days: HIV infection (odds ratio [OR], 6.89; 95% CI, 1.32-71.9), severe acute malnutrition (SAM; OR, 10.8; 95% CI, 2.91-61.1), and dehydration treatment plans B (OR, 3.93; 95% CI, 1.80-9.27) and C (OR, 7.54; 95% CI, 2.71-22.9). For the fatal outcome, none of them independently showed any significant correlations by the PLR, although younger age and SAM were positively associated by bivariate analysis.

Conclusions

Comorbidities such as SAM and HIV, being on plan B or C, and deteriorating and requiring more intense treatment are associated with longer hospitalization. Risk factors for mortality need to be further investigated.

Risk factors for cholera mortality: A scoping review

OBJECTIVES

Cholera is an easily treatable disease, but many people are still unnecessarily dying from it. To improve current case management practices and prevent mortality requires a comprehensive understanding of who is at higher risk of dying. To identify the most common risk factors, a scoping review was undertaken, to explore the literature and summarise the evidence on cholera mortality and reported risk factors.

METHODS

Following the scoping review framework proposed by Arksey and O'Malley (2005), Pubmed, EMBASE, Web of Science, LILACS, Scielo, Cochrane and Open Grey and African Journals Online were searched on 24 November 2021, without restrictions in language or date. After screening and assessing the records across predefined criteria, we performed a thematic analysis on mortality.

RESULTS

A total of 77 studies were included in the final review. The potential reasons explaining the observed mortality were classified in the following categories: Patient characteristics; Healthcare; and Health-seeking behaviour. The identified risk factors were multi-dimensional, inter-dependent and context-specific. When exploring the patients' characteristics, the available data suggested that in many contexts, case fatality ratios were higher among males and older people, especially those aged 50 or above. Twelve studies reported the place of death, with the percentage of community deaths ranging from 23% to 96%. Evidence on comorbidities and cholera deaths was too scarce for analysis.

CONCLUSIONS

Cholera has been a disease of global importance for more than two centuries. Despite this, our review highlighted that there has been limited published evidence about factors that increase the risk of cholera-related death. Collecting, reporting and analysing baseline characteristics such as age, sex and predisposing conditions can improve our understanding of cholera mortality risk factors and guide improvements in future case management recommendations.

Update on CVD 103-HgR single-dose, live oral cholera vaccine

Cholera remains endemic in >50 countries, putting millions at risk, especially young children for whom killed vaccines offer limited protection. An oral, live attenuated vaccine - CVD 103-HgR (Vaxchora vaccine) - was licensed by the US FDA in 2016 for adults aged 18-64 years traveling to endemic regions, based on clinical trials in human volunteers showing the vaccine was well tolerated and conferred 90% efficacy within 10 days. The evidence base for Vaxchora vaccine has expanded with additional clinical trial data, in older adults (aged 46-64 years) and children (aged 2-17 years), demonstrating that the vaccine produces a strong vibriocidal antibody response. Over 68,000 doses have been administered in the United States, with no new safety signals. The dose volume has been reduced in children to improve acceptability, and cold chain requirements are less st ringent, at +2°C─+8°C. The vaccine has recently been licensed in the Untied States for children aged 2-17 years, in Europe for individuals aged ≥2 years, and for home administration in Europe. Next steps include a Phase 4 study in infants (6-23 months). Additional information is needed regarding duration of immunity, the need for and timing of revaccination, and efficacy data from lower-middle-income countries.

Identifying and quantifying the factors associated with cholera-related death during the 2018 outbreak in Nigeria

Introduction

cholera outbreaks in Nigeria are often associated with high case fatality rates; however, there is a dearth of evidence on context-specific factors associated with the trend. This study therefore aimed to identify and quantify the factors associated with cholera-related deaths in Nigeria.

Methods

using a cross-sectional design, we analysed surveillance data from all the States that reported cholera cases during the 2018 outbreak, and defined cholera-related death as death of an individual classified as having cholera according to the Nigeria Centre for Disease Control case definition. Factors associated with cholera-related death were assessed using multivariable logistic regression and findings presented as adjusted odds ratios (ORs) with 95% Confidence Intervals (95% CIs).

Results

between January 1 and November 19, 2018, 41,394 cholera cases were reported across 20 States, including 815 cholera-related deaths. In the adjusted multivariable model, older age, male gender, living in peri-urban areas or in flooded states, infection during the rainy season, and delay in seeking health care by >2 days were positively associated with cholera-related death; whereas living in urban areas, hospitalisation in the course of illness, and presentation to a secondary hospital were negatively associated with cholera-related death.

Conclusion

cholera-related deaths during the 2018 outbreak in Nigeria appeared to be driven by multiple factors, which further reemphasises the importance of adopting a multisectoral approach to the design and implementation of context-specific interventions in Nigeria.

Immune responses to O-specific polysaccharide (OSP) in North American adults infected with Vibrio cholerae O1 Inaba

Background

Antibodies targeting O-specific polysaccharide (OSP) of Vibrio cholerae may protect against cholera; however, little is known about this immune response in infected immunologically naïve humans.

Methodology

We measured serum anti-OSP antibodies in adult North American volunteers experimentally infected with V. cholerae O1 Inaba El Tor N16961. We also measured vibriocidal and anti-cholera toxin B subunit (CtxB) antibodies and compared responses to those in matched cholera patients in Dhaka, Bangladesh, an area endemic for cholera.

Principal findings

We found prominent anti-OSP antibody responses following initial cholera infection: these responses were largely IgM and IgA, and highest to infecting serotype with significant cross-serotype reactivity. The anti-OSP responses peaked 10 days after infection and remained elevated over baseline for ≥ 6 months, correlated with vibriocidal responses, and may have been blunted in blood group O individuals (IgA anti-OSP). We found significant differences in immune responses between naïve and endemic zone cohorts, presumably reflecting previous exposure in the latter.

Conclusions

Our results define immune responses to O-specific polysaccharide in immunologically naive humans with cholera, find that they are largely IgM and IgA, may be blunted in blood group O individuals, and differ in a number of significant ways from responses in previously humans. These differences may explain in part varying degrees of protective efficacy afforded by cholera vaccination between these two populations.

Trial registration number

ClinicalTrials.gov NCT01895855.

Cholera is an acute, secretory diarrheal disease caused by Vibrio cholerae O1. There is a growing body of evidence that immune responses targetting the O-specific polysaccharide (OSP) of V. cholerae are associated with protecton against cholera. Despite this, little is known about immune responses targeting OSP in immunologically naive individals. Cholera affects populations in severely resource-limited areas. To address this, we assessed anti-OSP immune responses in North American volunteers experimentally infected with wild type V. cholerae O1 El Tor Inaba strain N16961. We found that antibody responses were largely IgM and IgA, cross-reacted to both Inaba and Ogawa serotypes, and correlated with vibriocidal responses. We found no association of responses to severity of disease, but did find that blood group O individuals mounted lower IgA fold-changes to OSP than did non-blood group O individuals. Individuals with blood group O are at particular risk for severe cholera, and are less well protected against cholera following oral vaccination. We also compared anti-OSP responses in previously unexposed individuals to responses in matched endemic zone patients, and found a number of significant differences. Such differences may explain in part the varying degrees of protective efficacy afforded by cholera vaccination between these two populations.

Cholera: Immunity and Prospects in Vaccine Development

Vibrio cholerae is a prototypical noninvasive mucosal pathogen, yet infection generates long-lasting protection against subsequent disease. Vibriocidal antibody responses are an imperfect but established correlate of protection against cholera following both infection and vaccination. However, vibriocidal antibody responses are likely a surrogate marker for longer-lasting functional immune responses that target the O-polysaccharide antigen at the mucosal surface. While the current bivalent inactivated oral whole cell vaccine is being increasingly used to prevent cholera in areas where the disease is a threat, the most significant limitation of this vaccine is it offers relatively limited direct protection in young children. Future strategies for cholera vaccination include the development of cholera conjugate vaccines and the further development of live attenuated vaccines. Ultimately, the goal of a multivalent vaccine for cholera and other childhood enteric infections that can be incorporated into a standard immunization schedule should be realized.

Use and Interpretation of Enteropathogen Multiplex Nucleic Acid Amplification Tests in Patients With Suspected Infectious Diarrhea

Acute diarrheal illness due to gastrointestinal infection is a significant cause of morbidity and mortality in the United States and around the world. Determining the causative organism in a timely manner assists with patient care, identifying outbreaks, providing infection control, and administering antimicrobial therapy when indicated. Traditional diagnostic modalities based on culture and immunoassays are limited by their low sensitivity and long turnaround time. Nucleic acid amplification tests (NAATs) for enteric pathogens allow for the syndromic testing of stool for multiple pathogens simultaneously and have higher sensitivity with a shorter turnaround time. However, by not isolating the organism, NAATs do not provide drug susceptibility or confirmatory identification. Furthermore, NAATs cannot distinguish between true infection and carrier states. Nevertheless, several studies have demonstrated the cost-effectiveness of multiplex NAATs by reducing the length of hospital stay and cost of isolation. Five platforms are currently approved by the US Food and Drug Administration that can detect different bacteria, parasites, and viruses. The sensitivity and specificity of each platform depends on the targeted pathogens and whether the tests are performed on fresh stool, frozen stool, or in transport media. Overall, these tests have high sensitivity and specificity of more than 90% when used in symptomatic patients. Thus, multiplex NAAT gastrointestinal platforms offer several advantages compared to traditional methods. However, the interpretation of the results requires acknowledging the limitations of the tests and exercising clinical judgment. More studies are needed to establish the cost-effectiveness of multiplex NAATs and their impact on antibiotic stewardship and clinical outcomes.

Confirmation of cholera by rapid diagnostic test amongst patients admitted to the cholera treatment centre in Uvira, Democratic Republic of the Congo

INTRODUCTION

Cholera is endemic in the Eastern provinces of the Democratic Republic of the Congo since 1978, and Uvira in South-Kivu has been reporting suspected cholera cases nearly every week for over a decade. The clinical case definition for suspected cholera is relatively non-specific, and cases are rarely confirmed by laboratory methods, especially in endemic settings. This may lead to over-estimation of cholera cases and limit effective public health responses.

METHODS AND RESULTS

Between April 2016 and November 2017, 69% of the 2,059 patients admitted to the Uvira Cholera Treatment Centre (CTC) were tested for cholera with rapid diagnostic tests (RDTs). Of those admitted as suspected cholera cases, only 40% tested positive for cholera, equivalent to an estimated annual incidence of suspected/confirmed cholera in Uvira of 43.8 and 16.3 cases per 10,000 inhabitants respectively. A multivariable logistic regression indicates that boys aged 2 to 4 years, girls aged 5 to 15 years and adult men are respectively 1.9, 2.1 and 1.8 times more likely to test positive than adult women. On the contrary, boys under 2 are 10 times less likely to test positive. The odds of testing positive also increase as weekly admissions to the CTC rise, with up to a 5-fold increase observed during the weeks with the highest numbers of admissions compared to the lowest ones. Other predictors of cholera confirmation include duration of stay at the CTC, clinical outcome of admission, lower weekly rainfall and area of residence in Uvira, with the northern part of town having the highest confirmation rate.

CONCLUSION

Cholera is an on-going public health problem in Uvira but the majority of suspected cases admitted to the CTC were found to be negative for cholera after RDT testing. These findings may have important implications for cholera control strategies in favour of interventions that address cholera and other diarrhoeal diseases alike.

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.

Health Outcomes for Children in Haiti Since the 2010 Earthquake: A Systematic Review

BACKGROUND

Haiti remains the poorest country in the Americas and one of the poorest in the world. Children in Haiti face many health concerns, some of which were exacerbated by the 2010 earthquake. This systematic review summarizes published research conducted since the 2010 earthquake, focusing on health outcomes for children in Haiti, including physical, psychological, and socioeconomic well-being.

METHODS

A literature search was conducted identifying articles published from January 2010 through May 2016 related to pediatric health outcomes in Haiti. Two reviewers screened articles independently. Included research articles described at least one physical health, psychological health, or socioeconomic outcome among children less than 18 years of age in Haiti since the January 2010 earthquake.

RESULTS

Fifty-eight full-length research articles were reviewed, covering infectious diseases (non-cholera [N=12] and cholera [N=7]), nutrition (N=11), traumatic injuries (N=11), mental health (N=9), anemia (N=4), abuse and violence (N=5), and other topics (N=3). Many children were injured in the 2010 earthquake, and care of their injuries is described in the literature. Infectious diseases were a significant cause of morbidity and mortality among children following the earthquake, with cholera being one of the most important etiologies. The literature also revealed that large numbers of children in Haiti have significant symptoms of posttraumatic stress disorder (PTSD), peri-traumatic stress, depression, and anxiety, and that food insecurity and malnutrition continue to be important issues.

CONCLUSIONS

Future health programs in Haiti should focus on provision of clean water, sanitation, and other measures to prevent infectious diseases. Mental health programming and services for children also appear to be greatly needed, and food insecurity/malnutrition must be addressed if children are to lead healthy, productive lives. Given the burden of injury after the 2010 earthquake, further research on long-term disabilities among children in Haiti is needed. Dube A , Moffatt M , Davison C , Bartels S . Health outcomes for children in Haiti since the 2010 earthquake: a systematic review. Prehosp Disaster Med. 2018;33(1):77-88.

Clinical Features of Human Immunodeficiency Virus-Infected Patients Presenting with Cholera in Port-au-Prince, Haiti

Human immunodeficiency virus (HIV) infection has been postulated to alter the natural history of cholera, including increased susceptibility to infection, severity of illness, and chronic carriage of Vibrio cholerae Haiti has a generalized HIV epidemic with an adult HIV prevalence of 1.9% and recently suffered a cholera epidemic. We conducted a prospective study at the cholera treatment center (CTC) of GHESKIO in Haiti to characterize the coinfection. Adults admitted at the CTC for acute diarrhea were invited to participate in the study. Vital signs, frequency, and volume of stools and/or vomiting were monitored, and single-dose doxycycline was administered. After counseling, participants were screened for HIV by enzyme-linked immunosorbent assay and for cholera by culture. Of 729 adults admitted to the CTC, 99 (13.6%) had HIV infection, and 457 (63%) had culture-confirmed cholera. HIV prevalence was three times higher in patients without cholera (23%, 63/272) than in those with culture-confirmed cholera (7.9%, 36/457). HIV prevalence in patients with culture-confirmed cholera (7.9%) was four times higher than the adult prevalence in Port-au-Prince (1.9%). Of the 36 HIV-infected patients with cholera, 25 (69%) had moderate/severe dehydration versus 302/421 (72%) in the HIV negative. Of 30 HIV-infected patients with weekly stool cultures performed after discharge, 29 (97%) were negative at week 1. Of 50 HIV-negative patients with weekly stool cultures, 49 (98%) were negative at week 1. In countries with endemic HIV infection, clinicians should consider screening patients presenting with suspected cholera for HIV coinfection.

Effectiveness of Oral Cholera Vaccine in Haiti: 37-Month Follow-Up

The first oral cholera vaccine (OCV) campaign, since its prequalification by the World Health Organization, in response to an ongoing cholera epidemic (reactive vaccination) was successfully conducted in a poor urban slum of approximately 70,000 inhabitants in Port-au-Prince, Haiti, in 2012. Vaccine coverage was 75% of the target population. This report documents the impact of OCV in reducing the number of culture-confirmed cases of cholera admitted to the Groupe Haïtien d'Etude du Sarcome de Kaposi et des Infections Opportunistes (GHESKIO) cholera treatment center from that community in the 37 months postvaccination (April 2012-April 30, 2015). Of 1,788 patients with culture-confirmed cholera, 1,770 (99%) were either from outside the vaccine area (1,400 cases) or from the vaccinated community who had not received OCV (370 cases). Of the 388 people from the catchment area who developed culture-confirmed cholera, 370 occurred among the 17,643 people who had not been vaccinated (2.1%) and the remaining 18 occurred among the 52,357 people (0.034%) who had been vaccinated (P < 0.001), for an efficacy that approximates 97.5%. Despite not being designed as a randomized control trial, the very high efficacy is a strong evidence for the effectiveness of OCV as part of an integrated package for the control of cholera in outbreak settings.

Low prevalence of Vibrio cholerae O1 versus moderate prevalence of intestinal parasites in food-handlers working with health care personnel in Haiti

Food-handlers with poor personal hygiene working in food-service establishments could be potential sources of infection due to pathogenic organisms. In May 2011, a cross-sectional study was undertaken to determine the prevalence of bacteria and intestinal parasites among food-handlers working with Cuban health personnel in Haiti. Stool specimens were collected from 56 food-handlers and samples were examined using standard procedures. Of the food handlers, 26.8% had one bacterial or intestinal parasite. The most prevalent species of organism found were Blastocystis spp. (9%), followed by Vibrio cholerae O1 serotype Ogawa, Aeromonas spp. and Giardia intestinalis, each one with 4%. The prevalence of intestinal parasites was 19.7%. Five out of 56 food handlers had diarrhea at the time the study was conducted. It was found that there was a lower prevalence of V. cholerae O1 serotype Ogawa in comparison to intestinal parasites. The study highlights the importance of the precautions that must be taken in cholera-affected countries by medical teams and their organizations, with emphasis on the preparation, processing, and serving of meals. The recommendation is to intensify continuing education programs, periodical laboratory examinations to detect carriers and food-handlers reporting sick, and to observe strict adherence to hygienic food-handling practices. In addition, food handlers with diarrhea should refrain from preparation or delivery of food.

Evaluation of the xTAG Gastrointestinal Pathogen Panel Assay for the Detection of Enteric Pathogens in Kuwait

OBJECTIVE

To evaluate the utility of the Luminex xTAG gastrointestinal pathogen panel (GPP) assay in the detection of enteric pathogens from diarrheal stool samples in Kuwait.

MATERIALS AND METHODS

The Luminex xTAG GPP assay was used according to the manufacturer's instructions to evaluate single diarrheal stool samples from 109 hospitalized patients at Mubarak Al-Kabeer Hospital, Kuwait, from March 2014 to June 2015. The assay procedure involved nucleic acid extraction from stool samples, amplification of the target by reverse transcriptase polymerase chain reaction, hybridization of the amplified target by probe, detection of the target by the Luminex instrument and computerized data analysis. Conventional microbiological assays were used as the gold standard for comparison.

RESULTS

From the 109 diarrheal stool samples, 20 (18.4%) pathogens were detected by the xTAG GPP assay compared to 10 (9.2%) pathogens using conventional assays. Both methods detected 3 Salmonella spp., 3 Clostridium difficile, 2 rotavirus and 2 norovirus. In addition, the xTAG GPP assay detected 1 Shigella sp., 6 Campylobacter spp., 1 Cryptosporidium sp. and 2 Giardia lamblia which were missed by conventional assays.

CONCLUSIONS

In this study, xTAG GPP detected twice as many pathogens as the conventional assays. We recommend the introduction of this assay in routine diagnostic laboratories for a rapid and better diagnosis and treatment of diarrheal disease.

Immunogenicity of the Bivalent Oral Cholera Vaccine Shanchol in Haitian Adults With HIV Infection

We evaluated immune responses following bivalent oral cholera vaccination (Shanchol [Shantha Biotechnics]; BivWC) in a cohort of 25 human immunodeficiency virus (HIV)-infected adults in Haiti. Compared with adults without HIV infection, vaccination in HIV-infected individuals resulted in lower vibriocidal responses against Vibrio cholerae O1, and there was a positive relationship between the CD4(+) T-cell count and vibriocidal responses following vaccination. Nevertheless, seroconversion occurred at a rate of 65% against the Ogawa serotype and 74% against the Inaba serotype in adults with HIV infection. These results suggest that the vaccine retains substantial immunogenicity in adults with HIV infection and may benefit this population by protecting against cholera.

The Haiti research-based model of international public health collaboration: the GHESKIO Centers

For 3 decades, GHESKIO (the Groupe Haitien d'Etude du Sarcome de Kaposi et des Infections Opportunistes), the Haitian Ministry of Health, and Weill Cornell have pursued a tripartite mission of service, training, and translational research. The initial focus was on AIDS and tuberculosis. The mission has expanded to include the local community and now provides maternal-child health, family planning, cancer prevention and treatment, immunizations (including human papillomavirus, cholera), and primary education through vocational and microcredit programs. Outcome measures include a reduction in HIV prevalence from 6.2% to the current 2.2%, extensive tuberculosis and cholera prevention and treatment programs, and national training programs for biomedical and community health workers.

Importance of cholera and other etiologies of acute diarrhea in post-earthquake Port-au-Prince, Haiti

We estimated the proportion of diarrhea attributable to cholera and other pathogens during the rainy and dry seasons in patients seen in two urban health settings: a cholera treatment center (CTC) and oral rehydration points (ORPs). During April 1, 2011-November 30, 2012, stool samples were collected from 1,206 of 10,845 patients who came to the GHESKIO CTC or to the community ORPs with acute diarrhea, cultured for Vibrio cholerae, and tested by multiplex polymerase reaction. Vibrio cholerae was isolated from 409 (41.8%, 95% confidence interval [CI] = 38.7-44.9%) of the 979 specimens from the CTC and in 45 (19.8%, 95% CI = 14.8-25.6%) of the 227 specimens from the ORPs. Frequencies varied from 21.4% (95% CI = 16.6-26.7%) during the dry season to 46.8% (95% CI = 42.9-50.7%) in the rainy season. Shigella, enterotoxigenic Escherichia coli, rotavirus, and Cryptosporidium were frequent causes of diarrhea in children less than five years of age.