Novel duck orthoreovirus (NDRV) represents a major pathogen severely affecting the waterfowl farming industry in China, yet its evolutionary dynamics and reassortment patterns remain poorly defined. In this study, we sequenced the full genomes of 10 NDRV isolates obtained from Shandong and Jiangsu provinces (2018–2023) and analyzed their genetic features through sequence identity, phylogenetics, and reassortment detection. We also evaluated pathogenicity in 1‐day‐old ducklings for three representative isolates via intravenous injection. Our results show that nucleotide (nt) homologies across all gene segments ranged from 86.9% to 99.9%, and the L2, M1, S2, and S4 segments displayed greater sequence variability than the traditionally hypervariable S1 gene in our isolates. We identified recombination events in the M2 segment of strain XT18 (with SDYC and HN5d as parental strains) and the S4 segment of strain LY20 (with GX‐Y7 and SDYC as parents), which, to our knowledge, represent the first reports of recombination in the M2 and S4 segments of NDRV. In pathogenicity tests, strain SDYC induced the most severe splenic lesions and maintained the highest viral loads in vivo. Collectively, these findings clarify the molecular evolution and reassortment landscape of currently circulating NDRV strains and offer a scientific basis for selecting vaccine candidates and designing precision control strategies.
Brucella spp. are facultative intracellular bacteria that infect and induce brucellosis in a diverse range of mammalian hosts. Understanding the mechanisms underlying the intracellular survival of Brucella is of critical importance for the prevention and control of brucellosis. This study uncovers the mechanism by which Brucella abortus manipulates host lactate metabolism to facilitate its intracellular proliferation. Infection of macrophages by B. abortus enhanced L‐lactate production by the host macrophages, which in turn promoted bacterial proliferation. Proteomic and functional analyses identified the host glucose transporter protein Slc2a1 as a positive regulator of both B. abortus proliferation and host cellular lactylation. The B. abortus effector protein SepA upregulated Slc2a1 expression and host cellular lactylation. Lactylation of the transcription factor USF2 at lysine residues 255 and 275 suppressed production of the host lipid metabolism‐associated protein Fabp4, thereby enhancing bacterial survival. Moreover, Fabp4 inhibition attenuated B. abortus ‐induced M1 polarization and lipid metabolism in macrophages. These findings reveal a dual‐axis regulatory network through which B. abortus exploits host L‐lactate metabolic reprogramming via the SepA/Slc2a1 and L‐lactate‐USF2/Fabp4 axes to establish its intracellular niche, providing new insights into host– Brucella metabolic crosstalk.
Cardiopulmonary nematodes of canids are important veterinary pathogens, and their distribution across Europe is expanding, a trend driven by climate change and shifting wildlife dynamics. The golden jackal ( Canis aureus ), a highly adaptable mesocarnivore, could function as a key reservoir and intermediary host at the boundary between wild and domestic animals. This study provides a comprehensive, long‐term assessment of the cardiopulmonary nematode community in golden jackals from Northeastern Italy (Friuli Venezia Giulia [FVG]). From 2009 to 2025, 109 jackal carcasses were necropsied. The nematodes recovered were identified morphometrically and confirmed by PCR (targeting mtCOI, 18S rRNA and 12S rRNA genes). The infection parameters and the influence of host characteristics on infection probability were calculated. Spatial modelling was applied in order to assess how environmental and anthropogenic factors influence the probability of infection. Overall, 52 jackals (47.7%) were positive for at least one parasite species. The prevalence of Angiostrongylus vasorum was the highest (34.9%), followed by Eucoleus aerophilus (13.8%), Crenosoma vulpis (12.8%) and Dirofilaria immitis (4.6%). Host sex had a significant effect on the prevalence and abundance of C. vulpis , with higher rates in males. Mean annual precipitation and the extent of agricultural land cover (AGR) were significant positive predictors of A. vasorum and E. aerophilus infections. Our findings suggest that the golden jackal may serve as a reservoir for veterinary and zoonotic pathogens. As jackals increasingly exploit human‐dominated habitats, their role in maintaining and spreading these nematodes in the environment may become more relevant. Given the species’ ongoing westward expansion, integrated One Health surveillance programmes are essential to monitor pathogen spread within multispecies landscapes.
Swine influenza A virus (swIAV) is an important One Health pathogen due to its genetic diversity, ongoing reassortment, and implications for animal and public health. Between 2022 and 2023, nasal swabs (NSs) from pigs of multiple age groups were collected from 134 farms across 16 European countries and analyzed by real‐time quantitative PCR (RT‐qPCR), subtyping, and whole‐genome sequencing. Clinical and management metadata were integrated with viral genotypes. swIAV was detected in 93% of the targeted farms included in this study, with Clade 1A (H1pdmN1) and Clade 1C (H1avN1, H1avN2, and H1huN2) predominating. Sequencing identified 23 genotypes, including 12 previously unreported ones. Exploratory analysis suggested potential associations between specific hemagglutinin (HA) (sub)clades and clinical signs in piglets and with herd management factors. High genotype diversity—especially in Spain (ES)—suggests potential associations with intensive production systems. Overall, this large European survey indicates frequent circulation of swIAV within the targeted study population, accompanied by high genetic diversity and ongoing reassortment, underscoring the need for harmonized genomic surveillance to inform veterinary and public health preparedness.
African swine fever (ASF) remains a major threat to global pig production. An understanding of within‐pen transmission dynamics is essential for designing effective prevention and control. Three independent direct‐contact (DC) transmission experiments were conducted using Korean ASF virus (ASFV) isolates representing distinct epizootic phases in the Republic of Korea: Korea/Pig/Paju1/2019, Korea/Pig/Yeongwol/2021, and Korea/Pig/Hongcheon/2023. In each experiment, two inoculated donor pigs were cohoused with five DC‐susceptible pigs for up to 18 days postinoculation (dpi). Transmission parameters were estimated using two complementary modeling approaches. First, an approximate Bayesian computation sequential Monte Carlo (ABC‐SMC) framework was applied to a deterministic susceptible–exposed–infectious–removed (SEIR) ordinary differential equation (ODE) model. Second, a stochastic agent‐based model (ABM) was used to validate parameter estimates and quantify within‐pen outbreak probability. All DC pigs in the three experimental groups developed ASFV infection and died within 18 days postexposure. The Bayesian SEIR model estimated transmission coefficients ( β ) of 0.503, 0.435, and 0.308 per susceptible–infectious pair per day for Paju, Yeongwol, and Hongcheon isolates, respectively. Notably, the Korea/Pig/Hongcheon/2023 isolate exhibited a shorter posterior latent period ( ε = 3.78 days; 95% credible interval [CrI]: 2.78–4.83) than Korea/Pig/Paju1/2019 ( ε = 7.23 days; 95% CrI: 5.36–9.48) and Korea/Pig/Yeongwol/2021 ( ε = 6.11 days; 95% CrI: 4.57–7.73). ABM simulations using posterior parameter distributions yielded per‐donor secondary infection estimates ( R pd ; the mean number of DC pigs infected per‐donor pig, structurally bounded by the pen size) of 1.95, 2.10, and 2.37 for the Paju, Yeongwol, and Hongcheon isolates, respectively. In sensitivity analyses, the shorter latent period of the Hongcheon/2023 isolate was consistently observed under alternative exposure‐time assumptions, distance‐function weightings, and prior specifications, although the absolute values of β and ε depended on the assumed exposure time. This study provides the first comparative analysis of within‐pen transmission dynamics for multiple Korean ASFV isolates. Although overall transmission potential was similar across isolates, the Korea/Pig/Hongcheon/2023 isolate exhibited a shorter estimated latent period and a marginally higher R pd . Because isolate identity was confounded with experiment year, this difference requires confirmation in contemporaneous experiments; nevertheless, it may have implications for early detection and rapid spread within pig facilities.
