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PLoS Neglected Tropical Diseases Jun 2017Infectious diseases attributable to unsafe water supply, sanitation and hygiene (e.g. Cholera, Leptospirosis, Giardiasis) remain an important cause of morbidity and... (Review)
Review
Infectious diseases attributable to unsafe water supply, sanitation and hygiene (e.g. Cholera, Leptospirosis, Giardiasis) remain an important cause of morbidity and mortality, especially in low-income countries. Climate and weather factors are known to affect the transmission and distribution of infectious diseases and statistical and mathematical modelling are continuously developing to investigate the impact of weather and climate on water-associated diseases. There have been little critical analyses of the methodological approaches. Our objective is to review and summarize statistical and modelling methods used to investigate the effects of weather and climate on infectious diseases associated with water, in order to identify limitations and knowledge gaps in developing of new methods. We conducted a systematic review of English-language papers published from 2000 to 2015. Search terms included concepts related to water-associated diseases, weather and climate, statistical, epidemiological and modelling methods. We found 102 full text papers that met our criteria and were included in the analysis. The most commonly used methods were grouped in two clusters: process-based models (PBM) and time series and spatial epidemiology (TS-SE). In general, PBM methods were employed when the bio-physical mechanism of the pathogen under study was relatively well known (e.g. Vibrio cholerae); TS-SE tended to be used when the specific environmental mechanisms were unclear (e.g. Campylobacter). Important data and methodological challenges emerged, with implications for surveillance and control of water-associated infections. The most common limitations comprised: non-inclusion of key factors (e.g. biological mechanism, demographic heterogeneity, human behavior), reporting bias, poor data quality, and collinearity in exposures. Furthermore, the methods often did not distinguish among the multiple sources of time-lags (e.g. patient physiology, reporting bias, healthcare access) between environmental drivers/exposures and disease detection. Key areas of future research include: disentangling the complex effects of weather/climate on each exposure-health outcome pathway (e.g. person-to-person vs environment-to-person), and linking weather data to individual cases longitudinally.
Topics: Climate; Communicable Diseases; Models, Biological; Water Microbiology; Weather
PubMed: 28604791
DOI: 10.1371/journal.pntd.0005659 -
The Cochrane Database of Systematic... Dec 2016Acute diarrhoea is one of the main causes of morbidity and mortality among children in low-income countries. Glucose-based oral rehydration solution (ORS) helps replace... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Acute diarrhoea is one of the main causes of morbidity and mortality among children in low-income countries. Glucose-based oral rehydration solution (ORS) helps replace fluid and prevent further dehydration from acute diarrhoea. Since 2004, the World Health Organization (WHO) has recommended the osmolarity of less than 270 mOsm/L (ORS ≤ 270) versus greater than 310 mOsm/L formulation (ORS ≥ 310). Polymer-based ORS (for example, prepared using rice or wheat) slowly releases glucose and may be superior to glucose-based ORS.
OBJECTIVES
To compare polymer-based oral rehydration solution (polymer-based ORS) with glucose-based oral rehydration solution (glucose-based ORS) for treating acute watery diarrhoea.
SEARCH METHODS
We searched the following sources up to 5 September 2016: the Cochrane Infectious Diseases Group (CIDG) Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 9), MEDLINE (1966 to 5 September 2016), EMBASE (1974 to 5 September 2016), LILACS (1982 to 5 September 2016), and mRCT (2007 to 5 September 2016). We also contacted researchers, organizations, and pharmaceutical companies, and searched reference lists.
SELECTION CRITERIA
We included randomized controlled trials (RCTs) of people with acute watery diarrhoea (cholera and non-cholera associated) that compared polymer-based and glucose-based ORS (with identical electrolyte contents).
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed the search results and risk of bias, and extracted data. In multiple-treatment arms with two or more treatment groups, we combined outcomes as appropriate and compared collectively with the control group.
MAIN RESULTS
Thirty-five trials that included 4284 participants met the inclusion criteria: 28 trials exclusively included children, five included adults, and two included both adults and children. Polymer-based ORS versus glucose-based ORS (osmolarity ≤ 270) Eight trials (752 participants) evaluated this comparison, and seven trials used rice as a polymer source. Polymer-based ORS may decrease mean stool output in the first 24 hours by 24 mL/kg (mean difference (MD) -24.60 mL/kg, 95% CI -40.69 to -8.51; one trial, 99 participants, low quality evidence). The average duration of diarrhoea may be reduced by eight hours (MD -8.24 hours, 95% CI -13.17 to -3.30; I² statistic = 86%, five trials, 364 participants, low quality evidence) with polymer ORS but results are heterogeneous. Limited trials showed no observed difference in the risk of unscheduled use of intravenous fluid (RR 0.66, 95% CI 0.43 to 1.02; I² statistic = 30%; four trials, 376 participants, very low quality evidence), vomiting (very low quality evidence), and hyponatraemia (very low quality evidence). Polymer-based ORS versus glucose-based ORS (osmolarity ≥ 310) Twenty-seven trials (3532 participants) evaluated this comparison using a variety of polymers. On average, polymer ORS may reduce the total stool output in the first 24 hours by around 65 mL/kg (MD -65.47 mL/kg, 95% CI -83.92 to -47.03; 16 trials, 1483 participants, low quality evidence), and may reduce the duration of diarrhoea by around eight hours (MD -8.57 hours; SD -13.17 to -4.03; 16 trials, 1137 participants, low quality evidence) with substantial heterogeneity. The proportion of participants that required intravenous hydration was low in most trials with fewer in the polymer ORS group (RR 0.75, 95% CI 0.57 to 0.98; 19 trials, 1877 participant, low quality evidence) . Subgroup analysis by type of pathogen suggested an effect on unscheduled intravenous fluid in those infected with mixed pathogens (RR 0.63, 95% CI 0.41 to 0.96; 11 trials, 928 participants, low quality evidence), but not in participants positive for Vibrio cholerae (RR 0.94, 95% CI 0.66 to 1.34; 7 trials, 535 participants, low quality evidence). No difference was observed in the number of patients who developed vomiting (RR 0.91, 95% CI 0.72 to 1.14; 10 trials, 584 participants, very low quality evidence), hyponatraemia (RR 1.82, 95% CI 0.52 to 6.44; 4 trials, 385 participants, very low quality evidence), hypokalaemia (RR 1.29, 95% CI 0.74 to 2.25; 2 trials, 260 participants, low quality evidence), or persistent diarrhoea (RR 1.28, 95% CI 0.68 to 2.41; 2 trials, 885 participants, very low quality evidence).
AUTHORS' CONCLUSIONS
Polymer-based ORS shows advantages compared to glucose-based ORS (at ≥ 310 mOsm/L). Comparisons favoured polymer-based ORS over ORS ≤ 270 but analysis was underpowered.
Topics: Acute Disease; Adult; Child; Cholera; Dehydration; Diarrhea; Fluid Therapy; Humans; Infant; Oryza; Polymers; Randomized Controlled Trials as Topic; Rehydration Solutions
PubMed: 27959472
DOI: 10.1002/14651858.CD006519.pub3 -
The Science of the Total Environment Nov 2020Non-cholera Vibrio bacteria are a major cause of foodborne illness in the United States. Raw oysters are commonly implicated in gastroenteritis caused by pathogenic...
BACKGROUND
Non-cholera Vibrio bacteria are a major cause of foodborne illness in the United States. Raw oysters are commonly implicated in gastroenteritis caused by pathogenic Vibrio parahaemolyticus. In response to outbreaks in 1997-1998, the US Food and Drug Administration developed a nation-wide quantitative microbial risk assessment (QMRA) of V. parahaemolyticus in raw oysters in 2005. The QMRA identified information gaps that new research may address. Incidence of sporadic V. parahaemolyticus illness has recently increased and, as oyster consumption increases and sea temperatures rise, V. parahaemolyticus outbreaks may become more frequent, posing health concerns. Updated and region-specific QMRAs will improve the accuracy and precision of risk of infection estimates.
OBJECTIVES
We identify research to support an updated QMRA of V. parahaemolyticus from oysters harvested in Chesapeake Bay and Puget Sound, focusing on observational and experimental research on post-harvest practices (PHPs) published from 2004 to 2019.
METHODS
A predefined search strategy was applied to PubMed, Embase, Scopus, Science.gov, NAL Agricola, and Google Scholar. Study eligibility criteria were defined using a population, intervention, comparator, and outcome statement. Reviewers independently coded abstracts for inclusion/exclusion using predefined criteria. Data were extracted and study quality and relevance evaluated based on published guidance for food safety risk assessments. Findings were synthesized using a weight of evidence approach.
RESULTS
Of 12,174 articles retrieved, 93 were included for full-text review. Twenty-seven studies were found to be high quality and high relevance, including studies on cold storage, high hydrostatic pressure, depuration, and disinfectant, and other PHPs. High hydrostatic pressure consistently emerged as the most effective PHP in reducing abundance of V. parahaemolyticus.
DISCUSSION
Limitations of the knowledge base and review approach involve the type and quantity of data reported. Future research should focus on PHPs for which few or no high quality and high relevance studies exist, such as irradiation and relaying.
Topics: Animals; Colony Count, Microbial; Food Contamination; Food Safety; Foodborne Diseases; Ostreidae; Seafood; Vibrio parahaemolyticus
PubMed: 32731065
DOI: 10.1016/j.scitotenv.2020.140795 -
Systematic Reviews Apr 2022Waterborne diarrhea diseases are among the leading causes of morbidity and mortality globally. These diseases can be mitigated by implementing various interventions. We...
BACKGROUND
Waterborne diarrhea diseases are among the leading causes of morbidity and mortality globally. These diseases can be mitigated by implementing various interventions. We reviewed the literature to identify available interventions to mitigate the risk of waterborne diarrheal diseases.
METHODS
We conducted a systematic database review of CINAHL (Cumulative Index to Nursing and Allied Health Literature), PubMed, Web of Science Core Collection, Cochrane library, Scopus, African Index Medicus (AIM), and LILACS (Latin American and Caribbean Health Sciences Literature). Our search was limited to articles published between 2009 and 2020. We conducted the review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement checklist. The identified studies were qualitatively synthesized.
RESULTS
Our initial search returned 28 773 articles of which 56 studies met the inclusion criteria. The included studies reported interventions, including vaccines for rotavirus disease (monovalent, pentavalent, and Lanzhou lamb vaccine); enhanced water filtration for preventing cryptosporidiosis, Vi polysaccharide for typhoid; cholera 2-dose vaccines, water supply, water treatment and safe storage, household disinfection, and hygiene promotion for controlling cholera outbreaks.
CONCLUSION
We retrieved few studies on interventions against waterborne diarrheal diseases in low-income countries. Interventions must be specific to each type of waterborne diarrheal disease to be effective. Stakeholders must ensure collaboration in providing and implementing multiple interventions for the best outcomes.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42020190411 .
Topics: Animals; Caribbean Region; Cholera; Diarrhea; Disease Outbreaks; Humans; Sheep; Vaccines
PubMed: 35436979
DOI: 10.1186/s13643-022-01947-y -
The American Journal of Tropical... Aug 2018Case-control studies are conducted to identify cholera transmission routes. Water, sanitation, and hygiene (WASH) exposures can facilitate cholera transmission (risk... (Meta-Analysis)
Meta-Analysis
Case-control studies are conducted to identify cholera transmission routes. Water, sanitation, and hygiene (WASH) exposures can facilitate cholera transmission (risk factors) or interrupt transmission (protective factors). To our knowledge, the association between WASH exposures and cholera from case-control studies has not been systematically analyzed. A systematic review was completed to close this gap, including describing the theory of risk and protection, developing inclusion criteria, searching and selecting studies, assessing quality of evidence, and summarizing associations between cholera and seven predicted WASH protective factors and eight predicted WASH risk factors using meta-analysis and sensitivity analysis. Overall, 47 articles describing 51 individual studies from 30 countries met the inclusion criteria. All eight predicted risk factors were associated with higher odds of cholera (odds ratio [OR] = 1.9-5.6), with heterogeneity () of 0-92%. Of the predicted protective factors, five of seven were associated with lower odds of cholera (OR = 0.35-1.4), with heterogeneity of 57-91%; exceptions were insignificant associations for improved water source (OR = 1.1, heterogeneity 91%) and improved sanitation (OR = 1.4, heterogeneity 68%). Results were robust; 3/70 (5%) associations changed directionality or significance in sensitivity analysis. Meta-analysis results highlight that predicted risk factors are associated with cholera; however, predicted protective factors are not as consistently protective. This variable protection is attributed to 1) cholera transmission via multiple routes and 2) WASH intervention implementation quality variation. Water, sanitation, and hygiene interventions should address multiple transmission routes and be well implemented, according to international guidance, to ensure that field effectiveness matches theoretical efficacy. In addition, future case-control studies should detail WASH characteristics to contextualize results.
Topics: Association; Case-Control Studies; Cholera; Hand Disinfection; Humans; Odds Ratio; Risk Factors; Sanitation; Water; Water Microbiology; Water Supply
PubMed: 29968551
DOI: 10.4269/ajtmh.17-0897 -
BMC Public Health Feb 2022Floods have affected 2.3 billion people worldwide in the last 20 years, and are associated with a wide range of negative health outcomes. Climate change is projected...
BACKGROUND
Floods have affected 2.3 billion people worldwide in the last 20 years, and are associated with a wide range of negative health outcomes. Climate change is projected to increase the number of people exposed to floods due to more variable precipitation and rising sea levels. Vulnerability to floods is highly dependent on economic wellbeing and other societal factors. Therefore, this systematic review synthesizes the evidence on health effects of flood exposure among the population of sub-Saharan Africa.
METHODS
We systematically searched two databases, Web of Science and PubMed, to find published articles. We included studies that (1) were published in English from 2010 onwards, (2) presented associations between flood exposure and health indicators, (3) focused on sub-Saharan Africa, and (4) relied on a controlled study design, such as cohort studies, case-control studies, cross-sectional studies, or quasi-experimental approaches with a suitable comparator, for instance individuals who were not exposed to or affected by floods or individuals prior to experiencing a flood.
RESULTS
Out of 2306 screened records, ten studies met our eligibility criteria. We included studies that reported the impact of floods on water-borne diseases (n = 1), vector-borne diseases (n = 8) and zoonotic diseases (n = 1). Five of the ten studies assessed the connection between flood exposure and malaria. One of these five evaluated the impact of flood exposure on malaria co-infections. The five non-malaria studies focused on cholera, scabies, taeniasis, Rhodesian sleeping sickness, alphaviruses and flaviviruses. Nine of the ten studies reported significant increases in disease susceptibility after flood exposure.
CONCLUSION
The majority of included studies of the aftermath of floods pointed to an increased risk of infection with cholera, scabies, taeniasis, Rhodesian sleeping sickness, malaria, alphaviruses and flaviviruses. However, long-term health effects, specifically on mental health, non-communicable diseases and pregnancy, remain understudied. Further research is urgently needed to improve our understanding of the health risks associated with floods, which will inform public policies to prevent and reduce flood-related health risks.
Topics: Cholera; Cross-Sectional Studies; Floods; Humans; Outcome Assessment, Health Care; Scabies; Taeniasis
PubMed: 35144560
DOI: 10.1186/s12889-022-12584-4 -
PloS One 2019Vibrio vulnificus necrotizing skin and soft tissue infections (VNSSTIs) are associated with a high mortality rate that varies remarkably with host susceptibility.... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vibrio vulnificus necrotizing skin and soft tissue infections (VNSSTIs) are associated with a high mortality rate that varies remarkably with host susceptibility. Hepatic disease (HD) is considered the key risk factor for high VNSSTIs incidence and mortality; however, there is limited evidence in the literature to support this observation.
METHODOLOGY
We examined all reported cases of VNSSTIs and associated mortality rates between 1966 and mid-2018. The PubMed, Medline and Cochrane Library databases were systematically searched for observational studies on patients with VNSSTIs. Twelve studies with 1157 total patients with VNSSTIs were included in the analysis. From the pooled dataset, nearly half (46.8%) of the patients with VNSSTIs had HD. The mortality rate in HD patients with VNSSTIs was 53.9% (n = 292/542), which was considerably higher than the mortality rate of 16.1% (n = 99/615) in non-HD patients. Patients with HD contracted VNSSTIs were found to be two or more times (RR = 2.61, 95% CI = 2.14-3.19) as likely to die compared with those without HD. Besides, liver cirrhosis (LC), the end-stage HD, was confirmed to be a significant risk factor, with risk ratios of 1.84 (95% CI 1.21-2.79) and 2.00 (95% CI 1.41-2.85) when compared to non-LC and non-HD, respectively.
CONCLUSIONS
HD with or without LC can be associated with infections and complications from V. vulnificus. Clinicians should aggressively approach care and management of acutely and/or critically ill patients with VNSSTIs.
Topics: Humans; Incidence; Liver Diseases; Mortality; Odds Ratio; Skin Diseases, Bacterial; Soft Tissue Infections; Vibrio Infections; Vibrio vulnificus
PubMed: 31652263
DOI: 10.1371/journal.pone.0223513 -
PLoS Neglected Tropical Diseases Dec 2021Cholera is a major cause of mortality and morbidity in low-resource and humanitarian settings. It is transmitted by fecal-oral route, and the infection risk is higher to... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Cholera is a major cause of mortality and morbidity in low-resource and humanitarian settings. It is transmitted by fecal-oral route, and the infection risk is higher to those living in and near cholera cases. Rapid identification of cholera cases and implementation of measures to prevent subsequent transmission around cases may be an efficient strategy to reduce the size and scale of cholera outbreaks.
METHODOLOGY/PRINCIPLE FINDINGS
We investigated implementation of cholera case-area targeted interventions (CATIs) using systematic reviews and case studies. We identified 11 peer-reviewed and eight grey literature articles documenting CATIs and completed 30 key informant interviews in case studies in Democratic Republic of Congo, Haiti, Yemen, and Zimbabwe. We documented 15 outbreaks in 12 countries where CATIs were used. The team composition and the interventions varied, with water, sanitation, and hygiene interventions implemented more commonly than those of health. Alert systems triggering interventions were diverse ranging from suspected cholera cases to culture confirmed cases. Selection of high-risk households around the case household was inconsistent and ranged from only one case to approximately 100 surrounding households with different methods of selecting them. Coordination among actors and integration between sectors were consistently reported as challenging. Delays in sharing case information impeded rapid implementation of this approach, while evaluation of the effectiveness of interventions varied.
CONCLUSIONS/SIGNIFICANCE
CATIs appear effective in reducing cholera outbreaks, but there is limited and context specific evidence of their effectiveness in reducing the incidence of cholera cases and lack of guidance for their consistent implementation. We propose to 1) use uniform cholera case definitions considering a local capacity to trigger alert; 2) evaluate the effectiveness of individual or sets of interventions to interrupt cholera, and establish a set of evidence-based interventions; 3) establish criteria to select high-risk households; and 4) improve coordination and data sharing amongst actors and facilitate integration among sectors to strengthen CATI approaches in cholera outbreaks.
Topics: Cholera; Congo; Family Characteristics; Haiti; Humans; Hygiene; Retrospective Studies; Sanitation; Yemen; Zimbabwe
PubMed: 34919551
DOI: 10.1371/journal.pntd.0010042 -
The Lancet. Infectious Diseases Feb 2019Oral vaccines underperform in low-income and middle-income countries compared with in high-income countries. Whether interventions can improve oral vaccine performance... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Oral vaccines underperform in low-income and middle-income countries compared with in high-income countries. Whether interventions can improve oral vaccine performance is uncertain.
METHODS
We did a systematic review and meta-analysis of interventions designed to increase oral vaccine efficacy or immunogenicity. We searched Ovid-MEDLINE and Embase for trials published until Oct 23, 2017. Inclusion criteria for meta-analysis were two or more studies per intervention category and available seroconversion data. We did random-effects meta-analyses to produce summary relative risk (RR) estimates. This study is registered with PROSPERO (CRD42017060608).
FINDINGS
Of 2843 studies identified, 87 were eligible for qualitative synthesis and 66 for meta-analysis. 22 different interventions were assessed for oral poliovirus vaccine (OPV), oral rotavirus vaccine (RVV), oral cholera vaccine (OCV), and oral typhoid vaccines. There was generally high heterogeneity. Seroconversion to RVV was significantly increased by delaying the first RVV dose by 4 weeks (RR 1·37, 95% CI 1·16-1·62) and OPV seroconversion was increased with monovalent or bivalent OPV compared with trivalent OPV (RR 1·51, 95% CI 1·20-1·91). There was some evidence that separating RVV and OPV increased RVV seroconversion (RR 1·21, 95% CI 1·00-1·47) and that higher vaccine inoculum improved OCV seroconversion (RR 1·12, 95% CI 1·00-1·26). There was no evidence of effect for anthelmintics, antibiotics, probiotics, zinc, vitamin A, withholding breastfeeding, extra doses, or vaccine buffering.
INTERPRETATION
Most strategies did not improve oral vaccine performance. Delaying RVV and reducing OPV valence should be considered within immunisation programmes to reduce global enteric disease. New strategies to address the gap in oral vaccine efficacy are urgently required.
FUNDING
Wellcome Trust, Bill & Melinda Gates Foundation, UK Medical Research Council, and WHO Polio Research Committee.
Topics: Administration, Oral; Adolescent; Adult; Child; Child, Preschool; Cholera; Cholera Vaccines; Female; Humans; Immunogenicity, Vaccine; Infant; Infant, Newborn; Male; Poliomyelitis; Poliovirus; Poliovirus Vaccine, Oral; Rotavirus; Rotavirus Infections; Rotavirus Vaccines; Salmonella typhi; Seroconversion; Treatment Outcome; Typhoid Fever; Typhoid-Paratyphoid Vaccines; Vaccination; Vibrio cholerae; Young Adult
PubMed: 30712836
DOI: 10.1016/S1473-3099(18)30602-9 -
Human Vaccines & Immunotherapeutics Feb 2018World Health Organization recommends oral cholera vaccine (OCV) to prevent and control cholera, but requires cost-effectiveness evidence. This review aimed to provide a...
World Health Organization recommends oral cholera vaccine (OCV) to prevent and control cholera, but requires cost-effectiveness evidence. This review aimed to provide a critical appraisal and summary of global economic evaluation (EE) studies involving OCV to guide future EE study. Full EE studies, published from inception to December 2015, evaluating OCV against cholera disease were included. The included studies were appraised using WHO guide for standardization of EE of immunization programs. Out of 14 included studies, almost all (13/14) were in low- and middle-income countries. Most studies (11/14) evaluated mass vaccination program. Most of the studies (9/14) incorporated herd protective effect. The most common influential parameters were cholera incidence, OCV coverage, herd protection and OCV price. OCV vaccination is likely to be cost-effective when targeted at the population with high-risk of cholera and poor access to health care facilities when herd protection effect is incorporated and OCV price is low.
Topics: Cholera; Cholera Vaccines; Developing Countries; Humans; Immunization Programs; World Health Organization
PubMed: 29099647
DOI: 10.1080/21645515.2017.1392422