Tropical Medicine & International Health最新文献

Introduction: Dengue fever poses a significant public health threat in tropical regions, with Aedes aegypti as the primary vector. This study investigated dengue virus prevalence and serotype distribution in field-collected Ae. aegypti mosquitoes across the Red Sea governorate during 2023-2024.

Methods: A surveillance study was conducted across five districts (Shoaib, Al-Garf, Al-Owaina, Al-Odwa and Al-Ashraaf) from April 2023 to March 2024. A total of 1330 adult females Ae. aegypti mosquitoes were organised into 133 pools for molecular analysis. Molecular identification using mitochondrial cytochrome oxidase I and internal transcribed spacer 2 markers were used to assure the presence of Aedes vector. Dengue virus RNA detection employed nested RT-PCR with serotype-specific amplification.

Results: All specimens were confirmed as Ae. aegypti with characteristic cytochrome oxidase I (714 bp) and internal transcribed spacer 2 (313 bp) amplification products and morphological examinations. Dengue virus RNA was detected in 13 adults out of 1330 females from all visited districts, with total MIR estimated as 0.97. Al-Odwa district showed the highest infection rate (1.3) followed by Shoaib (0.83), Al-Owaina and Al-Garf (1), while Al-Ashraaf had the lowest percentage (0.4). Peak viral activity occurred in December 2023 across all districts, with no summer detections (June-September 2023). Three serotypes circulated in our habitat: DENV-2 (all five districts), DENV-1 (four districts) and DENV-3 (Al-Odwa only). DENV-4 was absent. Four districts showed DENV-1/DENV-2 co-circulation, while Al-Odwa uniquely harboured DENV-2/DENV-3.

Conclusion: This study demonstrates active dengue virus circulation in Red Sea governorate with distinct spatial-temporal patterns. The identification of three co-circulating serotypes with geographic variation highlights regional epidemiological complexity. Seasonal patterns suggest that environmental influences affect transmission dynamics, providing crucial baseline data for targeting surveillance and control strategies.

Objectives: Childhood mortality is a key indicator of progress in health and development in low- and middle-income countries, traditionally measured through household surveys with face-to-face interviews. This study explored an alternative approach that used mobile phone interviews with women in Mozambique.

Methods: Using two sampling approaches, we interviewed women of reproductive age about their pregnancy history through mobile phones. The first method used an existing database of phone numbers collected from a national mortality surveillance, Countrywide Mortality Surveillance for Action (COMSA). The second employed random digit dialling (RDD) to generate phone numbers. The COMSA phone sample successfully reached 13,545 women while the RDD sample reached 10,359 women. We compared neonatal (NMR), infant (IMR) and under-five mortality rates (U5MR) to estimates from the United Nations (UN), COMSA and the 2022 Demographic and Health Survey (DHS). The mobile phone-based mortality rates were adjusted using the raking approach.

Results: The mobile phone interviews incorporating pregnancy history yielded recent childhood mortality rates comparable to those reported by the DHS. The 2020-2021 U5MRs were estimated at 59.3 (95% confidence interval [95% CI]: 41.9-76.7) in the COMSA phone sample and 44.9 (95% CI: 9.0-80.7) in the RDD sample, compared to 59.6 (95% CI: 53.7-65.6) in the DHS. These estimates were lower than the UN projections at 71.6 (95% CI: 65.5-87.1) and COMSA at 80.0 (95% CI: 69.0-91.0). We observed similar trends for NMR and IMR. Childhood mortality trends were comparable between the COMSA phone sample and the DHS sample. In contrast, the RDD sample appeared to consistently underestimate childhood mortality compared to the other samples.

Conclusion: Mobile phone surveys, including standard full pregnancy history tools, produced recent childhood mortality levels and trends for national and subnational levels similar to face-to-face approaches such as the DHS.

Introduction: Tuberculosis, although curable, presents challenges related to treatment adherence, which compromises treatment effectiveness. Individual, social and structural barriers interfere with patients' ability to properly follow the therapeutic regimen, thereby impacting treatment outcomes. Given the limitations of the conventional healthcare model, which relies primarily on in-person consultations and standard treatment protocols without additional adherence support technologies, new approaches have been explored to improve patient outcomes. This study seeks to identify effective communication approaches in this context.

Objective: To identify the most effective communication strategies to optimise treatment adherence and improve therapeutic success in patients diagnosed with tuberculosis.

Methods: A systematic review with meta-analysis was conducted. We included studies available in the MEDLINE (via PubMed), EMBASE and SCOPUS databases, with publication dates between January 2005 and December 2024. The primary outcomes were adherence to and success in tuberculosis treatment.

Results: This systematic review included 17 studies on tuberculosis treatment adherence. Of these, 12 were included in the meta-analysis for adherence and 8 for treatment success. The most effective strategies for adherence were community education (2 studies; RR: 0.25, 95% CI: 0.11-0.56) and video observed therapy (VDOT) (2 studies; RR: 0.29, 95% CI: 0.21-0.40). The combination of electronic devices with SMS also showed positive results (3 studies; RR: 0.53, 95% CI: 0.37-0.77). SMS alone (5 studies) and electronic devices alone (3 studies) were not effective. For treatment success, only the combination of electronic devices with SMS (RR: 0.31, 95% CI: 0.17-0.55) and community education (RR: 0.51, 95% CI: 0.40-0.64) were effective.

Conclusion: The combination of electronic devices with SMS and community education is an effective strategy for improving adherence and therapeutic success in tuberculosis treatment. Isolated interventions with SMS or electronic technologies did not show significant results. Adapting approaches to local realities is crucial for optimising outcomes.

Leprosy presents a broad clinical spectrum influenced by the host's immune response, and co-infections may further modulate disease progression. This study evaluated clinically diagnosed leprosy patients (n = 251) from Sergipe and Minas Gerais, Brazil, along with healthy controls (n = 43), soil-transmitted helminths-positive controls (n = 15), and household contacts (n = 176). Enzyme-linked immunosorbent assays were performed using predicted B-cell epitopes from immunogenic proteins of Ascaris sp., Trichuris trichiura, Strongyloides stercoralis, Ancylostoma duodenale and Necator americanus. Among leprosy patients, 123 (49%) were IgG seropositive for at least one soil-transmitted helminths antigen. Nine (7.3%) had optical density (OD) values exceeding 2-fold the cut-off, six (4.9%) surpassed 3-fold and one exceeded 7-fold. In patients with documented reactions (n = 34), seropositivity was observed in 6 with neuritis, 14 with type 1 reaction (T1R) and 14 with type 2 reaction (T2R), totaling 61.8%. Among household contacts, 96 (54.5%) were seropositive. Stratified analyses revealed significant differences in IgG levels between soil-transmitted helminths-seropositive and seronegative individuals within both paucibacillary and multibacillary groups, despite no overall association with operational classification. These findings suggest that helminth exposure may influence immune responses within leprosy subtypes and contribute to reactional episodes. The high seroprevalence observed in both patients and household contacts highlights shared environmental exposure and supports the inclusion of helminth monitoring in leprosy control strategies. Early detection and treatment of co-infections may reduce immune imbalances and severe inflammatory outcomes. Further studies are needed to elucidate the immunological mechanisms underlying helminth-leprosy interactions and to strengthen integrated approaches in public health.

The routine diagnostic method used for clinical samples suspected of filarial infection in our laboratory is the Filaria-real time-PCR (F-RT-PCR). The drawback of this method is the need for melting temperature analysis and PCR products' electrophoresis to identify the filarial species. Therefore, the aim of this study was to design a quantitative real-time PCR (qPCR) assay using filarial-specific hydrolysis probes, targeting 18S rRNA and ITS1 genes, allowing the simultaneous diagnosis of loiasis, mansonellosis and other human filariasis without the need of electrophoresis or melting temperature analysis. To achieve this objective, three filarial probes (Fil-Hum-GT1, Loa-Hum-GT2 and Mp-Hum-GT2) were designed, optimised and validated for integration into a single qPCR assay, named filarial-multiplexed probe-quantitative PCR (F-mp-qPCR). For the optimisation and validation of the F-mp-qPCR method, a total of 304 clinical samples as dried blood spot were used with their corresponding thick blood smears stained by Giemsa 3%. The detection limit of the Fil-Hum-GT1, Loa-Hum-GT2 and Mp-Hum-GT2 probes was 0.05, 0.5 and 3 mF/mL, respectively. The most sensitive and specific probe was the general filarial probe Fil-Hum-GT1, with a sensitivity of 92.0% to detect L. loa, 88.6% to detect M. perstans and 85.7% to detect mixed infections, with 100% specificity. Agreement with microscopy was excellent for the Fil-Hum-GT1 probe. In contrast, the Mp-Hum-GT2 probe showed the lowest performance, with a sensitivity of 81.8% to detect M. perstans, decreasing to 42.9% for mixed infections. Although the developed method did not prove to be significantly more sensitive than microscopy, this novel method is faster and easier to perform compared to microscopy and is very useful for screening large population groups in a context of medium-to-low human filariasis transmission.

Background: Chagas disease, caused by Trypanosoma cruzi, remains a significant public health challenge in Latin America, with diagnostic limitations hindering control efforts.

Aim: Our study aimed to assess the diagnostic performance of four chimeric recombinant T. cruzi antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) in a highly endemic region in southern Brazil.

Methods: Serum samples from 333 individuals residing in Canguçu, Rio Grande do Sul, were tested using an in-house ELISA platform. We assessed the sensitivity, specificity, accuracy, and diagnostic odds ratio (DOR) of individual and combined IBMP antigens through serial and parallel testing strategies.

Results: All antigens exhibited 100% specificity and high accuracy (≥ 93.4%), with IBMP-8.1 and IBMP-8.4 showing the best overall performance (sensitivities of 80.0% and 76.7%; DORs of 109,136 and 89,659, respectively). Parallel testing using the combinations IBMP-8.1 + IBMP-8.3 and IBMP-8.1 + IBMP-8.4 achieved ≥ 95% sensitivity and > 99% accuracy.

Conclusions: These findings support the use of IBMP chimeric antigens, particularly in combination, as reliable tools for Chagas disease diagnosis and surveillance, and highlight the importance of region-specific validation to ensure diagnostic equity in diverse endemic settings.

Background: Dengue vector control plays an important role in reducing the burden of dengue infection. This study aimed to summarise the evidence of published systematic reviews on the efficacy of dengue vector control interventions.

Methods: Systematic reviews of cluster randomised controlled trials and randomised controlled trials in populations/people exposed to the risk of dengue infection in the presence of the vector were included. All dengue vector control, all comparators and any outcomes were considered in this review. Electronic databases and reference lists were searched. Screening, full-text reviews, data extractions and quality assessments were conducted independently by two reviewers with resolution by a third reviewer.

Results: A total of 15 systematic reviews were included in this study, but narrative synthesis was performed for only 3 reviews that reviewed cluster randomised controlled trials or randomised controlled trials. Community mobilisation and insecticide-treated materials were weakly effective interventions reported by two systematic reviews that have acceptable methodological quality. However, the non-overlapping of randomised controlled trials and cluster randomised controlled trials included in their respective reviews may affect the findings.

Conclusion: There is insufficient evidence to recommend a method of dengue vector control management. Novel dengue vector control methods are highly encouraged for urgent trials. Until then, the current respective local governments' vector control management may still play a vital role in controlling the mosquito's propagation and transmission of dengue infection.

Objective: This study aimed to assess the prevalence of dengue virus (DENV) infection in Aedes aegypti mosquitoes and evaluate associated ecological and environmental factors in three inland districts (Bahi, Kyela, Ngorongoro) with distinct agro-ecological characteristics and no prior dengue outbreak reports.

Methods: A cross-sectional entomological study was conducted during the wet (April-June 2022) and dry (October-November 2022) seasons. Adult mosquitoes were collected indoors and outdoors using battery-powered aspirators, and immature stages were sampled from natural and artificial water containers. Mosquito pools were screened for DENV RNA using RT-qPCR.

Results: A total of 6459 Ae. aegypti mosquitoes were sampled (54% females). DENV RNA was detected in 0.6% (4/631) of the tested pools: one from Bahi and three from Kyela. No infections were detected in Ngorongoro. High mosquito density was observed in Kyela, particularly in paddy plantations and rice farms. Among DENV-positive pools, 100% (4/4) were collected near vegetation, suggesting that outdoor habitats are high-risk sites. The minimum infection rate was 0.6 (95% CI: 0.2-1.6) per 1000 mosquitoes.

Conclusion: This study confirms silent DENV circulation in Ae. aegypti populations in Tanzanian regions without prior epidemic reports. The detection of DENV in mosquitoes from Bahi and Kyela highlights the risk of future outbreaks and underscores the need for enhanced vector surveillance and integrated control strategies. These findings emphasise the urgency of preemptive public health measures to mitigate dengue spread in Tanzania. Limitations of the study include reliance on RT-qPCR without viral isolation or serotyping and the absence of concurrent human clinical data.

Objectives: The 2022 outbreak of Sudan ebolavirus in central Uganda was the country's largest in two decades. It was accompanied by reports of stigma towards affected individuals, households and communities. The objectives of this study were to (1) describe how Ebola disease stigma emerged and manifested during the 2022 Sudan ebolavirus outbreak in central Uganda, (2) examine its impacts, including on outbreak control and (3) identify insights that could inform stigma reduction strategies in future outbreaks.

Methods: We conducted qualitative in-depth interviews with 12 key informants involved in the Ebola disease outbreak response using Microsoft Teams. Participants included frontline healthcare workers, burial team members, psychosocial support staff, survivor programme staff, village health team members, local outbreak response leadership and Ebola survivors. Transcribed interviews were coded in NVivo Release 1.7.2 and analysed using framework analysis.

Results: Contextual drivers of stigma included mistrust of authorities, limited knowledge about the disease and conspicuous survivor follow-up. These drivers fuelled negative thoughts and emotions, predominantly blame and fear. Interviewees described how stigma manifested as negative attitudes, verbal and physical harm, unwarranted avoidance and structural disadvantage, which persisted beyond the outbreak itself. Stigma was seen to impact outbreak control by discouraging symptom reporting, delaying care-seeking and exacerbating workforce shortages in clinical centres. Factors that mitigated stigma included psychosocial support and survivor advocacy.

Conclusions: Ebola-related stigma complicates outbreak control and has adverse psychosocial effects that linger long after the outbreak is declared over. We provide a range of multilevel strategies for reducing stigma, including engagement with trusted community leaders, survivor-centred support systems and provision of psychological support for responders.