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Microbiological Research

Elsevier BV

Preprints posted in the last 7 days, ranked by how well they match Microbiological Research's content profile, based on 19 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.

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Uncovering the mechanisms of clinically-relevant altered antibiotic responses of Staphylococcus aureus under wound infection-mimetic conditions

Rieger, C. D.; Molaeitabari, A.; Dahms, T. E. S.; El-Halfawy, O. M.

2026-04-17 microbiology 10.64898/2025.12.22.696073 medRxiv
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Standard in vitro antimicrobial susceptibility testing (AST) using Mueller-Hinton broth (MHB) does not reflect infection-site conditions, and its results often do not correlate with therapeutic outcomes. Here, we compared the antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA), a common chronic wound pathogen, in simulated wound fluid (SWF) resembling wound exudate versus MHB, revealing discordant AST results across six of nine tested antibiotic classes. The most significant were 128-fold increased resistance to tetracyclines and 256-fold sensitization to {beta}-lactams in SWF. Tetracycline resistance was mediated by MntC, an extracellular manganese-binding protein, whereas {beta}-lactam sensitization was driven by cell envelope remodelling in SWF. Galleria mellonella wound infection results matched the SWF susceptibility phenotypes, suggesting SWF better predicts in vivo wound infection therapeutic outcomes. These comprehensive phenotypic and mechanistic insights into MRSA antibiotic responses under wound-infection-mimetic conditions with direct in vivo validation identify a potential new antibiotic adjuvant target and may guide improved antibiotic therapy for MRSA wound infections.

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A conserved grain-associated immunosuppressive niche in Sudanese patients with mycetoma.

Osman, M.; Ashwin, H.; Calder, G.; O'Toole, P.; Bakhiet, S. M.; Musa, A. M.; Kaye, P. M.; Fahal, A. H.

2026-04-13 infectious diseases 10.64898/2026.04.09.26350374 medRxiv
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Mycetoma is a neglected tropical disease caused by various bacterial and fungal pathogens that has a significant health impact across a broad geographically defined "mycetoma belt" spanning South America, Africa and Asia. Histologically, mycetoma is characterised by invasive and destructive granuloma development in the skin, deep tissues and bone, leading to tissue destruction, deformities and high morbidity. The presence of macroscopic, highly compacted pathogen microcolonies, or "grains," is a key diagnostic feature, and the formation of grains supports pathogen persistence and disease chronicity. However, there is a paucity of information on immune responses in mycetoma patients and on the relative importance of phylogeny and/or grains in establishing the local immune landscape. Here, we used spatial proteomics to examine the distribution of 43 immune-related proteins in surgical biopsies from 11 patients with mycetoma of bacterial (Actinomycetoma; Actinomadura pelletierii and Streptomyces somaliensis; n=6) and fungal (Eumycetoma; Madurella mycetomatis; n=5) origin. Using mixed-effects modelling, an exploratory analysis across species and pathogen classes revealed few significant differences in immune marker expression. In contrast, and independently of pathogen class, the cellular infiltrate closest to grain boundaries had higher per-cell expression of CD66b+, ARG1, and VISTA. The preferential accumulation of CD66b+ARG1+VISTA+ cells at grain boundaries was confirmed by quantitative immunofluorescence analysis. Hence, the local tissue microenvironment surrounding the mycetoma grain represents a specialised immunosuppressive niche, with parallels to the tumour microenvironment.

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Genomic Surveillance of Third-Generation Cephalosporin-Resistant Klebsiella pneumoniae in Tunisian AMR Surveillance System Hospitals

Itani, D.; Smaoui, H.; Thabet, L.; Zribi, M.; Dhraief, S.; Kanzari, L.; Meftah, K.; Achour, W.; Baker, D. J.; Moss, C.-J.; Philips, L. T.; Foster-Nyarko, E.; Boutiba-Ben Boubaker, I.; Holt, K. E.

2026-04-10 infectious diseases 10.64898/2026.04.08.26350452 medRxiv
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Third-generation cephalosporin (3GC)-resistant Klebsiella pneumoniae are an increasing public health threat in Tunisia, yet there is limited data on the circulating lineages and antimicrobial resistance (AMR) determinants underlying this threat. Here, we employed whole-genome sequencing (WGS) in the Tunisian AMR surveillance system (TARSS) to characterize the 3GC resistance mechanisms, population structure, virulence, and transmission across three participating sentinel hospitals in Tunis and Ben Arous. We sequenced a balanced sample of stored 3GC-resistant (3GCR) isolates from blood and urine collected between 2018 and 2022. Of 322 sequenced isolates, 286 (89%) were confirmed as K. pneumoniae, representing 28.5% of all stored 3GC-resistant isolates. The population structure was diverse (68 sublineages) and distinct between hospitals, although several globally distributed sublineages were detected across sites (SL383, SL101, SL307, SL15). Extended-spectrum {beta}-lactamases (ESBL) genes were detected in 77% of genomes, with blaCTX-M-15 (65.4%) and blaCTX-M-14 (8%) dominant at all sites and across diverse sublineages. AmpC genes occurred in 9%, and carbapenemase in 19.6% (blaOXA-48, 14.7%; blaNDM-5, 4.5%; blaNDM-1, 3.8%), with carbapenemases mainly observed amongst SL147 and SL383 at Hospital B (41.7%). Despite sequencing less than a third of the unique 3GCR infections in each hospital, we identified 24 probable nosocomial transmission clusters involving 64 isolates. Each cluster was restricted to a single hospital, although many were detected across multiple wards in the same hospital. The acquired virulence-associated locus (ICEKp) encoding yersiniabactin was common (48.6%). Hypervirulence-associated markers (encoding aerobactin, salmochelin, and/or hypermucoidy) were rare (8.7%) but increasing over time. These were mostly found in sublineages in which convergence of ESBL and hypervirulence has been reported in other settings (including SL147, SL101 and SL383), suggesting international dissemination of convergent strains. These findings show sustained ward-level nosocomial transmission of 3GCR K. pneumoniae lineages and site-specific differences in ESBL and carbapenemase burdens, which call for targeted infection prevention and control and for future routine integration of WGS into TARSS.

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Abscess Complications and Prolonged Care in Five-Biomarker-Defined Hypervirulent Klebsiella pneumoniae Bloodstream Infection

Watanabe, N.; Watari, T.; Otsuka, Y.; Matsumiya, T.

2026-04-11 infectious diseases 10.64898/2026.04.10.26350004 medRxiv
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Background Five-biomarker-defined hypervirulent Klebsiella pneumoniae (hvKp) causes invasive infections, but its burden in bloodstream infections versus classical K. pneumoniae (cKp) is unclear. Methods This retrospective cohort study at a tertiary hospital in Japan included K. pneumoniae bloodstream infection episodes from January 2022-December 2024. hvKp was defined by the presence of all 5 genotypic biomarkers (rmpA, rmpA2, iucA, iroB, and peg-344). The primary outcome was abscess complications, and secondary outcomes were length of stay and antibiotic duration. Whole-genome sequencing was performed for 164 isolates. Results Among the 207 episodes, 28 (14%) were of hvKp. Abscess complication occurred in 17 (61%) hvKp versus 23 (13%) cKp episodes (adjusted odds ratio 10.7; 95% CI, 4.36-26.2). Median length of stay in hvKp versus cKp was 28 versus 14 days (adjusted ratio 1.60; 95% CI, 1.18-2.16) and median antibiotic duration was 43 versus 14 days (adjusted ratio 2.13; 95% CI, 1.64-2.77). These associations were attenuated after adjusting for abscess-related complications. No significant difference in 30-day mortality was observed, although the study was underpowered. Multidrug resistance was less frequent in hvKp strains than in cKp strains (11% vs. 30%; P = .040). Among the sequenced hvKp episodes, abscess rates varied across lineages, from 9 of 10 in ST23 to 1 of 4 in ST412. Conclusions Five biomarker-defined hvKp strains delineated a bloodstream infection subgroup with frequent abscess complications and prolonged care. hvKp and cKp present distinct clinical challenges; diagnostic tools distinguishing these subgroups may aid abscess evaluation and source control.

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Decoding resistance: interpretable machine learning to predict ciprofloxacin resistance in Shigella spp

Gohari, M. R.; Zhang, P.; Villegas, A.; Rosella, L. C.; Patel, S. N.; Hopkins, J. P.; Duvvuri, V. R.

2026-04-11 infectious diseases 10.64898/2026.04.07.26350353 medRxiv
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Antimicrobial resistance (AMR) is a growing global public health threat that complicates the treatment and control of bacterial infections. Shigella spp., a leading cause of bacterial diarrhea worldwide, has increasingly exhibited resistance to multiple antimicrobial agents that are commonly recommended therapy for severe shigellosis. Although conventional antimicrobial susceptibility testing (AST) remains the reference standard, it is time-consuming and provides limited insight into the genetic mechanisms underlying resistance. Whole-genome sequencing (WGS) has emerged as a complementary approach for AMR detection by enabling direct identification of resistance genetic determinants encoded in bacterial genomes. Machine learning (ML) methods applied to genomic features such as k-mers have shown promise for predicting resistance phenotypes from WGS data; however, applications to Shigella remain limited. In this study, we developed and evaluated an interpretable ML framework for predicting ciprofloxacin resistance using k-mer features derived from WGS data of 1,424 Shigella isolates collected in Ontario, Canada, between 2018 and 2025. K-mers were extracted from known gene targets associated with ciprofloxacin resistance, including chromosomal quinoline resistance-determining regions (QRDRs: gyrA and parC) and plasmid-mediated determinants (qnr). Supervised ML approaches were trained and compared. We evaluated the influence of k-mer lengths (k=11, 15, 21 and 31) on predictive performance and model interpretability; and compared models based on chromosomal determinants alone and models incorporating both chromosomal and plasmid-mediated determinants. Randon Forest classifier achieved the most consistent performance across models. Inclusion of plasmid-mediated determinants improved predictive accuracy relative to chromosomal-only models. Although differences across k-mer lengths were modest, k = 11 produced the highest area under the receiver operating characteristic curve (AUC) and the lowest Brier score. SHAP analyses localized high-impact features within QRDRs of gyrA and parC, supporting biological interpretability. These findings demonstrate that biologically-informed k-mer-based ML models can accurately and transparently predict ciprofloxacin resistance in Shigella, supporting their potential integration into genomic AMR surveillance and digital public health frameworks. Author summaryIn this study, we used genome sequencing data to develop machine learning models that predict ciprofloxacin resistance for Shigella directly from bacterial DNA. We focused on small DNA fragments (k-mers) derived from known resistance genes and mutations. Among the approaches tested, a Random Forest model showed the most consistent performance. Combining chromosomal mutations with plasmid-mediated resistance genes improved prediction accuracy and helped identify key genetic regions associated with resistance. These findings demonstrate that machine learning applied to genomic data can accurately and interpretable predict antibiotic resistance, supporting its potential use in genomic surveillance and public health monitoring.

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One Health genomics of Acinetobacter baumannii reveals sector-specific lineages and permeable ecological barriers

Plantade, J.; Escobar, C.; Godeux, A.-S.; Poire, L.; Andre, A.; Deromelaere, V.; Cassier, P.; Rasigade, J.-P.; Nazaret, S.; Coluzzi, C.; Venner, S.; Laaberki, M.-H.; Charpentier, X.

2026-04-11 infectious diseases 10.64898/2026.04.09.26350516 medRxiv
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Acinetobacter baumannii is a major cause of severe hospital-acquired infections, with a steadily increasing global prevalence driven by a few clinically adapted lineages. Animals and natural environments also harbor A. baumannii populations, but assessing their connections to clinical lineages is limited by sparse genomic data and a lack of integrated sampling. We conducted a local One Health genomic epidemiology study, sampling, isolating, sequencing, and characterizing several hundred A. baumannii isolates from clinical, animal, and environmental contexts. Within a geographically restricted area, we recovered several globally distributed clinical lineages (international clones, ICs), as well as livestock- and environment-associated lineages shared across Europe, highlighting widespread dissemination beyond clinical settings. Isolates closely related to the emerging clinical lineage IC11 were found in livestock, but no other clinically associated lineages were detected outside clinical contexts. Among these, the epidemic superlineage IC2 was identified in both human and veterinary clinical settings, indicating that similar practices in human and animal medicine select for closely related opportunistic pathogens. We found that hospitals host distinct, antibiotic-sensitive endemic populations capable of causing infection. These populations belong to a diversifying clade spanning clinical and environmental contexts and carry a high load of insertion sequences. Strong plasmid conservation further suggests frequent horizontal gene transfer across ecological compartments. Overall, A. baumannii comprises diverse, context-adapted lineages with a high potential for global spread. Although intercontext transmission appears limited, plasmids may overcome these ecological barriers. Our findings underscore the need for integrated One Health surveillance to better understand transmission pathways and limit the emergence of clinically adapted strains.

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Primary care metronidazole prescription in public and private facilities of South Benin: A register-based cross-sectional study

TANKPINOU ZOUMENOU, H.; Faucher, J.-F.

2026-04-14 infectious diseases 10.64898/2026.04.07.26350314 medRxiv
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Background: Metronidazole (MTZ) is a first-line antibiotic for several enteric infections. Its use is common in low-income countries, where most primary-care consultations are conducted by nurses. However, increasing resistance among some enteric pathogens is a growing concern. Using WHO guidelines, we conducted a register-based cross-sectional study to assess MTZ prescribing practices and their determinants in public and private primary healthcare facilities in South Benin. Methods: We performed a register-based cross-sectional study covering the year 2020 in 11 primary healthcare facilities (5 public and 6 private) in Abomey-Calavi, South Benin, following WHO recommendations. In total, 200 visits per facility were selected using systematic random sampling. The primary outcome was the prevalence of MTZ prescription. Determinants of MTZ prescription were identified using multivariable logistic regression analysis. Results: In total, 2,200 medical visits were analyzed. The median age of patients was 19 years, and 57% were female. Antimalarials were prescribed in 52% of visits. Antibacterial agents were prescribed in the majority of visits, with MTZ being the second most frequently prescribed antibiotic (18%), after aminopenicillins (27%). In multivariable analysis, digestive symptoms (adjusted odds ratio [aOR], 8.65; 95% confidence interval [CI], 6.49-11.6), genitourinary symptoms (aOR, 6.84; 95% CI, 3.18-15.0), and skin lesions (aOR, 2.39; 95% CI, 1.58-3.60) were independently associated with increased odds of MTZ prescription. In contrast, fever (aOR, 0.66; 95% CI, 0.49-0.87), respiratory symptoms (aOR, 0.44; 95% CI, 0.26-0.71), and malaria (aOR, 0.21; 95% CI, 0.15-0.28) were associated with decreased odds. Visits in the private sector were also associated with higher odds of MTZ prescription compared with the public sector (aOR, 2.31; 95% CI, 1.78-3.02). Conclusion: MTZ is the second most commonly prescribed antibiotic in primary care in the study area, with its use largely driven by digestive symptoms. Further studies are needed to assess the appropriateness of this prescription. Additionally, research is warranted to understand better the determinants of higher antimicrobial prescribing in the private healthcare sector.

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Recombinant zoster vaccination in patients with dementia is associated with improved survival and better cognitive preservation

Soltys, K.; Sara-Buchbut, R.; Ish Shalom, N.; Stokar, J.; Klein, B. Y.; Calderon-Margalit, R.; Greenblatt, C. L.; Ben-Haim, M. S.

2026-04-13 epidemiology 10.64898/2026.04.09.26350509 medRxiv
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Dementia affects tens of millions of people worldwide, yet disease-modifying treatments remain strikingly limited. Although the recombinant zoster vaccine Shingrix has been associated with reduced dementia incidence, its potential influence on individuals already living with dementia is unknown. Here, we followed a propensity-score matched cohort of 68,960 US dementia patients using a nationwide electronic health record network, comparing Shingrix recipients within two years of diagnosis to recipients of any other vaccine. Shingrix was associated with substantially reduced all-cause mortality across the first three years of follow-up (hazard ratios 0.74, 0.88, and 0.89; P[≤]0.006), robust across multiple sensitivity analyses. Furthermore, within-individual subgroup analyses of repeated Mini-Mental State Examinations conducted 3-6 years apart revealed significantly divergent cognitive decline rates across groups (time-by-group interaction P=0.002). Interval vaccination was associated with more stable cognition, contrasting with steeper declines in unvaccinated individuals. These findings support prospective evaluation of recombinant zoster vaccination as a potential strategy to improve outcomes in patients with established dementia.

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A multidomain intrinsic capacity score tracks longitudinal health trajectories in the UK Biobank

Zhai, T.; Babu, M.; Fuentealba, M.; Al Dajani, S.; Gladyshev, V. N.; Furman, D.; Snyder, M.

2026-04-13 epidemiology 10.64898/2026.04.10.26350621 medRxiv
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Quantitative measures for tracking functional health have generally been lacking. Intrinsic capacity (IC) has been proposed as an appropriate measure, but its metrics have been derived in small datasets and sparse longitudinal data. Using harmonized measures of cognition, locomotion, sensory function, vitality, and psychological well-being from 501,615 UK Biobank participants and followed for a median of 15.5 years, we derived domain-specific and composite IC scores. We examined associations with incident disease, cause-specific mortality, multimorbidity, lifestyle and socioeconomic factors, and multi-omic profiles from Olink proteomics, NMR metabolomics, clinical biochemistry, and blood-cell traits. We found that composite IC declined non-linearly with age, and within-person decline was steeper than the cross-sectional age measures. Participants with greater baseline morbidity, those who subsequently developed incident disease, and those who died earlier in follow-up showed lower IC trajectories across adulthood. The IC domains were only modestly correlated with one another, supporting multidimensionality, yet higher overall IC was associated with lower risk of most diseases examined. The dominant IC domain varied by endpoint, with cognition informative for dementia, sensory function for hearing loss, psychological capacity for depression, locomotion for osteoarthritis, and vitality for cardiometabolic outcomes. IC was also associated cross-sectionally with physical activity, insomnia, smoking, medication burden, and socioeconomic disadvantage. More proteins were found predictive for vitality, and enrichment converged on immune/inflammatory and metabolic pathways. Blood-based surrogates recapitulated part of the phenotypic signal, particularly for vitality. Overall, this IC framework captures longitudinal health trajectories and broad disease vulnerability in a large middle- to older-aged cohort and supports IC as a clinically meaningful, multidomain phenotype of aging and identifies blood-based correlates that may facilitate at-scale future monitoring of aging-related function declines.

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Effect of a sanitation intervention on the nutritional status of children in Maputo, Mozambique: a controlled before-and-after trial

Knee, J.; Sumner, T.; Adriano, Z.; Opondo, C.; Holcomb, D.; Viegas, E.; Nala, R.; Brown, J.; Cumming, O.

2026-04-13 epidemiology 10.64898/2026.04.09.26350506 medRxiv
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BackgroundThe rapid growth of the worlds urban population has contributed to the expansion of informal urban settlements in many cities across the world. In these settings, lack of safe sanitation combined with high population density and poverty contributes to heightened health risks for often vulnerable populations. The aim of this study was to evaluate the effect of a shared, onsite sanitation intervention on the nutritional status of children in Maputo, Mozambique. MethodsThe Maputo Sanitation (MapSan) trial was a controlled before-and-after study to evaluate the effect of a shared, onsite sanitation intervention on child health in Maputo, Mozambique. Here, we report the effects on childhood stunting, wasting and underweight, and height-for-age, weight-for-height and weight-for-age z-scores. Children were enrolled aged 1-48 months at baseline and outcomes were measured before and 12 and 24 months after the intervention, with concurrent measurement among children in a comparable control arm. The primary analysis was intention-to-treat. The trial was registered at ClinicalTrials.gov, number NCT02362932. ResultsWe enrolled 757 and 852 children in the intervention and control groups respectively. There was no evidence for an effect of the intervention on any outcome at 12 or 24 months of follow-up except for wasting where there was very weak evidence for an effect (adjusted prevalence ratio: 0.497; 95% CI: 0.22-1.11; p=0.09). In two exploratory analyses - one including only those children born into compounds post-intervention and a second excluding children in control compounds which had independently improved their sanitation facilities during follow-up - we found that stunting increased in the intervention group whilst wasting decreased. ConclusionsThis study contributes to the growing evidence on the role of sanitation in shaping child health outcomes in informal urban settlements. We found no evidence for an effect on stunting and weak evidence for an effect on wasting. More research is needed to understand how sanitation can reduce childhood undernutrition in complex urban environments.

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WITHDRAWN: Detection of Measles Virus RNA in Wastewater: Monitoring for Wild-Type and Vaccine-Derived Strains in a National Preparedness Trial

Ahmed, W.; Gebrewold, M.; Verhagen, R.; Koh, M.; Gazeley, J.; Levy, A.; Simpson, S.; Nolan, M.

2026-04-13 epidemiology 10.64898/2026.04.09.26350527 medRxiv
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Wastewater surveillance (WWS) is established as a vital tool for monitoring polio and SARS-CoV-2 with potential to improve surveillance for many other infectious diseases. This study evaluated the feasibility of detecting measles virus (MeV) RNA in wastewater as part of a national WS preparedness trial in Brisbane, Australia, from March to June 2025. Composite and passive sampling methods were employed in parallel at three wastewater treatment plants serving populations between 230,000 and 584,000. Nucleic acids were extracted and analyzed using RT-qPCR targeting MeV N and M genes to distinguish wild-type and vaccine strains. MeV RNA were detected in both 24-hour composite and passive samples on May 26 to 27, 2025 from the largest catchment of 584,000 which also included an international airport. No measles cases were reported in this city or region within 4 weeks of the WS detections. These were confirmed as vaccine-derived measles virus (MeVV) strain via specific RT-qPCR assay. Extraction recoveries varied (11.5% to 70.5%), with passive sampling showing higher efficiency. This is the first report of use of passive samples for detection of MeV. These findings are consistent with other studies reporting WWS results of both MeVV genotype A and wild type genotype B and/or D. It demonstrates the potential for sensitive MeV WWS with rapid differentiation of MeVV from wild type MeV shedding, including in airport transport hubs and with different sample types. Use of WWS could strengthen measles surveillance by enabling rapid detection of MeV RNA and supporting outbreak preparedness and response. This requires optimised methods which are specific to or differentiate wild-type MeV from MeVV. Furthermore, the successful detection of MeV using passive sampling in this study highlights its potential for deployment in diverse global contexts which may include non-sewered settings.

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Understanding community knowledge, attitudes and practices related to participation in household transmission investigations during infectious disease outbreaks

Meagher, N.; Hettiarachchi, D.; Hawkins, M. R.; Tavlian, S.; Spirkoska, V.; McVernon, J.; Carville, K. S.; Price, D. J.; Villanueva Cabezas, J. P.; Marcato, A. J.

2026-04-13 epidemiology 10.64898/2026.04.08.26350464 medRxiv
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BackgroundThe World Health Organization has developed several global template protocols for epidemiological investigations, including for household transmission investigations (HHTIs). These investigations facilitate rapid characterisation of novel or re-emerging respiratory pathogens and support evidence-based public health actions. Beyond technical readiness, community buy-in is central to the feasibility and acceptability of HHTIs. Research is needed to determine the perceived legitimacy among the community to inform local protocol adaptation and development of implementation plans that consider community attitudes and needs. MethodsIn 2025, we conducted a convenience survey of community members living in Victoria, Australia to explore: their understanding of emerging respiratory diseases; their willingness to take part in public health surveillance activities such as HHTIs; the acceptability of clinical and epidemiological data collection and respiratory/blood sample collection as main components of HHTIs, and; participant comfort towards including their companion animals in HHTIs. ResultsWe received 282 survey responses, of which 235 were included in the analysis dataset. Compared to the general Victorian population, our participants included a higher proportion of participants who reported being female, tertiary-educated, of Aboriginal and/or Torres Strait Islander heritage, born in Australia and speaking only English at home. Participants indicated overall high levels of comfort and acceptability towards participation in HHTIs, particularly in relation to clinical and epidemiological data collection, with lesser but still high levels of comfort with providing multiple respiratory specimens in a 14-day period. Participants were least comfortable with other specimens such as urine and blood. Involving companion animals in HHTIs was similarly acceptable as human-focused components. ConclusionsDespite our survey population being non-representative of the general Victorian population, our findings provide valuable descriptive insights into the acceptability of HHTIs in Victoria, Australia from which to benchmark future local and international surveys and community engagement activities.

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SARS-CoV-2 Introductions into Lao PDR Revealed by Genomic Surveillance, 2021-2024

Panapruksachat, S.; Troupin, C.; Souksavanh, M.; Keeratipusana, C.; Vongsouvath, M.; Vongphachanh, S.; Vongsouvath, M.; Phommasone, K.; Somlor, S.; Robinson, M. T.; Chookajorn, T.; Kochakarn, T.; Day, N. P.; Mayxay, M.; Letizia, A. G.; Dubot-Peres, A.; Ashley, E. A.; Buchy, P.; Xangsayarath, P.; Batty, E. M.

2026-04-13 epidemiology 10.64898/2026.04.09.26349480 medRxiv
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We used 2492 whole genome sequences from Laos to investigate the molecular epidemiology of SARS-CoV-2 from 2021 through 2024, covering the major waves of COVID-19 disease in Laos including time periods of travel restrictions and after relaxation of travel across international borders. We identify successive waves of COVID-19 caused by shifts in the dominant lineage, beginning with the Alpha variant in April 2021 and continuing through the Delta and Omicron variants. We quantify a shift from a small number of viral introductions responsible for widespread transmission in early waves to a larger number of introductions for each variant after travel restrictions were lifted, and identify potential routes of introduction into the country. Our study underscores the importance of genomic surveillance to public health responses to characterize viral transmission dynamics during pandemics.

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Time to diagnosis among children and adolescents with cancer in Quebec, Canada: a population-based study

Mullen, C.; Barr, R. D.; Strumpf, E.; El-Zein, M.; Franco, E. L.; Malagon, T.

2026-04-13 epidemiology 10.64898/2026.04.09.26350491 medRxiv
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BackgroundTimely cancer diagnosis in children and adolescents is critical to improving outcomes, yet substantial variation in diagnostic intervals persists across cancer types and care settings. We aimed to quantify time to diagnosis and assess variations by patient, demographic, and system-level factors. MethodsWe conducted a retrospective population-based study of children and adolescents aged 0-19 years diagnosed with one of 12 common cancers between 2010 and 2022 in Quebec, Canada. The diagnostic interval was defined as the time from first cancer-related healthcare encounter to diagnosis. We calculated medians and interquartile ranges (IQR) overall and by cancer type and used multivariable quantile regression to identify factors associated with time to diagnosis at the 25th, 50th, and 75th percentiles. ResultsAmong 2,927 individuals with cancer, diagnostic intervals varied by cancer type and age. Median intervals were longest for carcinomas (100 days; IQR 33-192) and shortest for leukemias (8 days; IQR 3-44). Compared with children living in Montreal, living in regional areas and other large urban centres was associated with longer 50th and 75th percentiles of time to diagnosis for hepatic and central nervous system (CNS) tumours. Diagnostic intervals were shorter in the post-pandemic period (2020-2022) across several cancer sites, with CNS tumours showing reductions across all quantiles. InterpretationDiagnostic timeliness differed by cancer type, age, and rurality, but not by sex, material, or social deprivation. The shorter diagnostic intervals observed in the post-pandemic period suggest that pandemic-related changes in care pathways may have expedited diagnosis for some cancers.

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Frequency of bacterial STI testing amongst people accessing sexual health services in England, 2024: a cross-sectional analysis of national surveillance data

Baldry, G.; Harb, A.-K.; Findlater, L.; Ogaz, D.; Migchelsen, S. J.; Fifer, H.; Saunders, J.; Mohammed, H.; Sinka, K.

2026-04-13 epidemiology 10.64898/2026.04.08.26349546 medRxiv
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ObjectivesWe determined the frequency of sexually transmitted infection (STI) testing among people accessing sexual health services (SHS) in England. MethodsWe assessed STI testing frequency in face-to-face and online SHSs in England using data from the GUMCAD STI surveillance system. We quantified different combinations of tests (e.g. single chlamydia test or full STI screen), number of tests completed in 2024 and test positivity by sociodemographic and behavioural characteristics, as well as clinical setting and outcomes. ResultsOverall, there were 2,222,028 attendances at SHS in England in 2024 that involved tests for chlamydia, gonorrhoea, syphilis and/or HIV. Most of these attendances involved tests for all four of these STIs. Most people accessing SHS in England tested once (80.1%), and a small minority (1.9%) tested at least quarterly (4+ times). Some groups had a comparably larger proportion of quarterly testers; these included gay, bisexual, and other men who have sex with men (GBMSM) (6.7%), London residents (3.6%), online testers (2.5%), people using HIV-PrEP (13%), and people with 5+ partners in the previous 3 months (10.6%). Only 10.5% of GBMSM reporting higher-risk sexual behaviours tested quarterly despite recommendations for quarterly testing in this group. ConclusionsThe majority of those who tested for STIs in England in 2024 only tested once. The minority who tested at least quarterly had a higher proportion of GBMSM, people using HIV-PrEP, London residents and people reporting higher risk behaviours. Quarterly testing often appears to be aligned with current testing recommendations in England; however, we also observed that only a low proportion of behaviourally high-risk GBMSM and HIV-PrEP users are meeting these recommendations. It is important to acknowledge groups with lower or higher testing frequency when developing interventions and updating guidelines related to STI testing. WHAT IS ALREADY KNOWN ON THIS TOPICThe effectiveness of asymptomatic testing for chlamydia and gonorrhoea in gay, bisexual and other men who have sex with men (GBMSM), and the potential impact of the consequent increased antibiotic use on rising antimicrobial resistance and individual harm has recently been questioned. Testing and treatment remains a key pillar of STI prevention and management; despite this, there is limited evidence of STI testing frequency within sexual services (SHS) on a national level. WHAT THIS STUDY ADDSThis analysis shows that the majority of people attending SHSs in England in 2024 tested once, and only a small proportion of behaviourally high-risk people tested frequently. HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICYAwareness of groups that are behaviourally high risk but testing infrequently is important to guide interventions and messaging regarding STI testing. The low levels of frequent testing, even among those who would be recommended quarterly testing under UK guidelines, provides important context for wider discussion around asymptomatic STI screening.

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Wearable-derived physiological features for trans-diagnostic disease comparison and classification in the All of Us longitudinal real-world dataset

Huang, X.; Hsieh, C.; Nguyen, Q.; Renteria, M. E.; Gharahkhani, P.

2026-04-13 epidemiology 10.64898/2026.04.07.26350352 medRxiv
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Wearable-derived physiological features have been associated with disease risk, but most current studies focus on single conditions, limiting understanding of cross-disease patterns. This study adopts a trans-diagnostic approach to examine whether wearable data capture shared and condition-specific physiological signatures across multiple chronic conditions spanning physical and mental health, and then evaluates the utility of these features for disease classification. A total of 9,301 patients with at least 21 days of consecutive FitBit data from the All of Us Controlled Tier Dataset version 8 were analyzed. Disease subcohorts included cardiovascular disease (CVD), diabetes, obstructive sleep apnea (OSA), major depressive disorder (MDD), anxiety, bipolar disorder, and attention-deficit/ hyperactivity disorder (ADHD), chosen based on prevalence and relevance. Logistic regression and XGBoost models were fitted for each disease subcohort versus the control cohort. We found that compared to using just baseline demographic and lifestyle features, incorporating wearable-derived features enabled improved classification performance in all subcohorts for both models, except for ADHD where improvement was mainly observed for ROC-AUC in logistic regression model likely due to the smaller sample size in ADHD subcohort. The largest performance gains were observed in MDD (increase in ROC-AUC of 0.077 for Logistic regression, 0.071 for XGBoost; p < 0.001) and anxiety (increase in ROC-AUC of 0.077 for logistic regression, 0.108 for XGBoost; p < 0.001). This study provides one of the first comprehensive transdiagnostic evaluations of wearable-derived features for disease classification, highlighting their potential to enhance risk stratification in the real-world setting as a practical complement to clinical assessments and providing a foundation to explore more fine-grained wearable data. Author summaryWearable devices such as fitness trackers and smartwatches are becoming increasingly popular and affordable, providing continuous measurements of heart rate, physical activity, and sleep. Alongside the growing digitization of health records, this creates new opportunities for large-scale, real-world health studies. In this study, we analyzed wearable-derived physiological patterns across a range of chronic conditions spanning both physical and mental health to better understand how these signals relate to disease risk. We found that incorporating wearable-derived heart rate, activity and sleep features improved disease risk classification across several conditions, with particularly strong gains for major depressive disorder and anxiety. By examining how individual features contributed to model predictions, we also identified meaningful associations between physiological signals and disease risk. For example, both duration and day-to-day variation of deep and rapid eye movement (REM) sleep were associated with increased risk in certain conditions. Our study supports the development of real-time, automated tools to assess disease risk alongside clinical care.

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Non-genetic component of height as a surrogate marker for childhood socioeconomic position and its association with cardiovascular and brain health: results from HCHS/SOL

Moon, J.-Y.; Filigrana, P.; Gallo, L. C.; Perreira, K. M.; Cai, J.; Daviglus, M.; Fernandez-Rhodes, L. E.; Garcia-Bedoya, O.; Qi, Q.; Thyagarajan, B.; Tarraf, W.; Wang, T.; Kaplan, R.; Isasi, C. R.

2026-04-13 epidemiology 10.64898/2026.04.08.26350438 medRxiv
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Childhood socioeconomic position (SEP) can have lifelong effects on health. Many studies have used adult height as a surrogate marker for early-life conditions. In this study, we derived the non-genetic component of height, calculated as the residual from sex-specific standardized height regressed on genetically predicted height, as a surrogate for childhood SEP, using data from the Hispanic Community Healthy Study/Study of Latinos (2008-2011). A positive residual would indicate favorable early-life conditions promoting growth, while a negative residual indicates early-life adversity that may stunt the development. The height residual was associated with early-life variables such as parental education, year of birth, US nativity and age at first migration to the US (50 states/DC), supporting the validity of height residual as a surrogate for early-life conditions. Furthermore, a height residual was positively associated with better cardiovascular health (CVH) and cognitive function among middle-aged and older adults. Interestingly, among <35 years old, the height residual was negatively associated with the "Lifes Essential 8" clinical CVH scores. These results suggest the non-genetic component of height as a surrogate for childhood environment, with predictive value for CVH and cognitive function.

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Five-Domain Accelerometer-Derived Behavioral Exposome and Incident Cancer Risk in UK Biobank

Ni Chan Chin (Chengqin Ni), M.; Berrio, J. A.

2026-04-12 epidemiology 10.64898/2026.04.07.26350369 medRxiv
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BackgroundAccelerometer-derived behavioral phenotype captures multidimensional aspects of human behavior extending well beyond physical activity, encompassing light exposure, step counts, physical activity patterns, sleep, and circadian rhythms. Whether these five domains constitute a unified behavioral architecture underlying cancer risk and whether circadian organization and light exposure confer incremental predictive value beyond movement volume alone remains to be comprehensively established. MethodsWe conducted an accelerometer-wide association study (AWAS) encompassing the complete accelerometer-derived behavioral exposome across five behavioral domains in UK Biobank participants with valid wrist accelerometry data. Incident solid cancers were designated as the primary endpoint, with prespecified site-specific solid cancers and hematological malignancy as secondary outcomes. Cox proportional hazards models with age as the timescale were used. The minimal covariate set served as the primary reporting tier, followed by sensitivity analyses additionally adjusting for adiposity/metabolic factors, independent activity patterns, shift work history, and accelerometry measurement quality. Nominal statistical significance was defined as two-sided P < 0.05 ResultsAmong 89,080 participants, 6,598 incident solid cancer events were observed over a median follow-up of 8.39 years. In the minimally adjusted model, the pan-solid-tumor association atlas was dominated by signals from activity volume, inactivity fragmentation, and circadian rhythm. Higher overall acceleration (HR per SD: 0.91, 95% CI: 0.89-0.94) and higher daily step counts (HR: 0.93, 95% CI: 0.90-0.95) were independently associated with reduced solid cancer risk, while inactivity fragmentation metrics were consistently linked to higher risk. Notably, circadian rhythms, most prominently cosinor mesor (Midline Estimating Statistic of Rhythm under cosinor model), emerged as leading inverse risk signals, underscoring the independent contribution of circadian behavioral architecture. Site-specific analyses revealed pronounced heterogeneity across tumor sites. Lung cancer exhibited a robust inverse activity-risk gradient, while breast cancer showed reproducible associations with MVPA. Most strikingly, nocturnal light exposure demonstrated a tumor-site-specific association confined to pancreatic cancer, a signal absent across all other sites examined. Associations for uterine cancer were predominantly inactivity-related and substantially attenuated following adjustment for adiposity and metabolic factors. ConclusionsAcross five accelerometer-derived behavioral domains, solid cancers as a whole were most consistently associated with a high-movement, low-fragmentation, and circadian-coherent behavioral profile. While site-specific heterogeneity exists, the broad cancer risk landscape is dominated by movement volume, inactivity fragmentation, and circadian rhythmicity. Light exposure, although more localized in its contribution, demonstrates a potentially novel and specific association with pancreatic cancer risk. These findings support a five-domain behavioral exposome framework for cancer epidemiology and, importantly, position circadian rhythm integrity and nocturnal light exposure as critically understudied dimensions warranting dedicated mechanistic investigation.

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Dengue risk perception and public preferences for vector control in Italy and France: utility and regret-based choice experiments

Andrei, F.; Tizzoni, M.; Veltri, G. A.

2026-04-11 epidemiology 10.64898/2026.04.10.26350604 medRxiv
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Background: Dengue is rapidly emerging in parts of Europe. How households value vector control attributes, and whether inferences depend on decision models or message framing, is unclear. Methods: We conducted a split-ballot online experiment among adults in Italy and France, as well as a hotspot subsample from Marche, Italy. National samples included 1,505 respondents in Italy and 1,501 in France; 183 respondents were recruited in Marche. Participants were randomised to a discrete choice experiment (random utility maximisation) or a regret-based choice experiment (random regret minimisation) and to one of three pre-task messages (control, loss aversion, community values). Each respondent completed 12 choice tasks comparing two dengue control programmes and an opt-out. We estimated mixed logit and mixed random-regret models with random parameters and treatment effects. Results: Across frameworks, nearby cases and high mosquito prevalence were the dominant drivers of programme uptake, whereas cost and operational burden were secondary. In pooled analyses, loss-aversion messaging increased the weight on high mosquito prevalence in both models (from 0.483 to 0.547 in the utility model; from 0.478 to 0.557 in the regret model). Cost effects were small nationally but larger in the hotspot subsample. Conclusions: Risk salience dominates preferences for dengue vector control in these European settings. Random utility and random regret models yield consistent rankings of attributes but differ in behavioural interpretation and some secondary effects; messaging effects were modest and context dependent.

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Prevalence and Factors Associated with Family-Based HIV Index Case Testing in Wolaita Zone, Southern Ethiopia, 2023: A Cross-Sectional Study

Koyra, A. B.; Mohammed, F.; Eshete, T.

2026-04-11 epidemiology 10.64898/2026.04.08.26350444 medRxiv
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BackgroundFamily-based HIV index case testing identifies family members with unknown HIV status and links them to care. Data are limited in southern Ethiopia. MethodsA facility-based cross-sectional study was conducted among 377 adults on antiretroviral therapy (ART) in Wolaita Zone, Southern Ethiopia, from November 2022 to May 2023. Participants were selected using systematic random sampling. Data were collected via interviewer-administered semi-structured questionnaire. Multivariable logistic regression identified factors associated with index case family testing. Adjusted odds ratios (AOR) with 95% confidence intervals (CI) were calculated, and statistical significance was declared at p < 0.05. ResultsThe proportion of index case family testing for HIV was 84.9% (95% CI: 81.2- 88.6). In multivariable analysis, urban residence (AOR = 2.8; 95% CI: 1.16-6.75), duration on ART greater than 12 months (AOR = 13.0; 95% CI: 4.6-36.9), disclosure of HIV status to family members (AOR = 5.6; 95% CI: 1.9-16.5), discussion of HIV status with family members (AOR = 6.6; 95% CI: 1.9-23.2), and being counselled by health professionals to bring families for testing (AOR = 6.3; 95% CI: 2.1-19.0) were significantly associated with index case family testing. ConclusionThe prevalence of family-based HIV index case testing in Wolaita Zone was 84.9%, below the national 95% target. Health professionals should strengthen counselling on ART adherence, status disclosure, family discussion, and active referral to improve testing uptake among family members of people living with HIV.