Quantitative analysis of burden of bacillary dysentery associated with floods in Hunan, China

Mortality and morbidity risks associated with floods: A systematic review and meta-analysis

BACKGROUND

Flood disasters are projected to increase in severity, duration, and frequency in the context of climate change, and the risks of mortality and morbidity may increase after floods, which will overwhelm health systems.

OBJECTIVE

This study aims to synthesize current epidemiological evidence about the impacts of floods on mortality and morbidity.

METHOD

After performing a systematic literature search from 2000 to 2023, we included studies involving human participants, with exposures of floods, and with outcomes of mortality or morbidity.

RESULTS

In total, 37 studies were included in evidence syntheses. Meta-analyses yielded an overall relative risk of 1.26 (95% confidence interval [CI]: 1.10, 1.46), 1.10 (1.08, 1.13), 1.11 (1.04, 1.20), and 1.38 (1.18, 1.62) for all-cause mortality and morbidities of overall gastrointestinal diseases, diarrhea diseases, and dysentery, respectively. Although meta-analyses were not conducted, evidence from at least three studies consistently supported that exposure to floods was associated with increased risks of malaria and respiratory diseases. The evidence for other outcomes was reported but either limited or uncertain.

CONCLUSION

This study suggests that exposure to floods is associated with increased risks of all-cause mortality and morbidities of overall gastrointestinal diseases, diarrhea diseases, dysentery, malaria, and respiratory diseases, while further research is urgently called.

A systematic review and meta-analysis of ambient temperature and precipitation with infections from five food-borne bacterial pathogens

Studies on climate variables and food pathogens are either pathogen- or region-specific, necessitating a consolidated view on the subject. This study aims to systematically review all studies on the association of ambient temperature and precipitation on the incidence of gastroenteritis and bacteraemia from Salmonella, Shigella, Campylobacter, Vibrio, and Listeria species. PubMed, Ovid MEDLINE, Scopus, and Web of Science databases were searched up to 9 March 2023. We screened 3,204 articles for eligibility and included 83 studies in the review and three in the meta-analysis. Except for one study on Campylobacter, all showed a positive association between temperature and Salmonella, Shigella, Vibrio sp., and Campylobacter gastroenteritis. Similarly, most of the included studies showed that precipitation was positively associated with these conditions. These positive associations were found regardless of the effect measure chosen. The pooled incidence rate ratio (IRR) for the three studies that included bacteraemia from Campylobacter and Salmonella sp. was 1.05 (95 per cent confidence interval (95% CI): 1.03, 1.06) for extreme temperature and 1.09 (95% CI: 0.99, 1.19) for extreme precipitation. If current climate trends continue, our findings suggest these pathogens would increase patient morbidity, the need for hospitalization, and prolonged antibiotic courses.

Climate Change and Respiratory Diseases: Relationship between SARS and Climatic Parameters and Impact of Climate Change on the Geographical Distribution of SARS in Iran

Climate change affects human health, and severe acute respiratory syndrome (SARS) incidence is one of the health impacts of climate change. This study is a retrospective cohort study. Data have been collected from the Iranian Ministry of Health and Medical Education between 17 February 2016 and17 February 2018. The Neural Network Model has been used to predict SARS infection. Based on the results of the multivariate Poisson regression and the analysis of the coexistence of the variables, the minimum daily temperature was positively associated with the risk of SARS in men and women. The risk of SARS has increased in women and men with increasing daily rainfall. According to the result, by changes in bioclimatic parameters, the number of SARS patients will be increased in cities of Iran. Our study has shown a significant relationship between SARS and the climatic variables by the type of climate and gender. The estimates suggest that hospital admissions for climate-related respiratory diseases in Iran will increase by 36% from 2020 to 2050. This study demonstrates one of the health impacts of climate change. Policymakers can control the risks of climate change by mitigation and adaptation strategists.

Floods and diarrheal morbidity: Evidence on the relationship, effect modifiers, and attributable risk from Sichuan Province, China

Background

Although studies have provided the estimates of floods-diarrhoea associations, little is known about the lag effect, effect modification, and attributable risk. Based on Sichuan, China, an uneven socio-economic development province with plateau, basin, and mountain terrains spanning different climatic zones, we aimed to systematically examine the impacts of floods on diarrheal morbidity.

Methods

We retrieved information on daily diarrheal cases, floods, meteorological variables, and annual socio-economic characteristics for 21 cities in Sichuan from January 1, 2017 to December 31, 2019. We fitted time-series Poisson models to estimate the city-specific floods-diarrhoea relation over the lags of 0-14 days, and then pooled them using meta-analysis for cumulative and lag effects. We further employed meta-regression to explore potential effect modifiers and identify effect modification. We calculated the attributable diarrheal cases and fraction of attributable morbidity within the framework of the distributed lag model.

Results

Floods had a significant cumulative association with diarrhoea at the provincial level, but varied by regions and cities. The effects of the floods appeared on the second day after the floods and lasted for 5 days. Floods-diarrhoea relations were modified by three effect modifiers, with stronger flood effects on diarrhoea found in areas with higher air pressure, lower diurnal temperature range, or warmer temperature. Floods were responsible for advancing a fraction of diarrhoea, corresponding to 0.25% within the study period and 0.48% within the flood season.

Conclusions

The impacts imposed by floods were mainly distributed within the first week. The floods-diarrhoea relations varied by geographic and climatic conditions. The diarrheal burden attributable to floods is currently low in Sichuan, but this figure could increase with the exposure more intensive and the effect modifiers more detrimental in the future. Our findings are expected to provide evidence for the formulation of temporal- and spatial-specific strategies to reduce potential risks of flood-related diarrhoea.

Association between floods and the risk of dysentery in China: a meta-analysis

The association between floods and the risk of dysentery remain controversial. Therefore, we performed a meta-analysis to clarify this relationship. A literature search was performed in PubMed, Web of science, and Embase for relevant articles published up to November 2019. Random-effects model was used to pool relative risks with 95% confidence intervals. The sensitivity analysis was carried out to evaluate the stability of the results. Publication bias was estimated using Egger's test. Eleven studies from 10 articles evaluated the association between floods and the risk of dysentery in China. The pooled RR (95% CI) of dysentery for the flooded time versus non-flooded period was 1.48 (95% CI: 1.14-1.91). Significant association was found in subgroup analysis stratified by dysentery styles [dysentery: 1.61 (95% CI: 1.34-1.93) and bacillary dysentery: 1.46 (95% CI: 1.06-2.01)]. The pooled RR (95%CI) of sensitivity analysis for dysentery was 1.26 (95% CI: 1.05-1.52). No significant publication bias was found in our meta-analysis. This meta-analysis confirms that floods have significantly increased the risk of dysentery in China. Our findings will provide more evidence to reduce negative health outcomes of floods in China.

Associations between floods and bacillary dysentery cases in main urban areas of Chongqing, China, 2005-2016: a retrospective study

BACKGROUND

Understanding the association between floods and bacillary dysentery (BD) incidence is necessary for us to assess the health risk of extreme weather events. This study aims at exploring the association between floods and daily bacillary dysentery cases in main urban areas of Chongqing between 2005 and 2016 as well as evaluating the attributable risk from floods.

METHODS

The association between floods and daily bacillary dysentery cases was evaluated by using distributed lag non-linear model, controlling for meteorological factors, long-term trend, seasonality, and day of week. The fraction and number of bacillary dysentery cases attributable to floods was calculated. Subgroup analyses were conducted to explore the association across age, gender, and occupation.

RESULTS

After controlling the impact of temperature, precipitation, relative humidity, long-term trend, and seasonality, a significant lag effect of floods on bacillary dysentery cases was found at 0-day, 3-day, and 4-day lag, and the cumulative relative risk (CRR) over a 7-lag day period was 1.393 (95%CI 1.216-1.596). Male had higher risk than female. People under 5 years old and people aged 15-64 years old had significantly higher risk. Students, workers, and children had significantly higher risk. During the study period, based on 7-lag days, the attributable fraction of bacillary dysentery cases due to floods was 1.10% and the attributable number was 497 persons.

CONCLUSIONS

This study confirms that floods can increase the risk of bacillary dysentery incidence in main urban areas of Chongqing within an accurate time scale, the risk of bacillary dysentery caused by floods is still serious. The key population includes male, people under 5 years old, students, workers, and children. Considering the lag effect of floods on bacillary dysentery, the government and public health emergency departments should advance to the emergency health response in order to minimize the potential risk of floods on public.

The direct and interactive impacts of hydrological factors on bacillary dysentery across different geographical regions in central China

Previous studies found non-linear mutual interactions among hydrometeorological factors on diarrheal disease. However, the complex interactions of the hydrometeorological, topographical and human activity factors need to be further explored. This study aimed to reveal how hydrological and other factors jointly influence bacillary dysentery in different geographical regions. Using Anhui Province in China, consisted of Huaibei plain, Jianghuai hilly and Wannan mountainous regions, we integrated multi-source data (6 meteorological, 3 hydrological, 2 topographic, and 9 socioeconomic variables) to explore the direct and interactive relationship between hydrological factors (quick flow, baseflow and local recharge) and other factors by combining the ecosystem model InVEST with spatial statistical analysis. The results showed hydrological factors had significant impact powers (q = 0.444 (Huaibei plain) for local recharge, 0.412 (Jianghuai hilly region) and 0.891 (Wannan mountainous region) for quick flow, respectively) on bacillary dysentery in different regions, but lost powers at provincial level. Land use and soil properties have created significant interactions with hydrological factors across Anhui province. Particularly, percentage of farmland in Anhui province can influence quick flow across Jianghuai, Wannan regions and the whole province, and it also has significant interactions with the baseflow and local recharge across the plain as well as the whole province. Percentage of urban areas had interactions with baseflow and local recharge in Jianghuai and Wannan regions. Additionally, baseflow and local recharge could be interacted with meteorological factors (e.g. temperature and wind speed), while these interactions varied in different regions. In conclusion, it was evident that hydrological factors had significant impacts on bacillary dysentery, and also interacted significantly with meteorological and socioeconomic factors. This study applying ecosystem model and spatial analysis help reveal the complex and nonlinear transmission of bacillary dysentery in different geographical regions, supporting the development of precise public health interventions with consideration of hydrological factors.

Understanding the Impact of Rainfall on Diarrhea: Testing the Concentration-Dilution Hypothesis Using a Systematic Review and Meta-Analysis

BACKGROUND

Projected increases in extreme weather may change relationships between rain-related climate exposures and diarrheal disease. Whether rainfall increases or decreases diarrhea rates is unclear based on prior literature. The concentration-dilution hypothesis suggests that these conflicting results are explained by the background level of rain: Rainfall following dry periods can flush pathogens into surface water, increasing diarrhea incidence, whereas rainfall following wet periods can dilute pathogen concentrations in surface water, thereby decreasing diarrhea incidence.

OBJECTIVES

In this analysis, we explored the extent to which the concentration-dilution hypothesis is supported by published literature.

METHODS

To this end, we conducted a systematic search for articles assessing the relationship between rain, extreme rain, flood, drought, and season (rainy vs. dry) and diarrheal illness.

RESULTS

A total of 111 articles met our inclusion criteria. Overall, the literature largely supports the concentration-dilution hypothesis. In particular, extreme rain was associated with increased diarrhea when it followed a dry period [incidence rate ratio ( IRR ) = 1.26 ; 95% confidence interval (CI): 1.05, 1.51], with a tendency toward an inverse association for extreme rain following wet periods, albeit nonsignificant, with one of four relevant studies showing a significant inverse association (IRR = 0.911 ; 95% CI: 0.771, 1.08). Incidences of bacterial and parasitic diarrhea were more common during rainy seasons, providing pathogen-specific support for a concentration mechanism, but rotavirus diarrhea showed the opposite association. Information on timing of cases within the rainy season (e.g., early vs. late) was lacking, limiting further analysis. We did not find a linear association between nonextreme rain exposures and diarrheal disease, but several studies found a nonlinear association with low and high rain both being associated with diarrhea.

DISCUSSION

Our meta-analysis suggests that the effect of rainfall depends on the antecedent conditions. Future studies should use standard, clearly defined exposure variables to strengthen understanding of the relationship between rainfall and diarrheal illness. https://doi.org/10.1289/EHP6181.

Bacterial infection during wars, conflicts and post-natural disasters in Asia and the Middle East: a narrative review

Introduction: Bacterial infections resulting from wars and natural disasters represent a major public health problem. Over the past 50 years, Asia and the Middle East have suffered several wars. Moreover, East-Asian countries are considered the most natural disaster-prone countries in the world.Areas covered: This review focuses on bacterial infection occurring during wars and after natural disasters, among refugees, wounded citizens and soldiers as well as the prevention and control measures that must be taken.Expert opinion: During wars, refugees and soldiers represent the two main sources of bacterial infections. Refugees coming from countries with a high prevalence of antimicrobial resistance can spread these pathogens to their final destination. In addition, these refugees living in inadequate shelters can contribute to the spread of bacterial infections. Moreover, some factors including the presence of fixed imported fragments; environmental contamination and nosocomial transmissions, play a key role in the dissemination of bacteria among soldiers. As for natural disasters, several factors are associated with increased bacterial transmissions such as the displacement of large numbers of people into over-crowded shelters, high exposure to disease vectors, lack of water and sanitation. Here, we carry out a systematic review of the bacterial infections that follow these two phenomena.

Pathogen-Specific Impacts of the 2011-2012 La Niña-Associated Floods on Enteric Infections in the MAL-ED Peru Cohort: A Comparative Interrupted Time Series Analysis

Extreme floods pose multiple direct and indirect health risks. These risks include contamination of water, food, and the environment, often causing outbreaks of diarrheal disease. Evidence regarding the effects of flooding on individual diarrhea-causing pathogens is limited, but is urgently needed in order to plan and implement interventions and prioritize resources before climate-related disasters strike. This study applied a causal inference approach to data from a multisite study that deployed broadly inclusive diagnostics for numerous high-burden common enteropathogens. Relative risks (RRs) of infection with each pathogen during a flooding disaster that occurred at one of the sites-Loreto, Peru-were calculated from generalized linear models using a comparative interrupted time series framework with the other sites as a comparison group and adjusting for background seasonality. During the early period of the flood, increased risk of heat-stable enterotoxigenic E. coli (ST-ETEC) was identified (RR = 1.73 [1.10, 2.71]) along with a decreased risk of enteric adenovirus (RR = 0.36 [0.23, 0.58]). During the later period of the flood, sharp increases in the risk of rotavirus (RR = 5.30 [2.70, 10.40]) and sapovirus (RR = 2.47 [1.79, 3.41]) were observed, in addition to increases in transmission of Shigella spp. (RR = 2.86 [1.81, 4.52]) and Campylobacter spp. (RR = 1.41 (1.01, 1.07). Genotype-specific exploratory analysis reveals that the rise in rotavirus transmission during the flood was likely due to the introduction of a locally atypical, non-vaccine (G2P[4]) strain of the virus. Policy-makers should target interventions towards these pathogens-including vaccines as they become available-in settings where vulnerability to flooding is high as part of disaster preparedness strategies, while investments in radical, transformative, community-wide, and locally-tailored water and sanitation interventions are also needed.

Association between floods and hospital admissions for schizophrenia in Hefei, China: The lag effects of degrees of floods and time variation

BACKGROUND

Schizophrenia is a serious mental disorder, endangering 7.5 million patients in China. Floods, as the adverse consequence of temperature-rise, have a negative influence on mental health. However, the relationship between floods and schizophrenia is still insufficient. This study aimed to quantitative the relationship between floods and the admissions for schizophrenia in Hefei, China.

METHODS

A Poisson generalized linear model (GLM) combining a distributed lag non-linear model (DLNM) was used to quantify the lag effects of floods on schizophrenia and subgroups (male, female; ≤40 y, >40 y; the married, the unmarried) from 2005 to 2014, Hefei, China. We further explored the effects of different degrees (moderate and severe) of floods and their temporal changes on schizophrenia.

RESULTS

There was a significant association between floods and admissions risk for schizophrenia. And the lag effects for schizophrenia lasted ten days (lag 5-lag 14), with the greatest effect on lag 9 (RR = 1.036, 95% confidence interval (CI): 1.014-1.058). The married, ≤40 y were sensitive to floods. The significant difference wasn't found for genders. The effects of the severe flood were higher than moderate floods, with the largest RR of 1.073 (95%CI: 1.029-1.119). The adverse effects were found in the middle and late period with a decreasing trend in the later period.

CONCLUSIONS

This study suggests a significant association between floods and schizophrenia with ten days of lag effects in Hefei, China. Male, female, <40 y and the married are vulnerable to both moderate and severe floods. The findings might be used to allocate medical resources of mental health after floods.

Development of a water cycle management approach to Sponge City construction in Xi'an, China

In recent years, climate change, population growth, and inefficient use of water have exacerbated the water resources scarcity problems around the world. Hence, this paper establishes a new approach of Sponge City construction (SCC) based on water cycle management (WCM) for the sustainable exploitation of groundwater, recycled wastewater and rainwater in the Xi'an Siyuan University. The University is located in an isolated area that is far away from the city center so that no centralized water supply system could be utilized. To mitigate water scarcity problems in the University, 39% of the annual rainfall is harvested and stored from impervious surfaces and grasslands by using the Curve Number (CN) method. This stored water is reused for non-potable purposes: 40% for toilet flushing and 60% as miscellaneous water. According to findings, the available rainwater of500-700 m³/d accounts for 16-23% of the non-potable water from April to December. Moreover, the utilization rate of water resources increases from 204% to 227%. With the minimum volume of large-scale rainwater harvesting cistern of 52,760 m³, the environment could be adequately watered while improving the expansion and development conditions on the campus. Furthermore, water scarcity problems could be mitigated through optimization of the water resources utilization system. This study demonstrates that this new approach of SCC based on WCM could alleviate water resources scarcity problems in Xi'an Siyuan University effectively. It is hoped that this study will provide a model and example of the new approach for future applications.

Short-term effects of moderate and severe floods on infectious diarrheal diseases in Anhui Province, China

BACKGROUND

Previous studies showed that floods can lead to diarrheal diseases outbreaks; however, the short-term effects of different severity floods on diarrheal diseases are not clear. This study aims to examine 0-14 days lagged effects of moderate and severe floods on diarrhea in Anhui Province, one heavily flood-prone area in China.

METHODS

Daily diarrheal cases from January 1, 2013 to August 31, 2017 in 16 cities of Anhui were extracted from the National Notifiable Disease Surveillance System. Meteorological data were obtained, and moderate or severe floods were identified according to Comprehensive Study Group of Major Natural Disasters of the State Science and Technology Commission in China. The quasi-Poisson generalized linear models were applied to evaluate effects of floods on daily diarrheal cases in each city with 0-14 days lag, and we divided post-flood periods into week 1 and week 2, further conducted provincial-level meta-analysis.

RESULTS

Immediate effects of floods on diarrheal diseases were observed within 7 days, and at provincial level moderate floods had a RR of 1.05 (95% CI: 1.02-1.09) and severe floods RR = 1.04 (95% CI: 1.01-1.08) controlling for population size, temperature and relative humidity etc., but less effects appeared in the second week. Impacts of flooding on diarrheal diseases varied among cities. Moderate floods in week 1 had a RR of 1.51 (95% CI: 1.29-1.78) in Bozhou, and severe floods had a RR = 1.31 (95% CI: 1.05-1.64) in Chuzhou. The severe floods may have higher RR in week 1 compared with moderate floods in Anqing (1.10 vs 1.06), Chuzhou (1.31 vs 1.07) and Luan (1.18 vs 1.00).

CONCLUSIONS

Both moderate and severe floods can significantly increase diarrheal risks in one week with regionally varied effects, and severe floods may lead higher risks. The findings have implications for preparing emergent interventions in hazard periods to reduce health risks of floods.

In situ reconstruction of long-term extreme flooding magnitudes and frequencies based on geological archives

Extreme flooding magnitudes and frequencies are essentially related to assessment of risk and reliability in hydrological design. Extreme flooding and its discharge are highly sensitive to regional climate change. Presently, its discharge can be reconstructed by a geological archive or record along the river valley. Two units of typical extreme flooding deposits (EFDs) carrying long-term information preserved in the Holocene loess-palaeosol sequence were found at Xipocun (XPC), which is located in Chengcheng County, China. It is situated in the downstream section of the Beiluohe (hereafter BLH) River. Based on multiple sedimentary proxy indices (grain-size distribution (GSD), magnetic susceptibility (MS), and loss-on-ignition (LOI), etc.), EFDs were interpreted as well-sorted clayey silt in suspension. They were then deposited as a result of riverbank flooding in a stagnant environment during high water level. Through the Optically Stimulated Luminescence (OSL) dating technique and stratigraphic correlations, chronologies of two identified extreme flooding periods were 7600-7400 a B.P. and 3200-3000 a B.P. Two phases of extreme flooding occurrence under climate abnormality scenarios were characterized as having high frequencies of hydrological extremes in river systems. According to simulation and verification using the Slope-Area Method and Hydrologic Engineering Center's River Analysis System (HEC-RAS) model, the extreme flooding discharges at the XPC site were reconstructed between 9625 m³/s and 16,635 m³/s. A new long-term flooding frequency and peak discharge curve, involved gauged flooding, historical flooding at Zhuangtou station and in situ reconstructed extreme flooding events, was established for the downstream BLH River. The results improve the accuracy of low-frequency flooding risk assessment and provide evidence for predicting the response of fluvial systems to climate instability. Thus, this improves the analysis of the BLH River watershed.

Health impact of climate change in cities of middle-income countries: the case of China

BACKGROUND

This review examines the human health impact of climate change in China. Through reviewing available research findings under four major climate change phenomena, namely extreme temperature, altered rainfall pattern, rise of sea level and extreme weather events, relevant implications for other middle-income population with similar contexts will be synthesized.

SOURCES OF DATA

Sources of data included bilingual peer-reviewed articles published between 2000 and 2018 in PubMed, Google Scholar and China Academic Journals Full-text Database.

AREAS OF AGREEMENT

The impact of temperature on mortality outcomes was the most extensively studied, with the strongest cause-specific mortality risks between temperature and cardiovascular and respiratory mortality. The geographical focuses of the studies indicated variations in health risks and impacts of different climate change phenomena across the country.

AREAS OF CONTROVERSY

While rainfall-related studies predominantly focus on its impact on infectious and vector-borne diseases, consistent associations were not often found.

GROWING POINTS

Mental health outcomes of climate change had been gaining increasing attention, particularly in the context of extreme weather events. The number of projection studies on the long-term impact had been growing.

AREAS TIMELY FOR DEVELOPING RESEARCH

The lack of studies on the health implications of rising sea levels and on comorbidity and injury outcomes warrants immediate attention. Evidence is needed to understand health impacts on vulnerable populations living in growing urbanized cities and urban enclaves, in particular migrant workers. Location-specific climate-health outcome thresholds (such as temperature-mortality threshold) will be needed to support evidence-based clinical management plans and health impact mitigation strategies to protect vulnerable communities.

The impact of the 2016 flood event in Anhui Province, China on infectious diarrhea disease: An interrupted time-series study

Climate change may bring more frequent and severe floods which will heighten public health problems, including an increased risk of infectious diarrhea in susceptible populations. Affected by heavy rainfall and an El Niño event, a destructive flood occurred in Anhui province, China on 18th June 2016. This study investigates the impact of this severe flood on infectious diarrhea at both city-level and provincial level, and further to identify modifying factor. We obtained information on infectious diarrheal cases during 2013-2017 from the National Disease Surveillance System. An interrupted time-series design was used to estimate effects of the flood event on diarrhea in 16 cities. Then we applied a meta-analysis to estimate the area-level pooled effects of the flood in both flooded areas and non-flooded areas. Finally, a meta-regression was applied to determine whether proximity to flood was a predictor of city-level risks. Stratified analyses by gender and age group were also conducted for flooded areas. A significant increase in infectious diarrhea risk (RR = 1.11, 95% CI: 1.01, 1.23) after the flood event was found in flooded area with variation in risks across cities, while there was no increase in non-flooded areas. Diarrheal risks post-flood was progressively higher in cities with greater proximity to the Yangtze River. Children aged 5-14 were at highest risk of diarrhea post-flood in the flooded areas. Our study provides strong evidence that the 2016 severe flood significantly increased infectious diarrheal risk in exposed populations. Local public health agencies are advised to develop intervention programs to prevent and control infectious diarrhea risk when a major flood occurs, especially in areas close to water bodies and among vulnerable populations.

Identifying different types of flood-sensitive diarrheal diseases from 2006 to 2010 in Guangxi, China

Floods may influence different types of diarrheal diseases and epidemiological studies of pathogen-specific diarrhea due to floods in China are still needed. In addition, few studies have been conducted to quantify the lag and cumulative risk of diarrheal disease due to floods in Guangxi, China. Our study aimed to identify different types of diarrheal diseases that were sensitive to floods and to quantify their lag and cumulative impact. A matched analysis based on time series data of floods and infectious disease from 2006 to 2010 was conducted in Guangxi, China. Each flood day was treated as an independent unit in our study. A simplified assumption that each day of the flood confers the same risk was adopted before analysis. Each flood day was matched to a non-flood day by city and time. Log-linear mixed-effects regression models were used to quantify the association between different types of diarrheal diseases and floods. Lag and cumulative effects were also calculated to get delayed and overall effects. A total of 45,131 diarrhea cases were notified in the study area over the study period. After controlling for the long-term trend, seasonality, and meteorological factors, floods caused a significantly increased risk of total diarrheal diseases. The RR was highest at lag 2 days (RR=1.24, 95% CI: 1.11-1.40). Floods caused a significantly increased risk in bacillary dysentery and in other infectious diarrhea, but not in typhoid fever and paratyphoid fever. Floods were significantly associated with total diarrheal diseases and other infectious diarrhea for both cumulative lag 0-7 and 0-14 days. Our study provides strong evidence of a positive association between floods and diarrheal diseases including bacillary dysentery and other infectious diarrhea in study area. Public health interventions should be taken to prevent a potential risk of these flood-sensitive diarrheal diseases according to the different lag period after floods.

Climate Change-Related Water Disasters' Impact on Population Health

PURPOSE

Rising global temperatures have resulted in an increased frequency and severity of cyclones, hurricanes, and flooding in many parts of the world. These climate change-related water disasters (CCRWDs) have a devastating impact on communities and the health of residents. Clinicians and policymakers require a substantive body of evidence on which to base planning, prevention, and disaster response to these events. The purpose of this study was to conduct a systematic review of the literature concerning the impact of CCRWDs on public health in order to identify factors in these events that are amenable to preparedness and mitigation. Ultimately, this evidence could be used by nurses to advocate for greater preparedness initiatives and inform national and international disaster policy.

DESIGN AND METHODS

A systematic literature review of publications identified through a comprehensive search of five relevant databases (PubMed, Cumulative Index to Nursing and Allied Health Literature [CINAHL], Embase, Scopus, and Web of Science) was conducted using a modified Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach in January 2017 to describe major themes and associated factors of the impact of CCRWDs on population health.

FINDINGS

Three major themes emerged: environmental disruption resulting in exposure to toxins, population susceptibility, and health systems infrastructure (failure to plan-prepare-mitigate, inadequate response, and lack of infrastructure). Direct health impact was characterized by four major categories: weather-related morbidity and mortality, waterborne diseases/water-related illness, vector-borne and zoonotic diseases, and psychiatric/mental health effects. Scope and duration of the event are factors that exacerbate the impact of CCRWDs. Discussion of specific factors amenable to mitigation was limited. Flooding as an event was overrepresented in this analysis (60%), and the majority of the research reviewed was conducted in high-income or upper middle-/high-income countries (62%), despite the fact that low-income countries bear a disproportionate share of the burden on morbidity and mortality from CCRWDs.

CONCLUSIONS

Empirical evidence related to CCRWDs is predominately descriptive in nature, characterizing the cascade of climatic shifts leading to major environmental disruption and exposure to toxins, and their resultant morbidity and mortality. There is inadequate representation of research exploring potentially modifiable factors associated with CCRWDs and their impact on population health. This review lays the foundation for a wide array of further areas of analysis to explore the negative health impacts of CCRWDs and for nurses to take a leadership role in identifying and advocating for evidence-based policies to plan, prevent, or mitigate these effects.

CLINICAL RELEVANCE

Nurses comprise the largest global healthcare workforce and are in a position to advocate for disaster preparedness for CCRWDs, develop more robust environmental health policies, and work towards mitigating exposure to environmental toxins that may threaten human health.