Tropical Medicine and Health最新文献

Background: Acinetobacter baumannii has emerged as a significant global pathogen, and community-acquired infections are concerning due to their severe clinical outcomes and high mortality. Despite this, the molecular epidemiology and phenotypic characteristics of community-acquired/community-onset A. baumannii (CAAB/COAB) strains remain poorly understood. This study analyzed the genotypes, virulence traits, and clinical manifestations of 32 COAB isolates collected in Taiwan between 2015 and 2017.

Methods: Capsular types (KLs), sequence types (STs) from the Oxford and Pasteur schemes, and international clones (ICs) were identified among the 32 COAB isolates. In vitro virulence was assessed by evaluating biofilm formation, motility, resistance to desiccation and serum, and in vivo virulence was confirmed in a Galleria mellonella larvae model. Associations between KL/ST types and virulence phenotypes, as well as between KL/ST types and the clinical manifestations of patients, were also analyzed.

Results: The results showed that among the tested COAB isolates, KL49 was the predominant capsular type, representing 18.8% (n = 6) of samples, and ST10^Pas/IC8 (ST10^Pas: ST10 under the Pasteur scheme, IC8: international clone 8) was the major clone (15.6%, n = 5). Interestingly, we found that KL49/ST10^Pas, which is predominant in America and Australia but has never been reported for CAAB/COAB in Taiwan, had a hypervirulent phenotype with high serum resistance and high mortality in the G. mellonella larvae model. Furthermore, clinical records showed higher incidences of chronic obstructive pulmonary disease, pneumonia, elevated Pitt bacteremia scores, and 30-day mortality for patients with KL49/ST10^Pas infections than for patients with non-KL49/ST10^Pas infections.

Conclusions: This is the first report identifying KL49/ST10^Pas as a major clone of COAB in Taiwan. Its high virulence was demonstrated, highlighting a potential public health threat. This study lays a foundation for understanding the molecular epidemiology of COAB in Taiwan and supports future research on virulence and disease control strategies.

Background: Tuberculosis (TB) remains a significant public health challenge in the Western Pacific Region, which accounts for approximately 20% of the global TB burden. Despite effective diagnostic tools and treatment, many individuals with TB remain undiagnosed or unreported, particularly in high-burden countries. Systematic screening is a key strategy for identifying cases early and reducing transmission. This study presents a situational analysis of TB screening policies, practices, and challenges across seven high-burden countries in the region: Cambodia, China, Lao PDR, Mongolia, Papua New Guinea, the Philippines, and Viet Nam.

Main body: Data were collected through questionnaires, follow-up discussions, and a regional workshop involving National TB Programme representatives and WHO staff. Most countries have national guidelines for systematic screening, prioritising high-risk groups, like people living with HIV and household contacts. Common screening tools include symptom screening, chest X-rays, and WHO-recommended rapid molecular diagnostics. Although asymptomatic TB is increasingly recognised, symptom screening remains the primary initial tool. Chest X-rays with computer-aided detection technologies are available in most countries, but are often limited to donor-funded projects. Screening is conducted through routine healthcare visits, scheduled checks for specific populations (e.g., prisoners, older adults), and ad hoc campaigns. Implementation varies due to resource and infrastructure limitations. While integration with other health services and community-based approaches shows promise, these remain underutilised. Key challenges include limited funding, workforce shortages, low provider awareness, and stigma. The COVID-19 pandemic disrupted TB services, underscoring the need for resilient health systems.

Conclusion: Improving systematic TB screening requires scaling up sensitive diagnostic tools, decentralising implementation, and strengthening community engagement. Sustainable financing, robust health systems, and multi-sectoral collaboration are critical to reaching the "missing millions" and achieving the End TB goals. This analysis underscores the need for targeted, evidence-based strategies to enhance screening coverage and effectiveness across diverse epidemiological and resource settings.

Background: Hepatitis E virus (HEV) is recognized as a cause of acute viral hepatitis, particularly in low-resource and humanitarian settings, although its burden varies across different populations and geographic areas. Internally displaced persons (IDPs) are at high risk due to inadequate sanitation and contaminated water. This study aimed to characterize the molecular epidemiology and genotypes of HEV among IDPs in Al-Azaza Camp, Blue Nile State, Sudan.

Methods: A cross-sectional study was conducted from August to December 2021 during the rainy season. Serum samples from 1,078 participants were screened for anti-HEV IgM and IgG antibodies. A subset of 20 IgM-positive samples was selected for molecular analysis using real-time RT-PCR. Eighteen high-quality RNA-positive samples were sequenced, and genotyping was performed based on the ORF2 region. Phylogenetic analysis was conducted using the HEV Genotyping Tool and Geneious Prime software.

Results: Overall, 75.6% of participants tested positive for IgG antibodies. All sequenced isolates (n = 18) were classified as genotype 1, subtype 1e (HEV-1e), closely related to Paslahepevirus balayani. The isolates clustered with reference strains from Chad and Nigeria, indicating regional circulation and genetic conservation of HEV-1e in sub-Saharan Africa.

Conclusion: Despite the single-site scope and low RNA yield limitations, the study findings align with regional HEV-1e circulation patterns and emphasize the need for sustained surveillance and consideration of cross-border transmission.

Background: Chagas disease, caused by Trypanosoma cruzi, remains a significant public health problem in Venezuela, with evidence of re-emerging transmission and increasing concern over non-vectorial routes such as oral and congenital transmission. Effective public health strategies require a clear understanding of community-level knowledge, attitudes, and practices (KAP). This study aimed to characterize and identify predictors of KAP regarding Chagas disease in a rural, endemic community in Portuguesa state, Venezuela.

Methods: A cross-sectional survey was conducted in September 2024 in the "Virgen de Coromoto" community. Participants aged 18 and older were recruited via non-probabilistic sampling. Data were collected using a pre-validated 57-item questionnaire covering sociodemographic aspects, knowledge, attitudes, and practices. KAP levels were categorized as high/low, positive/negative, and appropriate/inappropriate using a data-driven two-step cluster analysis. Binomial logistic regression was used to identify factors associated with these KAP outcomes.

Results: A total of 317 individuals participated in the study. The median age was 36 years, and 57.7% (n = 183) were female. While a majority of participants demonstrated high knowledge (59.3%) and positive attitudes (57.4%), a significant proportion engaged in inappropriate preventive practices (61.8%). Knowledge deficits were identified concerning non-vectorial transmission routes, with only 24.9% correctly identifying contaminated food/juices and 40.7% identifying blood transfusions as risks. Women of reproductive age had significantly lower knowledge scores compared to the rest of the population (median score 9 vs. 11, p < 0.001). Being a woman of reproductive age (aOR = 1.75, 95% CI = 1.04-2.95, p = 0.034) and having negative attitudes (aOR = 1.82, 95% CI = 1.09-3.03, p = 0.021) were significant predictors of low knowledge. Having metallic screens on windows and doors was associated with a lower likelihood of inappropriate practices (aOR = 0.46, 95% CI = 0.22-0.97, p = 0.04).

Conclusions: Despite generally high awareness, a critical disconnect exists between knowledge and protective behaviours in this endemic community. Specific vulnerabilities, including poor understanding of oral and congenital transmission routes and lower knowledge among women of reproductive age, pose significant risks. These findings underscore the need for targeted, evidence-based educational interventions that move beyond general awareness to address specific behavioural barriers and protect vulnerable groups.

Background: Insecticide resistance in arbovirus vectors threatens the effectiveness of vector control strategies in many endemic regions. Understanding resistance profiles and identifying underlying mechanisms are essential for preventing operational failures. This study assessed the susceptibility of Aedes aegypti and Aedes albopictus to commonly used insecticides in southern Benin and investigated the contribution of knockdown resistance mutations and metabolic detoxification pathways.

Methods: Entomological surveillance was conducted in Lokossa, Bohicon, and Dassa, where ovitraps were used to collect eggs of Aedes species. Eggs were reared to the adult stage under controlled insectary conditions. Nonblood-fed females aged 2-5 days were tested using standard tube assays to determine susceptibility to deltamethrin at 0.05%, permethrin at 0.75%, and bendiocarb at 0.1%. Additional concentrations at fivefold and tenfold the diagnostic doses were used to measure resistance intensity. Polymerase chain reaction assays were performed to detect mutations in the voltage-gated sodium channel gene associated with knockdown resistance. Biochemical assays were conducted to quantify the activity of oxidases, glutathione-S-transferases, and esterases. Exact binomial tests were used to compute confidence intervals for mortality rates and allele frequencies.

Results: Aedes aegypti populations from the three communities showed resistance to deltamethrin and permethrin at the diagnostic dose while remaining fully susceptible to bendiocarb. Mortality increased substantially at elevated concentrations, indicating moderate resistance intensity. Aedes albopictus populations were fully susceptible to all tested insecticides. Three mutations in the voltage-gated sodium channel gene, F1534C, V1016G, and S989P, were identified in Aedes aegypti with allele frequencies ranging between 33.89% and 46.67%. Biochemical assays revealed elevated oxidase activity in all Aedes aegypti populations, with increased levels of glutathione-S-transferases and both alpha- and beta-esterases in Bohicon and Lokossa.

Conclusions: The study documents pyrethroid resistance in Aedes aegypti from southern Benin, while Aedes albopictus remains susceptible. Both species showed high susceptibility to bendiocarb. The presence of three knockdown resistance mutations at moderate frequencies together with increased detoxification enzyme activity indicates that both target-site and metabolic mechanisms contribute to resistance development. These findings underscore the need for integrated resistance management to preserve the effectiveness of insecticidal interventions.

Background: Ethiopia implemented the community-based management of possible serious bacterial infection to improve access to lifesaving care for sick young infants aged 0-2 months. However, service utilization has been low, and the quality of care was sub-optimal, emphasizing the need to identify challenges within the primary healthcare system. This study explored mothers' and healthcare providers' experiences and perspectives on the management of sick young infants, including those with possible serious bacterial infections to inform policy and practice.

Methods: We conducted a qualitative study including 25 in-depth and six key informant interviews with purposively selected participants, including mothers seeking facility care for their infants, health extension workers, health center staff, and supervisors of health extension workers. We audio-recorded and transcribed the interviews, and conducted inductive thematic analysis.

Results: We present four major themes: caregivers' perceptions of young infant illnesses, caregivers' choice of place to seek care, caregivers' experiences with caring for sick young infants at the health facility, and factors affecting the provision of quality care. Mothers acknowledged the need to seek care if their young infants became ill, although often delayed when not recognizing signs of illness, believing that it would resolve. Once identified, they had the autonomy to seek care but lacked awareness of health post services, bypassing these and seeking care at health centers, which were further away. Health extension workers viewed poor infrastructure and the perceived low quality of service as being linked to low service utilization at health posts. Mothers described long waiting times at health centers, inadequate assessment, and missing communication about their children's conditions and treatment. Health extension workers felt they had gaps in knowledge and skills. Inconsistent availability of drugs, weak referral and feedback mechanisms, low-quality supervision, limited mentorship, and inadequate district-level ownership of newborn care constrained the delivery of high-quality services.

Conclusions: This study identifies the challenges from the community to health system on sick young infants' service utilization and quality of care at primary healthcare settings. It highlights the importance of a comprehensive approach that integrates demand-creation activities with health system strengthening efforts to ensure the consistent availability of high-quality care.

Background: Men engaged in transactional sex (METS) are a critical population for HIV transmission dynamics in Sub-Saharan Africa (SSA). The interplay between multiple sexual partnerships and condom use, two key risk determinants, is complex and not fully understood. This study aimed to assess the prevalence and determinants of these interdependent behaviors among METS across SSA.

Methods: Cross-sectional data from 26 recent Demographic and Health Surveys (DHS) in SSA were pooled. A sample of 10,128 men who reported providing or receiving money or gifts in exchange for sex was analyzed. A recursive bivariate probit model was use to jointly model the propensity for multiple sexual partnerships and condom use, accounting for their potential correlation. Adjusted coefficients, predicted joint probabilities, and average marginal effects (AME) were reported.

Results: The weighted prevalence of multiple sexual partnerships was 55.3% (95%CI: 53.8-56.9) and of condom use was 32.9% (95%CI: 31.4-34.4). The model revealed a significant, positive correlation between the two behaviors (rho = 0.447, p < 0.05). Key determinants had compensatory effects: living in a couple was associated with a higher propensity for multiple partnerships (β = 0.39, p < 0.001) but a lower propensity for condom use (β = - 0.78, p < 0.001). Higher education was associated with both more multiple partnerships and increased condom use. HIV-related knowledge and testing were strong predictors of condom use but not of multiple partnerships. AME analysis showed that marital status had the largest effect, increasing the probability of the high-risk outcome (multiple partners, no condom) by 25.85 percentage points (p < 0.001). Media exposure and comprehensive HIV knowledge significantly increased the probability of protective behaviors.

Conclusion: Among METS in SSA, there is evidence of risk compensation, wherein factors associated with multiple sexual partnerships are also associated with increased condom use. However, the alarmingly high prevalence of multiple partnerships coupled with low condom use among married METS represents a critical intervention gap.

Introduction: Bacterial antimicrobial resistance (AMR) is a major and growing public health threat in East African Community (EAC) countries, where fragile health systems, inadequate diagnostics, and inappropriate antibiotic use drive high levels of resistant infections. Despite this, robust subregional mortality estimates remain limited.

Methods: We conducted a secondary pooled analysis of modelled, publicly available, country-level mortality estimates from the Global Research on Antimicrobial Resistance (GRAM) 2019 project. Data were extracted for six EAC countries: Burundi, Kenya, Rwanda, South Sudan, Tanzania, and Uganda. Because GRAM reports age-standardised mortality rates (ASMRs) with 95% uncertainty intervals, we derived standard errors from these intervals, assuming approximate normality, and used them in the pooled analysis. Using random-effects models with restricted maximum likelihood (REML), we pooled ASMRs per 100,000 population for deaths associated with and attributable to AMR. We calculated 95% confidence intervals and prediction intervals, assessed heterogeneity using I², and conducted leave-one-out sensitivity analyses to test robustness.

Results: Across the six EAC countries, there were an estimated 154,760 deaths associated with AMR and 36,480 deaths attributable to AMR in 2019. The pooled ASMR for AMR-associated deaths was 144.69 per 100,000 (95% CI 129.07-160.30) population, with a 95% prediction interval of 122.57-166.81. Country-specific ASMRs for AMR-associated deaths ranged from 129.5 per 100,000 population in Uganda to 167.0 per 100,000 population in Burundi. For AMR-attributable deaths, the pooled ASMR was 34.62 per 100,000 (95% CI 30.02-39.23) population, with a prediction interval of 28.10-41.14. Country-specific ASMRs for attributable deaths ranged from 30.80 per 100,000 population in Uganda to 41.90 per 100,000 population in Burundi. For both associated and attributable mortality, heterogeneity was negligible (I² = 0%), and sensitivity analyses confirmed that no country disproportionately influenced the pooled estimates.

Conclusion: This pooled secondary analysis indicates a substantial and regionally consistent mortality burden from bacterial AMR in East Africa. The findings reify the need for coordinated investment in AMR surveillance, stewardship, and overall response across the EAC.

Background: In 2022, a widespread dengue outbreak was reported in Nepal, with 4,593 cases reported by August escalating to 53,951 cases and 62 deaths by November. The caseload was significantly higher than in 2019, when the outbreak was last officially recorded with 17,999 cases and 6 fatalities.

Aims and objectives: This study aimed to identify Nepal's circulating dengue virus serotypes during the 2022 outbreak and analyze their distribution across different regions and hospitals.

Materials and methods: To better understand the circulating dengue virus serotypes, a study was conducted in collaboration with the Seven Provincial Hospital and National Public Health Laboratory (NPHL) with the Coordination of Epidemiology Diseases Control Division (Nepal). This study involved collecting and testing blood samples from various Provincial hospitals across Nepal, covering all the geographical patterns of Nepal.

Results: The results revealed a predominance of serotype 1, followed by serotypes 2 and 3, with some mixed infections. The findings underscore the diverse dengue serotype circulation and the potential for severe dengue infections in Nepal.

Conclusion: The 2022 dengue outbreak in Nepal was primarily driven by DENV-1, followed by DENV-2 and DENV-3. The detection of mixed infections and the absence of DENV-4 warrant further investigation to understand the transmission dynamics and potential for severe dengue cases.

Background: Malaria is a leading cause of morbidity and mortality among children under five in sub-Saharan Africa, especially in Ghana. Insecticide-treated nets (ITNs) are among the most effective prevention tools, yet disparities in use persist, undermining equitable malaria control. This study examined trends and inequalities in ITN use among Ghanaian children under five from 2003 to 2022.

Methods: A cross-sectional secondary analysis was conducted using six rounds of the Ghana Demographic and Health Surveys (2003-2022). The outcome variable was defined as whether a child had slept under an ITN on the night preceding the survey. Equity stratifiers were analysed using the WHO Health Inequality Toolkit. Inequalities were measured through difference (D), ratio (R), absolute concentration index (ACI), population attributable risk (PAR), and population attributable fraction (PAF), each with 95% confidence intervals (CIs).

Results: The study found that the national ITN use increased from 3.9% in 2003 to 54.1% in 2019, before declining to 49.0% in 2022. Wealth-based inequality widened substantially, with the ACI shifting from - 0.3 (95% CI - 1.4 to 0.8) in 2003 to - 7.9 (95% CI - 8.8 to - 7.1) in 2022. The difference between the poorest and richest quintiles rose from - 4.1% in 2003 to - 39.4% in 2022, while the ratio declined from 0.8 to 0.4. Regional disparities were also marked, with the difference increasing from 21.8% in 2003 to 39.5% in 2022, and ratios rising from 2.2 to 2.3. Residence-based inequalities grew, with rural-urban difference widening from - 0.2% in 2003 to - 25.1% in 2022. Sex and age contributed minimally, with ACIs fluctuating (- 2.5 in 2014 and 1.0 in 2022) for sex.

Conclusions: Although ITN use among Ghanaian children under five has increased substantially since 2003, widening inequities persist, particularly by wealth, region, and residence. Findings highlight the need for equity-focused policies to accelerate progress towards Sustainable Development Goal 3.3, ending malaria by 2030.