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

Are we joining the One Health dots? A scoping review of research on the one health effects of extreme weather events in eastern Australia

Extreme weather events such as floods, bushfires, cyclones, and drought, are projected to increase in eastern Australia. Understanding how these events influence the combined, sustainable well-being of humans, animals, and ecosystems - that is One Health - will enable development of transdisciplinary and ultimately more effective interventions. A scoping review was conducted to explore the research associated with the effects of extreme weather events in eastern Australia using a One Health lens, specifically identifying the type of extreme weather events studied, the research conducted in the context of One Health, and gaps to inform improved One Health implementation. The review followed JBI guidelines (based on PRISMA). Eligible research was peer-reviewed, in English, and published since 2007, in which primary research studies investigated the impact of extreme weather events in eastern Australia on at least two of ecosystems, human health, and animal health. Using structured search terms, six databases were searched. Following removal of duplicates, 870 records were screened by two reviewers. Eleven records were eligible for data extraction and charting. The scope of extreme weather events studied was relatively limited, with studies in flood and bushfire settings predominating, but relatively little research on cyclones. Major health themes included more than the impact of extreme weather events on physical health (zoonotic and vector-borne diseases) through investigation of social well-being and mental health in the context of the human-animal bond in evacuation behaviors and drought. Research gaps include studies across a broader range of extreme weather events and health topics, as well as a more comprehensive approach to including the impacts of extreme weather events on all three domains of One Health. The limited research focus inevitably translates to limited recommendations for policy, planning and response to manage extreme weather event emergencies. Given the expected increase in frequency of these events, there is a critical need for more comprehensive primary research to better identify strategies and facilitate implementation of One Health promotion for improved outcomes in extreme weather event emergencies.

Rapid mapping of global flood precursors and impacts using novel five-day GRACE solutions

Floods affect communities and ecosystems worldwide, emphasizing the importance of identifying their precursors and enhancing resilience to these events. Here, we calculated Antecedent Total Water Storage (ATWS) anomalies from the new 5-day (5D) Gravity Recovery and Climate Experiment (GRACE) and its Follow-On (GRACE-FO) satellite solutions to enhance the detection of pre-flood and active flood conditions and to map post-flood storage anomalies. The GRACE data were compared with ~ 3300 flood events reported by the Dartmouth Flood Observatory (2002-2021), revealing distinct ATWS precursor signals in 5D solutions, in contrast to the monthly solutions. Specifically, floods caused by saturation-excess runoff-triggered by persistent rainfall, monsoonal patterns, snowmelt, or rain-on-snow events-show detectable ATWS increases 15 to 50 days before and during floods, providing a valuable opportunity to improve flood monitoring. These 5D solutions also facilitate a more rapid mapping of post-flood storage changes to assess flood recovery from tropical cyclones and sub-monthly weather extremes. Our findings show the promising potential of 5D GRACE solutions, which are still in the development phase, for future integration into operational frameworks to enhance flood detection and recovery, facilitating the rapid analysis of storage changes relative to monthly solutions.

Analysis of environmental factors influencing endemic cholera risks in sub-Saharan Africa

The recurring cholera outbreaks in sub-Saharan Africa are of growing concern, especially considering the potential acceleration in the global trend of larger and more lethal cholera outbreaks due to the impacts of climate change. However, there is a scarcity of evidence-based research addressing the environmental and infrastructure factors that sustain cholera recurrence in Africa. This study adopts a statistical approach to investigate over two decades of endemic cholera outbreaks and their relationship with five environmental factors: water provision, sanitation provision, raising temperatures, increased rainfall and GDP. The analysis covers thirteen of the forty-two countries in the mainland sub-Saharan region, collectively representing one-third of the region's territory and half of its population. This breadth enables the findings to be generalised at a regional level. Results from all analyses consistently associate water provision with cholera reduction. The stratified model links increased water provision with a reduction in cholera risk that ranged from 4.2 % to 84.1 % among eight countries (out of 13 countries) as well as a reduction of such risk that ranged from 9.8 % to 68.9 % when there is increased sanitation provision, which was observed in nine countries (out of 13). These results indicate that the population's limited access to water and sanitation, as well as the rise in temperatures, are critical infrastructure and environmental factors contributing to endemic cholera and the heightened risk of outbreaks across the sub-Saharan region. Therefore, these are key areas for targeted interventions and cross-border collaboration to enhance resilience to outbreaks and lead to the end of endemic cholera in the region. However, it is important to interpret the results of this study with caution; hence, further investigation is recommended to conduct a more detailed analysis of the impact of infrastructure and environmental factors on reducing cholera risk.

Spatiotemporal dynamics of cholera epidemics in Ethiopia: 2015-2021

Since the onset of the seventh cholera pandemic, Ethiopia has been affected by recurrent epidemics. However, the epidemiology of cholera in this country remains poorly understood. This study aimed to describe cholera outbreak characteristics in Ethiopia from 2015 to 2021. During this period, Ethiopia experienced four epidemic waves. The first wave involved nationwide outbreaks during the second half of 2016 followed by outbreaks predominantly affecting Somali Region in 2017. The second wave primarily affected Tigray and Afar Regions. During the third wave, multiple smaller-scale outbreaks occurred during 2019. The fourth wave was limited to Bale Zone (Oromia Region) in 2021. Overall, a north to south shift was observed over the course of the study period. Major cholera transmission factors included limited access to safe water and sanitation facilities. Severe weather events (drought and flooding) appear to aggravate cholera diffusion. Cholera transmission between Ethiopia and nearby countries (Kenya and Somalia), likely plays a major role in regional cholera dynamics. Overall, this study provides the first understanding of recent spatiotemporal cholera dynamics in Ethiopia to inform cholera control and elimination strategies.

Transcription factor B-H2 regulates CYP9J34 expression conveying deltamethrin resistance in Culex pipiens pallens

BACKGROUND

Mosquitoes are vectors of various diseases, posing significant health threats worldwide. Chemical pesticides, particularly pyrethroids like deltamethrin, are commonly used for mosquito control, but the emergence of resistant mosquito populations has become a concern. In the deltamethrin-resistant (DR) strain of Culex pipiens pallens, the highly expressed cytochrome P450 9 J34 (CYP9J34) gene is believed to play a role in resistance, yet the underlying mechanism remains unclear.

RESULTS

Quantitative polymerase chain reaction with reverse transcription (qRT-PCR) analysis revealed that the expression of CYP9J34 was 14.6-fold higher in DR strains than in deltamethrin-susceptible (DS) strains. The recombinant production of CYP9J34 protein of Cx. pipiens pallens showed that the protein could directly metabolize deltamethrin, yielding the major metabolite 4'-OH deltamethrin. Through dual luciferase reporter assays and RNA interference, the transcription factor homeobox protein B-H2-like (B-H2) was identified to modulate the expression of the CYP9J34 gene, contributing to mosquito resistance to deltamethrin.

CONCLUSIONS

Our findings demonstrate that the CYP9J34 protein could directly degrade deltamethrin, and the transcription factor B-H2 could regulate CYP9J34 expression, influencing the resistance of mosquitoes to deltamethrin. © 2023 Society of Chemical Industry.

Change in emotional distress, anxiety, depression and PTSD from pre- to post-flood exposure in women residing in low-income settings in South Africa

Floods are increasing in frequency and may increase the risk for experiencing emotional distress, anxiety, depression and PTSD. The aim of this study was to determine the extent of damage, loss, injury and death resulting from floods that occurred in and around the city of Durban, South Africa, in April 2022, and associated changes in mental health pre- to post-floods in a low-income setting. Seventy-three women between the ages of 18 and 45, residing in flood affected, low-income settings, were interviewed prior to the floods occurring. Mental health measures were repeated with 69 of the 73 women during the post-flood interview along with a questionnaire measuring flood-related exposures. Loss of infrastructure (lacked access to drinking water, electricity, fresh food, could not travel to work, had to stay in a shelter and could not get hold of friends or family) was a predictor of post-flood change in levels of emotional distress and anxiety. Higher levels of prior trauma exposure were associated with higher post-flood levels of emotional distress. Higher pre-flood food insecurity was also associated with higher post-flood anxiety. Women affected by poverty, food insecurity and a history of trauma are vulnerable to the additive adverse mental health effects of floods. Proactive approaches to diminishing the impact of floods on the livelihood of women is needed and post-flood relieve efforts may be more affective if they are enhanced by providing mental health support.

Sporadic regional re-emergent cholera: a 19th century problem in the 21st century

Cholera, caused by Vibrio cholerae, is a severe diarrheal disease that necessitates prompt diagnosis and effective treatment. This review comprehensively examines various diagnostic methods, from traditional microscopy and culture to advanced nucleic acid testing like polymerase spiral reaction and rapid diagnostic tests, highlighting their advantages and limitations. Additionally, we explore evolving treatment strategies, with a focus on the challenges posed by antibiotic resistance due to the activation of the SOS response pathway in V. cholerae. We discuss promising alternative treatments, including low-pressure plasma sterilization, bacteriophages, and selenium nanoparticles. The paper emphasizes the importance of multidisciplinary approaches combining novel diagnostics and treatments in managing and preventing cholera, a persistent global health challenge. The current re-emergent 7th pandemic of cholera commenced in 1961 and shows no signs of abeyance. This is probably due to the changing genetic profile of V. cholerae concerning bacterial pathogenic toxins. Given this factor, we argue that the disease is effectively re-emergent, particularly in Eastern Mediterranean countries such as Lebanon, Syria, etc. This review considers the history of the current pandemic, the genetics of the causal agent, and current treatment regimes. In conclusion, cholera remains a significant global health challenge that requires prompt diagnosis and effective treatment. Understanding the history, genetics, and current treatments is crucial in effectively addressing this persistent and re-emergent disease.

The impact of environmental conditions on non-communicable diseases in sub-Saharan Africa: A scoping review of epidemiologic evidence

Background

The burden of non-communicable diseases (NCDs) in sub-Saharan Africa (SSA) is increasing. Environmental conditions such as heavy metals and air pollution have been linked with the incidence and mortality of chronic diseases such as cancer, as well as cardiovascular and respiratory diseases. We aimed to scope the current state of evidence on the impact of environmental conditions on NCDs in SSA.

Methods

We conducted a scoping review to identify environmental conditions linked with NCDs in SSA by identifying studies published from January 1986 through February 2023. We searched African Index Medicus, Ovid Medline, Scopus, Web of Science, and Greenfile. Using the PICOS study selection criteria, we identified studies conducted in SSA focussed on physical environmental exposures and incidence, prevalence, and mortality of NCDs. We included only epidemiologic or quantitative studies.

Results

We identified 6754 articles from electronic database searches; only 36 met our inclusion criteria and were qualitatively synthesised. Two studies were conducted in multiple SSA countries, while 34 were conducted across ten countries in SSA. Air pollution (58.3%) was the most common type of environmental exposure reported, followed by exposure to dust (19.4%), meteorological variables (13.8%), heavy metals (2.7%), soil radioactivity (2.7%), and neighbourhood greenness (2.7%). The examined NCDs included respiratory diseases (69.4%), cancer (2.7%), stroke (5.5%), diabetes (2.7%), and two or more chronic diseases (19.4%). The study results suggest an association between environmental exposures and NCDs, particularly for respiratory diseases. Only seven studies found a null association between environmental conditions and chronic diseases.

Conclusions

There is a growing body of research on environmental conditions and chronic diseases in the SSA region. Although some cities in SSA have started implementing environmental monitoring and control measures, there remain high levels of environmental pollution. Investment can focus on improving environmental control measures and disease surveillance.

The impact of the 2021 flood on the outpatient care in the North Rhine region, Germany: a cross-sectional study

BACKGROUND

In the summer of 2021, heavy precipitation led to extreme flooding across Western Europe. In Germany, North Rhine-Westphalia and Rhineland-Palatinate were particularly affected. More than 180 people lost their lives, and over 700 were left injured and traumatized. In the North Rhine district alone, more than 120 practices were only able to operate to a limited extent or had to close their practices completely. The aim of this study was to assess the impact of the 2021 flood on the outpatient care in the North Rhine region.

METHODS

The cross-sectional study was conducted in January 2022 in practices affected by the flood in the North Rhine region. For this purpose, 210 affected practices were identified using a list of the Association of Statutory Health Insurance Physicians for North Rhine (KVNO) and via telephone and/or e-mail. These practices were forwarded a questionnaire that addressed, among other things, the local accessibility of the practices before and after the flood, possibilities of patient care in different premises and received support.

RESULTS

A total of 103 practices (49.1%) returned the completed questionnaire, of which 1/4 were general practitioners. 97% of the practices reported power failure, more than 50% water supply damage and nearly 40% the loss of patient records. 76% of the participating practices stated that they needed to close their practice at least temporarily. 30 doctors took up patient care in alternative premises. The average number of patients seen by doctors per week before the flood was 206.5. In the first week working in alternative premises, doctors saw an average of 66.2 patients (-50.3%). Especially elderly/geriatric patients and patients with disabilities were identified as particularly vulnerable in terms of access to health care after the flood.

CONCLUSIONS

The flood had a significant negative impact on outpatient care. We determined not only a high number of closed practices and a large decrease in patient numbers but also differences in patient care assessment depending on the type of alternative premises. To address outpatient care disruptions after extreme weather events more effectively, appropriate measures should be implemented pre-emptively.

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.

Flood exposure and pregnancy loss in 33 developing countries

Floods have affected billions worldwide. Yet, the indirect health impacts of floods on vulnerable groups, particularly women in the developing world, remain underexplored. Here, we evaluated the risk of pregnancy loss for women exposed to floods. We analyzed 90,465 individual pregnancy loss records from 33 developing countries, cross-referencing each with spatial-temporal flood databases. We found that gestational flood exposure is associated with increased pregnancy loss with an odds ratio of 1.08 (95% confidence interval: 1.04 - 1.11). This risk is pronounced for women outside the peak reproductive age range (<21 or >35) or during the mid and late-stage of pregnancy. The risk escalated for women dependent on surface water, with lower income or education levels. We estimated that, over the 2010s, gestational flood events might be responsible for approximately 107,888 (CIs: 53,944 - 148,345) excess pregnancy losses annually across 33 developing countries. Notably, there is a consistent upward trend in annual excess pregnancy losses from 2010 to 2020, and was more prominent over Central America, the Caribbean, South America, and South Asia. Our findings underscore the disparities in maternal and child health aggravated by flood events in an evolving climate.

Climate change, environmental extremes, and human health in Australia: challenges, adaptation strategies, and policy gaps

Climate change presents a major public health concern in Australia, marked by unprecedented wildfires, heatwaves, floods, droughts, and the spread of climate-sensitive infectious diseases. Despite these challenges, Australia's response to the climate crisis has been inadequate and subject to change by politics, public sentiment, and global developments. This study illustrates the spatiotemporal patterns of selected climate-related environmental extremes (heatwaves, wildfires, floods, and droughts) across Australia during the past two decades, and summarizes climate adaptation measures and actions that have been taken by the national, state/territory, and local governments. Our findings reveal significant impacts of climate-related environmental extremes on the health and well-being of Australians. While governments have implemented various adaptation strategies, these plans must be further developed to yield concrete actions. Moreover, Indigenous Australians should not be left out in these adaptation efforts. A collaborative, comprehensive approach involving all levels of government is urgently needed to prevent, mitigate, and adapt to the health impacts of climate change.

Thunder storm mortality: Issues of medicolegal concern

Thunderstorms refer to atmospheric disturbances that are associated with electrical discharges in the form of lightning, with acoustic effects from thunder. They involve the rapid upward movement of warm, moist air which then cools and condenses creating typical cumulonimbus clouds with precipitation. Thunderstorms range in severity but are usually associated with heavy rains, winds and sometimes sleet, hail and snow. If the intensity of a storm increases there may be tornadoes or cyclones. In cases with lightning strikes and minimal or no rain there is an associated risk for the development of quite devastating wild (bush) fires. Lightning strikes may also be associated with the development, or an exacerbation, of potentially lethal natural cardiac or respiratory diseases.

Diagnosis and Management of Severe Water-Related Skin and Soft Tissue Sepsis: A Summative Review of the Literature

BACKGROUND

Skin and soft tissue infections (SSTIs) are common presentations in the emergency department. However, this is less common after contact with contaminated saltwater or freshwater. This review presents the diagnosis and management of water-related soft tissue sepsis in this vulnerable and difficult-to-treat subgroup of necrotizing soft tissue sepsis.

METHODS

A summative literature overview is presented regarding bacterial and fungal SSTI after contact with contaminated water, with practical diagnostic and management aspects.

RESULTS

The literature indicates that these wounds and infections remain difficult to treat. An approach using appropriate diagnostic tools with both medical and surgical management strategies is provided.

CONCLUSIONS

SSTIs due to water contamination of wounds involve unusual organisms with unusual resistance patterns, and require a nuanced and directed diagnostic approach with an adaptation of the usual antibiotic or antifungal selection to achieve a successful cure, along with aggressive debridement and wound care.

Health effects of climate change in Africa: A call for an improved implementation of prevention measures

The world's climate, particularly in Africa, has changed substantially during the past few decades, contributed by several human activities. Africa is one of the continents that is most vulnerable to climate change globally. Since the beginning of 2022, extreme weather events in Africa have affected about 19 million people and killed at least 4,000 individuals. Cyclones, floods, heatwaves, wildfires, droughts, and famine were among the severe weather occurrences. Natural disasters and extreme weather events brought on by climate change may compromise access to clean water, sanitation systems, and healthcare facilities, making people more vulnerable to a number of illnesses. Floods and drought can lead to both communicable and non-communicable diseases. The African population is more likely to experience more mental health disorders than before because of natural disasters, which result in the loss of property and sometimes loss of lives more frequently. We, therefore, call for an improved implementation of strategies to prevent the health effects of climate change so that the health of the people in Africa can be maintained.

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.