Severe Flooding and Malaria Transmission in the Western Ugandan Highlands: Implications for Disease Control in an Era of Global Climate Change

Floods and cause-specific mortality in the UK: a nested case-control study

BACKGROUND

Floods are the most frequent weather-related disaster, causing significant health impacts worldwide. Limited studies have examined the long-term consequences of flooding exposure.

METHODS

Flood data were retrieved from the Dartmouth Flood Observatory and linked with health data from 499,487 UK Biobank participants. To calculate the annual cumulative flooding exposure, we multiplied the duration and severity of each flood event and then summed these values for each year. We conducted a nested case-control analysis to evaluate the long-term effect of flooding exposure on all-cause and cause-specific mortality. Each case was matched with eight controls. Flooding exposure was modelled using a distributed lag non-linear model to capture its nonlinear and lagged effects.

RESULTS

The risk of all-cause mortality increased by 6.7% (odds ratio (OR): 1.067, 95% confidence interval (CI): 1.063-1.071) for every unit increase in flood index after confounders had been controlled for. The mortality risk from neurological and mental diseases was negligible in the current year, but strongest in the lag years 3 and 4. By contrast, the risk of mortality from suicide was the strongest in the current year (OR: 1.018, 95% CI: 1.008-1.028), and attenuated to lag year 5. Participants with higher levels of education and household income had a higher estimated risk of death from most causes whereas the risk of suicide-related mortality was higher among participants who were obese, had lower household income, engaged in less physical activity, were non-moderate alcohol consumers, and those living in more deprived areas.

CONCLUSIONS

Long-term exposure to floods is associated with an increased risk of mortality. The health consequences of flooding exposure would vary across different periods after the event, with different profiles of vulnerable populations identified for different causes of death. These findings contribute to a better understanding of the long-term impacts of flooding exposure.

Analysing the six-year malaria trends at Metehara Health Centre in Central Ethiopia: the impact of resurgence on the 2030 elimination goals

BACKGROUND

Despite Ethiopia's concerted efforts to eliminate malaria by 2030, the disease continues to pose a significant public health and socioeconomic challenge in the country. The year 2021 witnessed 2.78 million malaria cases and 8041 associated deaths, emphasizing the persistent threat. Monitoring the prevalence trend of malaria is crucial for devising effective control and elimination strategies. This study aims to assess the trend of malaria prevalence at the Metehara Health Centre in the East Shoa Zone, Ethiopia.

METHODS

A retrospective study, spanning from February to September 2023, utilized malaria registration laboratory logbooks at Metehara Health Centre to evaluate the prevalence of malaria from 2017/18 to 2022/23. Malaria and related data were collected using a pre-designed data collection sheet. Descriptive statistics were employed for data summarization, presented through graphs and tables.

RESULTS

Out of 59,250 examined blood films, 17.4% confirmed the presence of Plasmodium infections. Among the confirmed cases, 74.3%, 23.8%, and 1.84% were attributed to Plasmodium falciparum, Plasmodium vivax, and mixed infections, respectively. The trend of malaria exhibited a steady decline from 2017/18 to 2021/22, reaching 9.8% prevalence. However, an abrupt increase to 26.5% was observed in 2022/23. Males accounted for a higher proportion (66%) of cases compared to females (34%). The age group 15-24 years experienced the highest malaria incidence at 42%. Notably, malaria cases peaked during autumn (September to November) at 43% and reached the lowest percentage during spring (March to May) at 13%.

CONCLUSION

Malaria persists as a significant health challenge in and around Metehara, central Ethiopia, predominantly driven by Plasmodium falciparum. The five-year declining trend was interrupted by a notable upsurge in 2022/23, indicating a resurgence of malaria in the study area. It is imperative to adopt a reverse strategy to sustain the progress achieved by the national malaria control plan.

Evolution of Spatial Risk of Malaria Infection After a Pragmatic Chemoprevention Program in Response to Severe Flooding in Rural Western Uganda

BACKGROUND

Malaria epidemics result from extreme precipitation and flooding, which are increasing with global climate change. Local adaptation and mitigation strategies will be essential to prevent excess morbidity and mortality.

METHODS

We investigated the spatial risk of malaria infection at multiple timepoints after severe flooding in rural western Uganda employing longitudinal household surveys measuring parasite prevalence and leveraging remotely sensed information to inform spatial models of malaria risk in the 3 months after flooding.

RESULTS

We identified clusters of malaria risk emerging in areas (1) that showed the greatest changes in Normalized Difference Vegetation Index from pre- to postflood and (2) where residents were displaced for longer periods of time and had lower access to long-lasting insecticidal nets, both of which were associated with a positive malaria rapid diagnostic test result. The disproportionate risk persisted despite a concurrent chemoprevention program that achieved high coverage.

CONCLUSIONS

The findings enhance our understanding not only of the spatial evolution of malaria risk after flooding, but also in the context of an effective intervention. The results provide a "proof of concept" for programs aiming to prevent malaria outbreaks after flooding using a combination of interventions. Further study of mitigation strategies-and particularly studies of implementation-is urgently needed.

Malaria in adults after the start of Covid-19 pandemic: an analysis of admission trends, demographics, and outcomes in a tertiary hospital in the Gambia

BACKGROUND

Malaria remains a major public health concern in The Gambia. The study assessed the trend of malaria admissions and outcome of adult patients admitted after the start of the COVID-19 pandemic in a tertiary hospital in The Gambia.

METHODS

This was a retrospective hospital-based study and data was collected from the 18th October 2020 to 28th February 2023. Demographic data, clinical features, investigations, treatment, and outcomes were recorded.

RESULTS

A total of 499 malaria cases were admitted to the hospital over the 29 months of the study period. Data from 320 (67.2% of the total cases) adult patients admitted into the internal medicine department were analysed. The median age was 22 years, range (15-90) and 189 (59.1%) cases were youth with a youth (15-24 years) to older adult (> 24 years) ratio of 1.4:1. The majority of the patients were male 199 (62.2) with a male to female ratio of 1.6:1. The total number of malaria cases admitted into the internal medicine department increased from 103 cases in 2021 to 182 cases in 2022and admission peaked in November in both years. The total number of admitted malaria cases during the peak of the malaria season also increased from 92 patients between September 2021 and December 2021 to 132 patients from September 2022 to December 2022.There was also an increase in both severe and uncomplicated malaria during the same period. The total mortality was 31 (9.7%) and the rate was similar in 2021 9 (8.7%) and 2022 15 (8.4%). Patients with impaired consciousness were more likely to die when compared to those without impaired consciousness [19 (23.6%) vs 12 (5%), p  ≤ 0.001]. Patients with acute kidney injury were also more likely to die when compared with those without acute kidney injury [10 (20.4%) vs 15 (7.7%), p = 0.009].

CONCLUSION

The findings show an emerging and consistent trend of malaria admissions and the outcome in the youth and older adult population after the start of the COVID-19 pandemic in The Gambia. This, therefore, suggests the need for the implementation of targeted malaria prevention interventions in this population to further prevent the spread of the disease to the more vulnerable population.

Climate Drivers of Malaria Transmission Seasonality and Their Relative Importance in Sub-Saharan Africa

A new database of the Entomological Inoculation Rate (EIR) was used to directly link the risk of infectious mosquito bites to climate in Sub-Saharan Africa. Applying a statistical mixed model framework to high-quality monthly EIR measurements collected from field campaigns in Sub-Saharan Africa, we analyzed the impact of rainfall and temperature seasonality on EIR seasonality and determined important climate drivers of malaria seasonality across varied climate settings in the region. We observed that seasonal malaria transmission was within a temperature window of 15°C-40°C and was sustained if average temperature was well above 15°C or below 40°C. Monthly maximum rainfall for seasonal malaria transmission did not exceed 600 in west Central Africa, and 400 mm in the Sahel, Guinea Savannah, and East Africa. Based on a multi-regression model approach, rainfall and temperature seasonality were found to be significantly associated with malaria seasonality in all parts of Sub-Saharan Africa except in west Central Africa. Topography was found to have significant influence on which climate variable is an important determinant of malaria seasonality in East Africa. Seasonal malaria transmission onset lags behind rainfall only at markedly seasonal rainfall areas such as Sahel and East Africa; elsewhere, malaria transmission is year-round. High-quality EIR measurements can usefully supplement established metrics for seasonal malaria. The study's outcome is important for the improvement and validation of weather-driven dynamical mathematical malaria models that directly simulate EIR. Our results can contribute to the development of fit-for-purpose weather-driven malaria models to support health decision-making in the fight to control or eliminate malaria in Sub-Saharan Africa.

Floods in Sub-Saharan Africa; Causes, Determinants and Health Consequences

Climate change has become a global issue and affects various regions at different levels. The hydro-climatic conditions and the natural fragility of Sub-Saharan Africa (SSA) make it prone to floods. The review was intended to comprehensively explore the determinants of floods in the continent and their effects on public health. An extensive systematic literature search in English was conducted for peer-reviewed papers, abstracts and internet articles, grey literature, and official Government documents and analysed to identify common themes, findings, and outcomes. Finally, the findings were categorized into common themes. The review revealed that the frequency and intensity of precipitations have increased in recent decades in SSA. This is worsened by anthropogenic activities including urban sprawl, population growth, and land use changes. The health effects of floods are diverse, varied, and specific to a particular context which can be immediate and long-term. The economic losses due to the flood events in the continent are huge. In conclusion, Governments across the continent need to give flood management a top priority as part of national disaster preparedness, response, and mitigation. Floods cannot be managed in isolation; it has to be incorporated into national urban planning with urbanization to make cities resilient and sustainable.

Rainfall shocks, child mortality, and water infrastructure

I study the effect of rainfall shocks on child mortality at a sub-national level for a global set of developing countries. I establish that negative (positive) shocks to rainfall lead to an increase (drop) in child deaths overall. Low-income countries (LICs) and the group of countries reliant on agriculture are affected the most due to negative rainfall shocks. In LICs, the impact of negative rainfall shocks is mitigated by around 60% in districts located downstream to dams, an effect predominant among less affluent districts; in addition, the effect of rainfall fluctuations is persistent, lasting for up to three years following the shock. Results remain robust to the inclusion of relevant controls, to the consideration of relevant issues such as selective fertility and migration, and various other robustness tests.

Climate change and emergency care in Africa: A scoping review

Introduction

Climate change is a global public health emergency with implications for access to care and emergency care service disruptions. The African continent is particularly vulnerable to climate-related extreme weather events due to an already overburdened health system, lack of early warning signs, poverty, inadequate infrastructure, and variable adaptive capacity. Emergency care services are not only utilized during these events but also threatened by these hazards. Considering that the effects of climate change are expected to increase in intensity and prevalence, it is increasingly important for emergency care to prepare to respond to the changes in presentation and demand. The aim of this study was to perform a scoping review of the available literature on the relationship between climate change and emergency care on the African continent.

Methods

A scoping review was completed using five databases: Pubmed, Web of Science, GreenFILE, Africa Wide Information, and Google Scholar. A 'grey' literature search was done to identify key reports and references from included articles. Two independent reviewers screened articles and a third reviewer decided conflicts. A total of 1,382 individual articles were initially screened with 17 meeting full text review. A total of six articles were included in the final analysis. Data from four countries were represented including Uganda, Ghana, Tanzania, and Nigeria.

Results

Analysis of the six articles yielded three key themes that were identified: climate-related health impacts that contribute to surges in demand and resource utilization, opportunities for health sector engagement, and solutions to improve emergency preparedness. Authors used the outcomes of the review to propose 10 recommendations for decision-makers and leaders.

DXDiscussion

Incorporating these key recommendations at the local and national level could help improve preparedness and adaptation measures in highly vulnerable, populated areas on the African continent.

Wastewater-based epidemiology in hazard forecasting and early-warning systems for global health risks

With the advent of the SARS-CoV-2 pandemic, Wastewater-Based Epidemiology (WBE) has been applied to track community infection in cities worldwide and has proven succesful as an early warning system for identification of hotspots and changingprevalence of infections (both symptomatic and asymptomatic) at a city or sub-city level. Wastewater is only one of environmental compartments that requires consideration. In this manuscript, we have critically evaluated the knowledge-base and preparedness for building early warning systems in a rapidly urbanising world, with particular attention to Africa, which experiences rapid population growth and urbanisation. We have proposed a Digital Urban Environment Fingerprinting Platform (DUEF) - a new approach in hazard forecasting and early-warning systems for global health risks and an extension to the existing concept of smart cities. The urban environment (especially wastewater) contains a complex mixture of substances including toxic chemicals, infectious biological agents and human excretion products. DUEF assumes that these specific endo- and exogenous residues, anonymously pooled by communities' wastewater, are indicative of community-wide exposure and the resulting effects. DUEF postulates that the measurement of the substances continuously and anonymously pooled by the receiving environment (sewage, surface water, soils and air), can provide near real-time dynamic information about the quantity and type of physical, biological or chemical stressors to which the surveyed systems are exposed, and can create a risk profile on the potential effects of these exposures. Successful development and utilisation of a DUEF globally requires a tiered approach including: Stage I: network building, capacity building, stakeholder engagement as well as a conceptual model, followed by Stage II: DUEF development, Stage III: implementation, and Stage IV: management and utilization. We have identified four key pillars required for the establishment of a DUEF framework: (1) Environmental fingerprints, (2) Socioeconomic fingerprints, (3) Statistics and modelling and (4) Information systems. This manuscript critically evaluates the current knowledge base within each pillar and provides recommendations for further developments with an aim of laying grounds for successful development of global DUEF platforms.

Malaria reduction drives childhood stunting decline in Uganda: a mixed-methods country case study

BACKGROUND

Uganda has achieved a considerable reduction in childhood stunting over the past 2 decades, although accelerated action will be needed to achieve 2030 targets.

OBJECTIVES

This study assessed the national, community, household, and individual-level drivers of stunting decline since 2000, along with direct and indirect nutrition policies and programs that have contributed to nutrition change in Uganda.

METHODS

This mixed-methods study used 4 different approaches to determine the drivers of stunting change over time: 1) a scoping literature review; 2) quantitative data analyses, including Oaxaca-Blinder decomposition and difference-in-difference multivariable hierarchical modeling; 3) national- and community-level qualitative data collection and analysis; and 4) analysis of key direct and indirect nutrition policies, programs, and initiatives.

RESULTS

Stunting prevalence declined by 14% points from 2000 to 2016, although geographical, wealth, urban/rural, and education-based inequalities persist. Child growth curves demonstrated substantial improvements in child height-for-age z-scores (HAZs) at birth, reflecting improved maternal nutrition and intrauterine growth. The decomposition analysis explained 82% of HAZ change, with increased coverage of insecticide-treated mosquito nets (ITNs; 35%), better maternal nutrition (19%), improved maternal education (14%), and improved maternal and newborn healthcare (11%) being the most critical factors. The qualitative analysis supported these findings, and also pointed to wealth, women's empowerment, cultural norms, water and sanitation, dietary intake/diversity, and reduced childhood illness as important. The 2011 Uganda Nutrition Action Plan was an essential multisectoral strategy that shifted nutrition out of health and mainstreamed it across related sectors.

CONCLUSIONS

Uganda's success in stunting reduction was multifactorial, but driven largely through indirect nutrition strategies delivered outside of health. To further improve stunting, it will be critical to prioritize malaria-control strategies, including ITN distribution campaigns and prevention/treatment approaches for mothers and children, and deliberately target the poor, least educated, and rural populations along with high-burden districts.

Epidemiology of floods in sub-Saharan Africa: a systematic review of health outcomes

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12584-4.

Dihydroartemisinin-piperaquine chemoprevention and malaria incidence after severe flooding: evaluation of a pragmatic intervention in rural Uganda

BACKGROUND

Malaria epidemics are a well-described phenomenon after extreme precipitation and flooding, which account for nearly half of global disasters over the past two decades. Yet few studies have examined mitigation measures to prevent post-flood malaria epidemics.

METHODS

We conducted an evaluation of a malaria chemoprevention program implemented in response to severe flooding in western Uganda. Children ≤12 years of age from one village were eligible to receive 3 monthly rounds of dihydroartemisinin-piperaquine (DP). Two neighboring villages served as controls. Malaria cases were defined as individuals with a positive rapid diagnostic test result as recorded in health center registers. We performed a difference-in-differences analysis to estimate changes in the incidence and test positivity of malaria between intervention and control villages.

RESULTS

A total of 554 children received at least one round of chemoprevention with 75% participating in at least two rounds. Compared to control villages, we estimated a 53.4% reduction (aRR 0.47, 95% CI 0.34 - 0.62, p<.01) in malaria incidence and a 30% decrease in the test positivity rate (aRR=0.70, CI 0.50 - 0.97, p=0.03) in the intervention village in the six months post-intervention. The impact was greatest among children receiving the intervention, but decreased incidence was also observed in older children and adults (aRR=0.57, CI 0.38-0.84, p<.01).

CONCLUSIONS

Three rounds of chemoprevention with DP delivered under pragmatic conditions reduced the incidence of malaria after severe flooding in western Uganda. These findings provide a proof-of-concept for the use of malaria chemoprevention to reduce excess disease burden associated with severe flooding.

The Complex Epidemiological Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review

BACKGROUND

Climate change is expected to increase the frequency of flooding events. Although rainfall is highly correlated with mosquito-borne diseases (MBD) in humans, less research focuses on understanding the impact of flooding events on disease incidence. This lack of research presents a significant gap in climate change-driven disease forecasting.

OBJECTIVES

We conducted a scoping review to assess the strength of evidence regarding the potential relationship between flooding and MBD and to determine knowledge gaps.

METHODS

PubMed, Embase, and Web of Science were searched through 31 December 2020 and supplemented with review of citations in relevant publications. Studies on rainfall were included only if the operationalization allowed for distinction of unusually heavy rainfall events. Data were abstracted by disease (dengue, malaria, or other) and stratified by post-event timing of disease assessment. Studies that conducted statistical testing were summarized in detail.

RESULTS

From 3,008 initial results, we included 131 relevant studies (dengue n = 45 , malaria n = 61 , other MBD n = 49 ). Dengue studies indicated short-term (< 1  month ) decreases and subsequent (1-4 month) increases in incidence. Malaria studies indicated post-event incidence increases, but the results were mixed, and the temporal pattern was less clear. Statistical evidence was limited for other MBD, though findings suggest that human outbreaks of Murray Valley encephalitis, Ross River virus, Barmah Forest virus, Rift Valley fever, and Japanese encephalitis may follow flooding.

DISCUSSION

Flooding is generally associated with increased incidence of MBD, potentially following a brief decrease in incidence for some diseases. Methodological inconsistencies significantly limit direct comparison and generalizability of study results. Regions with established MBD and weather surveillance should be leveraged to conduct multisite research to a) standardize the quantification of relevant flooding, b) study nonlinear relationships between rainfall and disease, c) report outcomes at multiple lag periods, and d) investigate interacting factors that modify the likelihood and severity of outbreaks across different settings. https://doi.org/10.1289/EHP8887.

Outcomes of a Climate Change Workshop at the 2020 African Conference on Emergency Medicine

A changing climate will have demonstrable effects on health and healthcare systems, with specific and disproportionate effects on communities in Africa. Emergency care systems and providers have an opportunity to be at the forefront of efforts to combat the worst health effects from climate change. The 2020 African Conference on Emergency Medicine, under the auspices of the African Federation for Emergency Medicine, convened its first ever workshop on the topic of climate change and human health. Structured as a full day virtual course, the didactic sections were available for both live and asynchronous learning with more than 100 participants enrolled in the course. The workshop introduced the topic of the health effects of climate as they relate to emergency care in Africa and provided a forum to discuss ideas regarding the way forward. Lectures and focused discussions addressed three broad themes related to: health impacts, health care delivery, and advocacy. To our knowledge, this is the first workshop for health professionals to cover topics specific to emergency care, climate change, and health in Africa. The results of this workshop will help to guide future efforts aimed at advancing emergency care approaches in Africa with regard to medical education, research, and policy.

African relevance

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Climate-related extreme weather events are adversely affecting health and health care delivery in African countries.

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African organisations, cities, and nations have taken positive steps to adapt and build climate resilience.

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There are opportunities for emergency care professionals and scholars to continue to expand, and lead, climate and health education, research, and policy initiatives on the continent.

Assessing the effects of disasters and their aftermath on pregnancy and infant outcomes: A conceptual model

Although many studies have examined broad patterns of effects on pregnancy and infant outcomes after disasters, the causes of adverse outcomes are not always clear. Disasters cause interrelated exposure to environmental pollutants, psychological stressors, and lack of health care, and interacts with other social determinants of health. This topical review examines the short- and long-term effects of disasters on pregnancy and how they are mediated by social, behavioral, and environmental effects. In the short term, disasters are associated with physical trauma, adverse environmental exposures, and unstable housing. In the longer term, disasters may lead to relocation, changes in family functioning, and negative economic effects. These aspects of disaster exposure, in turn, lead to lack of access to health care, increased stress and negative mental health outcomes, and negative behavioral changes, including smoking and substance use, poor nutrition, physical overexertion and limited activity, and reduction in breastfeeding. All of these factors interact with social determinants of health to worsen effects on the most vulnerable women, infants, and communities. Few interventions after disasters have been tested. With the increase in disasters due to climate change and the ongoing coronavirus pandemic, the models of effects of disasters and their human health consequences need increasing refinement, and, more importantly, should be applied to interventions that improve disaster prevention, mitigation, and response.

Climate change and child health: a scoping review and an expanded conceptual framework

Climate change can have detrimental effects on child health and wellbeing. Despite the imperative for a fuller understanding of how climate change affects child health and wellbeing, a systematic approach and focus solely on children (aged <18 years) has been lacking. In this Scoping Review, we did a literature search on the impacts of climate change on child health from January, 2000, to June, 2019. The included studies explicitly linked an alteration of an exposure to a risk factor for child health to climate change or climate variability. In total, 2970 original articles, reviews, and other documents were identified, of which 371 were analysed. Employing an expanded framework, our analysis showed that the effects of climate change on child health act through direct and indirect pathways, with implications for determinants of child health as well as morbidity and mortality from a range of diseases. This understanding can be further enhanced by using a broader range of research methods, studying overlooked populations and geographical regions, investigating the costs and benefits of mitigation and adaptation for child health, and considering the position of climate change and child health within the UN Sustainable Development Goals. Present and future generations of children bear and will continue to bear an unacceptably high disease burden from climate change.

Geostatistical modeling of malaria prevalence among under-five children in Rwanda

BACKGROUND

Malaria has continued to be a life-threatening disease among under-five children in sub-Saharan Africa. Recent data indicate rising cases in Rwanda after some years of decline. We aimed at estimating the spatial variations in malaria prevalence at a continuous spatial scale and to quantify locations where the prevalence exceeds the thresholds of 5% and 10% across the country. We also consider the effects of some socioeconomic and climate variables.

METHODS

Using data from the 2014-2015 Rwanda Demographic and Health Survey, a geostatistical modeling technique based on stochastic partial differential equation approach was used to analyze the geospatial prevalence of malaria among under-five children in Rwanda. Bayesian inference was based on integrated nested Laplace approximation.

RESULTS

The results demonstrate the uneven spatial variation of malaria prevalence with some districts including Kayonza and Kirehe from Eastern province; Huye and Nyanza from Southern province; and Nyamasheke and Rusizi from Western province having higher chances of recording prevalence exceeding 5%. Malaria prevalence was found to increase with rising temperature but decreases with increasing volume for rainfall. The findings also revealed a significant association between malaria and demographic factors including place of residence, mother's educational level, and child's age and sex.

CONCLUSIONS

Potential intervention programs that focus on individuals living in rural areas, lowest wealth quintile, and the locations with high risks should be reinforced. Variations in climatic factors particularly temperature and rainfall should be taken into account when formulating malaria intervention programs in Rwanda.

Climate Variability and Malaria over West Africa

Malaria is a major public health problem in West Africa. Previous studies have shown that climate variability significantly affects malaria transmission. The lack of continuous observed weather station data and the absence of surveillance data for malaria over long periods have led to the use of reanalysis data to drive malaria models. In this study, we use the Liverpool Malaria Model (LMM) to simulate spatiotemporal variability of malaria in West Africa using daily rainfall and temperature from the following: Twentieth Century Reanalysis (20th CR), National Center for Environmental Prediction (NCEP), European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis of the Twentieth Century (ERA20C), and interim ECMWF Re-Analysis (ERA-Interim). Malaria case data from the national surveillance program in Senegal are used for model validation between 2001 and 2016. The warm temperatures found over the Sahelian fringe of West Africa can lead to high malaria transmission during wet years. The rainfall season peaks in July to September over West Africa and Senegal, and the malaria season lasts from September to November, about 1-2 months after the rainfall peak. The long-term trends exhibit interannual and decadal variabilities. The LMM shows acceptable performance in simulating the spatial distribution of malaria incidence. However, some discrepancies are found. These results are useful for decision-makers who plan public health and control measures in affected West African countries. The study would have substantial implications for directing malaria surveillance activities and health policy. In addition, this malaria modeling framework could lead to the development of an early warning system for malaria in West Africa.

Risk factors for Plasmodium falciparum infection in the Kenyan Highlands: a cohort study

BACKGROUND

Malaria transmission in African highland areas can be prone to epidemics, with minor fluctuations in temperature or altitude resulting in highly heterogeneous transmission. In the Kenyan Highlands, where malaria prevalence has been increasing, characterising malaria incidence and identifying risk factors for infection is complicated by asymptomatic infection.

METHODS

This all-age cohort study, one element of the Malaria Transmission Consortium, involved monthly follow-up of 3155 residents of the Kisii and Rachuonyo South districts during June 2009-June 2010. Participants were tested for malaria using rapid diagnostic testing at every visit, regardless of symptoms.

RESULTS

The incidence of Plasmodium falciparum infection was 0.2 cases per person, although infections were clustered within individuals and over time, with the majority of infections detected in the last month of the cohort study. Overall, incidence was higher in the Rachuonyo district and infections were detected most frequently in 5-10-year-olds. The majority of infections were asymptomatic (58%). Travel away from the study area was a notable risk factor for infection.

CONCLUSIONS

Identifying risk factors for malaria infection can help to guide targeting of interventions to populations most likely to be exposed to malaria.

The effects of climate change on human health in Africa, a dermatologic perspective: a report from the International Society of Dermatology Climate Change Committee

Throughout much of the African continent, healthcare systems are already strained in their efforts to meet the needs of a growing population using limited resources. Climate change threatens to undermine many of the public health gains that have been made in this region in the last several decades via multiple mechanisms, including malnutrition secondary to drought-induced food insecurity, mass human displacement from newly uninhabitable areas, exacerbation of environmentally sensitive chronic diseases, and enhanced viability of pathogenic microbes and their vectors. We reviewed the literature describing the various direct and indirect effects of climate change on diseases with cutaneous manifestations in Africa. We included non-communicable diseases such as malignancies (non-melanoma skin cancers), inflammatory dermatoses (i.e. photosensitive dermatoses, atopic dermatitis), and trauma (skin injury), as well as communicable diseases and neglected tropical diseases. Physicians should be aware of the ways in which climate change threatens human health in low- and middle-income countries in general, and particularly in countries throughout Africa, the world's lowest-income and second most populous continent.

Brain diseases in changing climate

Climate change is one of the biggest and most urgent challenges for the 21st century. Rising average temperatures and ocean levels, altered precipitation patterns and increased occurrence of extreme weather events affect not only the global landscape and ecosystem, but also human health. Multiple environmental factors influence the onset and severity of human diseases and changing climate may have a great impact on these factors. Climate shifts disrupt the quantity and quality of water, increase environmental pollution, change the distribution of pathogens and severely impacts food production - all of which are important regarding public health. This paper focuses on brain health and provides an overview of climate change impacts on risk factors specific to brain diseases and disorders. We also discuss emerging hazards in brain health due to mitigation and adaptation strategies in response to climate changes.

Climate drivers of malaria at its southern fringe in the Americas

In this work we analyze potential environmental drivers of malaria cases in Northwestern Argentina. We inspect causal links between malaria and climatic variables by means of the convergent cross mapping technique, which provides a causality criterion from the theory of dynamic systems. Analysis is based on 12 years of weekly malaria P. vivax cases in Tartagal, Salta, Argentina-at the southern fringe of malaria incidence in the Americas-together with humidity and temperature time-series spanning the same period. Our results show that there are causal links between malaria cases and both maximum temperature, with a delay of five weeks, and minimum temperature, with delays of zero and twenty two weeks. Humidity is also a driver of malaria cases, with thirteen weeks delay between cause and effect. Furthermore we also determined the sign and strength of the effects. Temperature has always a positive non-linear effect on cases, with maximum temperature effects more pronounced above 25°C and minimum above 17°C, while effects of humidity are more intricate: maximum humidity above 85% has a negative effect, whereas minimum humidity has a positive effect on cases. These results might be signaling processes operating at short (below 5 weeks) and long (over 12 weeks) time delays, corresponding to effects related to parasite cycle and mosquito population dynamics respectively. The non-linearities found for the strength of the effect of temperature on malaria cases make warmer areas more prone to higher increases in the disease incidence. Moreover, our results indicate that an increase of extreme weather events could enhance the risks of malaria spreading and re-emergence beyond the current distribution. Both situations, warmer climate and increase of extreme events, will be remarkably increased by the end of the century in this hot spot of climate change.

Impact of past and on-going changes on climate and weather on vector-borne diseases transmission: a look at the evidence

Background

The climate variables that directly influence vector-borne diseases’ ecosystems are mainly temperature and rainfall. This is not only because the vectors bionomics are strongly dependent upon these variables, but also because most of the elements of the systems are impacted, such as the host behavior and development and the pathogen amplification. The impact of the climate changes on the transmission patterns of these diseases is not easily understood, since many confounding factors are acting together. Consequently, knowledge of these impacts is often based on hypothesis derived from mathematical models. Nevertheless, some direct evidences can be found for several vector-borne diseases.

Main body

Evidences of the impact of climate change are available for malaria, arbovirus diseases such as dengue, and many other parasitic and viral diseases such as Rift Valley Fever, Japanese encephalitis, human African trypanosomiasis and leishmaniasis. The effect of temperature and rainfall change as well as extreme events, were found to be the main cause for outbreaks and are alarming the global community. Among the main driving factors, climate strongly influences the geographical distribution of insect vectors, which is rapidly changing due to climate change. Further, in both models and direct evidences, climate change is seen to be affecting vector-borne diseases more strikingly in fringe of different climatic areas often in the border of transmission zones, which were once free of these diseases with human populations less immune and more receptive. The impact of climate change is also more devastating because of the unpreparedness of Public Health systems to provide adequate response to the events, even when climatic warning is available. Although evidences are strong at the regional and local levels, the studies on impact of climate change on vector-borne diseases and health are producing contradictory results at the global level.

Conclusions

In this paper we discuss the current state of the results and draw on evidences from malaria, dengue and other vector-borne diseases to illustrate the state of current thinking and outline the need for further research to inform our predictions and response.

Electronic supplementary material

The online version of this article (10.1186/s40249-019-0565-1) contains supplementary material, which is available to authorized users.

Coping with Floods in Pikine, Senegal: An Exploration of Household Impacts and Prevention Efforts

African cities are at increasing risk for disasters, including floods. Pikine, Senegal—located on the outskirts of the Dakar metropolitan region—has experienced regular floods since 2005 due to a rising water table, dense settlement, and inadequate drainage. The goal of this research was to assess household experiences of floods through in-depth qualitative interviews in one area of Pikine. A total of 44 households were interviewed on the economic and health impacts of flooding and their perceptions of flood mitigation strategies. Our research confirmed that floods create substantial economic and health burdens for families and that infrastructure projects have helped, but not solved, the flooding issues. Our research also had some unexpected findings, particularly relating to concerns over drinking water, land tenure and housing prices, and perception of government intervention.

Forecasting Zoonotic Infectious Disease Response to Climate Change: Mosquito Vectors and a Changing Environment

Infectious diseases are changing due to the environment and altered interactions among hosts, reservoirs, vectors, and pathogens. This is particularly true for zoonotic diseases that infect humans, agricultural animals, and wildlife. Within the subset of zoonoses, vector-borne pathogens are changing more rapidly with climate change, and have a complex epidemiology, which may allow them to take advantage of a changing environment. Most mosquito-borne infectious diseases are transmitted by mosquitoes in three genera: Aedes, Anopheles, and Culex, and the expansion of these genera is well documented. There is an urgent need to study vector-borne diseases in response to climate change and to produce a generalizable approach capable of generating risk maps and forecasting outbreaks. Here, we provide a strategy for coupling climate and epidemiological models for zoonotic infectious diseases. We discuss the complexity and challenges of data and model fusion, baseline requirements for data, and animal and human population movement. Disease forecasting needs significant investment to build the infrastructure necessary to collect data about the environment, vectors, and hosts at all spatial and temporal resolutions. These investments can contribute to building a modeling community around the globe to support public health officials so as to reduce disease burden through forecasts with quantified uncertainty.

Impact of recent and future climate change on vector-borne diseases

Climate change is one of the greatest threats to human health in the 21st century. Climate directly impacts health through climatic extremes, air quality, sea-level rise, and multifaceted influences on food production systems and water resources. Climate also affects infectious diseases, which have played a significant role in human history, impacting the rise and fall of civilizations and facilitating the conquest of new territories. Our review highlights significant regional changes in vector and pathogen distribution reported in temperate, peri-Arctic, Arctic, and tropical highland regions during recent decades, changes that have been anticipated by scientists worldwide. Further future changes are likely if we fail to mitigate and adapt to climate change. Many key factors affect the spread and severity of human diseases, including mobility of people, animals, and goods; control measures in place; availability of effective drugs; quality of public health services; human behavior; and political stability and conflicts. With drug and insecticide resistance on the rise, significant funding and research efforts must to be maintained to continue the battle against existing and emerging diseases, particularly those that are vector borne.

Impact of the 2013 Floods on the Incidence of Malaria in Almanagil Locality, Gezira State, Sudan

Background: Heavy rain hit Sudan in August 2013 with subsequent flash floods in different parts of the country. This study investigated the impact of the flooding on incidence of malaria in Almanagil Locality in central Sudan.

Methods: This observational retrospective study compared malaria data sets during rainfall seasons in the Almanagil Locality in the year of flooding (2013) with those of corresponding rainfall seasons of previous two non-flood years (2011 and 2012).

Results: A marked increase of new malaria cases and incidence rate was observed in the 13 sentinel malaria notification sites in the locality  (IR increased from 6.09 per 100,000 person­days in 2011 [95 % CI: 5.93-6.26] and 6.48 in 2012 [95 % CI: 6.31-6.65] to 8.24 in 2013 [95 % CI: 8.05-8.43] ; P< 0.0001), with a peaking of the incidence rate in the under-5-years age group (IR for this age group jumped from 9.80 per 100,000 person­days in 2011 [95 % CI: 9.29­10.32] and 10.00 in 2012 [95 % CI: 9.52­10.49] to 15.02 in 2013 [95 % CI: 14.41­15.64]). A noticeable increase in the slide positivity rate (P< 0.0001) was observed in the 12-week period of 2013 (SPR = 20.86% [95 % CI: 20.40 ­21.32%]) compared with the same periods in 2011 (SPR = 8.72% [95 % CI: 8.36 ­9.08%]) and 2012 (SPR = 12.62% [95 % CI: 12.24 ­13.01%]), with a more marked rise of the SPR in the under-5-year age group. Hospital data showed increase in both the inpatient and outpatient incidence proportions in the study period of 2013 compared to those of the years 2011 and 2012. Hospital OPD incidence proportion in 2013 was 19.7% (95% CI: 19.24­20.18%) compared to 12.85% (95% CI: 12.48­13.23%) in 2011, and 12.16% (95% CI: 11.82­12.51%) in 2012. The < 5 year old groups were responsible for the overall rise in the proportion of malaria cases in 2013 , particularly the < 1 year old group which more than doubled in the 2013 period compared to both 2011 and 2012 periods (Age­specific proportion of the outpatient malaria cases of the < 1 year old group in 2013 was19.5% [95% CI: 18.5­20.6%]  compared to 7.7% [95% CI: 6.9­8.6%] in 2011 and 8.1% [95% CI: 7.3­8.9%] in 2012. Incidence proportion of severe malaria cases (inpatients) increased to 22.5 % (95 % CI: 21.5 to 23.6 %) in the study period of 2013 compared to 19.8 % (95 % CI: 18.6 to 21.0 %) in 2011 and 18.4 % (95 % CI: 17.4 to 19.5) in 2012. The increase in the proportion of severe malaria cases was mainly due to a higher proportion of children < 5 years of age and especially to a higher proportion of children < 1 year of age.

Conclusion: The study revealed a significant increase in the incidence rate of malaria in Almanagil Locality following the flash flood of August 2013. The flooding had the highest impact on the malaria incidence of the under-5-years age group, and particularly of the under-1-year age group.

Keywords: Flood, Flooding, Malaria, Disaster, Sudan, Gezira, Almanagil

Infectious Diseases After Hydrologic Disasters

Hydrologic disasters, including hurricanes, tsunamis, and severe flooding, have been associated with infectious diseases, particularly among vulnerable and displaced populations in resource-poor settings. Skin and soft tissue infections, gastrointestinal infections, respiratory infections, zoonotic infections, and vector-borne diseases each present unique threats to human health in this setting. Increased emergency physician awareness of these infectious diseases and their diagnosis and management helps optimize medical care for survivors after a hydrologic disaster and safeguard the health of disaster responders.

The impact of flooding on aquatic ecosystem services

Flooding is a major disturbance that impacts aquatic ecosystems and the ecosystem services that they provide. Predicted increases in global flood risk due to land use change and water cycle intensification will likely only increase the frequency and severity of these impacts. Extreme flooding events can cause loss of life and significant destruction to property and infrastructure, effects that are easily recognized and frequently reported in the media. However, flooding also has many other effects on people through freshwater aquatic ecosystem services, which often go unrecognized because they are less evident and can be difficult to evaluate. Here, we identify the effects that small magnitude frequently occurring floods (< 10-year recurrence interval) and extreme floods (> 100-year recurrence interval) have on ten aquatic ecosystem services through a systematic literature review. We focused on ecosystem services considered by the Millennium Ecosystem Assessment including: (1) supporting services (primary production, soil formation), (2) regulating services (water regulation, water quality, disease regulation, climate regulation), (3) provisioning services (drinking water, food supply), and (4) cultural services (aesthetic value, recreation and tourism). The literature search resulted in 117 studies and each of the ten ecosystem services was represented by an average of 12 ± 4 studies. Extreme floods resulted in losses in almost every ecosystem service considered in this study. However, small floods had neutral or positive effects on half of the ecosystem services we considered. For example, small floods led to increases in primary production, water regulation, and recreation and tourism. Decision-making that preserves small floods while reducing the impacts of extreme floods can increase ecosystem service provision and minimize losses.

Impact of climate change on dermatological conditions related to flooding: update from the International Society of Dermatology Climate Change Committee

Climate change contributes to the increase in severity and frequency of flooding, which is the most frequent and deadly disaster worldwide. Flood-related damage can be very severe and include health effects. Among those health impacts, dermatological diseases are one of the most frequently encountered. Both infectious and noninfectious dermatological conditions are increasing after flooding. We searched PubMed using the search term climate change OR global warming OR rainfall OR flooding OR skin. Articles published in the English-language literature were included. We also searched the International Society of Dermatology website library on climate change for additional articles. There is an increased risk of trauma during the course of a natural disaster. The majority of post-tsunami wound infections were polymicrobial, but gram-negative bacteria were the leading causes. Infectious diseases with dermatological manifestations, such as impetigo, leptospirosis, measles, dengue fever, tinea corporis, malaria, and leishmaniasis, are important causes of morbidity among flood-afflicted individuals. Insect bites and stings, and parasite infestations such as scabies and cutaneous larva migrans are also frequently observed. Inflammatory conditions including irritant contact dermatitis are among the leading dermatological conditions. Dermatological conditions such as alopecia areata, vitiligo, psoriasis, and urticaria can be induced or exacerbated by psychological conditions post disaster. Prevention is essential in the management of skin diseases because of flooding. Avoiding exposure to contaminated environments, wearing protective devices, rapid provision of clean water and sanitation facilities, prompt vector controls, and education about disease risk and prevention are important.

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.

Assessment of climate-driven variations in malaria incidence in Swaziland: toward malaria elimination

Background

Swaziland aims to eliminate malaria by 2020. However, imported cases from neighbouring endemic countries continue to sustain local parasite reservoirs and initiate transmission. As certain weather and climatic conditions may trigger or intensify malaria outbreaks, identification of areas prone to these conditions may aid decision-makers in deploying targeted malaria interventions more effectively.

Methods

Malaria case-surveillance data for Swaziland were provided by Swaziland’s National Malaria Control Programme. Climate data were derived from local weather stations and remote sensing images. Climate parameters and malaria cases between 2001 and 2015 were then analysed using seasonal autoregressive integrated moving average models and distributed lag non-linear models (DLNM).

Results

The incidence of malaria in Swaziland increased between 2005 and 2010, especially in the Lubombo and Hhohho regions. A time-series analysis indicated that warmer temperatures and higher precipitation in the Lubombo and Hhohho administrative regions are conducive to malaria transmission. DLNM showed that the risk of malaria increased in Lubombo when the maximum temperature was above 30 °C or monthly precipitation was above 5 in. In Hhohho, the minimum temperature remaining above 15 °C or precipitation being greater than 10 in. might be associated with malaria transmission.

Conclusions

This study provides a preliminary assessment of the impact of short-term climate variations on malaria transmission in Swaziland. The geographic separation of imported and locally acquired malaria, as well as population behaviour, highlight the varying modes of transmission, part of which may be relevant to climate conditions. Thus, the impact of changing climate conditions should be noted as Swaziland moves toward malaria elimination.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-017-1874-0) contains supplementary material, which is available to authorized users.

Improving the Specificity of Plasmodium falciparum Malaria Diagnosis in High-Transmission Settings with a Two-Step Rapid Diagnostic Test and Microscopy Algorithm

Poor specificity may negatively impact rapid diagnostic test (RDT)-based diagnostic strategies for malaria. We performed real-time PCR on a subset of subjects who had undergone diagnostic testing with a multiple-antigen (histidine-rich protein 2 and pan-lactate dehydrogenase pLDH [HRP2/pLDH]) RDT and microscopy. We determined the sensitivity and specificity of the RDT in comparison to results of PCR for the detection of Plasmodium falciparum malaria. We developed and evaluated a two-step algorithm utilizing the multiple-antigen RDT to screen patients, followed by confirmatory microscopy for those individuals with HRP2-positive (HRP2⁺)/pLDH-negative (pLDH^-) results. In total, dried blood spots (DBS) were collected from 276 individuals. There were 124 (44.9%) individuals with an HRP2⁺/pLDH⁺ result, 94 (34.1%) with an HRP2⁺/pLDH^- result, and 58 (21%) with a negative RDT result. The sensitivity and specificity of the RDT compared to results with real-time PCR were 99.4% (95% confidence interval [CI], 95.9 to 100.0%) and 46.7% (95% CI, 37.7 to 55.9%), respectively. Of the 94 HRP2⁺/pLDH^- results, only 32 (34.0%) and 35 (37.2%) were positive by microscopy and PCR, respectively. The sensitivity and specificity of the two-step algorithm compared to results with real-time PCR were 95.5% (95% CI, 90.5 to 98.0%) and 91.0% (95% CI, 84.1 to 95.2), respectively. HRP2 antigen bands demonstrated poor specificity for the diagnosis of malaria compared to that of real-time PCR in a high-transmission setting. The most likely explanation for this finding is the persistence of HRP2 antigenemia following treatment of an acute infection. The two-step diagnostic algorithm utilizing microscopy as a confirmatory test for indeterminate HRP2⁺/pLDH^- results showed significantly improved specificity with little loss of sensitivity in a high-transmission setting.