Bovine digital dermatitis (BDD) is a globally distributed infectious hoof disease that negatively impacts the wellbeing and productivity of the affected animal. Treponema species and in particular Treponema phagedenis are the microbes strongly associated with the disease. Recently, it has been reported that Bos indicus cattle are more resistant to BDD and to the colonization by Treponema phagedenis in contrast to many Bos taurus breeds. This study investigated whether Bos indicus mount a different immune response to Treponema phagedenis compared with Bos taurus cattle, to better understand the different disease outcome in the two subspecies. Therefore, we exposed freshly isolated primary bovine blood cells to Treponema phagedenis and dissected subsequent bovine immune responses. The comparison between the two subspecies revealed significant different immune responses to Treponema phagedenis. We observed a stronger Th1/proinflammatory cytokine induction in Bos taurus animals mainly driven by CD4[+] T and CD21[low] B cells in secreting IFN-γ. We assume that these distinct initial immune responses are linked to the control of Treponema phagedenis and the outcome of BDD. Additionally, we observed significant higher levels in the expression of the matrix metalloproteinase-9 by peripheral blood mononuclear cells in Bos indicus cattle, which likely benefits the host response to Treponema phagedenis.

Between 14 October 2024 and 24 March 2025, 43 cases of clade 2.3.4.4b highly pathogenic avian influenza (HPAI) type A (H5N1) infections in wild birds and 1 case in a leopard cat were detected through the national HPAI surveillance program. We performed whole-genome sequencing of 51 isolates and investigated their phylogenetic relationships. Phylogenetic analyses identified nine distinct genotypes, designated Kor24-25A to Kor24-25I. The most commonly detected genotype, Kor24-25A (n = 24), was frequently detected in Pelecaniformes and was most prevalent between December 2024 and January 2025. Bayesian continuous and discrete trait phylodynamic analyses using HA gene sequences identified the three most probable routes of viral introduction via Gyeonggi, Jeju, and the southern coastal areas of the Korean Peninsula and suggested that wild ducks served as the primary reservoirs facilitating viral transmission in the wild bird population. During the 2024-2025 season, great egrets (Ardea alba) appeared to be more frequently affected than other wild bird species, suggesting possible seasonal differences in species-specific disease outcomes among wild birds. This study provides valuable insights into the phylodynamics, host associations, and transmission patterns of HPAI H5N1 viruses. It emphasizes the importance of enhanced surveillance programs targeting key avian hosts and high-risk geographic areas.

Bovine viral diarrhea virus (BVDV) is an important infectious pathogen responsible for substantial economic losses in the global cattle industry. The structural protein E2 serves as a major protective antigen of BVDV and is the main target for host neutralizing immune responses. However, its antigenic structure and epitope distribution remain poorly understood. Here, five novel monoclonal antibodies (mAbs) against the E2 protein of BVDV-1 were generated using hybridoma technology, and their reactivity patterns, biological properties, and recognized epitopes were systematically characterized. As a result, one mAb, TBH033, specifically reacted with BVDV, while four mAbs, TBH002, TBH004, TBH008, and TBH009, exhibited broad-spectrum reactivity against different subgenotypes of classical swine fever virus (CSFV) and BVDV, as well as E2 proteins from eight pestivirus species (BVDV-1, BVDV-2, BVDV-3, CSFV, BDV, PPeV, GPeV, and ovIT PeV). All five mAbs exhibited high binding affinity to the E2 protein and potent cross-neutralizing activity against BVDV strains of different subgenotypes. Epitope mapping with chimeric recombinant and site-mutated E2 proteins revealed that TBH002, TBH004, TBH008, and TBH009 recognized a linear epitope in the DA domain, comprising [70]H, [72]R, [74]L and [76]T as critical residues; TBH033 targeted a BVDV-specific conformational epitope in the DB domain, defined by the conserved amino acid motifs [103]LCP[105], [123]GP[124]. These findings enrich our understanding of the antigenic structure of the E2 protein and may facilitate the design of E2-based diagnostic tools and vaccines.

Host defense peptides (HDPs) possess both direct bacteriocidal and immunomodulatory activities. In this study, chicken cathelicidin-1 (cCATH-1) and chicken cathelicidin-3 (cCATH-3) were selected based on their markedly different minimum inhibitory concentrations (MICs) against avian pathogenic Escherichia coli (APEC) strains, with MICs of cCATH-1 being 4- to 16-fold lower than those of cCATH-3. However, following intraperitoneal challenge with APEC strain E058 (4 × 10[6] CFU/mouse), 80% of cCATH-3 treated mice survived while 20% of cCATH-1 treated mice survived. Flow cytometry (FC) revealed significantly lower peripheral blood Ly6C[high] monocytes but higher peritoneal Ly6C[high] macrophages in cCATH-3-treated mice at 4 and 8 h post-treatment. Peritoneal CCL3 secretion was significantly upregulated in cCATH-3 treated mice at 8 h post-treatment. Upon knockout of macrophages, the protection of cCATH-3 in mice against APEC E058 challenge was markedly abolished. In vitro, peritoneal macrophages treated with cCATH-3 showed stronger bacteriocidal activity than those treated with cCATH-1. Mouse CCL-3 (mCCL3)-specific antibody neutralize the effect of mCCL3 on macrophages chemotaxis in vitro. mCCL3-specific antibody administration resulted in 0% survival in cCATH-3-treated mice versus 60% survival in cCATH-3-treated mice administered with mock antibody, while cCATH-1-treated mice showed 0% survival administered with either mCCL3-specific antibody or mock antibody after APEC E058 strain challenge. In summary, cCATH-3 provides robust protection against APEC infection compared with cCATH-1 in mice, partially through CCL3-mediated macrophage chemotaxis and enhanced bacteriocidal activity in activated macrophages, revealing a novel mechanism of avian cathelicidins and supporting HDPs as alternatives to antibiotics for controlling avian colibacillosis.

Actinobacillus pleuropneumoniae (A. pleuropneumoniae) is the etiologic agent of porcine pleuropneumonia, a severe respiratory disease characterized by hemorrhagic, necrotizing lung lesions that cause significant economic losses on the global swine industry. However, the molecular mechanisms underlying the lung pathogenicity of A. pleuropneumoniae remain unclear. Here we demonstrate that A. pleuropneumoniae infection induces lung injury through activating the NLRP3-mediated inflammatory response mediated by the YadA-like head region (Adh) of Apa1, a bacterial adhesin that mediates attachment to host cells. Importantly, we show that Adh triggers the NLRP3-mediated inflammatory response by engaging olfactory receptor family 5 subfamily M member 11 (OR5M11), a host receptor previously shown to interact with Adh. Furthermore, OR5M11 contributes to the Adh-activated inflammatory response by promoting mitochondrial DNA release. Taken together, our results provide new insights into the pathogenesis of A. pleuropneumoniae, particularly regarding NLRP3-mediated inflammatory pathology.

Mycoplasma hyopneumoniae (Mhp) is the primary etiological agent of porcine enzootic pneumonia and establishes infection through close association with the respiratory ciliated epithelium. Classical models of Mhp colonization have focused mainly on specific interactions between adhesins, particularly P97, and ciliary receptors. Although this framework has provided important insights into ciliary attachment, increasing evidence indicates that Mhp adhesion involves multiple surface proteins and host ligands, including sulfated glycosaminoglycans (GAGs), fibronectin, plasminogen (Plg) and extracellular actin. In this review, we synthesize current evidence and propose a glycocalyx-mediated infectious niche framework for early Mhp colonization. Within this framework, sulfated glycans within the respiratory glycocalyx may contribute to bacterial positioning at the airway interface, while multiligand adhesin interactions may contribute to attachment and Plg-binding surface proteins may facilitate host-factor recruitment. Among these interactions, plasminogen recruitment provides a potential link between adhesion and local interface modification, including possible extracellular matrix remodeling and epithelial injury. Other processes, including potential GAG-mediated local retention, host glycan-dependent variation in attachment and glycocalyx remodeling, remain hypotheses requiring further validation. By distinguishing experimentally supported interactions from mechanistic inferences, this review presents Mhp colonization as a dynamic host-pathogen interface process rather than a simple adhesin-receptor event. This framework provides a basis for future investigation of early colonization mechanisms and anti-adhesion strategies in porcine enzootic pneumonia.

Glässer's disease, caused by Glaesserella parasuis (GPS), causes substantial economic losses in the swine industry worldwide. This situation is largely attributable to the poor cross-protective efficacy of currently available vaccines. In this study, a multi-antigen cocktail subunit vaccine against GPS infection was developed. In silico antigenicity analysis, the immunoprotective efficacy, and antibody titers of 14 GPS antigens were assessed in a murine model. Finally, VacJ, PtsG, and GAPDH were identified as the component of the cocktail vaccine, with Gel-01 as the optimal adjuvant. Immunization of the cocktail vaccine induced robust humoral and cellular immune responses. The vaccine conferred effective cross-protection against lethal-dose GPS4 and GPS5 infections in mice. As supported by a pilot study, it also demonstrated favorable immunoprotective efficacy against GPS infection in piglets. Furthermore, immune sera from vaccinated mice significantly inhibited the growth of GPS4 and GPS5. Overall, these results suggested that the subunit cocktail vaccine established in this study exhibits great potential for preventing GPS infection under experimental conditions, and further large‑scale pig trials are still required to validate its practical applicability in field production.

To improve detection of equine back-related disorders, it is important to establish how movement dynamics in horses' thoraco-lumbo-sacral spine are normally affected by intrinsic and extrinsic factors. This cross-sectional study aimed to quantify how discipline, gait, and surface impact differential rotational and translational movements along the backs of 107 horses from the military and police forces. The horses were walked and trotted in-hand in a straight-line over hard and soft surfaces. During the exercises, nine inertial sensors (XSens MTw) were mounted to the poll, withers, thoracic vertebrae-13 (T13) and 18 (T18), lumbar vertebra-3 (L3), sacrum (between tubera sacrale), left and right tubera coxae, and caudal sacrum ('tail'). Linear mixed models assessed whether horse discipline (load pulling or non-load pulling), surface (soft or hard), age, or stride time influenced rotational and translational range of motion differences between adjacent sensors at either walk or trot (significance at p < 0.05). When compared to non-load pullers, it was apparent that the load pullers had reductions in differential rotational movements (0.5-3.1º in walk, p ≤ 0.039; and 0.5-2.3º in trot, p ≤ 0.049) and reductions in differential cranio-caudal, medio-lateral and dorso-ventral translations (2.2-15.0 mm in walk, p ≤ 0.039; and 1.2-7.6 mm, p ≤ 0.045 in trot), plus an increase in differential cranio-caudal translation at the Poll-Withers (12.8 mm in trot, p < 0.001). Soft surfaces increased differential rotational movements (0.1-1.2º in walk, p ≤ 0.048; and 0.2-2.9º in trot, p ≤ 0.007) and differential translational movements (1.4-16.3 mm in walk, p ≤ 0.002; and 0.5-2 mm in trot, p ≤ 0.007) in most regions of the thoraco-lumbo-sacral spine compared to hard surfaces. The amplitude of differential rotational and translational movements did not show systematic patterns with stride time and age. Further work is needed to understand whether the observed changes to differential rotational and translational movements along the equine thoraco-lumbo-sacral spine, imposed by working discipline and surface conditions, impact long-term equine health, well-being, or susceptibility to injury. This work will lay foundations for the development of an equine back dynamics reference framework, to which individual data may be compared.

Brucella is a successful intracellular bacteria, regulating various physiological activities within host cells by secreting multiple virulence factors. However, the specific molecular mechanisms underlying these processes remain unclear. Through interactions with host proteins, Brucella can influence cellular physiological processes to evade immune responses and enhance the bacteria survival and reproductive abilities. The type IV secretion system (T4SS) of Brucella plays a significant role in the process of Brucella infecting cells. This study revealed the interaction between BtpB and YWHAZ (14-3-3ζ) by analyzing the interaction network of 112 host proteins interacting with Brucella effector protein BtpB. Furthermore, we discovered that BtpB regulates the expression of YWHAZ protein and the deletion of its TIR domain abolishes this interaction as well as the effect on YWHAZ protein expression. Moreover, BtpB activates pro-apoptotic markers leading to apoptosis induction in cells. Our results provide mechanistic evidence that BtpB-dependent apoptosis regulation is contingent upon interaction with YWHAZ, and further characterize YWHAZ as a host factor governing Brucella's intracellular survival capacity. This study provides valuable understanding of the immune response mechanism against intracellular bacterial infections in hosts and offers a theoretical basis for future prevention and treatment strategies for Brucellosis.