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PubMed2026

VisPan: real-time visualisation of multiplex amplicon-based sequencing panels for rapid syndromic surveillance and pathogen detection.

MOTIVATION: Infectious diseases persist as a major global public health challenge. Diverse factors, including climate change, globalization, deforestation, human-animal interactions, lifestyle choices, and various biological factors, can contribute to their emergence and reemergence. Rapid detection and characterization of (re)emerging pathogens are therefore critical for effective outbreak management and for enhancing our understanding of epidemics by monitoring the transmission, spread, evolution, and genomics of pathogens. In this context, next-generation sequencing technologies (NGS), particularly long-read platforms such as Oxford Nanopore Technologies (ONT), have opened new avenues for real-time pathogen monitoring. However, the bioinformatics bottleneck remains a challenge, emphasizing the need for efficient, accessible, and user-friendly analysis tools. RESULTS: Here, we present a tool adapted from the RAMPART software that enables real-time data visualisation of multiplex PCR syndromic panels combined with Oxford Nanopore sequencing. This real-time analysis enables rapid pathogen detection, from raw data acquisition to taxonomic assignment, within minutes. The interface offers dynamic visual tracking of the sequencing run and amplicon coverage, facilitating immediate insights during diagnostic workflows. Validation experiments confirmed the system's reliability, accurately identifying all pathogens present in complex clinical or environmental samples. This tool provides an integrated, user-friendly solution for genomic pathogen surveillance in field or clinical settings.

Software↗

PubMed2026

Strengthening supply chains for pathogen genomic surveillance in Asia.

INTRODUCTION: While pathogen genomics using next-generation sequencing (NGS) has been recommended by the WHO as an essential tool for national communicable disease surveillance programmes, procurement and supply chain management (PSM) systems for this new technology are still evolving. To assess the status of PSM systems for pathogen genomics, we examined perspectives from end-users and manufacturers across South and Southeast Asia. METHODS: Between 2022 and 2023, a cross-sectional survey was conducted among institutional partners supporting pathogen genomics among primarily low- and middle-income countries in South and Southeast Asia. This was complemented by qualitative interviews with the major regional NGS manufacturers. A PSM framework was employed to assess sales, procurement, production, distribution and post-sales support. Analyses are expressed as proportions and means or medians for continuous variables. RESULTS: A total of 42 partners across 13 countries, 3 genomics manufacturers and 22 laboratory personnel contributed data to this assessment. PSM challenges were reported by all countries and for all sequencing platforms. High costs of equipment and consumables were identified by 85% of respondents. Long equipment purchasing lead times and reagent re-supply times were reported by 69% and 77% of countries, respectively, with reagent resupply times averaging 8 weeks (IQR 6.2-9.0). Additional barriers included customs clearance, variability of import procedures, taxes and duties. Manufacturers reported a range of strategies to respond to PSM bottlenecks, including establishing regional hubs, distributor networks and financing schemes. CONCLUSION: Coordinated national and regional efforts are required to improve PSM systems for pathogen genomic sequencing to enhance timely early disease detection and response capacity in South and Southeast Asia.

Humans↗

PubMed2026

Public Health Indoor Air Surveillance for Respiratory Pathogens: From Pilot to Citywide Implementation.

CONTEXT: Environmental surveillance has become an essential component of public health pathogen surveillance programs. Indoor air surveillance is a promising environmental surveillance method but has yet to be scaled citywide and incorporated into state and local public health programs. PROGRAM: The Chicago Department of Public Health established a citywide indoor air surveillance program to enhance monitoring of airborne pathogens and address gaps in existing surveillance. IMPLEMENTATION: The program began with a pilot phase from February to April 2023 at 5 sites, which informed expansion to 17 sites and 20 samplers across emergency departments (5), congregate (3), and community settings (15), across the city. Site staff conducted weekly cartridge exchanges for seven-day sample collection periods using AerosolSense and AirPrep Cub samplers, which were then processed at the Regional Innovative Public Health Laboratory for SARS-CoV-2, influenza, and respiratory syncytial virus. Samples were tested using quantitative polymerase chain reaction, and SARS-CoV-2-positive samples underwent whole genome sequencing to characterize circulating viral lineages. EVALUATION: From February 2023 to August 2025, 1246 samples were processed, with a mean compliance of 85% (SD = 0.149) for weekly cartridge exchanges and minimal operational disruption. The program data supported its use as a surveillance tool for respiratory pathogen detection and SARS-CoV-2 lineage monitoring, with 74% samples positive for at least 1 virus and 68% detecting SARS-CoV-2. DISCUSSION: The program successfully scaled to citywide coverage and was shown to be feasible and acceptable across sites. These results highlight the value of indoor air monitoring as a complementary surveillance tool and offer a framework for other jurisdictions seeking to enhance respiratory pathogen detection through establishing a citywide indoor air surveillance program. Facility-level sampling is aggregated across sites to capture citywide trends complementing clinical and wastewater surveillance, and provides insights into facility-level pathogen burden, not captured by other surveillance methods.

Humans↗

PubMed2026

Multimodal genomic surveillance for respiratory pathogens at four U.S. international airports: A comparison of air, wastewater, clinical, and national surveillance data.

Early detection of outbreaks and emerging pathogens is critical for public health and global biosecurity. Airports, as major international travel hubs with dense, enclosed populations, are high-risk settings for disease transmission and potential pathogen introduction. The U.S. Centers for Disease Control and Prevention, in collaboration with Ginkgo Biosecurity and the University of Wisconsin-Madison, implemented air monitoring for pathogen surveillance in congregate areas at four U.S. international airports. From October 2023 to August 2024, SARS-CoV-2 was detected by PCR in 98.3% of air samples and influenza A in 17.2%. Influenza A positivity in air samples correlated with aviation wastewater (r = 0.48), traveler nasal swab positivity (r = 0.73), and national clinical surveillance (r = 0.86), whereas SARS-CoV-2 measurements did not correlate significantly across these modalities. Targeted amplicon sequencing of SARS-CoV-2 from air samples identified contemporaneous lineages also detected in wastewater collected from the same airports. Targeted enrichment sequencing detected 30 viral species and recovered high-quality genomes for SARS-CoV-2, influenza, bocavirus, and seasonal coronaviruses. Together, these findings demonstrate that air sampling can complement aviation wastewater surveillance at ports of entry, although performance and concordance vary by pathogen and sample type.

Journal Article↗

PubMed2025

PathoSeq-QC: a decision support bioinformatics workflow for robust genomic surveillance.

MOTIVATION: Recommendations on the use of genomics for pathogens surveillance are evidence that high-throughput genomic sequencing plays a key role to fight global health threats. Coupled with bioinformatics and other data types (e.g., epidemiological information), genomics is used to obtain knowledge on health pathogenic threats and insights on their evolution, to monitor pathogens spread, and to evaluate the effectiveness of countermeasures. From a decision-making policy perspective, it is essential to ensure the entire process's quality before relying on analysis results as evidence. Available workflows usually offer quality assessment tools that are primarily focused on the quality of raw NGS reads but often struggle to keep pace with new technologies and threats, and fail to provide a robust consensus on results, necessitating manual evaluation of multiple tool outputs. RESULTS: We present PathoSeq-QC, a bioinformatics decision support workflow developed to improve the trustworthiness of genomic surveillance analyses and conclusions. Designed for SARS-CoV-2, it is suitable for any viral threat. In the specific case of SARS-CoV-2, PathoSeq-QC: (i) evaluates the quality of the raw data; (ii) assesses whether the analysed sample is composed by single or multiple lineages; (iii) produces robust variant calling results via multi-tool comparison; (iv) reports whether the produced data are in support of a recombinant virus, a novel or an already known lineage. The tool is modular, which will allow easy functionalities extension. AVAILABILITY AND IMPLEMENTATION: PathoSeq-QC is a command-line tool written in Python and R. The code is available at https://code.europa.eu/dighealth/pathoseq-qc.

Genomics↗

PubMed2026

Emergence of carbapenemase-producing Escherichia coli in acute care hospitals in 32 European countries (the CCRE survey): a prospective, multicentre, cross-sectional, epidemiological, microbiological, and genomic surveillance study.

BACKGROUND: The emergence of carbapenem resistance in Escherichia coli is of major concern due to the high propensity of spread of this species and scarce treatment options. Herein, we examined the occurrence and spread of carbapenem-resistant E coli based on the carbapenem-resistant and/or colistin-resistant Enterobacterales (CCRE) survey performed across European countries in 2019. METHODS: We analysed epidemiological, microbiological, and whole-genome sequencing data of 548 E coli isolates from individual patients from 156 hospitals in 32 European countries over 6 months in 2019. These hospitals collected the first ten successive isolates of carbapenem-resistant or carbapenem-susceptible increased exposure (carbapenem-R/I) Klebsiella pneumoniae species complex or E coli, and carbapenem-susceptible (carbapenem-S) comparator isolates of the same species. Antimicrobial susceptibility testing was performed for 19 antimicrobial agents. Whole-genome sequencing was performed centrally using Illumina technology. Isolates from the CCRE survey were compared with those from the European Survey of Carbapenemase-Producing Enterobacteriaceae (EuSCAPE) study. FINDINGS: Of the 548 E coli isolates, 211 (38·5%) were carbapenem-resistant or susceptible, increased exposure (carbapenem-R/I), and 337 (61·5%) were carbapenem-susceptible (carbapenem-S). Five sequence types (STs) accounted for 96 (45·5%) of 211 carbapenem-R/I isolates: ST131 (27), ST410 (20), ST38 (19), ST167 (16), and ST648 (14). Carbapenemase genes were identified in 182 (86·3%) carbapenem-R/I isolates, a pronounced increase from the 2013-14 EuSCAPE study (36 of 99, 36·4%). The most common genes were blaNDM-5 (62 of 182, 34·1%) and blaOXA-48 (40 of 182, 22·0%). blaNDM-5 carriage increased substantially compared with that in EuSCAPE (two of 99, 2·02%). Phylogenetic analysis showed substantial clonal spread of globally disseminated blaNDM-5-harbouring lineages, with numerous introductions into Europe but minimal onward transmission. INTERPRETATION: High-risk STs of E coli carrying carbapenemase genes are rapidly spreading globally, although our results indicate that, in 2019, most cases in Europe were sporadic. We urge vigilant monitoring, including genomic surveillance, and strengthening of control efforts, to reduce mortality and morbidity associated with the impending rise in carbapenem-R/I E coli cases. FUNDING: European Centre for Disease Prevention and Control and the Centre for Genomic Pathogen Surveillance.

Humans↗

PubMed2025

4CMenB vaccine coverage of invasive serogroup B meningococci collected in Belgium between 2016 and 2022.

Neisseria meningitidis infections can cause life-threatening meningitis and septicemia. In Europe, serogroup B (MenB) is the leading cause of invasive meningococcal disease (IMD), particularly in young children. Genomic surveillance of circulating MenB strains through whole genome sequencing (WGS) provides a powerful tool to assess the potential impact of vaccination strategies, including the 4CMenB vaccine, which is available for infants from 2 months of age. Here, we present a retrospective WGS-based analysis of clinical MenB IMD cases (n = 311) recovered in Belgium from 2016 to 2022 by the Belgian National Reference Center. High-quality WGS data were obtained for 281 of these strains, demonstrating high genetic diversity of the antigen targets included in the 4-component meningococcal serogroup B vaccine 4CMenB (fHbp, PorA, NHBA and NadA) and at the 4CMenB Antigen Sequence Types (BAST) level. Novel antigen combinations, not yet assigned a BAST ID, were detected in 23.5% of isolates. Vaccine coverage was predicted using the Genetic Meningococcal Antigen Typing System (gMATS) and the Meningococcal Deduced Vaccine Antigen Reactivity (MenDeVAR) index. Of the 281 strains, 79.5% (lower limit-upper limit: 68.0-91.5%) were predicted to be covered by the vaccine by gMATS, and 80.7% (lower limit-upper limit: 66.5-95.4%) by MenDeVAR. No evidence of variation in vaccine coverage was found throughout the study period nor between different age groups, demonstrating the broad applicability of 4CMenB. This study highlights the benefits of a pathogen surveillance program and the need for experimental characterization of continuously evolving antigenic subvariants of Neisseria meningitidis.

Humans↗

PubMed2025

Genotypic Analysis and Clinical Findings of Sapovirus-Associated Acute Gastroenteritis in Mie Prefecture, Japan, 2010-2022.

Sapovirus (SaV) is one of the major viruses causing acute gastroenteritis. Of the 1981 fecal specimens collected through sentinel pediatric acute gastroenteritis pathogen surveillance in Mie Prefecture, Japan (2010-2022), 236 were positive for SaV, according to PCR screening. Whole or near-whole genome sequences were determined for 158 strains by next-generation sequencing. Genotype GI.1 was the most common of the nine SaV genotypes detected, followed by GII.3 and GII.1. Phylogenetic analysis showed that SaVs of these three genotypes separated into three different clusters depending on the year of detection, suggesting continuous genetic changes in the same genotype. Coinfections involving different SaV genotypes, as well as reinfections with SaV in the same individual, were observed in this study. The main clinical manifestations were diarrhea (68.4%) and vomiting (61.6%), with an increased rate of emesis, particularly in patients over 3 years of age. In addition, 18.1% of the children had fever. This study clarified the prevalence of viral genotypes as well as clinical findings of SaV-positive gastroenteritis in children, and revealed trends by age.

Humans↗

PubMed2027

Nanopore Sequencing for Chikungunya Virus: Principles and Application.

Nanopore sequencing is transforming viral genomics through real-time, portable, long-read analysis of RNA and DNA. Unlike traditional short-read platforms, it detects nucleotide sequences by measuring ionic current changes as nucleic acids pass through nanoscale pores, enabling direct single-molecule sequencing and base modification detection. Its simplicity, flexibility, and capacity for ultra-long reads make it ideal for resolving complex genomic regions, structural variants, and full viral genomes. These advantages have accelerated its use in pathogen surveillance and outbreak response, especially in resource-limited settings. For chikungunya virus (CHIKV), nanopore sequencing allows rapid, culture-independent recovery of complete genomes from clinical and vector samples, enabling real-time tracking of viral diversity, evolution, and spread. Experiences from Ebola, Zika, and COVID-19 have demonstrated the power of portable sequencing, now applied to CHIKV monitoring. Advances in tools such as Guppy, Dorado, Minimap2, and Medaka enhance read quality, consensus accuracy, and downstream analyses. Despite challenges in basecalling and error correction, robust quality control pipelines ensure reliable results. Ongoing improvements in chemistry, flow cell design, and machine learning will further enhance fidelity and throughput, establishing nanopore sequencing as a cornerstone of CHIKV genomic surveillance and epidemic preparedness.

Chikungunya virus↗

PubMed2026

Primer design through submodular function estimation.

MOTIVATION: Multiplex PCR-based enrichment is widely used in viral genome sequencing and pathogen surveillance. However, designing large sets of primers that maximize genome coverage while minimizing primer-primer interactions remains a major computational challenge. Existing methods such as SADDLE and Olivar use heuristics to optimize a Badness score for primer dimers but lack theoretical guarantees on solution quality. RESULTS: We introduce PRISM, a new framework that formulates multiplex primer design as a constrained submodular maximization problem. Our method defines an objective that balances genome coverage and dimer risk, and applies a local search algorithm with a constant-factor approximation guarantee. Evaluations on viral genome datasets demonstrate that PRISM consistently achieves lower Badness scores compared to PrimalScheme, Olivar, and primerJinn. These results highlight the scalability and theoretical rigor of submodular optimization in primer design. AVAILABILITY: PRISM is open-source and available at https://github.com/yhhan19/PRISM-new. The experimental data, scripts, and results used in this paper are archived on Figshare at https://doi.org/10.6084/m9.figshare.32806499.

Algorithms↗

PubMed2026

Comparative genomics reveals lineage-associated structural variation and diversification in a barley fungal pathogen.

Leaf rust, caused by Puccinia hordei, is a major barley disease worldwide. Despite repeated shifts in virulence, contrasting reproductive histories, and emerging fungicide insensitivity, the genomic basis of its diversification and adaptation remains poorly understood. In this study, we generated haplotype-resolved, chromosome-level genome assemblies for two isolates with contrasting virulence and analyzed 41 Australian isolates collected over 54 yr (1966-2020), integrating comparative and population genomics, mating-type gene phylogenies, chromosome-specific k-mer profiling, genome-wide copy-number variation (CNV) analysis, and gene-expression analysis. We identified a structurally dynamic chromosome characterized by repeat-associated rearrangements, structural variation, and lineage-associated CNV, representing the first evidence in a rust fungus of chromosome-scale structural diversification of this extent. Population analyses distinguished clonally expanded lineages from recombination-associated lineages, with mating-type gene phylogenies providing further support for lineage differentiation. More recently collected isolates showed increased duplication-associated variation, and CNV boundaries were associated with structural-variant breakpoints. We also identified lineage-associated amplification of Cyp51, with increased copy number associated with higher transcript abundance, supporting a potential role in fungicide adaptation. Overall, our findings highlight structural variation, contrasting reproductive histories, and lineage-associated CNV as important contributors to diversification in P. hordei, providing insights for future rust pathogen surveillance and management strategies.

Cyp51 gene↗

PubMed2026

Molecular surveillance of foodborne bacterial pathogens and resistome in food products from Hong Kong.

Foodborne infections pose an increasing public health challenge worldwide. The problem has been aggravated by the dissemination of antimicrobial resistance genes among zoonotic pathogens, which results in a sharp increase in antibiotic resistance rate recorded among the major foodborne pathogens. To obtain an overview of the extent to which food products purchased in the markets in Hong Kong were contaminated by foodborne pathogens, we collected 95 raw meat samples from wet markets and isolated 236 bacterial strains of various species, with Escherichia coli being the most dominant species (131 strains). Contamination of food products by multiple foodborne pathogens was commonly observed. These include both Gram-positive and Gram-negative bacteria that exhibit various levels of resistance, with some possessing multiple clinically important antibiotic resistance genes. Seventeen bacterial strains of various species isolated from three food samples were comprehensively analysed by the Oxford Nanopore R10.4 technology. Novel conjugative plasmids carrying antimicrobial resistance gene-bearing mobile genetic elements were commonly detectable in the test strains. Some of the plasmids were shown to have originated from other environmental sources or other bacterial species, indicating that raw foods in the local market may serve as a reservoir of resistance-encoding genetic elements from which such elements are disseminated to various microbial pathogens. These findings suggest a need to perform periodic but comprehensive surveillance of multidrug-resistant bacterial pathogens and the major antimicrobial resistance genes in common food products, so as to disrupt the transmission routes of such organisms and the resistance-encoding genetic elements that they harbour.

Hong Kong↗

PubMed1978

A study of acute respiratory disease in the community of Port Chalmers. I. Illnesses within a group of selected families and the relative incidence of respiratory pathogens in the whole community.

A study of respiratory diseases in the semi-isolated community of Port Chamlers, New Zealand, began in April 1973. The intensive surveillance of a selected group fo 26 families involved the weekly reporting of illness, the collection of specimens for virus, Group A streptococci and Mycoplasma pneumoniae isolation and the collection of sera at 6-month intervals. A total of 956 illnesses were reported during 32 months. The median number of illnesses per year were: infants 4.4, children 2.5, female adults 2.4 and male adults 2.0. Of all these illnesses, 57% were upper respiratory, 31% were lower respiratory and 9% were enteric. The severity of these illnesses was not greater than would be expected in open communities. Surveillance by pathogen isolation only of the whole community through the patients in the general practice was carried out concurrently. A total of 640 nasopharyngeal swab specimens were collected from which 161 viruses, 47 Group A streptococci and 2 M. pneumoniae were isolated. The overall isolation rate was 33%. The similarities between the epidemiological patterns of respiratory disease in the open community and the isolated community are discussed.

Adolescent↗

PubMed2026

Evaluation of one-step amplicon-based targeted enrichment for SARS-CoV-2 whole-genome sequencing using the Midnight amplicon scheme.

Genomic surveillance proved invaluable during the COVID-19 pandemic for tracking SARS-CoV-2 variants and guiding outbreak responses, underscoring the ongoing need to reduce whole-genome sequencing (WGS) costs and improve workflow efficiency to ensure accessibility in resource limited settings. Here, we evaluated a one-step reverse transcription polymerase chain reaction (RT-PCR) approach using the Midnight V2 primer scheme for targeted amplification of the SARS-CoV-2 genome, assessed its compatibility with Illumina sequencing, and compared its performance to a well-established two-step method. Initially, we determined optimal RT-PCR reaction conditions using the Midnight V2 primer panel for the one-step RT-PCR kit and scaled reaction volumes for both RT-PCR and library preparation. Clinical specimens (n = 53) that had undergone routine WGS for surveillance purposes using the established two-step RT-PCR method were compared using the one-step RT-PCR assay. For samples with genome completeness greater than 70%, both methods gave comparable results with similar sequence coverage and 100% concordance for lineage assignment. Further investigation revealed a higher percentage of reads aligning to the SARS-CoV-2 genome with a greater depth of coverage using the one-step method compared to the two-step method. Finally, analysis of scaled one-step and library reaction volumes revealed significant cost savings for samples undergoing WGS. Overall, the results presented here verify the accuracy and reproducibility of one-step targeted amplification and offer an efficient and cost-effective workflow for routine SARS-CoV-2 genomic surveillance.

Humans↗

PubMed2025

Prospective characterisation of drug-resistant bloodstream infections in Africa and Asia (ACORN2): a surveillance network assessment.

BACKGROUND: Antimicrobial resistance (AMR) is a major global health threat, but there is scarcity of laboratory surveillance data linked to clinical information to determine burden and inform interventions, especially from low-income and middle-income countries. The ACORN2 study sought to address this through prospective case-based surveillance in 19 hospitals across Africa and Asia to characterise drug-resistant infections by origin, clinical syndrome, patient age, outcome, and geographical location. METHODS: Patients were enrolled on selected wards and clinical data were collected daily for community-acquired infections (CAIs). Point prevalence surveys for hospital-acquired infections (HAIs) were conducted weekly. Mortality was assessed at discharge and after 28 days. Linked microbiology data were extracted from local laboratory databases. Primary descriptive analyses focused on WHO Global Antimicrobial Resistance and Use Surveillance System pathogen (target organism) bloodstream infections (BSIs). Comparisons were adjusted for clustering by site using random effects models. FINDINGS: Over 31 months, 41 907 infections were characterised from 41 032 admissions. Two-thirds were children (19 351; 47·2%) or neonates (6649; 16·2%). There were marked differences in pathogen incidence and antibiotic resistance when clinical infections were stratified by patient age category and infection origin (CAI/HAI). The highest rates of target organism AMR BSI were third-generation cephalosporin-resistant (3GC-R) Escherichia coli (718·56/100 000 blood cultured infection episodes), meticillin-resistant Staphylococcus aureus (586·89/100 000 blood cultured infection episodes), and 3GC-R Klebsiella pneumoniae (364·92/100 000 blood cultured infection episodes). In-hospital mortality was 13·1% (166/1265) in patients with target organism BSI versus 6·2% (1357/21 845) in those with negative blood cultures, p<0·0001. INTERPRETATION: ACORN2 has shown practical implementation of collecting linked clinical-laboratory AMR data in low-income and middle-income countries and identified a significant burden of WHO GLASS BSI. Adoption of the ACORN2 approach at scale might enhance use of diagnostic microbiology and improve the volume of clinical data included in national and global AMR surveillance datasets. FUNDING: Wellcome.

Humans↗

PubMed2026

A species-discriminatory aerA TaqMan qPCR assay for rapid quantification of Aeromonas veronii in fish tissues and aquaculture water.

Aeromonas veronii is a major bacterial pathogen in freshwater aquaculture, yet rapid species-level quantification remains challenging within the genetically complex genus Aeromonas. We developed a singleplex hydrolysis-probe (TaqMan) quantitative PCR (qPCR) assay targeting an A. veronii-discriminatory region of the aerolysin gene (aerA) and validated it according to MIQE recommendations. Plasmid standards gave a linear range of 2 to 2 × 106 copies/reaction (R2 = 0.9962) with 100.5% amplification efficiency. The endpoint limit of detection was 2 copies per reaction, and 20 copies per reaction was set as the practical reporting limit based on reproducible detection and low intra- and inter-assay variation. Analytical specificity was evaluated with genomic DNA from an 18-strain panel, with reproducible amplification observed only for A. veronii. The assay was further tested in 55 fish-tissue and 11 aquaculture-water DNA extracts. NH8B-1D2 sample-process monitoring was used for matrix-level recovery correction, and tissue and water extraction blanks were undetermined. The aerA target was detected in all tested gill, stomach/intestine, spleen, kidney/head kidney, pond-water filter and Xiamen seawater filter extracts, and in 10/11 liver extracts. Median NH8B-corrected loads were highest in gill among tissues and higher in pond-water filters than in Xiamen seawater filters. A separate Vibrio harveyi inhibition-check assay indicated no obvious amplification-stage inhibition. This assay supports rapid quantification of aerA-positive A. veronii in fish and aquaculture-water matrices.

Animals↗

PubMed2025

Reference-Free Variant Calling with Local Graph Construction with ska lo (SKA).

The study of genomic variants is increasingly important for public health surveillance of pathogens. Traditional variant-calling methods from whole-genome sequencing data rely on reference-based alignment, which can introduce biases and require significant computational resources. Alignment- and reference-free approaches offer an alternative by leveraging k-mer-based methods, but existing implementations often suffer from sensitivity limitations, particularly in high mutation density genomic regions. Here, we present ska lo, a graph-based algorithm that aims to identify within-strain variants in pathogen whole-genome sequencing data by traversing a colored De Bruijn graph and building variant groups (i.e. sets of variant combinations). Through in silico benchmarking and real-world dataset analyses, we demonstrate that ska lo achieves high sensitivity in single-nucleotide polymorphism (SNP) calls while also enabling the detection of insertions and deletions, as well as SNP positioning on a reference genome for recombination analyses. These findings highlight ska lo as a simple, fast, and effective tool for pathogen genomic epidemiology, extending the range of reference-free variant-calling approaches. ska lo is freely available as part of the SKA program (https://github.com/bacpop/ska.rust).

Polymorphism, Single Nucleotide↗

PubMed2026

Genetic diversity and recombination of NA-PRRSV field strains in Vietnam: Implications for vaccine efficacy.

Porcine reproductive and respiratory syndrome (PRRS) causes severe reproductive losses in pregnant sows and piglets, resulting in substantial economic impact on the swine industry worldwide. However, due to the significant genetic diversity and rapid evolutionary changes of the pathogen, continuous surveillance and detailed genetic analysis of circulating strains are essential. The current study aimed to evaluate the genetic diversity of the hypervariable (HV) region of non-structural protein 2 (nsp2) among North American PRRSV strains isolated from swine farms in Vietnam. Phylogenetic analysis and multiple sequence alignment were conducted to determine subtype classification and assess genetic variability. A total of 48 field isolates were obtained, of which 12.5% belonged to classical NA-PRRSV, 16.6% to NADC30-like and 70.9% to HP-PRRSV, primarily distributed across sublineages 1.4, 5.1, 8.7 and 8.9. Amino acid comparisons found multiple insertions, deletions and substitutions at various positions within the hypervariable region of nsp2. The study revealed substantial genetic variation in the HV region of nsp2 among NA-PRRSV field strains, largely associated with recombination and immune escape. These findings highlight epidemiological risks to vaccine efficacy and underscore the need for continuous molecular surveillance to support effective PRRSV control in Vietnam.

PRRSV↗