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Climate variation and serotype competition drive dengue outbreak dynamics in Singapore.
Get PDFDengue poses a rapidly increasing threat to global health, with Southeast Asia among the most affected regions. Climate-informed early warning systems can help mitigate outbreaks; however, prediction of large outbreaks with sufficient lead time remains a challenge. In this study, we quantified the role of climatic variation and serotype competition in shaping dengue risk in Singapore using over 20 years of weekly case data. We integrated these insights into a forecasting framework capable of predicting dengue outbreaks up to two months ahead and generated counterfactual projections to assess the impact of novel interventions, such as Wolbachia. While a climate-informed model improved predictive power by 54% compared to a seasonal baseline, including serotype information increased this to 60%, better explaining interannual variation in dengue incidence. By incorporating serotype competition as a proxy for population immunity, this work advances the field of climate-informed dengue prediction and demonstrates the value of long-term virus surveillance
Healthcare providers' perspectives on antimicrobial resistance in Northwest Syria: an exploratory qualitative study.
Get PDFBACKGROUND: Armed conflict contributes to the development and spread of antimicrobial resistance (AMR). Understanding healthcare providers' perceptions is essential for identifying key determinants and developing contextualised recommendations. This study explored perceptions of AMR among healthcare providers in northwest Syria - a conflict-affected area- before the fall of the Syrian regime in December 2024.
METHODS: A qualitative study was conducted using semi-structured interviews with healthcare providers who had worked in northwest Syria within the previous five years. Seventeen interviews were conducted remotely in Arabic in July-August 2023. Participants were identified through purposive and snowball sampling. Transcriptions were analysed using deductive thematic analysis.
RESULTS: Of the 17 key informants, (11 doctors, 6 pharmacists); most were from Idlib governorate. Emerging themes included healthcare professionals' understanding of AMR, perceived drivers, conflict- and disaster-related influences, and examples of good practice. Frequently cited drivers of AMR were over-the-counter availability of antimicrobials, pharmacy-led dispensing, and community insistence on antibiotics. Inadequate microbiology diagnostic capacity was also highlighted as a key factor.
CONCLUSION: Interviews highlighted perceived contributors to AMR in northwest Syria, including ineffective or absent policies regulating antibiotic dispensing, lack of antimicrobial guidelines or poor enforcement, and limited access to diagnostics. These findings support the development of contextualised recommendations during the transition of Syria's health system
Determining the influence of livelihoods, land access, and location on household food and nutrition security in KwaZulu-Natal, South Africa.
Get PDFAccess to healthy food varies across socioeconomic circumstances such as primary livelihood, and access to shops, land, farms, and cities. We compared household food and nutrition security across households with food-producing and non-food-producing livelihoods, access to farms and non-farm greenspaces, and their location relative to farms, non-farm greenspaces, shops, and urban centres. We used household survey data and landscape spatial data from five sites across the socioeconomic gradient. Food security was higher in wealthier, more educated, urban households, and dietary diversity was highest in rural and agrarian households. Non-farm greenspaces such as communal and informal land, and backyard and communal gardens, were significant food sources. On-farm diversification, smallholder support, and provisioning of non-farm greenspaces can improve food and nutrition security. Agricultural extension and spatial planning policy should target smallholder capacitation, and development of fruit and vegetable gardens in both rural and urban areas, for sustainable, equitable, healthy food environments
Timing of Intrapartum Antibiotics at Caesarean Section and Risk of Asthma, Eczema and Allergic Rhinitis: Results From a Natural Experiment.
Get PDFOBJECTIVE: To investigate whether the risk of asthma, eczema and allergic rhinitis at 5 years in children born by caesarean section (CS) differs by the timing of antibiotic administration to the mother (pre-incision vs. post-cord clamping). DESIGN: Natural experiment using birth cohort data. SETTING: UK single centre population-based birth cohort. PARTICIPANTS: 3013 liveborn children delivered by CS, from the Born in Bradford (BiB) cohort born 2007-2011 and BiB's Better Start (BiBBS) cohort born 2016-2019. Only the first-born of multiple births was included. MAIN OUTCOME MEASURES: Risk of asthma, atopic eczema and allergic rhinitis at age 5 years. RESULTS: Among 3013 children, 579 (19.2%) were exposed to pre-incision antibiotics. At 5 years, 272 (9.0%) children had asthma, 672 (22.3%) had eczema and 180 (6.0%) had allergic rhinitis. There was no evidence of an increased risk of asthma (adjusted risk ratio [aRR] 1.01, 95% CI 0.56, 1.83; adjusted risk difference [aRD] 0.08 per 100, 95% CI -5.28, 5.44), eczema (aRR 0.96, 95% CI 0.68, 1.35; aRD -1.01 per 100, 95% CI -8.65, 6.63) or allergic rhinitis (aRR 1.16, 95% CI 0.59, 2.28; aRD 0.88 per 100, 95% CI -3.17, 4.92) at 5 years in children exposed to pre-incision antibiotics versus post-cord clamping. CONCLUSIONS: This study found no evidence of an association between pre-incision antibiotics for CS and increased risk of asthma, eczema or allergic rhinitis by age 5. These findings contribute to the evidence base informing the optimum timing of maternal antibiotic prophylaxis for CS, balancing risks and benefits to the mother and her child
Failure of pyriproxyfen at recommended application frequency and doses to control Aedes mosquitoes in Thailand.
Get PDFBACKGROUND/OBJECTIVES: Mosquito-borne diseases like malaria, dengue fever, and Zika virus remain global health concerns. Pyriproxyfen is effective in controlling mosquitoes by disrupting their development. This study seeks to assess pyriproxyfen's ability to prevent Aedes aegypti emergence from water sources. It is part of a trial evaluating pyriproxyfen's impact on reducing mosquito infestation and dengue transmission, verifying its persistence and effectiveness in real-world and laboratory conditions.
METHODS: The study was conducted in Khon Kaen province (northeastern region) and Prachuap Khiri Khan province (western region) of Thailand. We assessed pyriproxyfen residual effectiveness, inhibition of mosquito larval emergence and active ingredients among batches in a pyriproxyfen-based mosquito control trial in Khon Kaen. In Prachuap Khiri Khan we evaluated pyriproxyfen effectiveness across various water sources. The active ingredients in two pyriproxyfen batches were analyzed in a Sumitomo laboratory and in an independent laboratory.
RESULTS: Thirty days after field water containers were treated with pyriproxyfen the inhibition of mosquito larval emergence declined to ~60% and 60 days post-treatment the inhibition of emergence was just ~10%. Two batches of pyriproxyfen tested in the laboratory had > 85% inhibition of emergence and the active ingredient concentrations varied from 0.45-0.52%, close to the manufacturer's specifications of 0.5%. In laboratory experiments, the inhibition of mosquito emergence of pyriproxyfen in different water sources started declining after 42 days. Rain- and groundwater had higher inhibition rates (20-30%) than tap water (~10%) after 98 days. Emergence inhibition rates correlated negatively with water pH (F(1,118) = 5.626, p < 0.001) and positively with total dissolved solids, conductivity, and salinity of the water (F(1,118) = 48.302, p < 0.001), (F(1,118) = 37.022, p < 0.001), and (F(1,118) = 36.699, p < 0.001), respectively.
CONCLUSIONS: Pyriproxyfen failed to control Aedes mosquitoes at the recommended application frequency and doses in the field. The potential reasons for lack of effectiveness may be caused by environmental factors, such as pH, water source, and other water characteristics or social factors, such as homeowners' behaviors and water storage practices. The study underscores the importance of understanding environmental and social factors to tailor application strategies and ensuring sustained efficacy through regular monitoring, particularly in diverse contexts
Neuroimaging correlates and prognostic utility of accelerated long‐term forgetting in presymptomatic autosomal dominant Alzheimer's disease
Get PDFAbstract
Background
In Alzheimer's disease (AD), sensitive measures of cognitive decline prior to overt symptoms are urgently needed. Accelerated long‐term forgetting (ALF), where information is retained normally over 10‐30 minutes but lost at an accelerated rate over subsequent days to weeks, has been identified cross‐sectionally in presymptomatic autosomal dominant and sporadic AD cohorts. However, two key questions remain: 1) what neuroanatomical changes underlie ALF; and 2) can ALF testing predict proximity to symptom onset?
Method
Twenty‐one asymptomatic autosomal dominant AD (ADAD) mutation carriers and 14 non‐carriers (Table 1) underwent ALF assessment with 1) a list, 2) a story, and 3) a visual figure, with testing of 30‐minute and 7‐day recall. Baseline T
1
and diffusion‐weighted MRI was obtained. Cortical thickness was estimated for 13 pre‐defined grey matter regions (Table 2), with streamline tractography used to assess associated structural connectivity. Participants underwent annual clinical follow‐up for a median of 7 years.
Result
ALF test score was significantly lower in mutation carriers than non‐carriers across the three tests. In mutation carriers, verbal ALF (list and story) was associated with lower baseline cortical thickness in the prefrontal cortex (PFC) across four contiguous regions bilaterally (Table 2). This association was not present in non‐carriers. No associations were found between ALF and the thickness/volume of medial temporal lobe (MTL) structures. There was some association between ALF and PFC structural connectivity, although weaker than for cortical thickness. 9/20 mutation carriers developed symptoms during follow‐up. Those who became symptomatic had lower baseline ALF scores for both list (
p
= 0.03) and story (
p
<0.001) (Figure 1). Story ALF (AUC=0.82) and list ALF (AUC=0.73) discriminated between those who did and did not develop symptoms.
Conclusion
Our results suggest that ALF in presymptomatic ADAD is related to early focal structural changes in the PFC, but not the MTL. Follow‐up demonstrated that ALF severity is not only associated with the presence of AD pathology but also is predictive of clinical onset, identifying those at highest risk of imminent decline. ALF testing is a biologically relevant measure that offers promise in aiding presymptomatic trial recruitment, as a presymptomatic cognitive endpoint, and potentially as a screening tool in the wider population
Infection and telomere length: A systematic review.
Get PDFBACKGROUND: Infections may increase the risk of age-related diseases such as dementia. Accelerated immunological ageing, measurable by telomere length (TL), may be a potential mechanism. However, the relationship between different infections and TL or telomere attrition remains unclear. This systematic review synthesises existing evidence on whether infections contribute to TL or telomere attrition and highlights research gaps to inform future studies. OBJECTIVE: To summarise the literature on associations between infections and telomere length or attrition. METHODS: We conducted comprehensive searches across six databases (MEDLINE, EMBASE, Web of Science, Scopus, Global Health, Cochrane Library) from inception to 22 May 2025, using concepts of infections, TL, and study type. Two researchers independently screened studies, extracted data, and assessed risk of bias (ROB) using the ROBINS-E tool. Meta-analysis was unfeasible due to heterogeneity, so a narrative synthesis was conducted. Studies were grouped by infection type, telomere measurement assay, cell type, and statistical approach. A GRADE assessment was performed to evaluate evidence quality. RESULTS: Our searches identified 10,349 studies, of which 73 met eligibility criteria. Most (59) were cross-sectional and most were published after 2000, with the earliest from 1996. Most studies were from the USA (17). HIV was the most frequently studied infection (35 studies), with 79% (excluding overlapping samples) reporting an association between HIV and reduced TL or increased telomere attrition. Findings for other infections, including herpesviruses and Human Papillomavirus were more variable. Variation in infection type, measurement assay, cell type, and statistical approach made cross-study comparisons challenging. Most studies had a high ROB, mainly due to unmeasured confounding. The GRADE assessment rated evidence quality as very low. CONCLUSIONS: Our review highlights a potential link between HIV and TL and telomere attrition. More robust longitudinal studies with standardised measurements and better confounder control are needed, particularly for non-HIV infections. PROSPERO (ID:CRD42023444854)
Impact of temperature and humidity on SARS-CoV-2 transmissibility: a systematic review and meta-analysis.
Get PDFBACKGROUND: The SARS-CoV-2 pandemic remains crucial for understanding the epidemiology of future respiratory infections. Gaining insights into the climatic factors influencing the transmissibility of SARS-CoV-2 is an important public health issue in the control and prevention of the disease. Hence, this study aimed to assess the association between SARS-CoV-2 transmissibility and both humidity and temperature. METHODS: Articles published between December 2019 and August 2024 were identified from PubMed, Africa Journal Online, Science Direct, and Hinari databases following PRISMA guidelines. The focus was on studies that reported transmissibility based on basic reproductive number, specifically correlation coefficients between basic reproductive number and temperature, or humidity, or corresponding regression coefficients, and their standard errors. The Joanna Briggs Institute (JBI) Critical Appraisal Checklist was used to assess the risk of bias. Random effect models were applied. The meta-analysis was done in R version 4.3.0. RESULTS: 9 studies qualified, but 5 were excluded for missing coefficients, leaving 4 for meta-analysis. The study analysis revealed a significant negative correlation between temperature and SARS-CoV-2 transmissibility (r = -0.509, 95% CI: -0.680 to -0.338, p < 0.001). Similarly, a significant but weaker negative correlation was found between humidity and SARS-CoV-2 transmissibility (r = -0.426, 95% CI: -0.548 to -0.303, p < 0.001). A unit increase in humidity measured in percentage was associated with a decrease in transmissibility by 0.006 (95% CI: -0.007 to -0.004, p < 0.001), while a unit increase in temperature in Celsius (°C) was associated with a reduction of transmissibility by 0.008 (95% CI: -0.030 to -0.030, p < 0.001). CONCLUSION: Temperature and humidity were negatively associated with SARS-CoV-2 transmissibility; thus, disease transmissibility decreased as temperature or humidity increased. Climatic factors are important considerations for effective disease surveillance and preparedness strategies. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO, CRD42025637440
Evaluation of knowledge, perception, and attitude of malaria burden in the Upper River region of The Gambia.
Get PDFBACKGROUND: Despite increased malaria interventions, the Upper River Region of The Gambia still faces a higher malaria burden compared to other parts of the country. This issue may be related to the population's knowledge of malaria, as well as environmental and socioeconomic factors that influence their prevention and treatment choices. Therefore, this study focused on assessing the level of malaria knowledge, perceptions, and attitudes among the residents of the Upper River Region, as limited studies have been conducted across the region's seven districts. METHODS: To achieve the study's objectives, a descriptive research survey using a parallel mixed method was adopted, with a robust multistage sampling approach for selecting 381 household heads involved in the quantitative study, 31 key informants, and 7 focus group discussions for the qualitative study. Descriptive statistics were performed on the assessed variables using StataSE18, and the association of socio-demographic factors with malaria prevalence was analyzed using Chi-square (Χ2). Thematic analysis was conducted for the qualitative part using NVivo. RESULTS: The results indicate a very high level of knowledge of basic malaria concepts, with a percentage index of 81. There is a statistically significant influence from factors such as district, number of health centers in the region, gender, distance to the health centre, and occupation, all at < 5%. Using a treated bed net was the most effective prevention tool, while hospital visits and herbs remain the main treatment options among the population. The trend of malaria infection shows a general decrease across most communities, although a few still experience an increase over the year. Malaria profile data reveal an 87% reduction in cases for individuals above 5 years old and a 45% reduction for those under five. Additionally, mortality rates have decreased by 98% and 89%, respectively, over the 12 years (2011-2023). DISCUSSION AND CONCLUSION: This study examined knowledge, perception, and attitudes toward malaria prevention and treatment. Results showed a high level of understanding of basic malaria concepts among the population, which influenced their perceptions and fostered a positive attitude toward managing and preventing the infection. However, differences in knowledge levels exist across districts, along with some contradictions in perceptions and attitudes. An overall decline in malaria cases has been observed across the districts and communities in the region, with a few exceptions. These findings are expected to inform the national malaria prevention efforts and assist policymakers in planning the next steps for the malaria elimination campaign
The evolution of facility-based deliveries at primary healthcare centres during an insecurity and conflict crisis in Burkina Faso: a geospatial analysis.
Get PDFBACKGROUND: Access to healthcare in Burkina Faso, particularly obstetric care, is severely reduced by nearby armed conflict. However, systematic assessments of the spatial distribution of facility-based delivery rates and their evolution, as well as how they relate to conflict intensity, facility characteristics, and geo-spatial determinants, are absent. METHODS: We analysed spatial and temporal shifts in facility-based deliveries in Burkina Faso's primary healthcare centers in relation to conflict. Using spatial analyses, we examined how conflict-related deaths influenced delivery patterns, considering variations by facility type and pre-conflict service volume. We obtained monthly healthcare facility data (2016-2021) from Burkina Faso's Health Management Information System (HMIS) and conflict event data from the Uppsala Conflict Data Program (UCDP). The study covered all primary healthcare centers in conflict-affected northern and eastern districts (> 10 UCDP conflict deaths, 2016-2021) and neighboring southern districts: 854 CSPSs (Centres de Santé et de Promotion Sociale) and 53 CMs (Centres Médicaux). RESULTS: The study identified geographical variations in facility-based delivery rates, notably from 2018-2019, with spatial clusters of lower rates becoming predominant in northern areas and higher rates doubling along southern routes and cities. This shift coincided spatially and timely with conflict escalation. In conflict hotspots, the average monthly rate of facility-based deliveries decreased over time, irrespective of pre-conflict service volume. However, CM facilities showed an upward trend, contrasting CSPS facilities. Outside conflict hotspots, facilities with exceptional pre-conflict service volume showed similar upward trends, while low- and high-volume facilities showed moderate increases. CM consistently maintained higher facility-based delivery rates over time than CSPS facilities. CONCLUSION: This research provides crucial insights for strengthening Burkina Faso's health system resilience to conflict by spatially identifying how facility characteristics and geo-spatial determinants shape healthcare disruptions. Mapping these elements at a fine scale enables adaptive policy interventions and dynamic resource allocation based on evolving conflict dynamics, enhancing obstetric care during conflict. By integrating the applied geospatial methods into national health systems, we can enhance responsiveness, enabling targeted and timely interventions, as well as efficient and flexible resource distribution (e.g., funding, personnel, and medical supplies). This also supports improved healthcare demand forecasting, ultimately ensuring a more proactive, data-driven, and conflict-sensitive approach to maternal health policy planning in crisis response