Viruses

Lumpy skin disease (LSD) is a transboundary viral disease of cattle for which rapid antigen detection could support field surveillance and outbreak investigations. This study aimed to develop and preliminarily evaluate a colloidal gold immunochromatographic strip targeting the P32 protein of lumpy skin disease virus (LSDV). Recombinant P32 proteins were expressed in Escherichia coli, and two P32-specific monoclonal antibodies, 5B1 and 7H4, were generated using hybridoma technology. Indirect ELISA with truncated P32 fragments showed that both antibodies reacted predominantly with P32-1 (amino acids 13–60), although their precise epitopes were not determined. Of four antibody combinations tested, gold-conjugated 5B1 paired with immobilized 7H4 produced the strongest test-line signal and was selected for strip development. Using recombinant His-tagged P32, the lowest concentration consistently detected in three replicate tests was 40 μg/mL, with results read after 15 min. The strip reacted with LSDV suspension and LSDV-positive skin nodule tissue, while no positive reactions were observed with the selected heterologous viral preparations or negative controls. In an evaluation of 30 bovine clinical specimens, the strip detected 9 of 11 qPCR-positive samples and correctly classified all 19 qPCR-negative samples. Using qPCR as the comparator method, positive percent agreement was 81.82% (95% CI, 48.22–97.72%), negative percent agreement was 100% (95% CI, 82.35–100%), and overall agreement was 93.33%. These findings demonstrate the feasibility of a P32-based antigen detection strip, although its diagnostic performance requires further evaluation in larger and more representative sample sets.

(1) Background: SARS-CoV-2 variants clinical presentation and severity may differ in children. This systematic review evaluated changes that occurred in pediatric COVID-19 across successive viral variants. (2) Methods: PubMed/MEDLINE, Embase, and Web of Science were searched through 26 September 2026 for comparative studies of SARS-CoV-2 variants in patients aged 18 years or younger. We assessed their methodological quality with the Newcastle–Ottawa Scale (NOS) and their clinical manifestations and severity outcomes were synthesized narratively. (3) Results: Twenty-nine studies were included. Delta was generally associated with a greater symptomatic burden than Alpha, even though the differences in severe outcomes were inconsistent. Omicron was associated with a distinct clinical phenotype, more frequent croup and seizures, some of which were reported as febrile seizure, while gastrointestinal findings varied across studies. Population-based studies generally indicated lower risks of hospitalization or severe disease with Omicron than Delta, but findings among hospitalized children were less consistent. Studies of Omicron subvariants identified differences in individual symptoms without a consistent trend in disease severity. (4) Conclusions: The clinical phenotype of pediatric COVID-19 evolved across SARS-CoV-2 variants. Omicron was particularly associated with increased upper-airway, particularly croup, while several studies also reported increased seizure frequency, including febrile seizures. Population-based studies generally suggesting less severe disease than Delta infections. Differences in age, study setting, variant ascertainment, and outcome definitions should be considered when interpreting these findings.

Noroviruses are leading causes of acute gastroenteritis worldwide, with host susceptibility and viral attachment influenced by interactions between the VP1 protruding (P) domain and histo-blood group antigens (HBGAs). Although HBGA recognition has been extensively investigated in human noroviruses, the structural capacity of animal-associated genotypes to accommodate HBGA-related glycans remains comparatively underexplored. In this study, we performed a comparative in silico analysis of the structural compatibility of VP1 P domains with six HBGA-related glycans: lacto-N-biose (LNB), H type 1, antigen A, antigen B, Lewis A, and Lewis Y. Human and animal-associated norovirus genotypes were evaluated using structural modeling, CB-Dock2/AutoDock Vina docking, Vina score-derived ligand efficiency, residue-contact mapping, and three independent 100 ns molecular dynamics simulations of the GII.4 P-domain–H type 1 complex. Site-informed selection of CB-Dock2 cavity-based poses yielded heavy-atom RMSD values of 0.327–1.895 Å for four crystallographic complexes, although only two selected poses were top-ranked among cavity-based outputs. Complementary carbohydrate-aware redocking with Vina–Carb recovered a crystallographically similar pose (<2 Å) among the top ten solutions for two of the four complexes, indicating complex-dependent pose-recovery performance. Score-derived ligand-efficiency distributions broadly overlapped between the analyzed human and animal-associated datasets. Analysis of selected docking configurations, guided by the literature, identified geometrically plausible glycan arrangements and recurrent polar and aromatic contact environments, with genotype-dependent variation in pocket organization. However, the automatically top-ranked blind-docking solutions were spatially separated from targeted P2 configurations in the four representative H type 1 complexes, indicating that P2-associated accommodation was dependent on site-directed sampling rather than independently identified by blind docking. In the replicated molecular dynamics simulations, the P-domain remained globally stable, whereas H type 1 displayed substantial positional mobility, intermittent increases in protein–ligand distance, and variable hydrogen-bond formation, indicating that the initial docking pose was not continuously maintained. Overall, the findings support a hypothesis-generating framework of structural compatibility and genotype-dependent topological variability under sampling conditions that are guided by the literature, without establishing biological glycan binding or quantitative binding affinity.