Macrophage phenotypic adaptation critically regulates inflammatory balance during infection; however, progress in equine immunology has been limited by a lack of specific tools for standardized identification. To address this gap, we established a reliable, antibody-based detection method for characterizing equine macrophage M1-like and M2-like marker profiles. After initially validating canonical marker genes via qPCR, we developed specific monoclonal antibodies targeting the differentially expressed surface proteins CD80 (M1-like) and CD163 (M2-like). These novel antibodies enabled the creation of a multi-modal detection approach combining flow cytometry, western blotting, and qPCR. Applying this methodology in vitro revealed distinct pathogen-specific marker profiles: Salmonella abortus equi, equine herpesvirus (EHV-1), and equine arteritis virus (EAV) promoted an early M1-like profile, whereas an attenuated equine infectious anemia virus (EIAV) strain drove an M2-like phenotype. Ultimately, this work provides a validated detection system for equine macrophage phenotyping, establishing a critical foundation for future research into host-pathogen interactions and targeted therapeutics.IMPORTANCEMacrophage phenotypic adaptation plays a critical role in infectious diseases, as pathogens often manipulate these states to evade immune responses or drive damaging inflammation. Accurately monitoring these functional shifts is vital for guiding disease treatment and evaluating vaccines. However, standardized detection tools for equine macrophages have been lacking. In this study, we established a reliable, antibody-based method utilizing novel monoclonal antibodies against equine CD80 and CD163 to identify M1-like and M2-like marker profiles. This straightforward and highly specific approach overcomes the limitations of previous indirect methods, providing a critical, accessible tool for assessing macrophage responses to equine pathogens and advancing veterinary immunology.
Assisted reproductive technologies (ART) are extensively used in domestic animal reproduction; however, improving their efficiency and consistency remains a major challenge for achieving reliable reproductive outcomes. The equine industry faces unique challenges related to sperm capacitation, which limited the success of conventional in vitro fertilization (IVF) for many years. Consequently, intracytoplasmic sperm injection (ICSI) became the most widely used technique for commercial in vitro embryo production. Even though a successful IVF protocol was recently developed, substantial opportunities remain to improve its efficiency and consistency in the equine species. In this context, strategies that enhance sperm functional competence represent a key avenue to improve equine in vitro embryo production. Sperm energy-restriction and recovery (SER) treatment has been shown to improve fertilization and embryo development rates in mice and bovine species following IVF and ICSI, respectively. Here, we evaluated the effect of SER on cryopreserved equine spermatozoa by assessing sperm functional parameters and embryo development after ICSI. Frozen-thawed sperm were incubated without pyruvate, lactate, and glucose (starvation; ST) and subsequently recovered using a complete medium (SER). Under ST conditions, sperm became immotile within 20 min, and motility was restored by SER to control levels. Compared with controls, SER-treated sperm exhibited increased curvilinear velocity (VCL; 246.4 vs. 201.6 µm/s) and lateral head displacement (ALH; 9.8 vs. 7.3 µm), accompanied by reduced linearity (LIN; 34.4 vs. 43.4%; p < 0.05). ST reduced ATP content and mitochondrial membrane potential and elevated intracellular Ca2+ levels; all were restored following SER. Consistent with this transient Ca2+ rise, ST sperm displayed a higher percentage of live acrosome-reacted cells than controls (p < 0.05). No differences were detected in PKA substrates or tyrosine phosphorylation, two markers of capacitation. Finally, ICSI using SER-treated sperm resulted in a greater proportion of day-7 blastocysts compared with controls (44.2% vs. 18%; p < 0.05). Collectively, these findings indicate that SER enhances equine sperm function and improves early embryo development, highlighting its potential to advance reproductive biotechnologies in this species. Ovum pick-up combined with intracytoplasmic sperm injection (OPU-ICSI) is the dominant assisted reproductive technology for in vitro embryo production in horses and is widely used in both research and commercial programs. Despite its success, OPU-ICSI outcomes remain highly variable, in part due to limitations in sperm selection strategies and the lack of effective sperm treatments capable of improving embryo development. Therefore, approaches that enhance sperm functional competence prior to injection represent an opportunity to optimize equine-assisted reproductive technologies. Sperm energy-restriction and recovery (SER) is a treatment that transiently deprives spermatozoa of energy substrates followed by their reintroduction. SER has been shown to improve fertilization and embryo development outcomes in other mammalian species following IVF or ICSI. In this study, frozen–thawed equine spermatozoa were subjected to SER. Energy restriction induced a reversible loss of sperm motility and was associated with changes in ATP content, mitochondrial membrane potential, and intracellular calcium levels. Upon restoration of energy substrates, sperm recovered motility with enhanced kinetic parameters. When used for ICSI, SER-treated sperm produced a higher proportion of embryos reaching the blastocyst stage. These findings indicate that SER enhances equine sperm function and fertilizing ability, representing a promising strategy to improve reproductive outcomes in the equine industry.
Mesenchymal stem/stromal cells (MSCs) hold great potential for treating various conditions, but their effectiveness and safety in allogeneic therapies can be affected by the recipient's immune response, among other factors. Allogeneic MSC administration has been associated with immune recognition in different species, including horses. These animals are both veterinary patients and translational models, offering valuable insights into how allogeneic MSCs interact with the immune system in vivo. Factors such as inflammation, chondrogenic differentiation, and major histocompatibility complex (MHC) compatibility between donor and recipient can influence immune responses, potentially affecting the feasibility of repeated MSC administrations. This study evaluates the humoral immune response following repeated administration of chondrogenically differentiated (MSC-chondro), pro-inflammatory primed (MSC-primed), and basal (MSC-naïve) equine MSCs into autologous, MHC-matched, and MHC-mismatched recipients. Equine MSC-chondro, MSC-primed or MSC-naïve were embedded into alginate scaffolds and repeatedly implanted subcutaneously into autologous, MHC-matched or MHC-mismatched allogeneic horse recipients. Serum samples collected before and 1, 3, and 6 weeks after each administration were analysed for cytotoxic allo-antibodies against donor MHC. Recipient sera (neat, 1:2 and 1:16 dilution) were tested against donor-derived target cells using two-stage microcytotoxicity assays. Autologous and MHC-matched recipients did not develop antibodies against the MHC of the donor, regardless of the MSC type administered. In contrast, MHC-mismatched horses developed allo-antibodies after the first administration, with a notable increase following the second administration. All the MSC types triggered a humoral immune response in MHC-mismatched recipients, but MSC-chondro provoked the strongest immune recognition. Donor-recipient MHC compatibility was more important than inflammatory priming or chondrogenic differentiation of equine MSCs to prevent the development of allo-antibodies. Thus, when donor and recipient are MHC-matched, different types of equine MSCs (MSC-chondro, MSC-primed or MSC-naïve) could be administered without producing a humoral response.
Sarcoids are the most common cutaneous tumors in horses, representing up to 90% (35%-90%) of skin neoplasms. Mostly caused by Bovine Papillomavirus (BPVs) infections, sarcoids are highly resistant to therapy and prone to recurring, posing a significant threat to equine health. The aim of this study is to explore molecular pathogenetic mechanisms underlying the development of equine sarcoids, by applying transcriptomic approach. After testing samples for viral DNA, both mRNA and small RNA expression was analyzed via high-throughput Illumina sequencing comparing 12 sarcoids and 12 healthy skin samples as controls. Differentially expressed genes (DEGs), DE miRNAs (sarcoids vs. controls) and miRNA-DEG couples with opposite expression trends, were retrieved and subjected to a functional analysis. Over 6K DEGs emerged, 3620 down-regulated and 2415 up-regulated along with 145 DE miRNAs, 56 downregulated and 89 upregulated. Among the enriched biological processes for DEGs, some were related to growth factors production and collagen binding, cell migration and proliferation, tissue morphogenesis and inflammatory response. Interestingly, "Pathways in cancer" and "Hippo signaling pathway" were enriched KEGG pathways for the miRNA-DEG couples. Our data identified a great transcription discrepancy between sarcoid lesions and healthy skin with an overall enrichment for processes related to cellular transformation. RNA-seq sequencing depth allowed the search for candidate chimeric transcripts associated with viral integration events. Chimeric RNAs can influence gene regulation and may contribute to tumor growth and immune modulation. Via computational analysis we identified six fusion loci in tumor samples and in two sarcoid margins, with the most frequent event involving WNT10B and FKBP11. This fusion, detected in 6/10 sarcoids, is of particular interest since WNT10B activates the WNT/β-catenin cascade, while FKBP11 has been implicated in osteosarcoma progression. Although functional validation is ongoing, this represents the first report of chimeric transcripts in equine sarcoids, opening new perspectives on BPV-driven oncogenesis.
This study examined how parents experienced the ASTride Equine-Assisted Occupational Therapy intervention for their children with ADHD, and the meanings they ascribed to changes observed in their children and themselves. Thirteen parents of children aged 7-12 who completed the ASTride intervention participated in in-depth, semi-structured interviews. A grounded theory approach guided the analysis, which included open coding, category mapping, and thematic modeling to identify central processes across narratives. (1) Parents' perceived benefits for children including emotional growth, improved regulation, and the transfer of skills beyond the stable; (2) Benefits for parents such as active involvement, reflection, and enhanced parenting strategies; and (3) Environmental benefits highlighting the calming, sensory-rich nature of the stable and interaction with animals. Parents experienced ASTride as a transformative, family-centered intervention that supported children's regulation and participation while fostering parental insight and engagement. Interviewing parents provided unique insight into how therapeutic changes were recognized, interpreted, and generalized across home, school, and family contexts. These findings demonstrate that parents' perspectives can inform the refinement of Equine Assisted Occupational Therapy by highlighting the processes through which families perceive children's participation, strategy transfer, and engagement in everyday life. Parent perceived the ASTride (Attention Skills Therapy), Equine-Assisted Occupational Therapy intervention as supporting their children’s emotional regulation, confidence and participation in daily activities.Parents described interaction with horses as facilitating engagement, motivation, and regulation processes relevant to rehabilitation goals.Parents perceived their involvement in the intervention as contributing to greater reflection and the use of supportive strategies that generalize to daily routines.Parents described the stable’s sensory-rich, natural environment may optimize participation and therapeutic responsiveness.
Messenger ribonucleic acid (mRNA) has emerged as a new class of therapeutic agent with unprecedented potential. In particular, the lipid nanoparticle (LNP)-mRNA formulations enabled safe and effective delivery of mRNA in vivo, leading to the success of mRNA vaccines during the COVID-19 pandemic. To control the potential misuse of LNP-mRNA agents in equine sports, a simple and sensitive method has been developed for the detection of ionisable lipids in equine plasma using supported liquid extraction (SLE) followed by liquid chromatography-high-resolution tandem mass spectrometry. To overcome the significant ionisable lipid-protein binding, plasma was diluted with isopropanol and heptane prior to SLE. This preparation technique yielded rapid and efficient recovery of a selection of nine candidate ionisable lipids and derivatives. Method validation showed adequate sensitivity and robustness, achieving estimated limits of detection as low as 5 pg/mL. The method has been successfully applied for the detection of ALC-0315 in plasma samples from a horse administered with LNP-mRNA. To the best of our knowledge, this is the first report of a detection method for the screening of ionisable lipids in equine biological samples, providing a practical tool for doping control of mRNA agents.
African horse sickness is a severe vector-borne viral disease of equines, associated with high mortality and substantial economic losses. In Ethiopia, where equines are essential for transport and agriculture, the disease remains endemic, yet epidemiological data are limited in many areas. This study aimed to estimate the seroprevalence of African horse sickness virus (AHSV) and describe variation in seropositivity across selected factors in equines in the Central Gondar Zone, Ethiopia. A cross-sectional study was conducted from December 2024 to August 2025, during which 384 serum samples were collected and tested using a blocking enzyme-linked immunosorbent assay (bELISA). Of these, 310 were seropositive, giving an overall seroprevalence of 80.7% (95% CI: 76.4-84.6%). Seroprevalence was slightly higher in East Dembia (81.3%) than in West Dembia (79.9%). Univariable logistic regression showed no statistically significant associations between seropositivity and the evaluated variables (p > 0.05). Although not statistically significant, higher odds were observed in donkeys and horses compared to mules, in older animals, and under sheltered management conditions. These findings indicate widespread exposure to AHSV in the study area. However, results should be interpreted cautiously due to the descriptive nature of the analysis. Further studies incorporating larger sample sizes, multivariable approaches, and complementary diagnostic methods are recommended to better understand infection dynamics. Strengthened vaccination, improved management practices, and effective vector control remain essential for reducing disease impact.
Introduction. The composition of the equine gut microbiome is associated with many aspects of gastrointestinal, respiratory and musculoskeletal health that have been reported in the horse. Scientific studies exploring the microbiome non-intestinal ecological niches in or on horses are lacking. The clinical use of bacterial community profiling in horses is currently limited by cost and by slow analytical workflows.Hypothesis/Gap Statement. Most equine microbiome studies have relied on 16S rRNA amplicon sequencing of bacterial DNA, using high-throughput short-read sequencing technologies. This is often provided by an external service due to the cost of Illumina and other sequencers. Analysis of such sequencing files relies upon the researcher to have prior experience of coding-based programs.Aim. To explore the utility of Oxford Nanopore long-read sequencing in the analysis of microbiomes from several anatomical sites of the horse as a quicker and cheaper alternative to short-read sequencing.Methodology. Bacterial DNA was extracted from horse (udder) skin swabs, saliva swabs, faecal samples and milk samples. Samples were prepared for Oxford Nanopore long-read sequencing and sequenced using a flow cell on the MinION Mk1D. Sequencing data were analysed using EPI2ME, along with extra analyses on exported taxa abundance data in R.Results. Diversity measures and taxonomic relative abundance from phylum to family level were comparable to previously published equine studies that used Illumina sequencing. Sequencing data were acquired within 3 days costing around £30 per sample. Long-read sequencing gave accurate taxa assignment for two positive controls included at phylum, class, order and family levels of taxonomic classification.Conclusion. This work demonstrates that long-read technologies such as Oxford Nanopore MinION sequencing can provide a reliable, quick and cost-effective alternative to short-read Illumina sequencing when characterizing microbial communities from a range of anatomical locations on/in the horse.
Describe the effects and outcomes of valacyclovir and heparin administration in equine herpesvirus-1 (EHV-1)-exposed horses. A multicenter retrospective study identified 111 horses naturally exposed to EHV-1 from August 2017 to March 2018. Equine herpesvirus-1 infection was confirmed via blood or nasal secretion PCR. Horses that developed neurologic signs were diagnosed with equine herpesvirus myeloencephalopathy (EHM). Clinical signs, treatment, and survival were reported. A subset of horses was treated with valacyclovir and heparin. Prophylactic medication administration was performed prior to development of EHV-1 clinical signs (temperature > 38.6 °C, limb edema, nasal discharge, or neurologic deficits). Medication administration to clinical cases was defined as metaphylactic. Survival and EHM incidence were assessed between horses that received valacyclovir and heparin and horses that did not. 22 horses were diagnosed with EHV-1, with 9 developing EHM. Fourteen EHV-1-positive horses received metaphylactic valacyclovir and heparin, with 5 developing EHM. Five EHV-1-positive horses received prophylactic valacyclovir and metaphylactic heparin, with 1 developing EHM. Four EHV-1 horses were not treated with valacyclovir or heparin; all developed grade 5/5 ataxia and were euthanized. All horses treated with valacyclovir and heparin survived. EHV-1 treatment with valacyclovir and heparin reduced the incidence of EHM and improved survival compared to horses that did not receive these medications. In confirmed EHV-1 outbreaks, the administration of valacyclovir prior to the development of EHV-1 clinical signs and the administration of heparin after the development of clinical signs may improve patient survival.
Equine OPU‑ICSI supports commercial IVEP, yet substantial variability persists. We retrospectively analyzed a large dataset generated in Brazil spanning Quarter Horses, Warmbloods, and Mangalarga to evaluate whether predictors previously identified in the literature show comparable patterns under distinct ecological and breeding conditions. Overall oocyte and embryo outcomes were aligned with broadly reported trends from previous studies. Oocytes retrieved from estrous mares bearing a dominant follicle exhibited higher maturation and blastocyst rates. Stallion effects segregated into distinct phenotypes, including a subset displaying low cleavage, but normal blastocyst development among cleaved embryos, indicative of impaired oocyte activation, and others showing normal cleavage, but reduced blastocyst formation, suggesting limitations at embryo genome activation, genome integrity, or epigenetic regulation. Practically, performing OPU during estrus in the presence of a dominant follicle and implementing stallion‑specific optimization of semen handling or activation‑support strategies appear to be promising approaches for improving blastocyst yield in equine OPU‑ICSI programs.
Equine Metabolic Syndrome (EMS) is a complex endocrine disorder characterized by insulin dysregulation (ID), and an increased risk of developing laminitis, often accompanied by generalized or regional adiposity. Despite growing awareness of EMS, early and accurate diagnosis remains challenging. In this pilot study, we investigated changes in the levels of circulating microRNAs (miRNAs) in plasma samples from horses diagnosed with EMS (n = 13), compared to overweight/obese (OW/OB) non-ID horses (n = 16) and healthy controls (n = 16). Using a targeted OpenArray, followed by a Kruskal-Wallis and Dunn's post hoc tests, we identified four miRNAs that were differentially expressed across the groups: miR-221, which was increased in EMS group vs healthy (p value= 0.013), miR-132, which was increased in OW/OB non-ID group vs both EMS and healthy (p value= 0.048 for both comparisons) and, miR-186 and miR-15a, which were increased in healthy controls vs EMS (p value = 0.019 for miR-186 and p value = 0.032 for miR-15a) and OW/OB non-ID (p value = 0.001 for miR-186 and p value = 0.009 for miR-15a). Functional enrichment analysis of their putative target genes revealed involvement in key insulin signalling mechanisms, including phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT), AMP-activated protein kinase (AMPK) and forkhead box O protein (FOXO) signalling pathways. Receiver Operating Characteristic (ROC) curve analysis demonstrated that combinations of these miRNAs provided discriminatory power between clinical groups (AUCs ranging from 0.79 to 0.93). These findings support the potential of circulating miRNA levels as non-invasive predictive biomarkers for EMS development. Moreover, the signalling pathways identified provide mechanistic insight and establish a foundation for future studies aimed at therapeutic target discovery.
A point-of-care (POC; stall-side) test for progesterone that delivers rapid, accurate results has the potential to transform equine reproductive care. We evaluated the analytical and clinical performance of a POC device (Sidekick) that incorporates a progesterone lateral-flow assay (LFA) with a reader, and compared it with established methods (radioimmunoassay [RIA] and chemiluminescence immunoassay [CLIA]). Analytical performance was assessed using serially diluted mare plasma (0-8 ng/mL progesterone) to estimate precision and percent recovery. Clinical accuracy was assessed by comparison with RIA and CLIA on 19 paired serum samples. Agreement was evaluated by regression analyses and ordinal concordance across clinically relevant progesterone bands. The LFA had excellent recovery (90-102%) across 4-8 ng/mL, strong repeatability (CV 4-15%), and high reproducibility between 2 laboratories (CV 9.9%). Ordinal agreement with reference standards was near-perfect in spiked samples (κ = 0.94) and substantial in clinical samples versus both RIA (κ = 0.77) and CLIA (κ = 0.79). Cross-reactivity with the synthetic progestin, altrenogest, was tested at pharmacologic concentrations; no cross-reactivity was detected. Limitations of our study include an observed bias, potentially caused by the matrix differing between methods (serum vs. plasma). Additionally, a narrow validated range could cause underestimation of high concentrations. The LFA in the Sidekick device provided rapid, accurate, and clinically meaningful progesterone results in mares across 4-8 ng/mL, which would enable on-the-spot decisions and avoid delays from sample processing, transport, and result reporting.
Cerebrospinal fluid (CSF) analysis is a critical component in the diagnosis of equine protozoal myeloencephalitis (EPM). Test results obtained may differ based on different collection sites. Compare results of EPM-specific diagnostic tests obtained from different collections sites in EPM-affected and non-EPM affected horses. Twenty control and 7 EPM-affected horses. Prospective observational study. CSF was collected from the lumbosacral (LS) and cranial sites (atlantooccipital or C1-2) in 27 horses and EPM-specific diagnostic tests were performed. Data were summarized by collection site and disease status. Results were compared by Wilcoxon signed rank test in the non-EPM and EPM-affected cohorts. The EPM-specific diagnostic test results (anti-Sarcocystis neurona CSF antibody titer, serum/CSF titer ratios, and S. neurona antibody index [AI]) in non-EPM affected horses did not differ based on collection site. In EPM-affected horses the median [interquartile range] CSF anti-S. neurona antibody titers were higher in samples from the LS site compared with fluid collected from the cranial sites (160 [1240] vs. 80 [600]; Wald test statistic, 21.0; P = .03) and the median serum/CSF titer ratio was also lower in fluid collected from the LS site (25 [46.8] vs 50 [93.7]; Wald test statistic, 0; P = .03). Median AI values did not differ based on CSF collection site. Results of EPM diagnostic tests on CSF may differ based on collection site and lead to misdiagnosis. The AI appears to be less affected by collection site than antibody titers or the serum/CSF titer ratio.
A 14-year-old American Quarter Horse mare developed a refractory deep surgical site infection following emergency celiotomy for acute right dorsal large colon displacement with 180° volvulus. Initial cultures revealed a high-burden polymicrobial infection with Escherichia coli and Enterococcus faecium, associated with delayed healing, and later followed by multidrug-resistant Pseudomonas aeruginosa, further limiting therapeutic options. Phage therapy was initiated using a customized lytic phage cocktail administered topically on a daily basis over a 35-day period, with cocktail composition guided by daily wound culture results. Phage therapy markedly reduced colony-forming units of targeted pathogens and promoted progressive healing. Wound microbial communities varied during treatment, demonstrating selective pathogen control while preventing residual populations from recolonizing the tissue. By the time of hospital discharge, the wound surface area had decreased by more than 85%, and the body wall had healed without evidence of acute herniation. This case highlights the feasibility, safety, and clinical potential of adaptive phage therapy for managing refractory multidrug-resistant equine wound infections.
Insect bite hypersensitivity (IBH) is the most common allergic skin disease in horses, but existing clinical scoring systems lack extensive validation, limiting standardized disease monitoring and therapeutic evaluation. Develop and validate a standardized, sensitive, and reproducible clinical scoring system for IBH in horses. Forty-four privately-owned horses with clinically diagnosed IBH examined under field conditions in Switzerland. In this prospective field validation study, the equine IBH severity score (EqIS) integrates a lesion severity score and an area score using a multiplicative algorithm. Six trained evaluators assessed horses independently. Primary outcomes were intra- and interobserver reliability of the lesion severity score and EqIS assessed using intraclass correlation coefficients (ICC). Secondary analyses included agreement of the area score (Pearson correlation), correlations between owner-reported visual analog scale (VAS) scores and EqIS, and comparison between EqIS and a simplified EqIS developed for field use. Intraobserver reliability was excellent (ICC = 0.995 for the lesion severity score and 0.989 for EqIS), and interobserver reliability was similarly high (ICC = 0.98 for both). The area score showed strong interobserver agreement (Pearson r = 0.86-0.94). Owner VAS scores correlated moderately with EqIS (ρ = 0.49-0.51) and strongly with each other (ρ = 0.88). The simplified EqIS demonstrated strong agreement with the validated version (R2 = 0.86). The EqIS is the first extensively validated IBH-specific scoring system and demonstrates excellent reproducibility across evaluators. It provides an objective tool for standardized disease assessment and therapeutic monitoring, whereas the simplified EqIS offers a practical alternative for routine field use.
Ultrasound is readily available to most practitioners and can be used in a straightforward manner to assess the liver. The liver can be assessed for size, shape, echogenicity, and architecture. Findings such as masses, cysts, granulomas, and biliary distention can be relatively specific as to suspected disease process. Other findings may be nonspecific but are useful to confirm concerns and aid in refining differential diagnosis. Findings should be interpreted considering the clinicopathologic picture and sampling performed when appropriate. Ultrasound can and should be used to identify optimal location for transcutaneous sampling.
African horse sickness (AHS) is a vector-borne and noncontagious disease caused by African horse sickness virus (AHSV) that poses a severe threat to the global equine industry. As a country historically free from AHS, China faces elevated risks due to recent outbreaks in Southeast Asia in 2020 and its ecological suitability of its border regions for AHSV vectors. Therefore, we conducted consecutive molecular and serological surveillance for AHSV in high-risk border regions from 2020 to 2024. A total of 3203 equine serum samples, 2909 whole-blood samples, and 1037 collections of blood-sucking insects were collected from 103 counties across five border provinces from June to October (peak Culicoides season). Samples were analyzed using World Organization for Animal Health (WOAH)-recommended RT-qPCR (targeting VP7 gene) and blocking ELISA. Morphological identification confirmed that the collected vectors were primarily Culicoides midges, with some mosquitoes. No AHSV nucleic acid or specific antibodies were detected, which is consistent with China's AHS-free status. Combined with predictive models and regional risk factors, the likelihood of AHSV occurrence in southern China is "likely." The study highlights the urgent need for continuous surveillance and risk assessment to safeguard China's equine industry. Further regional and ecological studies on vectors and animal transportation are also essential for understanding and mitigating the risks associated with AHSV introduction.
Repair options for maxillary and mandibular fractures in horses are dictated by the proximity of dentition, fracture configuration, and implant design. Jaw fractures can be repaired by minimising tension forces via intraoral splint constructs when dentition is present on either side of the fracture line. This repair option reduces iatrogenic damage to dentition while achieving reduction and stability until appliance removal. To first report a modified technique for jaw fracture repair in horses with cadaveric example images. Second, to report the clinical outcome of maxillary and mandibular fracture repair in clinical cases of horses that were treated with a modified wire-reinforced bis-acryl composite interdental splint with tubing (MWIST). Multi-institutional retrospective clinical case series. Medical records from three university hospitals and three private practices were searched for cases of equine mandibular or maxillary fractures treated with the MWIST technique from 2018 to 2025. Animals included in the study underwent oral examination, skull radiography or computed tomography, fracture repair with MWIST, and follow-up imaging at time of appliance removal. Eleven horses met the inclusion criteria. Nine cases involved fracture of the mandible and two involved fracture of the maxilla/premaxilla. Eight cases had fracture configurations that involved adjacent dentition. Appliances remained in place for an average of 8.9 weeks (median 8 weeks, range 6-20 weeks). Complications were generally minor and readily resolved, including wire loosening or breakage and bone sequestration. The main limitation to this study is the multi-institutional retrospective nature, which limits standardisation across diagnostic and surgical procedures, patient follow-up, and inclusion of a control group. The use of this modified repair technique in horses is feasible, cost effective, and biomechanically advantageous. The favourable outcome of all cases followed to appliance removal supports the application of this surgical technique on future equine jaw fracture cases.
Pneumosinus dilatans and pneumocoele sinus describe abnormal hyperpneumatisation of paranasal sinuses, with the latter being accompanied by thinning of bony walls. Although recognised in human and equine medicine, to the authors' knowledge, this condition's computed tomography (CT) findings and successful surgical approach in horses have not previously been reported in conjunction. Advanced imaging, particularly CT, is pivotal for identifying abnormal sinus expansion and associated nasal obstruction. Case report. A 2-year-5-month-old Cob filly presented with a 1-month history of progressive inspiratory stertor and weight loss, unresponsive to systemic corticosteroids. Physical examination revealed marked inspiratory stertor. Endoscopy suggested narrowing of nasal passages but was subjective and did not identify the underlying cause. Standing CT of the head demonstrated extensive, bilateral dilation of the dorsal and ventral conchal sinuses with marked thinning of axial sinus walls. The nasomaxillary apertures were occluded, and the dorsal and middle nasal meatuses were markedly narrowed or obliterated. No evidence of sinusitis or other intraluminal disease was present. Transnasal diode-laser fenestrations into the dorsal and ventral conchal sinuses established permanent communication with the nasal cavity. Foley catheters were placed for postoperative flushing. A temporary tracheostomy ensured airway patency. Seventeen days postoperatively, the filly showed complete resolution of inspiratory stertor. Endoscopic evaluation revealed large, epithelialised fistulae and restoration of normal nasal meatus dimensions. Long-term follow-up confirmed persistent clinical normality with no recurrence. Single case report. CT imaging was essential for diagnosis and surgical planning for a case of pneumocoele sinus in a horse. Creation of large, permanent fenestrations between the conchal sinuses and nasal cavity successfully equalised sinus pressure, reversed nasal obstruction, and resulted in an excellent long-term outcome. This condition should be considered as a differential diagnosis in equine upper airway obstruction.
Streptococcus equi subspecies equi (SEE) causes a highly contagious disease colloquially known as "strangles" in equids. This disease is typically characterized by pyrexia, mucopurulent nasal discharge, and abscessation of the submandibular and retropharyngeal lymph nodes. Although typically localized to the upper respiratory tract, the infection can disseminate via lymphatic or hematogenous routes, leading to disseminated strangles involving peripheral lymph nodes and thoracic and abdominal organs. A 21-year-old Welsh Pony cross gelding presented for urine dribbling and presumptive cystolithiasis due to urine retention and bladder distention. Urinary catheterization and urethrocystoscopy revealed a large volume of hematuria, no urinary calculi, and an abnormal ureteral opening. Imaging revealed nonspecific renal abnormalities consistent with chronic kidney disease, with secondary acute kidney injury, and a mass near the aortic bifurcation. Aerobic urine culture yielded SEE identified via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with a score >2.0 and confirmed by PCR. The pony was euthanized due to poor prognosis, and autopsy results revealed pituitary pars intermedia hyperplasia and microadenoma and neutrophilic, hemorrhagic, and necrotizing pyelonephritis. The pyelonephritis is likely due to hematogenous or lymphatic dissemination of the organism to the kidney. We speculate that immunosuppression related to pars pituitary intermedia dysfunction may have predisposed this animal to this atypical manifestation. There are limited reports of metastatic strangles presenting as pyelonephritis in equids. This case highlights the potential for a common equine pathogen to manifest as an unexpected presentation and underscores the need to consider strangles in the differential diagnosis of equine renal disease.