Neglected Tropical Diseases in the Context of Climate Change in East Africa: A Systematic Scoping Review

An epidemiological and spatiotemporal analysis of visceral leishmaniasis in West Pokot, Kenya, between 2018 and 2022

BACKGROUND

Visceral leishmaniasis (VL) remains a significant public health concern in West Pokot County, Kenya, where a large outbreak between 2020 and 2022 emphasised the need for improved VL control strategies. However, these measures are partially hampered by limited insight into the geographical distribution of cases and localised outbreaks of the disease. This study aimed to describe the epidemiology and spatiotemporal patterns of VL in West Pokot between 2018 and 2022, in order to map the spread of VL transmission and identify regions that should be prioritised for control interventions.

METHODS

VL patient demographics and village of residence were retrieved from admission records of Kacheliba Sub-County Hospital in West Pokot, Kenya. The temporal trend in VL admissions between 2018 and 2022 was analysed using seasonal decomposition analysis. To describe the spatial distribution of VL cases, geographic coordinates of villages of residence were collected from pre-established databases, and VL incidence was mapped at the sub-location level. Hotspot analysis was performed per study year to identify villages with high VL incidence, and scan statistics were applied to detect spatiotemporal clusters of VL cases during the study period.

RESULTS

A total of 1948 VL patients were reported between 2018 and 2022. The annual number of cases increased from 245 in 2019 to 598 in 2022, and VL admissions were generally higher at the start of the wet seasons. 70% of the VL cases could be georeferenced, and mapping of VL incidence revealed high case rates in the east of West Pokot during the complete study period. The eastern villages Lotongot and Chepaywat were marked as VL hotspots at a 99% confidence level in all study years. In addition, five significant spatiotemporal clusters were detected in the east and north, suggestive of local VL outbreaks in these regions.

CONCLUSIONS

The increase in VL hospital admissions during the study period stresses the need for enhanced VL control and outbreak mitigation in West Pokot. These control measures should be focused on the hotspot regions in the east of the county.

The "Doorstop Pocket" In Thioredoxin Reductases─An Unexpected Druggable Regulator of the Catalytic Machinery

Pyridine nucleotide-disulfide oxidoreductases are underexplored as drug targets, and thioredoxin reductases (TrxRs) stand out as compelling pharmacological targets. Selective TrxR inhibition is challenging primarily due to the reliance on covalent inhibition strategies. Recent studies identified a regulatory and druggable pocket in Schistosoma mansoni thioredoxin glutathione reductase (TGR), a TrxR-like enzyme, and an established drug target for schistosomiasis. This site is termed the "doorstop pocket" because compounds that bind there impede the movement of an aromatic side-chain necessary for the entry and exit of NADPH and NADP+ during enzymatic turnover. This discovery spearheaded the development of new TGR inhibitors with efficacies surpassing those of current schistosomiasis treatment. Targeting the "doorstop pocket" is a promising strategy, as the pocket is present in all members of the pyridine nucleotide-disulfide oxidoreductase family, opening new avenues for exploring therapeutic approaches in diseases where the importance of these enzymes is established, including cancer and inflammatory and infectious diseases.

Impact of COVID-19 on the neglected tropical diseases: a scoping review

BACKGROUND

This study investigates the impact of the COVID-19 pandemic on the prevalence, management, and control of the neglected tropical diseases (NTDs) highlighting the current or prospective impact of COVID-19 on research and development funding for, and execution of, NTD programmes. This review was conducted to determine if, and how, NTDs were affected by COVID-19, and whether those effects will delay the elimination goals of the Sustainable Development goals.

METHODS

Using open-source available data from policy and documentation from official websites of the relevant stakeholders including but not limited to World Health Organization (WHO) documents and policies, government foreign aid documents, and the Policy Cures G-Finder reports, this scoping review explored ongoing challenges to supporting research and development (R&D) for the NTDs and in maintaining NTD control programs; examined the constraints posed for NTD management by the pandemic from disruptions to healthcare services, reduction of finance and explored the potential long-term implications and consequences for those poorer, neglected populations in low and middle income-countries (LMICs). This was done by a scoping review literature search, publications were subject to an initial practical screening step to ensure the most relevant publications were selected for full screening, with the focus on scoping the designated topic of the impact of COVID-19 on NTDs. We further undertook an evaluation of the socio-economic factors exacerbating the impact of COVID-19 on NTD burden.

RESULTS

Multiple disruptions and setbacks, likely to affect NTD programmes and progress towards their elimination targets were identified in this study. R&D funding for the NTDs and AIDs and TB has declined since the funding high point of 2019, and for malaria since the high point of 2018. Significant changes in allocation of R&D funding within the NTDs are observed post pandemic, likely because of prioritization among donors. Diseases for which the least R&D investment was reported in place, prior to the pandemic (mycetoma, taeniasis/cysticercosis, trachoma and Buruli ulcer) have been particularly impacted post pandemic. We identified specific NTDs including schistosomiasis, leprosy, and rabies that have been affected by the COVID-19 pandemic and disruptions caused to on ongoing NTD control and elimination programs. Pandemic restrictions disrupted essential medical supply manufacturing and distribution impacting immunization programs and hindered efforts to control the spread of infectious diseases. NTD programmes have experienced numerous setbacks including delays in mass drug administration programs (e.g. for schistosomiasis), cancelled or delayed vaccination programs (e.g. for rabies) and closure of testing facilities has resulted in reduced diagnosis, treatment, and disease elimination for all NTDs. Lockdowns and clinic closures causing disruption to essential healthcare services restricted NTD surveillance and treatment programs. Community fears around contracting COVID-19 exacerbated the constraints to service delivery. Disparities in global vaccine distribution have widened with LMICs facing limited access to vaccines and disruption to immunization programs. Finally, the pandemic has led to increased poverty with poor and marginalized communities, impacting nutrition, healthcare access and education all of which have long term implications for NTD management and control.

CONCLUSIONS

The COVID-19 pandemic profoundly impacted global health research and global health equity. Attention and funding were diverted from all sectors, significantly affecting research and development efforts set out in the World Health Organization's NTD elimination Roadmaps. Ongoing changes to funding, economic crises, logistics and supply chain disruptions as well as deepening poverty has put a strain on already weak healthcare systems and exacerbated LMIC healthcare challenges. In particular, the delays and constraints to NTD management and elimination programs will have long-reaching consequences highlighting the need for global cooperation and renewed investment to put the NTD roadmap back on track. Targets and milestones are unlikely to be met without significant investment for recovery, in place.

Climate change, biodiversity loss, and Indigenous Peoples' health and wellbeing: A systematic umbrella review

Indigenous Peoples worldwide are experiencing a cascade of impacts on their health and wellbeing as a result of climate change and biodiversity loss. Existing literature at the interface of climate change, biodiversity loss, and Indigenous health tells us that Indigenous Peoples are among those most disproportionately and acutely affected by these impacts. Yet, a gap exists with respect to comprehensively and critically synthesizing the impacts reported across this literature and identifying Indigenous-led responses. Guided by an Indigenous advisory group, we employed a systematic umbrella review methodology, following PRISMA guidelines, to characterize the global secondary literature (PROSPERO registration #: CRD42023417060). In so doing, we identified the proximal, intermediate, distal, and gendered impacts of climate change and biodiversity loss on Indigenous health and wellbeing as well as Indigenous-led responses. Five databases were searched for published reviews, along with a grey literature search that focused on underrepresented geographic regions in the academic literature. Two independent reviewers conducted two-stage screening, data extraction, and quality assessment of retrieved records. Basic descriptive statistics were calculated. Qualitative data were analyzed thematically, using a constant comparative approach. A total of 38 review articles met the eligibility criteria and 37 grey literature records were retrieved and included in the review. Reviews were published between 2010-2023 and geographically clustered in the Circumpolar North. Intersecting proximal, intermediate, and distal impacts were characterized as place-based and specific, and linked to colonialism as an antecedent to and driver of these impacts. Gendered impacts were underexplored within reviews. Reviewed literature underscored the value of engaging diverse knowledge systems; platforming localized, community-led adaptation to climate change and biodiversity loss, while addressing sociopolitical constraints to these efforts; and applying a broader conceptualization of health that aligns with Indigenous frameworks. Going forward, we must foreground equity- and rights-based considerations within integrated responses to climate and biodiversity crises.

Neglected tropical disease (NTD) diagnostics: current development and operations to advance control

Neglected tropical diseases (NTDs) have become important public health threats that require multi-faceted control interventions. As late treatment and management of NTDs contribute significantly to the associated burdens, early diagnosis becomes an important component for surveillance and planning effective interventions. This review identifies common NTDs and highlights the progress in the development of diagnostics for these NTDs. Leveraging existing technologies to improve NTD diagnosis and improving current operational approaches for deployment of developed diagnostics are crucial to achieving the 2030 NTD elimination target. Point-of-care NTD (POC-NTD) diagnostic tools are recommended preferred diagnostic options in resource-constrained areas for mapping risk zones and monitoring treatment efficacy. However, few are currently available commercially. Technical training of remote health care workers on the use of POC-NTD diagnostics, and training of health workers on the psychosocial consequences of these diagnostics are critical in harnessing POC-NTD diagnostic potential. While the COVID-19 pandemic has challenged the possibility of achieving NTD elimination in 2030 due to the disruption of healthcare services and dwindling financial support for NTDs, the possible contribution of NTDs in exacerbating COVID-19 pandemic should motivate NTD health system strengthening.

Conflict-climate-displacement: a cross-sectional ecological study determining the burden, risk and need for strategies for neglected tropical disease programmes in Africa

OBJECTIVES

Complex challenges such as political instability, climate change and population displacement are increasing threats to national disease control, elimination and eradication programmes. The objective of this study was to determine the burden and risk of conflict-related and climate-related internal displacements and the need for strategies for countries endemic with neglected tropical diseases (NTDs).

DESIGN, SETTING AND OUTCOME MEASURES

A cross-sectional ecological study was conducted including countries that are endemic with at least one of five NTDs requiring preventive chemotherapy in the African region. For each country, the number of NTDs, population size and the number and rate per 100 000 of conflict-related and natural disaster-related internal displacements reported in 2021 were classified into high and low categories and used in unison to stratify and map the burden and risk.

RESULTS

This analysis identified 45 NTD-endemic countries; 8 countries were co-endemic with 4 or 5 diseases and had populations classified as 'high' totalling >619 million people. We found 32 endemic countries had data on internal displacements related to conflict and disasters (n=16), disasters only (n=15) or conflict only (n=1). Six countries had both high conflict-related and disaster-related internal displacement numbers totalling >10.8 million people, and five countries had combined high conflict-related and disaster-related internal displacement rates, ranging from 770.8 to 7088.1 per 100 000 population. Weather-related hazards were the main cause of natural disaster-related displacements, predominately floods.

CONCLUSIONS

This paper presents a risk stratified approach to better understand the potential impact of these complex intersecting challenges. We advocate for a 'call to action' to encourage national and international stakeholders to further develop, implement and evaluate strategies to better assess NTD endemicity, and deliver interventions, in areas at risk of, or experiencing, conflict and climate disasters, in order to help meet the national targets.

The Prospective Effects of Climate Change on Neglected Tropical Diseases in the Eastern Mediterranean Region: a Review

An increase in the annual daily temperature is documented and predicted to occur in the coming decades. Climate change has a direct effect and adverse impact on human health, as well as on multiple ecosystems and their species. The purpose of this paper is to review the effect of climate change on neglected tropical diseases including leishmaniasis, schistosomiasis, and lymphatic filariasis in the Eastern Mediterranean Region (EMR). A list of engine web searches was done; 280 full-text records were assessed for eligibility. Only 48 original records were included within the final selection for the review study. Most research results show an alteration of neglected diseases related to climate change influencing specifically the Eastern Mediterranean Region, in addition to the expectation of more effects at the level of vectors and reservoir whether its vector transmission route or its egg hatching and replication or even the survival of adult worms in the coming years. At the same time, not all articles related to the region interpret the direct or indirect effect of climate variations on these specific diseases. Although few studies were found describing some of climate change effects on neglected tropical diseases in the region, still, the region lacks research funding, technical, and mathematical model expertise regarding the direct effect of climate change on the ecosystems of these neglected tropical diseases.

Climate Change and Vector-Borne Diseases in China: A Review of Evidence and Implications for Risk Management

Simple Summary

Vector-borne diseases are among the most rapidly spreading infectious diseases and are widespread all around the world. In China, many types of vector-borne diseases have been prevalent in different regions, which is a serious public health problem with significant association with meteorological factors and weather events. Under the background of current severe climate change, the outbreaks and transmission of vector-borne diseases have been proven to be impacted greatly due to rapidly changing weather conditions. This study summarizes research progress on the association between climate conditions and all types of vector-borne diseases in China. A total of seven insect-borne diseases, two rodent-borne diseases, and a snail-borne disease were included, among which dengue fever is the most concerning mosquito-borne disease. Temperature, rainfall, and humidity have the most significant effect on vector-borne disease transmission, while the association between weather conditions and vector-borne diseases shows vast differences in China. We also make suggestions about future research based on a review of current studies.

Abstract

Vector-borne diseases have posed a heavy threat to public health, especially in the context of climate change. Currently, there is no comprehensive review of the impact of meteorological factors on all types of vector-borne diseases in China. Through a systematic review of literature between 2000 and 2021, this study summarizes the relationship between climate factors and vector-borne diseases and potential mechanisms of climate change affecting vector-borne diseases. It further examines the regional differences of climate impact. A total of 131 studies in both Chinese and English on 10 vector-borne diseases were included. The number of publications on mosquito-borne diseases is the largest and is increasing, while the number of studies on rodent-borne diseases has been decreasing in the past two decades. Temperature, precipitation, and humidity are the main parameters contributing to the transmission of vector-borne diseases. Both the association and mechanism show vast differences between northern and southern China resulting from nature and social factors. We recommend that more future research should focus on the effect of meteorological factors on mosquito-borne diseases in the era of climate change. Such information will be crucial in facilitating a multi-sectorial response to climate-sensitive diseases in China.

Impact of climate change and biodiversity collapse on the global emergence and spread of infectious diseases

The reality of climate change and biodiversity collapse is irrefutable in the 21st century, with urgent action required not only to conserve threatened species but also to protect human life and wellbeing. This existential threat forces us to recognise that our existence is completely dependent upon well-functioning ecosystems that sustain the diversity of life on our planet, including that required for human health. By synthesising data on the ecology, epidemiology and evolutionary biology of various pathogens, we are gaining a better understanding of factors that underlie disease emergence and spread. However, our knowledge remains rudimentary with limited insight into the complex feedback loops that underlie ecological stability, which are at risk of rapidly unravelling once certain tipping points are breached. In this paper, we consider the impact of climate change and biodiversity collapse on the ever-present risk of infectious disease emergence and spread. We review historical and contemporaneous infectious diseases that have been influenced by human environmental manipulation, including zoonoses and vector- and water-borne diseases, alongside an evaluation of the impact of migration, urbanisation and human density on transmissible diseases. The current lack of urgency in political commitment to address climate change warrants enhanced understanding and action from paediatricians - to ensure that we safeguard the health and wellbeing of children in our care today, as well as those of future generations.

Distribution of tungiasis in latin America: Identification of areas for potential disease transmission using an ecological niche model

Background

Tungiasis is a neglected tropical disease (NTD) found in Sub-Saharan Africa and Latin America. Despite the high frequency in marginalized populations, little information is available on the geography and estimates of the population at risk in endemic regions. Here we used a geostatistical model to map the potential geographic distribution of areas suitable for tungiasis transmission in Latin America and estimated the at-risk population.

Methods

We developed an ecological niche model (ENM) using tungiasis occurrence records and remotely sensed environmental and socioeconomic data. The potential geographic distribution was then compared to the current population distribution of the region to derive the total population living in urban and rural areas.

Findings

We identified a total of 138 records of occurrences of tungiasis in Latin America, ranging from Mexico to Argentina; 27 reports were not included in the modeling, due to missing detailed geographic information. The occurrences with detailed geographic information (n = 112) included 17 countries in Latin America and the Caribbean. The locations were in environments that primarily consisted of forests (29%), croplands (16•5%), and shrublands (10•9%). We predicted environmentally suitable areas for tungiasis transmission in 45 countries. The estimated human population living in these areas is 450,546,547 with urban centers accounting for 347,007,103 and rural areas 103,539,444. Countries with significant ecological suitability and documented occurrences include Brazil, Colombia, Mexico, Argentina, Bolivia, Ecuador, French Guyana, Guatemala, Haiti, Paraguay, Peru, Trinidad and Tobago, and Venezuela.

Interpretation

This is the first study mapping the potential distribution of tungiasis in Latin America, evidencing the need for population-based studies and elaboration of integrated control measures.

Funding

This project was supported in part by an appointment to the Research Participation Program at the Centers for Disease Control and Prevention administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the Centers for Disease Control and Prevention.

The impact of climate change on neglected tropical diseases: a systematic review

Neglected tropical diseases (NTDs) are a diverse group of diseases that continue to affect >1 billion people, with these diseases disproportionately impacting vulnerable populations and territories. Climate change is having an increasing impact on public health in tropical and subtropical areas and across the world and can affect disease distribution and transmission in potentially diverse ways. Improving our understanding of how climate change influences NTDs can help identify populations at risk to include in future public health interventions. Articles were identified by searching electronic databases for reports of climate change and NTDs between 1 January 2010 and 1 March 2020. Climate change may influence the emergence and re-emergence of multiple NTDs, particularly those that involve a vector or intermediate host for transmission. Although specific predictions are conflicting depending on the geographic area, the type of NTD and associated vectors and hosts, it is anticipated that multiple NTDs will have changes in their transmission period and geographic range and will likely encroach on regions and populations that have been previously unaffected. There is a need for improved surveillance and monitoring to identify areas of NTD incursion and emergence and include these in future public health interventions.

Challenges and Opportunities for Climate Change Education (CCE) in East Africa: A Critical Review

It is undoubtedly clear that climate change is happening, and its adverse impacts could reverse the progress made toward meeting sustainable development goals. The global crisis poses one of the most severe challenges to reducing poverty and existing inequalities, especially in developing countries that are projected to be highly vulnerable to climate variability. However, the education sector provides an untapped opportunity for successful climate change adaptation and mitigation through knowledge and skill acquisitions, and consequently, positive behavioral change. Specifically, education can capacitate individuals and communities to make informed decisions and take practical actions for climate-resilient sustainable development. This study is focused on East Africa, a region whose economy heavily relies on climate-dependent activities. At present, East African governments are already embedding climate change in their school curriculum. However, they lack coherent approaches to leverage climate change education as a tool in their adaptation and mitigation strategies. Therefore, this review explores some of the critical barriers to climate change education and possible opportunities for leveraging learning to promote sustainable development in East Africa.