Bovine leukemia virus (BLV) encodes a cluster of viral microRNAs (miRNAs) that remain abundantly expressed during latency, when viral protein production is restricted. Naturally occurring single-nucleotide polymorphisms (SNPs) within this locus are common, yet their functional consequences for miRNA output and host gene regulation remain poorly defined. Peripheral blood leukocytes from 53 naturally BLV-infected cattle were analyzed, and the 554-nt BLV miRNA locus was amplified and sequenced. Field-derived variants containing mutations within RNA polymerase III promoter motifs, seed regions, and termination signals were selected for functional evaluation. Reference and variant loci were co-expressed with a BLVΔ-miRNA infectious clone in HEK293T cells under controlled conditions. Mature miRNA levels were quantified by stem-loop reverse-transcription quantitative polymerase chain reaction (RT–qPCR), and global host transcriptional responses were assessed using oligonucleotide microarrays. Predicted miRNA targets were identified using bioinformatic analyses. Sequence analysis identified 84 polymorphic sites, with a substantial proportion mapping to Pol III regulatory elements and seed regions. Variant loci displayed altered accumulation of selected mature miRNAs and shifts in predicted seed-dependent target repertoires. Transcriptome profiling revealed variant-associated modulation of innate immune-signaling components, interferon-responsive genes, antigen-presentation pathways, tumor-suppressor networks, and extracellular matrix-related processes. Enrichment analysis demonstrated a statistically significant overlap between predicted miRNA targets and downregulated transcripts. Natural polymorphisms within the BLV miRNA cluster modulate miRNA expression and are associated with distinct host regulatory signatures in a controlled experimental system. These findings suggest that sequence variation in the viral miRNA locus may contribute to differential host–virus interactions and influence mechanisms supporting viral persistence.
Nigeria faces significant HIV prevalence disparities. Existing studies are limited, hindering targeted interventions. A comprehensive national analysis of socio-demographic and behavioral factors is crucial for effective strategies. This study addresses this gap by providing an in-depth, nationwide assessment of HIV prevalence determinants. It aims to examine the socio-demographic determinants of HIV prevalence across Nigeria, investigating the influence of gender, marital status, education, wealth, and regional differences on HIV risk to inform targeted intervention strategies. A cross-sectional study was conducted utilizing nationally representative data from the 2018 Nigeria AIDS Indicator and Impact Survey (NAIIS). The sample comprised 173,716 adults and 32,484 children. Descriptive statistics, chi-square tests, and multivariate logistic regression were employed to assess associations between socio-demographic factors and HIV prevalence. The overall HIV prevalence among adults in Nigeria was 1.36
Clade 2.2 H5N1 influenza viruses have caused an unusually high number of human infections, providing a unique opportunity to investigate early molecular steps associated with host adaptation. Although most work has focused on hemagglutinin (HA), the contribution of neuraminidase (NA) to these early adaptive events has remained unclear. By analyzing publicly available sequences from clade 2.2-infected patients, we identified 20 NA mutations and compared their phenotypes to 20 mutations acquired during diversification in primary human airway cells under drug-free conditions. Most patient-derived NA mutations resulted in modest reductions in sialidase activity, keeping activity within a functional range that supported improved replication in α2,6 sialylglycan (α2,6 Sia)-dominant environments, whereas excessive reduction impaired fitness. Notably, the phenotypes of culture-selected and patient-derived mutations were highly concordant, suggesting that these NA changes arose through natural selection rather than antiviral pressure. Re-analysis of patient sequences further revealed that many adaptive NA mutations co-occur with HA mutations that confer only weak, partial α2,6 Sia binding. Using reverse genetics, we found that such naturally occurring HA/NA mutation pairs acted cooperatively in a receptor-context-dependent manner to support α2,6-associated replication relative to HA-only mutants, placing these variants within a constrained "early-adaptation space" characterized by limited α2,6 engagement and moderately reduced NA activity. Together, these findings indicate that early human adaptation of clade 2.2 H5N1 involves not only HA and PB2, but also incremental, cooperative tuning of NA function. Monitoring coordinated HA-NA evolution may therefore improve risk assessment frameworks for zoonotic influenza viruses poised at early stages of human host adaptation.
Viral infections can cause increased mortality of honey bee colonies. Because of an asymptomatic course of infections their detection in honey bees is only possible by the use of sensitive and specific diagnostic methods. Nowadays, the conventional RT-PCR assays are routinely employed for detection of honey bee viruses, but none of them have had their diagnostic usefulness confirmed through documented optimization and validation process. The aim of this study was to develop of the two in-house multiplex RT-PCR (mRT-PCR) assays for the detection of CBPV, iflaviruses (DWV-A, SBV) and dicistroviruses (ABPV, IAPV, BQCV) of bees. The sequences of the primers used in the developed Ifla-CBPV and Dicistro mRT-PCRs were refined to include point mutations observed in the respective genome fragments of honey bee viruses detected worldwide so far, including newly characterised virus strains from Poland. The optimization of the PCR mixtures composition and temperature-time profiles of the assays was performed. To avoid false negative results, an internal amplification control (IAC) was prepared and incorporated into the Ifla-CBPV and Dicistro mRT-PCR assays. The developed IAC-controlled mRT-PCR assays allow for simultaneous detection of mixed viral infections caused by six virus species commonly occurring in worldwide population of bees. The use of IAC during molecular detection enables monitoring of the assays correct performance.
Ornithobacterium rhinotracheale (ORT) is an emerging avian respiratory pathogen of global concern, causing significant economic losses, particularly in turkeys. Although its distribution is worldwide, genomic data from different geographic regions remain scarce, limiting understanding of its genetic diversity, virulence-associated features, and antimicrobial resistance profiles. In this study, we performed whole-genome sequencing of 49 O. rhinotracheale isolates recovered from respiratory tract and joint lesions during outbreaks of ornithobacteriosis in turkeys in Poland to characterize sequence types and explore the genomic diversity and the distribution of virulence- and resistance-associated genes. Comparative multilocus sequence typing revealed high genetic heterogeneity, including three novel sequence types (ST46, ST50, ST51), highlighting ongoing local diversification within a globally distributed pathogen. Whole-genome core single nucleotide polymorphism (SNP)-based phylogenetic analysis further resolved genetic relationships among isolates and identified major genomic clusters. Genomic profiling identified several virulence-associated genes and insertion sequences, including IS4351 and ISMlu9. Distinct resistance gene patterns observed between major STs (ST3, ST46) were observed. These findings provide new insights into the genomic diversity of O. rhinotracheale populations and contribute to a broader understanding of its epidemiology and antimicrobial resistance in poultry worldwide.
