Tropical Medicine & International Health最新文献

Background: Dengue fever, a rapidly expanding mosquito-borne disease influenced by environmental and climatic factors, has increasingly affected Nepal's Gandaki Province, prompting this study to investigate its spatial distribution and drivers from 2021 to 2024.

Methods: This study analysed the spatial distribution of dengue incidence in Gandaki Province, Nepal, from 2021 to 2024 by integrating environmental variables such as temperature, precipitation, vegetation, and water indices using remote sensing datasets. Spatial autocorrelation and cluster patterns were assessed through Global and Local Moran's I and Local Indicators of Spatial Association using QGIS and GeoDa software.

Results: From 2021 to 2024, the incidence of dengue in Gandaki Province surged from 4.56 to 431 cases per 100,000 population. Spatial autocorrelation analysis showed weak negative clustering from 2021 to 2023 (Moran's I = -0.016, -0.056, -0.031, respectively), followed by the emergence of weak positive clustering in 2024 (Moran's I = 0.049). Local spatial analysis identified dengue hotspots in Devghat, Bandipur and Pokhara. Over time, environmental variables such as Normalised Difference Vegetation Index, Normalised Difference Water Index, Land Surface Temperature, precipitation and Leaf Area Index showed stronger positive correlations with dengue, highlighting the growing influence of climate on transmission patterns.

Conclusions: This study highlights the increasing influence of environmental and climatic factors on dengue transmission in Gandaki Province. Spatial analysis identified key hotspots and revealed shifting correlations between dengue incidence and variables such as temperature, vegetation and precipitation. These findings underscore the need for integrated surveillance and early warning systems that incorporate environmental data to enhance dengue prevention and control strategies in the region.

Wolbachia-based vector control is an emerging tool in malaria prevention research. This study evaluates Wolbachia infection in Iranian mosquitoes, focusing on seven known malaria vectors. Mosquitoes were collected from nine provinces of Iran (2016-2019), and Wolbachia infection status was analysed via PCR targeting eight genes: wsp, gatB, ftsZ, dnaA, groEL, gltA, CoxA and fbpA. We examined 1094 specimens from seven malaria vectors (Anopheles stephensi Liston, 1901; Anopheles culicifacies s.l. James, 1901; Anopheles fluviatilis s.l. James, 1902; Anopheles maculipennis s.l. Meigen, 1818; Anopheles sacharovi Favr, 1903; Anopheles dthali Patton, 1905; Anopheles superpictus s.l. Grassi, 1899), four non-malaria vectors (Anopheles mongolensis Linton, Lee and Curtis, 2005; Anopheles hyrcanus Pallas, 1771; Anopheles claviger Meigen, 1804; Anopheles turkhudi Liston, 1901) and three Culex species ( Culex pipiens Linnaeus, 1758; Culex perexiguus Theobald, 1903; Culex theileri Theobald, 1903). PCR revealed Wolbachia DNA exclusively in An. dthali and Culex species, with infection rates of 73.4% for An. dthali and 77.78%-96.77% for Culex, notably higher in males. Wolbachia was detected in all regions except one in the north. Phylogenetic analysis revealed Wolbachia strains in An. dthali and Culex belong to supergroup B, closely related to strains in An. moucheti and An. demeilloni. This suggests broader applications for biocontrol strategies. The high Wolbachia prevalence in An. dthali is promising for malaria prevention. Future research should confirm cytoplasmic incompatibility and explore wAdth's potential to block malaria transmission.

Objective: The objective of this study is to describe malaria-related deaths and assess their risk factors.

Methods: This is a case-control study using data from Brazil's Ministry of Health (2011-2020) on malaria-related deaths (ICD-10: B50-B54). A probabilistic record linkage was performed to match epidemiological data (Sivep-Malaria and Sinan) with death records from the Mortality Information System (SIM). Cases were defined as individuals who died of malaria, and controls were malaria cases that did not result in death. Logistic regression models were used to identify the factors associated with malaria mortality.

Results: A total of 632 malaria-related deaths were recorded, with 454 (71.8%) occurring in the Amazon region and 178 (28.1%) outside it. Risk factors in the Amazon included age (< 6 months or > 60 years; p ≤ 0.01), delayed treatment (> 48 h; p < 0.001), illiteracy (p = 0.01), and living in indigenous population villages (p < 0.001), while active case detection was protective (p = 0.01). In the Extra-Amazon, risk factors included delayed treatment (p = 0.049), P. falciparum or mixed infections (p < 0.049), foreign-acquired infections (p = 0.01), and higher education level (p = 0.03)-which is a proxy for increased income and travel frequency, which may increase the likelihood of exposure in endemic areas and delayed diagnosis upon return.

Conclusion: This nationwide record-linkage study shows that malaria deaths remain concentrated in socially vulnerable groups: infants, older adults, and especially indigenous populations living in the Amazon. Delayed treatment is also a determinant for deaths, in both endemic and non-endemic regions, while active case detection markedly reduces the odds of death. To reach Brazil's zero-malaria-death target by 2030, it is needed to improve timely diagnosis and treatment, to enhance epidemiological information systems along with active surveillance amplification in remote communities. Finally, integrating national health-information systems allows real-time monitoring, and with coordinated action, eliminating malaria deaths remains achievable.

Background: Ensuring a continuum of care in accessing antenatal to postnatal healthcare services is crucial for improving maternal and child health outcomes. This study aims to explore trends in the continuum of care over the years, both nationally and across regions; to provide district-level estimates; and to examine socio-economic disparities and determinants of continuum of care uptake in Bangladesh.

Methods: A total of 28,260 samples were analysed. Continuum of care was considered as the outcome variable. District, wealth index, and several socio-demographic factors were included as explanatory variables. Trends of the continuum of care estimates were illustrated over survey years using descriptive statistics. Additional exploration of inequality was conducted across wealth quintiles, educational attainment and urban-rural residence through Equiplot. Finally, a multilevel multinomial logistic regression model was used to assess the factors associated with continuum of care.

Results: The study revealed a significant increase in the highest level of continuum of care, rising from 6.0% in 2004 to 30.5% in 2017/2018, before declining to 24.8% in 2022. However, notable dropouts from the continuum of care were observed, particularly during the transitions from Antenatal Care to Skilled Birth Attendant and from Skilled Birth Attendant to postnatal Care. The analysis also identified district-level variations, urban-rural disparities and differences across wealth quintiles. Maternal socio-demographic characteristics, such as higher education and belonging to a higher wealth quintile, were associated with increased likelihoods of achieving moderate to the highest levels of continuum of care. In contrast, higher parity and rural residence were associated with lower likelihoods of attaining these levels of care.

Conclusion: The findings underscore substantial progress in maternal healthcare services uptake in Bangladesh over the years, alongside persistent challenges in ensuring continuous care throughout the maternal healthcare continuum and district-level variations. Addressing district-level disparities and socioeconomic inequalities is crucial, necessitating tailored, area-specific policies and programmes to achieve universal access to quality maternal healthcare services across the country.

Background: Antigen cross-reactivity in infections may induce heterologous immunity, leading to immunological protection against widely divergent organisms. We hypothesised that this may be a factor in the varying intensity of COVID-19 infection globally.

Methods: During the COVID-19 pandemic, we tested 46 symptomatic patients for both COVID-19 antibodies and the Typhidot test. The kappa statistic in STATA 16.0 was used to analyse agreement between the two tests. Python-based k-mer analysis was used to identify overlapping fragments between SARS-CoV-2 and Salmonella typhi proteins. PEP-Fold3, TM-align and RasMol software were used to evaluate the 3D-structural changes. World COVID-19 and Typhoid mortality and infection statistics were obtained from published data. Line graphs were used to assess correlations between Typhoid cases and COVID-19 mortality.

Results: There was a high degree of agreement between Typhidot and COVID-19 antibody tests (Cohen's kappa = 0.43, p = 0.0016). A 5-amino-acid peptide, NGVEG, located in the receptor binding motif (RBM) of the SARS-CoV-2 Spike protein matched with the Typhoid flagellar-H protein on k-mer analysis. SARS-CoV-2 Delta (B.1.617.2) variant 3D structure displayed marked changes that may have altered this cross-reactivity. COVID-19 mortality between Pre-Delta (2020) and Post-Delta (2021) periods showed a negative correlation in Typhoid endemic regions and a reverse trend in non-endemic regions.

Conclusion: Cross-reactivity of Typhoid flagellar-H protein antibodies with SARS-CoV-2, mediated by a peptide in the RBM, may have provided partial heterologous immunity to COVID-19 in Typhoid endemic regions and this was eliminated by the Delta variant.

Background: Indonesia faces a dual burden of high tuberculosis (TB) burden and rising diabetes mellitus (DM) prevalence. Given that DM is a significant risk factor for TB, screening people with TB for DM comorbidity is important for early management to mitigate adverse outcomes.

Objectives: This study aimed to measure the degree of implementation fidelity, moderating factors, and barriers to implementing DM screening among TB patients in Indonesia's Primary Healthcare setting.

Methods: A sequential explanatory mixed method was used. A cross-sectional survey was conducted with 42 Directly Observed Treatment, Short-course providers to assess adherence to DM screening guidelines. Screening coverage was evaluated through the TB information system. In-depth interviews with providers, managers, and patients identified key barriers and enablers.

Results: Screening coverage ranges from 36.3% to 97.6% between 2020 and 2024. High fidelity was reported among providers, with 95% screening for DM at the time of TB diagnosis. Facilitators included TB-DM policy availability, screening affordability, provision of equipment, and patients' responsiveness. However, delays in data reporting and insufficient cross-sector collaboration posed challenges to the implementation.

Conclusion: Despite positive progress in integrating TB-DM care, addressing barriers is essential to optimize the programme's impact. Strengthening reporting mechanisms and fostering collaboration could enhance programme outcomes.

Background and objectives: Scabies is a neglected disease believed to be more prevalent in resource-poor nations. Published data describing global trends in scabies incidence and prevalence rates and factors associated with global regional differences are limited. Identifying regions with scabies prevalence rates over 10% and implementing mass-drug administration is recommended. We aimed to identify global high-risk areas to facilitate region-specific targeted interventions.

Methods: Data on scabies incidence and prevalence in 204 countries and regions from 1990 to 2021 were extracted from the Global Burden of Disease database. Temporal trends in age-standardised rates were estimated using Joinpoint regression. Local indicators of spatial association were used to determine contiguous areas of high prevalence. The association of socio-demographic and economic factors with scabies was determined using locally weighted scatterplot smoothing and log-normal regression models.

Results: Global prevalence of scabies in 2021 was 2.71% (95% confidence interval [CI]: 2.41% to 3.04%). Age-standardised rates of scabies have marginally declined globally from 1990 to 2021 with an Average Annual Percentage Change (AAPC) of -0.10 (95% CI: -0.05 to -0.14) for incidence and -0.09 (95% CI: -0.05 to -0.14) for prevalence. Spatial clustering of high scabies prevalence was present in tropical Latin America, Southeast Asia, and the Pacific Islands. Rates have shown an increasing trend over time in high-income regions such as Australasia and parts of Europe. Scabies rates have increased over time in high-middle and high sociodemographic index regions. There is a significant positive association between warmer latitudes with increasing urbanisation and scabies prevalence.

Conclusion: Owing to the exploratory nature of the GBD data, our findings are hypothesis generating, rather than confirmatory. Scabies prevalence remains high in several global regions. Progress to reduce scabies prevalence is slow with existing programmes. Scabies control policies should be further prioritised to accelerate progress in reducing the prevalence of this important tropical disease.

Background: The expansive scale-up of malaria interventions resulted in substantial reductions in malaria morbidity and mortality in the past 20 years. Intervention effectiveness has traditionally been estimated through research studies and trials, nationally representative surveys, and mathematical modelling. Because of their sheer volume across space and time, data reported routinely through health management information systems can complement and even offer an alternative to surveys and modelling to assess intervention effectiveness, and ultimately impact on health outcomes. This scoping review describes the different analytical approaches for estimating the effectiveness of malaria interventions using routine health management information systems data.

Methods: We examined PubMed using combination searches of the following terms: 'malaria' AND 'intervention' AND 'effect*' OR 'impact' AND 'system' OR 'surveillance'. Other key terms such as 'routine' or 'information systems' were not included in the search strategy to have a more comprehensive search and were used during abstract and full text screening. We limited inclusion to studies and analyses that were conducted in the past decade, as that is when countries' routine health management information systems began to substantially mature, with data reported by these systems progressively becoming more robust.

Results: Out of 957 records generated from the PubMed search, following title and abstract screening, 93 were included for full-text review, with 49 records ultimately meeting the inclusion criteria for the scoping review. We summarise included studies by publication year, geography, outcome variables, target populations, interventions assessed, health management information systems data platform used-broadly, analytical approaches used a range of modelling or non-modelling approaches to assess intervention effectiveness.

Conclusion: This scoping review shows that routine health management information systems data can be used to regularly assess the effectiveness of various malaria interventions-an important exercise to ensure that implemented interventions continue to be effective, have the desired effect, and ultimately help countries progress towards their national strategic goals and targets.