Infectious Diseases of Poverty最新文献

Background: India accounts for over a quarter of the global tuberculosis (TB) burden. Among the most affected are India's Scheduled Tribes (STs) communities, experiencing a disproportionately higher TB prevalence compared to non-STs. Encouragingly, two successive rounds of National Family Health Survey (NFHS) showed the declined trend in overall TB prevalence in India, the rate of decline was markedly slower among STs, signalling that national gains have not translated into equitable progress. This study examines the point prevalence of TB and its determinants among STs and non-STs populations in constitutionally protected Scheduled and Non-Scheduled areas of India.

Methods: We analysed data from 2,077,924 individuals aged 15 and above from NFHS-5 (2019-2021) in India. Districts were stratified into: (1) Scheduled Area districts (with protections under Schedules V/VI), (2) non-Scheduled districts with > 60% STs, and (3) non-Scheduled districts with < 60% STs. We estimated TB point prevalence per 100,000 among STs and non-STs across these categories and examined associated socio-demographic, environmental, and behavioural factors. Multivariable logistic regression models assessed the adjusted odds of TB.

Results: STs experienced significantly higher TB prevalence (416/100,000) than non-STs (277/100,000). This disparity persisted across all district categories. STs in Scheduled area districts had the lowest TB prevalence (330 per 100,000), while non-Scheduled districts with > 60% STs populations had the highest prevalence (608 per 100,000). Tribal identity remained an independent risk factor for TB [adjusted odd ratio (aOR) = 1.47; 95% confidence internal (CI) 1.38 -1.56], even after adjusting for covariates. Additional risk factors included older age, male sex, low household wealth, adverse household environments, tobacco and alcohol consumption, and hypertension and diabetes.

Conclusions: Tribal communities continue to shoulder a disproportionate TB burden, reflecting deep-rooted social and structural inequities. While constitutional protections in Scheduled Areas appear to offer some safeguards, disparities between STs and non-STs remain stark. Our findings serve as evidence and a call to action to ensure that tribal communities are at the forefront of TB control initiatives, so that the burden of TB is no longer borne disproportionately by those already burdened by socio-economic disadvantage.

Background: Thailand aims to eliminate malaria in all provinces by 2030, where 37 out of 77 provinces have been verified as malaria-free by 2021. Thailand is accelerating its elimination activities and preventing re-establishment of malaria through implementation of the 1-3-7 reactive surveillance and response (RASR) strategy, which entails case notification within one day, case investigation within three days and case investigation survey within seven days after detecting an index malaria case. This study aimed to assess how this 1-3-7 malaria RASR strategy was implemented to understand how it may be optimised to achieve national malaria elimination goals.

Methods: A cross-sectional mixed-method study was conducted in Tak, Songkhla and Yala provinces of Thailand between January and April 2023. Quantitative survey with purposively recruited malaria programme stakeholders (n = 33) and frontline malaria service providers (FMSPs) (n = 41), qualitative focus group discussions with malaria programme stakeholders, FMSPs and mobile migrant population, and individual in-depth interviews with malaria programme stakeholders were conducted face-to-face in Thai language. Quantitative and qualitative data were analysed descriptively and thematically.

Results: About half of survey participants (40/74, 54.1%) perceived that malaria cases were notified within the specified one day timeframe. Almost all participants (73/74, 98.7%) reported that case investigation, focus investigation and response activities were conducted within the required timeframes, except in border areas where malaria burden was high. Despite every participant (74/74, 100.0%) being aware of and considering the 1-3-7 strategy as efficient, challenges such as limited human resources and budget, low levels of community participation, and difficult terrain and telecommunication were reported in performing RASR activities.

Conclusions: The overall implementation of RASR activities was reported to be timely except for malaria case notification and focus response activities in border areas. Despite good acceptability towards RASR activities, the 1-3-7 strategy is not a one-size-fits-all approach; its feasibility for implementation depends on health system capacity and malaria incidence of the area. There are still several challenges to be addressed particularly for successful implementation of RASR activities for cross-border malaria.

Background: Schistosomiasis japonica, caused by Schistosoma japonicum, remains a significant public health concern in the Philippines, where 12.4 million people are at risk due to persistent transmission in endemic regions. The distribution of schistosomiasis is closely linked to the distribution of its snail intermediate host. This study aims to assess the potential of using soil samples to detect the environmental presence of Oncomelania hupensis quadrasi and Schistosoma japonicum.

Methods: This cross-sectional observational study utilized a soil-based environmental DNA (eDNA) detection system for simultaneous detection of O. h. quadrasi, and S. japonicum mitochondrially encoded cytochrome c oxidase subunit 1 gene in multiplex quantitative real-time PCR and digital PCR platforms. A two-phase sample collection and testing were carried out in December 2023 (Phase 1) and March 2024 (Phase 2) across 30 selected sampling sites in Ekiran village, Leyte, Philippines. Wilcoxon two-sample/Mann-Whitney U test was used to determine whether there was a significant difference in eDNA presence and edaphic factors, while percent agreement was used to assess the concordance among methods.

Results: This study reveals that S. japonicum eDNA can be detected in soil samples and confirms the strong applicability of soil-based eDNA for detecting O. h. quadrasi snails and even in sites without visible snail presence. Furthermore, it demonstrates the superiority of soil-eDNA system compared to classical malacological surveys in detecting O. h. quadrasi and S. japonicum microhabitats: in Phase 1, eDNA detected O. h. quadrasi and S. japonicum in 50% (3/6) and 66.67% (4/6) of sites, respectively, while malacological surveys detected them in only 50% and 16.67% (1/6) of sites. In Phase 2, eDNA detected O. h. quadrasi in 20% (6/30) of sites compared to only 10% (3/30) by malacological survey, and S. japonicum was detected only by eDNA in 10% (3/30) of sites. Among the measured soil parameters, only pH showed a statistically significant difference between eDNA-positive and eDNA-negative sites (P = 0.04).

Conclusions: Soil-based eDNA sensitively detected O. h. quadrasi and S. japonicum, enabling scalable, non-invasive transmission site identification and outperforming traditional surveys without visible snails. Its ability to detect S. japonicum highlights its value for comprehensive schistosomiasis monitoring.

Background: Sub-Saharan African (SSA) migrants may carry asymptomatic Plasmodium infections after leaving endemic regions, potentially posing public health challenges in host countries. However, data on the prevalence and persistence of infection after migration are currently limited. The objective of this study is to assess the burden of asymptomatic malaria among adult SSA migrants attending an outpatient clinic in Rome.

Methods: Between February 2024 and January 2025, SSA migrants attending the Lazzaro Spallanzani Institute's mobile population clinic in Rome, Italy were screened for malaria using rapid diagnostic tests (RDTs), loop-mediated isothermal amplification (LAMP), thick smears, and real-time polymerase chain reaction (RT-PCR). Eligibility criteria included age ≥ 16, absence of fever, and origin or transit through malaria-endemic regions. Descriptive statistics were used to summarize epidemiological, clinical, and laboratory data. Continuous variables were expressed as means ± SD or median (IQR), and categorical variables as counts and percentages. A P-value < 0.05 was considered significant.

Results: Among 87 asymptomatic migrants, malaria prevalence was 6%, all in male SSA migrants. One mixed infection was confirmed by microscopy. LAMP detected Plasmodium spp. in 5 cases (6.0%), confirmed by RT-PCR, while RDT identified only 2 (2.3%). Species identified by RT-PCR included P. falciparum, P. malariae, P. ovale, and one mixed infection. The longest time since arrival among positives was 181 days; including detention in Libya, the median interval since departure from endemic areas exceeded 600 days.

Conclusions: Asymptomatic malaria can last for months after arrival and is often missed by RDTs. Incorporating RT-PCR diagnostics into routine screenings can improve early detection, lower local transmission risk, and enhance health outcomes.

Background: Since July 2025, an outbreak of mosquito-borne chikungunya fever has occurred in Foshan City, Guangdong Province, China. This was the second large-scale local outbreak in China after the one that occurred in Dongguan City, Guangdong Province, in 2010. As of 23 August, more than 10,000 human cases had been reported. This study aims to investigate mosquito infection and viral genomic characteristics during the Foshan outbreak.

Methods: Adult Aedes albopictus were collected using BioGents Sentinel trap in three hotspot towns (Beijiao, Chencun and Lecong). Mosquitoes were morphologically identified and pooled by species, sex and environment type. Each pool was homogenized, and the homogenate was clarified by centrifugation; and the supernatant was used for viral RNA isolation. The isolated RNA was screened using CHIKV RT-qPCR. Positive pools underwent Sanger sequencing and whole-genome sequencing. The CHIKV lineage and mutational profiles were inferred using maximum likelihood phylogenetic analysis and comparison with human- and mosquito-derived genomes.

Results: Over 11 days of trapping, 2803 mosquitoes were captured. 1569 (55.97%) female Ae. albopictus were divided into 77 pools and 9.09% (7/77) of these pools were CHIKV-positive. The minimum infection rate (MIR, per 1000 females) for local Ae. albopictus was 4.46, while the MIR for residences in Lecong Town was the highest at 9.17 per 1000 females. The MIR for parklands was slightly higher than for residences (4.60 vs. 4.30 per 1000 females). Five complete Ae. albopictus-derived CHIKV genome clustered within the East/Central/South African-Indian Ocean lineage genotype, and harbored novel E1 and E2 mutations consistent with those detected in the 2025 Reunion Island human strain. Amino-acid mutations E1-A226V/E2-L210Q were detected, enhancing adaptability to Ae. albopictus and increasing the transmission capacity.

Conclusions: This study represents the first mosquito-derived CHIKV whole-genome sequence obtained from the 2025 Foshan outbreak. Ae. albopictus was confirmed as the primary vector, and the presence of adaptive mutations indicated an enhanced transmission potential. Despite the outbreak emerging earlier in the season and affecting a dense urban population, it was effectively controlled through timely and intensive vector interventions. These findings highlighted the critical role of mosquito surveillance in early outbreak preparedness and effective vector management.

Background: Dengue fever remains a major global public health challenge, with increasing incidence and burden over recent decades. Global warming, urbanization, and increased international travel have fueled the global spread of dengue. Despite escalating global concern, recent and consistent estimates of the global dengue burden remain limited. This study aimed to quantify the shifting trends of dengue fever.

Methods: We analyzed the 2021 Global Burden of Disease (GBD) dataset to assess dengue fever's incidence, prevalence, mortality, and disability-adjusted life years (DALYs) from 1990 to 2021 across 204 countries/regions. Data were stratified by age, sex, and socio-demographic index (SDI) using age-standardized rates, and time-trend analysis was conducted with general linear regression. Correlations between SDI and disease burden metrics were evaluated using Spearman's rank correlation.

Results: From 1990 to 2021, the global burden of dengue increased, with age-standardized incidence rate (ASIR) rising by 0.56% (95% UI: 0.23-2.38), age-standardized prevalence rate (ASPR) by 0.56% (95% UI: 0.23-2.36), and age-standardized DALYs rate (ASDR) by 0.28% (95% UI: -0.38-0.92). In 2021, there were an estimated 58.96 million cases. Regionally, Tropical Latin America reported the highest ASIR (5774.82; 95% UI: 1774.73-11,624.76). At the national level, variations in the change of the ASIR were observed across countries with Tonga reporting the highest ASIR in 2021. From 1990 to 2021, males exhibited a higher ASDR compared to females, particularly in the 0-14 age group. Dengue burden trends varied across SDI regions, with high-middle and middle SDI regions showing increased ASIR, while low SDI regions experienced a decline.

Conclusions: The analysis highlights the increase in dengue burden globally, with demographic and geographic disparities. The findings underscore the need for targeted prevention, control, and treatment strategies to mitigate the growing burden of dengue fever worldwide.

Background: Following the onset of an index chikungunya case on July 8, 2025, a significant outbreak occurred in Foshan, Guangdong Province, China. This study aimed to quantify the outbreak's transmissibility between June 16 and July 21, 2025.

Methods: Data were obtained from local Government, Statistics Bureau, Centers for Disease Control and Prevention, and the relevant literature. We employed a transmission dynamic model that integrated human host-vector transmission to estimate the basic reproduction number ( $R_0$ ). The key parameters of the model were calibrated using early-phase limited surveillance data on the cumulative number of cases. We calculated the correlation coefficient to evaluate the accuracy of this calibration. Sensitivity analyses were conducted to quantify the uncertainties in the parameter inputs.

Results: Between June 16 and July 31, 2025, cumulative cases reached 2658, with 92.96% concentrated in the Shunde District. Model simulations showed that a cumulative case count is consistent with local reports (Pearson r = 0.99, P < 0.001). The median overall $R_0$ of this outbreak was 7.2807 [interquntile range (IQR): 7.2809‒7.2811], suggesting sustained transmission. Human-to-mosquito transmission (Median: 22.79, IQR: 5.44‒40.14) had a higher median $R_0$ than mosquito-to-human transmission (Median: 2.33, IQR:0.58‒4.07) (Mann-Whitney U P < 0.001). Symptomatic infections (Median: 19.60, IQR: 4.68‒34.52) had a higher median $R_0$ than asymptomatic infections (Median: 3.19, IQR: 0.76‒5.62) (Mann-Whitney U P < 0.001). The model simulated cumulative cases were sensitive to parameters $a$ , $b$ , ${\omega }_m$ , and ${\omega }_p$ . The overall $R_0$ and mosquito-to-human $R_0$ were sensitive to parameters $a$ and $b$ . The human-to-mosquito and symptomatic human-to-mosquito $R_0$ were sensitive to parameter $\gamma$ , while asymptomatic human-to-mosquito $R_0$ was sensitive to parameter ${\omega }_p\text{'}.$ CONCLUSIONS: The transmissibility of CHIKV is high. Human-to-mosquito transmission, especially symptomatic infections to mosquito transmission, was the main driver of chikungunya virus transmission. These findings underscore the critical need for enhanced screening of travellers from endemic regions, timely case isolation, and targeted vector control to mitigate autochthonous transmission.

Background: Hemorrhagic fever with renal syndrome (HFRS) poses a significant public health concern in China. However, the spatiotemporal patterns and underlying drivers of its transmission are not fully understood. This study aims to investigate spatiotemporal heterogeneity of HFRS incidence at the city level and explore its potential influencing factors.

Methods: Joinpoint regression was utilized to analyze city-level HFRS incidence data (n = 314 cities, 2005-2021) collected from the National Infectious Disease Surveillance System. Furthermore, we employed the Geodetector method to identify the potential driving factors from a set of meteorological, vegetation, and urbanization variables.

Results: The results from Joinpoint regression analysis revealed an overall declining trend in city-level HFRS incidence across China from 2005 to 2021. Of the cities analyzed, 126 showed an upward trend [the average annual percent change,(AAPC) > 0], 176 a downward trend (AAPC < 0), and 12 remained stable (AAPC = 0). Notably, upward-trend cities were predominantly concentrated in South China. Geodetector analysis indicated that selected climatic and vegetation factors accounted for 19-56% of the spatiotemporal heterogeneity in HFRS incidence, whereas urbanization factors explained only 3-5%. However, synergistic interactions between temperature and urbanization-related variables (i.e., land-use, economic, and demographic dimensions) significantly enhanced their explanatory power, particularly in upward-trend cities, where the combinations increased explanatory capacity by 124-184%.

Conclusion: In summary, while climatic and vegetation factors remain the primary drivers of the spatiotemporal heterogeneity of HFRS epidemics in China, urbanization also exerts non-negligible influence on city-level incidence. This research offers valuable insights for public health authorities to strengthen their intervention capabilities against this disease.

Background: Schistosomiasis, an infectious disease of poverty, remains a public health challenge worldwide. Although praziquantel chemotherapy has been proven to be an effective antiparasitic intervention, real-world evidence indicates that in patients with hepatointestinal schistosomiasis, hepatic fibrosis may continue to progress even after treatment. The current understanding of the mechanisms underlying persistent liver fibrosis progression in Schistosoma-infected individuals post-treatment is unclear. The aim of this commentary is to analyze the critical yet multifactorial determinants contributing to the persistent progression of liver fibrosis and to advocate for a comprehensive research focus to support the global elimination of this disease.

Main text: Multiple mechanisms may contribute to the persistent progression of liver fibrosis in schistosomiasis. These include the continued presence of viable Schistosoma eggs, co-infection with hepatitis viruses, alterations in splenic structure and function, disruption of the intestinal mucosal barrier, hepatic ischemia and hypoxia, hepatocyte death, specific types of collagen deposition, and host genetic variations. However, additional factors potentially contributing to host pathology warrant further investigation.

Conclusions: In the post-schistosomiasis control era, expanding the focus of research to include the "post-treatment" phase is essential. Investigating the mechanisms underlying the persistent progression of liver fibrosis and identifying future research priorities may enhance efforts toward the global elimination of schistosomiasis and improve long-term health outcomes for individuals who have received praziquantel treatment.

Background: Whole blood samples are often used to generate whole genome sequences, which provide valuable insights into the genetic make-up of viruses. However, the collection and management present significant challenges, particularly in remote and resource-limited communities, where maintaining a cold chain is often difficult and costly. The use of dry blood spots (DBS) is gradually increasing to overcome these logistical barriers with reduced biosafety constraints. We propose an alternative approach using native DBS Lassa virus (LASV)-positive samples as a substitute for whole blood.

Findings: Next-generation sequencing (NGS) was performed on RNA extracted from whole blood and DBS samples using Illumina technology. RNA concentration, cycle threshold (Ct) values and sequence read counts were statistically compared. A total of 78 samples from 39 LASV-positive Mastomys atalensis were analysed. Whole blood had significantly higher mean RNA concentration (26.5 ± 1.9) than DBS (3.4 ± 0.3), P < 0.05. Mean Ct values in whole blood were significantly lower than in DBS (P = 0.0001). Log mean sequence reads and NGS coverage for both S and L segments were significantly higher in whole blood (P = 0.0001). RNA concentration showed no association with sequence coverage (P = 0.382), while Ct values showed a strong association (P = 0.0001).

Conclusions: Our study demonstrates that DBS is a viable alternative for whole genome sequencing of LASV, although whole blood samples consistently outperform DBS in terms of RNA concentration, Ct values and NGS coverage.