Transactions of The Royal Society of Tropical Medicine and Hygiene最新文献

Background: The overlapping clinical and radiographic features of pulmonary melioidosis and lung cancer present diagnostic challenges to healthcare providers in endemic settings.

Methods: We compared the clinical, laboratory and imaging characteristics of 19 pulmonary melioidosis cases with those of 15 cases of small cell lung cancer (SCLC) and 17 cases of non-small cell lung cancer (NSCLC).

Results: Compared with SCLC/NSCLC cases, those with pulmonary melioidosis were more likely to have diabetes, have fever, neutrophilia and leukocytosis on presentation (p<0.05). While certain CT imaging features were shared between pulmonary melioidosis and SCLC ('frozen mediastinum sign', 'vascular encasement sign'), extensive liquefactive necrosis, uneven ring-enhancement, circular lesions and 'air-bubble' signs were more commonly seen in pulmonary melioidosis cases than in those with SCLC/NSCLC (p<0.05).

Conclusions: Despite the similarities in presentation of pulmonary melioidosis, SCLC and NSCLC, several clinical, laboratory and imaging factors may help delineate these diagnoses and improve patient care.

Background: Trust is an important driver of various outcomes, but little is known about whether trust in institutions affects actual vaccination campaign outcomes rather than only beliefs and intentions.

Methods: We used nationally representative, individual-level data for 114 countries and combined them with data on vaccination policies and rates. We measured the speed of the vaccination campaign for each country using the estimated growth rate of a Gompertz curve. We then performed country-level regressions in the global sample and explored heterogeneity across World Bank development groups.

Results: Globally, higher trust in institutions significantly increased vaccination rates (p<0.01) and vaccination speed (p<0.01). The effect was strong in low- and middle-income countries but statistically not significant in high-income countries.

Conclusions: Our findings have implications for the design of vaccination campaigns for national governments and international organizations. The findings highlight the importance of trust in institutions when designing communication strategies around vaccination campaigns in low- and middle-income countries.

Background: The head louse, Pediculus humanus capitis, is an obligate ectoparasite and its infestation remains a major public health issue worldwide. Determining the genetic characteristics of the existing clades is essential to identify the population structure and to develop head lice-control programs. Hence, we aimed to investigate the genetic diversity of head lice among infested individuals in northern Iran.

Methods: Adult head lice were collected from 100 infested individuals referring to the health centers throughout five geographical regions in Mazandaran Province, Iran. Partial fragments of the mitochondrial cytb gene were amplified by PCR, then consequently sequenced.

Results: The results of the phylogenetic tree of collected head lice confirmed the existence of two clades, A and B, in the studied areas. Thirteen haplotypes were detected in the studied populations, of which 11 were novel haplotypes. Clade A was the dominant form and accounted for 75% of samples, while clade B included the rest. Haplotype and nucleotide diversity were 0.999 and 0.0411, respectively.

Conclusions: Clade A and B of Pediculus humanus capitis exist among the human populations of northern Iran. We observed high genotypic diversity of this head lice.

This commentary discusses an influential study from 1993 that demonstrated, among West African children, an overall mortality benefit of insecticide-impregnated bednets, and the reduction of malaria prevalence by chemoprophylaxis. Led by Brian Greenwood and colleagues in The Gambia, the trial also showed these tools to be affordable and practicable. In the years since, >2 billion bednets have been provided to high-risk populations and have contributed greatly to reductions in malaria-attributable mortality. Seasonal malaria chemoprevention now protects 50 million African children annually. Few interventions in tropical medicine have achieved such an impact.

Background: in vitro susceptibility testing for the non-sporulating fungus Madurella mycetomatis is performed with a hyphal suspension as starting inoculum and a viability dye for endpoint reading. Here we compared the performance of four different viability dyes for their use in in vitro susceptibility testing of M. mycetomatis.

Methods: To compare the reproducibility and the agreement between the viability dyes 2,3-bis-(2-methoxy-4-nitro-5-sulfphenyl)-2H-tetrazolium-5-carboxanilide salt (XTT), resazurin, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt (MTS) and luciferin, the in vitro susceptibilities of 14 genetically diverse M. mycetomatis isolates were determined for itraconazole and amphotericin B. The reproducibility, agreement, price and ease of use were compared.

Results: Each of the four dyes gave highly reproducible results with >85.7% reproducibility. Percentage agreement ranged between 78.9% and 92.9%. Resazurin was the most economical to use (0.0009 €/minimal inhibitory concentration [MIC]) and could be followed in real time. Luciferin omitted the need to transfer the supernatant to a new 96-well plate, but cost 6.07 €/MIC.

Conclusion: All four viability dyes were suitable to determine the in vitro susceptibility of M. mycetomatis against itraconazole and amphotericin B. Based on the high reproducibility, high percentage agreement, price and possibility to monitor in real time, resazurin was the most suited for routine in vitro susceptibility testing in the diagnostic laboratory in mycetoma-endemic countries. Because luminescence could be measured directly without the need to transfer the supernatant to a new 96-well plate, luciferin is suitable for drug-screening campaigns.

Lay summary: To determine the in vitro susceptibility testing in the non-sporulating fungus Madurella mycetomatis, a viability dye is needed for endpoint reading. In this study we tested the viability dyes XTT, resazurin, MTS and luciferin for their use in in vitro susceptibility testing. It appeared that they all could be used but there were differences in time to result and costs associated with them.

Background: Visceral leishmaniasis (VL) is a neglected tropical disease that mostly affects the working class and impoverished segments of society, having a significant negative effect on the economic development of the affected nation. While anti-leishmanial medications lower mortality among VL patients, patients may still die or require more time to recover while receiving treatment. In this regard, there are limited studies in Ethiopia. This study aims to determine the time to recovery and its associated predictors among adult VL patients at Metema Hospital, Metema, Ethiopia.

Methods: A hospital-based cross-sectional study was employed and the data were collected from patient's charts from September 2017 to September 2021. Data were entered and analysed using EpiData version 3.1, Stata version 14.2 and R version 3.4.0 statistical software. Kaplan-Meier survival curves and logrank tests were used to compare the survival time. The Cox proportional hazards model assumption and model fitness were checked and used to identify statistical association predictors in VL patients.

Results: The Cox proportional hazards model was fitted. The overall medium recovery time was 7 d (minimum 4, maximum 14). The variables of nasal bleeding (adjusted hazard ratio [aHR] 0.44 [95% confidence interval {CI} 0.19 to 0.89]), no comorbidity (aHR 2.29 [95% CI 1.27 to 4.11]), relapse of VL (aHR 0.33 [95% CI 0.15 to 0.75]), low parasite load (aHR 2.58 [95% CI 1.48 to 4.51]) and ambulatory (aHR 3.26 [95% CI 2.45 to 6.53]) were significantly associated with time to recovery in VL patients.

Conclusions: Patients with comorbidities, nasal bleeding, relapse of VL, bedridden and high parasite load should be treated and monitored carefully to recover quickly from their illness.

Background: Infections may contribute to Alzheimer's disease (AD) risk. Limited evidence suggests Toxocara spp. infection/exposure could influence AD development.

Methods: We investigated Toxocara seropositivity and AD in Iranian adults using a matched case-control study. Our sample included 90 AD cases and 91 healthy older adults. Anti-Toxocara immunoglobulin G (IgG) antibodies were assessed via enzyme-linked immunosorbent assay. We computed the odds ratios (ORs) and 95% confidence intervals (CIs) through univariable and multivariable analyses, adjusting for potential confounders.

Results: There were 33/90 (36.67% [95% CI 26.75 to 47.48]) anti-Toxocara IgG seropositive individuals identified among the AD cases and 21/91 (23.07% [95% CI 14.89 to 33.09]) among the healthy controls. In univariable analysis, a significant association was identified between anti-Toxocara IgG seropositivity and AD (OR 1.93 [95% CI 1.01 to 3.69], p<0.001). Moreover, the association remained significant (OR 2.18 [95% CI 1.05 to 4.49], p<0.001) in multivariable analysis after adjustment for covariates. There was no association between anti-Toxocara IgG seropositivity and the severity of AD (OR 0.75 [95% CI 0.21 to 2.61], p=0.47).

Conclusions: Our findings indicated that Toxocara exposure/infection could be a potential risk factor for development of AD. To better understand a real causality between Toxocara exposure/infection and AD and related dementias, follow-up designed and adequately powered studies are needed.

Background: Haemophagocytic lymphohistiocytosis (HLH) is a rare complication of dengue fever with potentially life-threatening consequences and high mortality. Therefore, this study aims to investigate the prevalence, management and outcome of HLH in dengue fever.

Methods: The major electronic databases, including PubMed, ScienceDirect and Ovid SP, were searched from inception until 31 January 2024 to identify relevant studies. Pooled prevalence and mortality were calculated using the random-effects generic inverse variance model with a 95% CI. All the statistical analysis was conducted using R programming.

Results: A total of nine studies with 157 patients with HLH, 576 patients with severe dengue and 5081 patients with dengue fever were included in this meta-analysis. The prevalence of HLH in severe dengue (22.1%, 95% CI 8.07 to 48.0%) was significantly higher than the prevalence in dengue fever (3.12%, 95% CI 0.37 to 21.9%). The prevalence of HLH in severe dengue was higher in the paediatric population (22.8%, 95% CI 3.9 to 68.4%) compared with the adult population (19.0%, 95% CI 3.0 to 63.9%). The overall mortality rate was 20.2% (95% CI 9.7 to 37.2%).

Conclusion: The prevalence of dengue-associated HLH was low in patients with dengue fever but is significantly higher in patients with severe dengue and a high mortality rate.

Japanese encephalitis virus (JEV) transmission in temperate Australia has underscored a critical need to characterise transmission pathways and identify probable hosts of the virus. This systematic review consolidates existing research on the vertebrate hosts of JEV that are known to exist in Australia. Specifically, we aim to identify probable species involved in JEV transmission, their potential role as hosts and identify critical knowledge gaps. Data were extracted from studies involving experimental infection, seroprevalence and virus isolation and were available for 22 vertebrate species known to reside in Australia. A host competence score was calculated to assess the ability of each species to generate and sustain a viraemia. Based on the host competence score and ecology of each species, we find that ardeid birds, feral pigs and flying foxes have potential as maintenance hosts for JEV in the Australian context. We also note that domestic pigs are frequently infected during outbreaks, but their role as amplification hosts in Australia is unclear. Evidence to confirm these roles is sparse, emphasising the need for further targeted research. This review provides a foundation for future investigations into JEV transmission in Australia, advocating for enhanced surveillance and standardised research methodologies to better understand and mitigate the virus's impact.

Scrub typhus and leptospirosis are re-emerging zoonotic infections with significant morbidity and mortality rates in India. Overlapping aetiological and epidemiological patterns indicate a high possibility of their co-infection in India, which can be a diagnostic challenge due to non-specific clinical features. A systematic search of the PubMed/MEDLINE, Scopus and Embase databases was conducted to identify relevant studies published through 31 August 2023. Studies reporting co-infection of scrub typhus and leptospirosis among the Indian population were included. Data extraction, quality assessment and statistical analysis were performed in accordance with established guidelines. Six studies met the inclusion criteria, comprising a total of 58 co-infection cases. Pooled prevalence of scrub typhus-leptospirosis co-infection among acute undifferentiated febrile illness patients was 3.7% (95% confidence interval [CI] 0.00 to 0.126). Among scrub typhus patients, the prevalence of co-infection with leptospirosis was 13.7% (95% CI 0.027 to 0.304). Significant heterogeneity was observed among the included studies, highlighting the need for cautious interpretation of prevalence estimates. This meta-analysis underscores the clinical importance of scrub typhus-leptospirosis co-infection in India and emphasizes the need for enhanced clinical awareness, improved diagnostic strategies and targeted research efforts to address this emerging infectious disease threat.