Emerging Infectious Diseases

Dermatophilus congolensis is a zoonotic gram-positive bacterium causing dermatophilosis, a skin infection primarily affecting animals and uncommonly reported in humans. Although human infections have traditionally been associated with animal contact, recent reports suggest alternative transmission pathways. We investigated an outbreak among contact sport athletes in Trondheim, Norway, during July to September 2025, using structured interviews and whole-genome sequencing. Nine confirmed cases were identified. Symptoms were mild and consisted mainly of pustular lesions affecting the face, arms, back, and chest. None of the cases reported animal contact. Genomic analysis confirmed species identity and showed that outbreak isolates were highly related, differing by only 0-7 core-genome single nucleotide polymorphisms. The Trondheim isolates clustered with strains from recent outbreaks in Spain and France, suggesting international dissemination of a shared clone. These findings identify contact sports as a potential setting for transmission of human dermatophilosis and highlight the value of genomic surveillance for outbreak investigation.

Background. West Nile virus (WNV) genomic surveillance in the United States relies largely on mosquito and avian sequencing, while human-derived genomes remain scarce. Nucleic acid testing (NAT)-reactive blood donations provide a standardized source of acute human-phase virus, but low donor viremia complicates genome recovery. This study evaluated a sequencing strategy for WNV surveillance using these samples. Study Design and Methods. Amplicon sequencing, hybridization capture, and shotgun RNA-seq were evaluated for WNV lineage 1a recovery from donor plasma. Amplicon performance was characterized using a WHO International Standard dilution panel quantified by RT-dPCR, contemporary 2025 donations, archival 2010-2011 donations, and technical replicates. Two donations were processed by all three methods from matched plasma to compare performance metrics and consensus concordance. Results. Amplicon sequencing recovered near-complete genomes across the full dilution panel, including the lowest measured input, and across the viral-load range represented by the selected donor samples. Recovery from the two archival plasma samples was similar to that observed among contemporary donations. In the two matched donations, all three methods generated identical consensus sequences across shared callable positions. At lower input, amplicon and capture maintained near-complete recovery, whereas shotgun RNA-seq decreased to 87.2% coverage at 10X. For libraries achieving near-complete recovery, WNV-mapped-read requirements were similar, but amplicon sequencing required substantially fewer total reads. Discussion. NAT-reactive blood donations can support WNV genomic surveillance. Amplicon sequencing is an efficient first-pass approach for expected lineage 1a WNV, with capture and shotgun RNA-seq serving as escalation strategies for divergent lineages or unbiased pathogen detection.

Objectives: To estimate early growth rate, back-calculate transmission onset, and characterise the case-fatality trajectory of the 2026 Bundibugyo virus disease (BDBV) outbreak in the Democratic Republic of the Congo, the largest recorded BDBV outbreak to date. Design or methods: We analysed a corrected daily surveillance series (65 observations, 14 May to 27 July 2026) using non-linear least-squares regression and a Bayesian Poisson growth model fitted by Markov chain Monte Carlo, with five sensitivity analyses. Results: Early confirmed cases grew at 0.1261 per day (95% CI 0.0885-0.1636), a doubling time of 5.50 days (4.24-7.83), three-fold faster than previous BDBV outbreaks (15-18 days). Bayesian back-calculation placed transmission onset on 19 April 2026 (95% highest-density interval 9-27 April), 16 days before the WHO alert and 25 days before laboratory confirmation. Confirmed case-fatality ratio rose from 12.1% to 44.3%; a higher ratio among suspected than confirmed cases on 21 May (23.6% vs 10.8%; p=0.0080) supported progressive reclassification rather than increasing virulence. Conclusions: Rapid BDBV growth leaves little time for outbreak-triggered mobilisation. Sentinel alerts based on unexplained healthcare-worker death clusters, together with pre-positioned surveillance, diagnostic, and response capacity, could reduce avoidable amplification before confirmation.

Low pathogenic avian influenza A(H7N7) virus detected in a poultry worker in Taiwan, 2026 was related to viruses circulating in Asian wild birds and possessed PB2 E627K, a mammalian adaptation marker. Enhanced surveillance for H7 viruses in poultry and rapid characterization of human cases are essential to assess pandemic potential.

Trachoma programs are increasingly using serological tools to complement clinical indicators and to measure current and historical transmission of Chlamydia trachomatis (Ct). In January 2024, the Amhara Trachoma Program in Ethiopia implemented the Pgp3 lateral flow assay (LFA) for trachoma serosurveillance through the regional public health laboratory system. Three Amhara Public Health Institute Trachoma Molecular Laboratory scientists were trained and passed competency testing on the assay. The scientists then conducted LFA testing on dried blood spot (DBS) samples collected during a December 2023 trachoma impact survey in Tach Gaynt, Amhara. During testing, 2,542 DBS samples were processed over 12 days. Age-specific seroprevalence and seroconversion rates (SCRs) were estimated. Among children ages 1-5 years, seroprevalence was 20.8% (95% confidence interval [CI]): 17.4-24.7%), and the SCR was 7.9 per 100 child-years (95% CI: 4.6-13.5). Among children ages 1-9 years, seroprevalence was 26.0% (95% CI: 22.9-29.3%), and the SCR was 7.0 per 100 child-years (95% CI: 4.6-10.6). Seroprevalence among individuals ages 15 years and older was 85.8% (95% CI: 83.9-87.4%). Trachomatous inflammation-follicular prevalence among children ages 1-9 years (TF1-9) was 28.6% (95% CI: 22.1-35.4%), and Ct infection among children ages 1-5 years was 5.7%, suggesting ongoing transmission. The concordance between LFA results, TF1-9 prevalence, and Ct infection prevalence supports the utility of the LFA for trachoma surveillance in Ethiopia, with Pgp3 LFA testing performed in a regional public health laboratory. Integrating LFA-based serology into the Ethiopia national trachoma surveillance systems offers a scalable approach to guide programmatic decisions and support trachoma elimination as a public health problem.

High pathogenicity avian influenza (HPAI) H5 clade 2.3.4.4b is the main driver of the ongoing unprecedented global panzootic. The recently emerged HPAI H5N1 clade 2.3.4.4b genotype EA-2024-DI.2.1 has become predominant in Europe, with migratory wild birds, particularly waterfowl, playing a major role in its dissemination. Egypt lies along major Afro-Eurasian migratory flyways, which have historically played an important role in the introduction of emerging H5Nx viruses into the country. In this study, targeted surveillance was conducted on 416 wild birds offered for sale in in live bird markets (LBMs) and roadside trading points in northern Egypt, mainly in Damietta and Port Said. Of these, 118 birds showing mild clinical signs were examined post-mortem and lung and tracheal tissues were collected, while oropharyngeal and cloacal swabs were collected from apparently healthy birds. Avian influenza virus was detected by RT-qPCR in 22 wild birds, all from tissue samples, whereas all swabs from apparently healthy birds were negative. Waterfowl accounted for 16 of the 22 positive birds (72.7%), with Eurasian teal showing the lowest Ct values (21-25). Phylogenetic and whole-genome analyses showed that the sequenced wild-bird viruses clustered within the recently emerged EA-2024-DI.2.1 sub-lineage and were closely related to contemporary European viruses. Compared with the EA-2021-AB genotype currently circulating in Egyptian poultry, the EA-2024-DI.2.1 viruses showed several HA amino acid differences, including A83D, L104M and T195A. These findings provide evidence for the introduction of EA-2024-DI.2.1 into Egypt through migratory wild birds and highlight the importance of continued genomic surveillance at the wild bird domestic poultry interface and antigenic evaluation against vaccines currently used in Egypt.

The continued circulation of H5 clade 2.3.4.4b highly pathogenic avian influenza virus (HPAIV) has caused extensive mortality in wild bird populations worldwide with increasing spillover to mammals. In 2022, H5 HPAIV emerged in Svalbard, Norway, with subsequent detections in wild birds, walruses, polar bears, and arctic foxes. To understand the population-level exposure among Svalbard arctic foxes, we analysed body fluids from carcasses trapped in 2006-2015 (n = 56), 2023-2024 (n = 112), and 2024-2025 (n = 94) for antibodies to H5 avian influenza (anti-H5), influenza A nucleoprotein (anti-NP), and neuraminidase subtypes using ELISAs, haemagglutination inhibition (HI), and a multiplex assay. Only three samples from 2006-2015 tested positive for anti-H5 and were interpreted as false positives. In 2023-2024, seropositivity for anti-H5 was high (95%), supported by a lower anti-NP seropositivity (85%) and antibody profiles consistent with mixed H5N1 (42%) and H5N5 (52%) exposure. In 2024-2025, anti-H5 and anti-NP seroprevalences remained high (83% and 57%), with H5N5 (87%) exposure predominating over H5N1 (3%). A subset of anti-H5-positive samples tested positive by HI (2023-2024: 30%; 2024-2025: 14%). Juveniles with exposure limited to the previous season had higher odds of anti-H5 seropositivity in 2023-2024 than in 2024-2025 (OR 5.5). Analysis of paired lung extracts from a subset of individuals (n = 63) yielded results concordant with body fluids, using an indirect anti-H5 ELISA adapted for carnivores. Our findings demonstrate widespread H5 virus exposure. Together with occasional reports of progression to fatal HPAI, this highlights the need for continued population monitoring to evaluate ecological consequences.

Understanding the vertebrate hosts exploited by Culicoides biting midges is fundamental to assessing the transmission risk of livestock arboviruses. Blood meal analysis provides direct evidence of host-vector interactions under natural conditions; however, molecular data on Culicoides host feeding are lacking in Ireland. This study aimed to identify the vertebrate blood meal hosts of Culicoides species of veterinary importance and establish host-vector associations relevant to arbovirus transmission. A total of 115 morphologically blood-fed Culicoides females collected from 13 sites across Ireland were analysed using a sequential molecular workflow. Species-specific real-time PCR assays were used to screen for vertebrate hosts, with positive detections confirmed by mitochondrial DNA sequencing. Blood-fed Culicoides were subsequently identified to species level using DNA barcoding, enabling direct linkage between vector species and their vertebrate hosts. Vertebrate DNA was detected in 50 specimens, with cattle and horses accounting for the majority of identified blood meals. Culicoides obsoletus accounted for most cattle (n = 12) and horse (n = 11) blood meals. Culicoides scoticus fed on cattle (n = 6), horses (n = 4) and sheep (n = 1), while C. dewulfi and C. chiopterus fed predominantly on cattle, with occasional horse blood meals. Four cattle blood meals were identified from C. punctatus. No cervid-derived blood meals were detected. This study provides the first molecular characterisation of Culicoides blood meal hosts in Ireland, confirming host-vector associations between major vector species and livestock hosts of veterinary importance. Although the number of successfully characterised blood meals was modest, reflecting the inherent difficulty of recovering recently blood-fed Culicoides from field collections, the findings establish an important baseline for Ireland. The sequential molecular workflow provides a practical framework for future blood meal investigations and will support improved understanding of host-vector interactions relevant to arbovirus surveillance and risk assessment.

BackgroundHuman Mastadenovirus B (HAdV-B) causes ocular and respiratory infections and is capable of causing outbreaks in healthcare settings. HAdV-B114, a recombinant genotype only formally recognised in 2023, has been reported predominantly from Germany, the USA, China and Japan; genomic data from UK clinical settings remain limited. This study analysed 68 HAdV-B whole genomes from ocular and respiratory-associated samples collected at a Nottingham hospital across the pre- and post-COVID-19 restriction periods (2017-2023). MethodsClinical samples typed positive for HAdV-B by partial hexon Sanger sequencing were selected for whole-genome sequencing using a novel overlapping PCR amplicon strategy, sequenced on the Oxford Nanopore Technologies PromethION platform. Phylogenetic and pairwise difference analyses were used to characterise genotype composition and genomic relatedness. SimPlot and amino-acid comparison characterised divergence between sub-lineages. ResultsWhole-genome phylogenetics confirmed that two species B genotypes were detected in Nottingham University Hospitals between 2017-23: HAdV-B114 (n=56) and HAdV-B7 (n=12). HAdV-B114 was detected before and after COVID-19 restrictions, with an increase in 2022-2023, consistent with post-restriction expansion of a pre-existing lineage. Pairwise difference analysis identified 24 genomically identical B114 sequences; associated metadata argued against a single nosocomial transmission chain interpretation, with the pattern more consistent with repeated detection of a widely circulating community strain, with the possibility of localised onward transmission. Within the B114 clade, multiple monophyletic groups were identified by whole-genome phylogenetics. ConclusionsThis study adds whole-genome resolution to the existing UK HAdV-B114 data, demonstrates the utility of WGS for clinical adenovirus surveillance and shows the benefits of combining epidemiological data with genomic analysis.

Since 2020, highly pathogenic avian influenza (HPAI) A(H5Nx) clade 2.3.4.4b viruses have spread globally, causing extensive outbreaks in domestic and wild birds. Increased circulation has resulted in frequent spillover to mammals, and occasional mammal-to-mammal transmission. Although human infections remain rare, the zoonotic potential of these viruses continues to be a public health concern. We investigated six cases of HPAI in red foxes (Vulpes vulpes) in Norway during 2022-2024 and identified infections with H5N1 and H5N5 viruses. Pathological and virological investigations demonstrated systemic infection, with prominent lesions in the brain and/or lungs. Phylogenetic analyses showed high similarity between viruses detected in foxes and those concurrently circulating in wild birds. The mammalian adaptation marker PB2:E627K was identified in one H5N1 virus and as a minority variant in a second H5N1 virus.

Bundibugyo ebolavirus (BDBV) is causing an ongoing outbreak in the Democratic Republic of Congo (DRC) with no licensed vaccine available. Recent reports have shown the presence of BDBV-cross-reactive antibody responses in humans vaccinated against the related Ebola virus (EBOV). Here, we used an IFN-{gamma} ELISpot assay to assess T cell responses against the EBOV, BDBV and SUDV glycoproteins in clinical trial participants vaccinated with the licensed VSV-EBOV vaccine. We could show that BDBV-cross-reactive T cell responses are detectable in the majority of individuals and that conserved regions within the glycoprotein are targeted. In the absence of a BDBV-specific vaccine, these data support efficacy trials of the VSV-EBOV vaccine during the current outbreak.

Diarrhea remains a leading cause of child morbidity and mortality. Improved and ongoing estimates of the etiology of hospitalized pediatric diarrhea in low- and middle-income countries (LMICs) are needed to help prioritize and evaluate the use of existing and upcoming vaccines and interventions. The Global Pediatric Diarrhea Surveillance (GPDS) network is a World Health Organization (WHO)-coordinated public health surveillance network investigating the etiology of hospitalized diarrhea among children aged <5 years in LMICs. The GPDS network enrolls children hospitalized with diarrhea at 38 sentinel surveillance sites in 31 LMICs. Randomly selected stool specimens were tested by TaqMan Array Card quantitative reverse-transcription polymerase chain reaction (qPCR) for 16 pathogens associated with diarrhea. We estimated pathogen-specific attributable fractions (AFs) and incidence of diarrheal hospitalizations at the global, regional, and country levels during 3 time periods: 2017-2018, 2019-2020, and 2021-2022, with a focus on the most recent results. During 2017-2022, the GPDS network enrolled 70,750 children aged <5 years hospitalized with diarrhea, of which 16,458 (23.3%) were randomly selected for qPCR testing. The most prevalent pathogen detected, regardless of quantity or modeled etiologic attribution, was rotavirus (weighted prevalence 30.4%), followed by adenovirus 40/41 (19.1%), norovirus (17.9%), Shigella (14.1%), and Campylobacter jejuni/coli (8.6%). Overall, in 2017-2022, rotavirus was the leading etiology globally (AF 32.5%; 95% Confidence Interval (CI): 27.4, 37.6), followed by Shigella (9.8%; 8.4, 11.3), adenovirus 40/41 (8.6%; 6.3, 10.8) and norovirus (6.7%; 5.6, 7.7). Over time, rotavirus consistently declined from an AF of 36.7% (95% CI: 28.7, 46.7) in 2017-2018 to 26.7% (20.7, 34.1) in 2021-2022. Norovirus AF increased slightly from 6.2% (4.7, 7.7) in 2017-2018 to 7.3% (5.0, 9.2) in 2021-2022. Global Shigella burden remained stable, and adenovirus 40/41 demonstrated significant volatility, peaking globally in 2019-2020 (11.9%; 5.9, 17.5). In 2021-2022, rotavirus was the leading cause of hospitalized diarrhea in 6 of 9 geographic groupings, norovirus predominated in Central and South America, and Shigella was the leading etiology in South Asia. In the subset of countries that had introduced rotavirus vaccine, the leading etiologies in 2021-2022 were rotavirus (18.4%; 15.8, 21.5) and Shigella (16.4%; 11.8, 21.1). In 2021-2022, rotavirus had the highest attributable incidence of hospitalized diarrhea in children (2.3 per 1,000 child-years; 1.8, 3.0), followed by Shigella (0.9; 0.7, 1.1), norovirus (0.6; 0.4, 0.8) and adenovirus 40/41 (0.6; 0.4, 0.8). Despite the widespread use of rotavirus vaccines, rotavirus remained the leading cause of severe diarrhea among children aged <5 years in LMICs globally. However, the proportion of pediatric diarrhea attributable to rotavirus consistently declined from 2017-2018 to 2021-2022, and there were notable differences in the distribution of diarrheal etiologies between regions and across time periods. Shigella, norovirus, and enteric adenoviruses were also associated with a substantial burden of disease. Improving the efficacy and coverage of rotavirus vaccination and prioritizing interventions against other enteric pathogens could further reduce diarrhea morbidity and mortality.

Background: Faecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridioides difficile infections, yet the diversity of FMT formulations and delivery routes hampers comparisons across studies. Oral frozen capsules are widely used and current guidelines recommend storage at -80C for up to two years. Despite extensive use of FMT, data on the long-term persistence and maintenance of their microbial composition remains limited. Method: In this prospective study, we assessed the temporal stability of bacterial profiles in frozen FMT capsules derived from 48 donations of 10 healthy donors. Using metabarcoding, we longitudinally profiled one capsule per donation thawed within a month of production and after 3, 6, 12, and 24 months of storage. We used linear mixed effect models to evaluate changes in alpha diversity and community composition over time. Results: Species richness remained stable across all timepoints, whilst species evenness decreased slightly. Although changes in community composition were detectable, they were small and mostly affected low-abundance genera. Clinical efficacy, assessed in a subset of recipients, was not associated with storage duration. Conclusion: Our findings demonstrate that frozen FMT capsules preserve their bacterial community structure for at least two years of storage at -80C, supporting their suitability for long-term biobanking and standardised clinical or research use.

Background: Filoviruses, specifically Ebola virus (EBOV), Bundibugyo virus (BDBV), and Marburg virus (MARV), have been the etiologic agents of multiple outbreaks of severe disease in the Democratic Republic of the Congo (DRC). Two EBOV-specific vaccine regimens have been approved for use in outbreak scenarios, including the Ad26.ZEBOV/MVA-BN-Filo (Zabdeno/Mvabea) two-dose vaccine, where the MVA-BN-Filo booster dose contains EBOV, MARV, and Sudan (SUDV) virus glycoproteins (GPs) and the nucleoprotein from Tai Forest virus. While long-term immunogenicity of up to two years has been found in clinical trial settings, limited real-world data exists. Methods: Using a multiplexed immunoassay, samples (n=698 at baseline) collected in Mbandaka, Equateur province, DRC, between September 2023 and October 2024 were assessed for seroreactivity to six filovirus antigens (1 BDBV, 2 EBOV, 2 MARV, and 1 SUDV) at three distinct periods: baseline/pre-vaccination, 6-8 weeks post-first dose (Zabdeno), at booster administration (Mvabea), and one-year post-boost dose. Results: Substantial filovirus seroreactivity was found at baseline, with 48.7% (n=340/698) of individuals being seroreactive to at least one virus antigen. High baseline seroreactivity was found against BDBV GP (31.1%, n=217/698), with lower baseline seroreactivity to EBOV GP (15.5%, n=106/698), comparatively. Overall EBOV GP seroreactivity increased to 66.8% (n=376/563) at one year-post vaccine boost and 57.6% (n=250/434) of participants were seroreactive. Despite the booster dose inclusion of SUDV GP and MARV GP, there were no substantial increases in reactivity against either antigen at subsequent timepoints. Overall filovirus seroreactivity increased at all timepoints for the entire cohort, although filovirus reactivity decreased over the study period for those who were seroreactive at baseline. Findings: These data highlight detection of significantly elevated seoreactivity to EBOV GP following first-dose administration of Ad26.ZEBOV, which remained relatively stable one-year post-booster dose administration. Additionally, this study identifies high levels of baseline seroreactivity to BDBV GP despite no previous documented outbreaks in this region of DRC. These data suggest that vaccination with the Ad26.ZEBOV-MVA-BN-Filo vaccine induces stable seroreactivity against EBOV GP, but not to other filovirus antigens.

Human metapneumovirus (HMPV) and human parainfluenza viruses (HPIV 1-4) are common causes of seasonal respiratory illness, but their household transmission dynamics remain poorly defined. We analyzed weekly symptom data and nasal swabs from a prospective household surveillance study in Washington and Oregon from June 2022 to March 2024. Swabs were tested for HMPV and HPIV, and a subset underwent whole-genome sequencing. Distinct index cases occurred in 236 (23%) and 341 (36%) of 1,040 households for HMPV and HPIV, respectively. Household secondary attack rates (SAR) and median generation times were similar for HMPV (8.7%, 7 days) and HPIV (7.3%, 7 days). Sequenced samples reflected contemporaneous circulating strains during the same period, with household sequences clustering closely together. High-quality viral whole genome sequences were recovered for two or more individuals within a household in a total of 26 households for HMPV and 45 households for HPIV. Intra-household pairwise nucleotide (nt) distance ranged from 0 to 14 nt (median 0) for HMPV and 0-8 nt (median 1) for HPIV when cases occurred 0-15 days apart. Transmission occurred primarily from children to adults, emphasizing the importance of childcare- and school-associated spread and supporting child-focused prevention strategies to reduce household transmission.

Background: In settings where hepatitis E virus (HEV) is highly endemic, anti-HEV IgG seroprevalence approaches saturation, yet how often disease occurs in previously infected individuals, and how protective natural genotype 1 immunity is, remains unmeasured. IgG concentration cannot answer this as levels rise within days of symptom onset masking any pre-existing levels; IgG avidity, maturing over months, may serve as a useful tool to understand reinfections. Methods: We enrolled 1007 suspected HEV patients and measured anti-HEV IgG avidity in IgG-positive confirmed cases and an age-stratified sample of IgG-positive test-negatives (n = 366) in enhanced surveillance around a 2022 vaccination campaign in Bentiu, South Sudan. Using high avidity (avidity index greater than or equal to 50%) as a marker of past infection, we estimated (i) the reinfection fraction, (ii) protection from prior infection using a test negative design and (iii) associations with viral load and infection severity. Results: Median avidity index was 11% in cases versus 77% in test-negatives. Among unvaccinated cases, 11.6% (28/242) carried high-avidity IgG (indicative of mature immunity and therefore reinfection), rising with age (odds ratio 1.6 per decade, p=0.006). Mature immunity was associated with 95% lower odds of disease (adjusted OR 0.05, 95% CI 0.03-0.08), robust to threshold and case-definition. High-avidity cases were less often viremic (29% vs 78%) at matched time since onset, though we found no differences in liver function biomarkers between patients with high-avidity and low-avidity. Conclusions: Most HEV disease occurred in previously uninfected individuals, and prior immunity was strongly protective against detected disease. Avidity provides a population-level tool to read the immune landscape where seroprevalence may be uninformative.

Background Ecological surveillance indicates (regional) establishment of West Nile virus (WNV) and Usutu virus (USUV) in the Netherlands. However, the incidence of human infections remains unknown. Methods We identified WNV and USUV infections in the Netherlands in 2020-2023, using a longitudinal, nationwide population-based cohort, applying a two-tiered serology approach based on protein micro-array and virus neutralization. IgG data were used to estimate overall seroprevalence and infection incidence, and to study antibody longevity. Study set-up enabled tracking of the period of seroconversion and linking of self-reported travel history. The analyses took account of the survey design and weights were incorporated to match the Dutch population distribution following census data. Findings Among 4290 participants, we identified 113 probable WNV and/or USUV cases, including 55 seroconversions. Thirty-six cases were confirmed by antibody neutralization, of which 12 seroconverted. Six confirmed seroconverters were identified as autochthonous infections. The overall weighted seroprevalence was estimated at 0.54% (0.21-0.87%) for WNV and 0.25% (0.09-0.40%) for USUV. The weighted incidence for autochthonous WNV and USUV infection was estimated as respectively 0.06% (95% CI 0-0.12%) and 0.04% (95% CI 0-0.09%). Interpretation The estimated infection incidence and seroprevalence of WNV and USUV indicate a substantial underdiagnosis of clinical cases in the Netherlands in 2020-2023. These observations highlight the need for increased awareness among physicians to identify cases and the need for continued paired syndromic-laboratory surveillance for these viruses.

Background: Salmonella enterica serovar Enteritidis (S. Enteritidis) is one of the leading causes of foodborne gastroenteritis worldwide and an increasingly important driver of antimicrobial-resistant infections. Despite its public health importance, genomic surveillance of S. Enteritidis remains sparse across the Middle East, where integrated One Health studies linking human, food, and animal reservoirs are limited. This lack of regional genomic data has hindered understanding of the population structure, transmission dynamics, and dissemination of antimicrobial-resistant lineages. We therefore performed a large-scale One Health genomic investigation of S. Enteritidis in the Kingdom of Saudi Arabia, integrating human, food, poultry, and global genomic datasets to characterize its evolutionary history, transmission dynamics, and antimicrobial resistance. Methods: A total of 220 Salmonella enterica serovar Enteritidis (S. Enteritidis) isolates obtained in Saudi Arabia from human clinical infections and food products between 2020 and 2023 underwent whole-genome sequencing. To position these isolates within a global evolutionary context, they were integrated with all publicly available S. Enteritidis genomes, yielding a comparative dataset of 397 genomes. A comprehensive genomic analysis framework was employed, encompassing population genomic, phylogenetic, and phylodynamic analyses to define population structure, infer evolutionary history, and investigate transmission dynamics. In addition, the genomic determinants of antimicrobial resistance and virulence were characterized, with particular emphasis on plasmid architecture. Results: Isolates from Saudi Arabia belonged predominantly to a single globally distributed epidemiological cluster of S. Enteritidis and were embedded within globally circulating transmission networks rather than forming a distinct endemic population. Within this cluster, the Saudi isolates were distributed across seven Bayesian Analysis of Population Structure (BAPS) groups, representing distinct genomic sub-clones. Multiple lineages contained closely related isolates from Europe, North America, Oceania, and the Middle East, indicating repeated international introductions and extensive global connectivity. Human and food isolates were highly intermixed throughout the phylogeny, with food-associated isolates frequently occupying central positions within transmission networks, consistent with food reservoirs acting as dissemination hubs linking local and international transmission. Phylodynamic analyses indicated that the dominant Saudi-associated lineages emerged within the past 10-15 years and underwent rapid demographic expansion following introduction into the country. Recently emerged epidemic lineages carried significantly higher antimicrobial resistance burdens than ancestral populations and were characterized by near fixation of blaTEM-1 and tetA on IncX1 plasmids, whereas clinically important ESBL genes (blaCTX-M-8 and blaSHV-12) were detected exclusively in human-associated isolates on hybrid resistance-virulence plasmids. Conclusions: The population of S. Enteritidis in Saudi Arabia is shaped by repeated introductions of globally circulating clones, transmission between food and human reservoirs, and the dissemination of resistance plasmids across lineages. The emergence of successful epidemic clones is linked to plasmid-mediated acquisition of antimicrobial resistance determinants. These findings emphasize the importance of integrated One Health surveillance strategies for controlling foodborne transmission and monitoring the emergence of antimicrobial-resistant epidemic lineages.

Problem: Response personnel in the 2026 Bundibugyo virus disease (BVD) outbreak in eastern Democratic Republic of the Congo work amid protracted conflict and fragile health systems. Working conditions, security exposure and grievance handling were widely reported as sources of stress but had not been documented systematically. Approach: We conducted an anonymous, self-administered online survey in French among BVD response personnel in North Kivu, Ituri and South Kivu, covering staffing, EPI supply, remuneration, security incidents, grievances and psychosocial well-being. Of 55 submissions, 54 respondents consented and were analysed; denominators fall further, to 21, for grievance items because of within-survey drop-off. Findings are descriptive. Local setting: Respondents (94% men) worked for the Ministry of Health, international non-governmental organizations, the Red Cross and as unpaid volunteers, mostly with one to three months on the response. Relevant changes: 61% judged staffing insufficient; 67% had one or no rest day per week. 63% reported EPI stock-outs and 43% had performed a task judged riskier than necessary. 44% had pay delayed, partial or unpaid though promised, and 85% had advanced personal funds for work costs. 67% reported a security incident in three months; among the smaller subgroup reaching the grievance questions, 57% feared reprisal. Lessons learnt: Staffing, supply, payment and security shortfalls compound one another and are visible to communities; weak grievance channels and fear of reprisal let them persist unaddressed. Working conditions, security and grievance management should be monitored as core infection-prevention-and-control and occupational-risk indicators, not as a peripheral human-resources matter.

Routine facility-based testing for hepatitis C virus (HCV) remains underutilised in India despite national screening policy. WHO has recommended HCV self-testing (HCVST) since 2021 to increase access to testing services. This study evaluated the HCVST by assessing its reach and uptake in urban-slum communities within Haridwar, Uttarakhand, India. The implementation study (CTRI/2023/07/054590) took place between 12th July 2023 and 31st August 2024. Three Primary Healthcare Centre (PHC) catchment areas were assigned to deliver either (1) facility-based HCVST, (2) home-based HCVST, or (3) standard of care (SoC). Facility-based delivery involved trained users offering kits to patients visiting the PHC (Site 1: Jwalapur 1), whereas home-based delivery (Site 2: Jwalapur 2) involved trained users and ASHAs approaching community households selected via a KISH grid. Primary outcomes were OPD-footfall standardized operational reach; the proportion offered testing out of the PHC catchement areas footfall, and uptake (acceptance among those offered). Secondary analysis explored demographic and behavioural predictors of those that refused to test. Of 7,091 outpatient department (OPD) footfall, 724 (10.2%) individuals were offered HCVST at intervention sites, of which 465 (64.2%) agreed to self-test. Operational reach was 17.8% (393/2,212; 95% CI: 16.2 to 19.5%) through the facility-based intervention and 14.4% (331/2,296; 95% CI: 13.0 to 15.9%) in the home-based intervention.HCVST uptake was higher through the home-based model (71.9%, 238/331, 95% CI: 66.7 to 76.7%) than in the facility (57.8%, 227/393, 95% CI: 52.7 to 62.7%). At the SoC site, only 11 individuals received standard of care HCV testing. The study HCV positivity was 1.1% (5/465; 95% CI: 0.35% to 2.49%): with four testing positive at the facility site (4/227), one at the community site (1/238), and none at the SoC site (0/11). Men were more likely to refuse HCVST than women (OR 0.54, 95% CI 0.37 to 0.78, p=0.001).Participants in the facility-based model had 1.87 times higher odds of refusal compared to those in the home-based delivery model. There is minimal routine HCV testing in the OPD setting of Urban PHCs despite national screening policy. HCVST improved testing coverage and uptake in urban slums compared to SoC. However, HCV positivity was low overall, suggesting that untargeted screening - whether facility-based or home-based - may identify few infections without additional strategies to reach higher-risk populations.