Genomic surveillance of enterovirus D68 circulating in 2025 reveals the emergence of a novel A2/B3 recombinant lineage

Dengue virus in Solomon Islands 2023-2025: a whole genome surveillance study

First detection and molecular characterization of influenza D virus in livestock from Kazakhstan reveals circulation of the D/Yama2019 lineage

Influenza D virus (IDV) is an emerging Orthomyxovirus primarily associated with cattle and increasingly recognized as a pathogen of veterinary and zoonotic relevance. Despite growing evidence of its circulation across Asia, Europe, and North America, no data have previously been available from Kazakhstan or Central Asia. This study investigated the presence of IDV in domestic livestock samples collected during active surveillance between 2023 and 2026. A total of 867 biological samples were obtained from cattle ( n  = 611), camels ( n  = 175), Maral Deer ( n  = 51), and pigs ( n  = 30) across multiple regions of Kazakhstan. Viral RNA was screened by reverse transcription polymerase chain reaction (RT-PCR) targeting the HEF , PB1 , PB2 , and P3 genes using a newly designed primer panel. Positive amplicons were subjected to Sanger sequencing and phylogenetic analysis. IDV RNA was detected in 11 animals, corresponding to an overall prevalence of 1.27%. Positive samples were identified in several geographically distinct regions, indicating wider circulation than previously recognized. Complete HEF gene sequences were successfully obtained from two representative cattle strains, designated D/bovine/Zhetysu/KAZ/678/2025 and D/bovine/Zhetysu/KAZ/680/2025. Phylogenetic analysis demonstrated that both strains clustered within the D/Yama2019 lineage and shared >98.83% nucleotide identity with contemporary Asian strains. To our knowledge, this is the first report of IDV detection in Kazakhstan. These findings expand the known geographic range of IDV and suggest possible transboundary transmission routes across Central Asia. Continued molecular surveillance is warranted to clarify epidemiology, host range, and potential economic impact.

Epidemiology and molecular evolution of norovirus GII.17 in the United States, 2021-2025.

BACKGROUND GII.4 noroviruses have been the leading cause of acute gastroenteritis outbreaks in the United States (U.S.) for the past decade. Recently, GII.17 viruses have emerged globally, raising concerns about changes in disease burden and potential replacement of GII.4 as the predominant strain. METHODS We characterized molecular and epidemiological features of U.S. GII.17 norovirus outbreaks from September 2021-August 2025 submitted to CaliciNet. Norovirus-positive outbreak samples were sequenced followed by RdRp and VP1 phylogenetic analyses. CaliciNet and National Outbreak Reporting System data were linked to compare GII.17 and GII.4 epidemiologic and clinical characteristics. Virus-like particles binding to gastric mucin and antibody blockade assays were conducted to assess antigenic variation among GII.17 variants. RESULTS Among 1,412 outbreaks, GII.17 prevalence increased from 5.0% (2021-2022) to 74.8% (2024-2025). Compared with GII.4, GII.17 was more frequently reported with foodborne exposure (16.4% vs 9.6%), affected persons aged 10-49 years compared with other groups (31.1% vs 23.1%), and associated with slightly higher rates of vomiting (78.2% vs 72.2%), abdominal cramps (34.2% vs 30.1%), and fever (15.9% vs 10.9%). Phylogenetic analysis detected GII.17[P17] Romania-like (93.3%) followed by GII.17[P17] Kawasaki308-like strains (4.6%) and two novel tentative variants: Santa Clara (1.3%) and London (0.1%). Despite substitutions in key P2 antigenic sites, surrogate antibody neutralization remained conserved. CONCLUSION These findings indicate a recent shift in norovirus genotype dominance in the U.S., likely driven by enhanced transmissibility or population susceptibility rather than increased virulence. Continued molecular surveillance is essential to monitor viral evolution and public health impact of norovirus.

Molecular characterization of a rare norovirus GII.8[P8] strain detected during pediatric acute gastroenteritis surveillance in Harbin, China.

Epidemiology and Molecular Characterization of Human Metapneumovirus in Influenza-Like Illness: A Decade of Surveillance in Dibrugarh, Assam (2014-2025).

BACKGROUND Human metapneumovirus (hMPV) is a globally recognized cause of influenza-like illness (ILI), especially among children, but data from Northeast India are limited. This study analyzed epidemiological and molecular features of hMPV detected in Dibrugarh, Assam, over a decade-long surveillance period. METHODS Between May 2014 and November 2025, 3,597 ILI patients were screened for hMPV at a tertiary hospital in Dibrugarh, Assam. Clinical samples (nasopharyngeal/throat swabs) were tested using multiplex respiratory panels and TaqMan-based real-time RT-PCR. Partial sequencing of the G gene was performed by Sanger sequencing, followed by phylogenetic and glycosylation analyses using MEGA 11, NetNGlyc, and NetOGlyc tools. Statistical analysis was done using SPSS v26. RESULTS Overall, hMPV prevalence was 3.1% (112/3597), significantly higher among children aged <5 years than older individuals (3.9% vs. 1.3%; p = 0.003). hMPV activity exhibited marked winter seasonality, with significantly higher positivity during the colder months (5.6% vs. 0.8%; p < 0.001). Phylogenetic analysis demonstrated the circulation of A2.2.1 (A2b1), A2.2.2 (A2b2), and B2 lineages in Assam. The two 2025 A2.2.2 strains harbored the characteristic 111-nucleotide G-gene duplication, while comparative glycosylation analysis revealed lineage-specific variation in predicted N- and O-linked glycosylation profiles. CONCLUSION hMPV remains an important cause of pediatric influenza-like illness in Northeast India, with marked winter seasonality. The detection of A2.2.1, A2.2.2, and B2 lineages, including A2.2.2 strains with the characteristic 111-nucleotide G-gene duplication, underscores the importance of continued molecular surveillance.

ORF5-Based Molecular Characterization of PRRSV Reveals Multiple Co-circulating Lineages in Vietnam, 2021-2026.

Porcine reproductive and respiratory syndrome virus (PRRSV) continues to pose a major challenge to swine production in Vietnam because of its rapid evolution and genetic diversity. Here, we analyzed 69 PRRSV-positive samples collected from 20 provinces in Vietnam between 2021 and 2026 using ORF5 gene sequencing to characterize the genetic diversity of circulating strains. Phylogenetic analysis demonstrated the co-circulation of multiple PRRSV-2 lineages (L1, L3, L5, L8, and L10), together with a limited presence of PRRSV-1, indicating a genetically diverse PRRSV population within the analyzed diagnostic samples. Among the PRRSV-2 strains, lineage 8 (L8), particularly sub-lineage L8E, was the most frequently detected, whereas lineage 10 (L10) accounted for 24.6% of the sequenced isolates and was detected only in samples collected from 2023 onwards. Independent maximum-likelihood phylogenetic and pairwise ORF5 distance analyses showed that the Vietnamese L10 strains formed a distinct monophyletic cluster within lineage 10. Analysis of the GP5 protein identified amino acid variation in previously described antigenic regions, providing descriptive information on the genetic diversity of circulating Vietnamese PRRSV strains. Collectively, these findings provide updated insights into the molecular epidemiology of PRRSV in Vietnam and highlight the value of continuous molecular surveillance for monitoring the emergence and distribution of PRRSV lineages.