Vinzenz Gerber

Background: Adherence to recommendations for environmental management is central to equine asthma (EA) treatment. Reasons for non‐adherence warrant further investigation. Objectives: To: (1) evaluate adherence to recommendations for environmental changes, identify reasons for incomplete implementation, assess changes in clinical signs and medication use; (2) evaluate owner acceptability, practicality and perceived usefulness of a structured stable‐side protocol. Study Design: (1) Retrospective online survey and (2) prospective onsite testing with owners of EA‐affected horses. Methods: (1) Online survey on implementation of standardised recommendations, clinical progression and medication use; and (2) environmental protocol evaluation during stable visits. Results: Seventeen of 40 horses still received dry hay and 13/40 were bedded on straw. Reasons for non‐implementation included time, financial and infrastructural constraints, boarding stable restrictions, group housing, weather dependence, use of self‐produced roughage, perceived ineffectiveness and individual horse preferences. Owners reported that overall clinical impression had improved and the proportion of coughing horses decreased from 88% to 55% ( p < 0.001, OR = 0.07, 95% CI 0.002–0.47, n = 40). The other clinical outcomes did not reach the Bonferroni‐adjusted significance threshold. Twenty‐two horses were still coughing, and 7/40 had received medication within the previous 3 months. All interviewed owners found the environmental protocol helpful, 11 reviewed it again and 5 used it for discussion with others. Main Limitations: Use of small convenience samples, lack of a control group and potential selection and recall bias. Conclusion: Owner non‐adherence arose from diverse and often structural constraints. The environmental protocol was well accepted by owners and helped to structure discussions on risk factors.

We report two cases of equine encephalomyelitis associated with the recently emerged European Shamonda virus type 1 (SHAV-EU1). Shamonda virus has not yet been described in horses but has caused an unprecedented outbreak in cattle in Western Europe this summer (2026). Both horses showed neurological deficits and lymphocytic cerebrospinal fluid pleocytosis associated with encephalomyelitis, vasculitis and hemorrhages in brain and spinal cord. Pan-Simbu RT-qPCR confirmed viral RNA in brain tissue, and Metatranscriptomic sequencing identified full-genome SHAV-EU1 sequences, proofing correlation to the outbreak in Swiss cattle.

We report two cases of equine encephalomyelitis associated with European Shamonda virus type 1 (SHAV-EU1) infection. Both horses showed neurological deficits and lymphocytic cerebrospinal fluid pleocytosis associated with encephalomyelitis, vasculitis and hemorrhages in brain and spinal cord. Metatranscriptomic sequencing identified SHAV-EU1, and pan-Simbu RT-qPCR confirmed viral RNA in brain tissue.

Background/Objectives: Bulk RNA sequencing (RNA-seq) averages signals across heterogeneous cell populations. Computational deconvolution methods aim to infer cell type composition and cell type-specific gene expression from bulk data, but their performance in equine samples has not been evaluated. In this study, we assessed the ability of computational deconvolution to recover cellular composition and differential expression signals in bronchoalveolar lavage fluid (BALF) from horses with severe equine asthma (SEA) and controls (CTL). Methods: Cryopreserved BALF samples from six SEA and five CTL horses previously analyzed by scRNA-seq were used to generate bulk RNA-seq data. The matched scRNA-seq dataset served as the reference for deconvolution. Performance was evaluated by comparing deconvolution raw and mRNA-corrected estimates with scRNA-seq cell proportions. Differential expression between SEA and CTL was analyzed on bulk RNA-seq, deconvoluted expression profiles, and scRNA-seq pseudobulk data. Results: Deconvolution primarily captured mRNA-derived cell type proportions rather than true cell counts: agreement with scRNA-seq cell counts was moderate (r = 0.62; 95% CI 0.45–0.75) but improved after mRNA content correction (r = 0.83; 95% CI 0.74–0.89). Comparison with mRNA-weighted scRNA-seq proportions showed near-perfect concordance (r = 0.98; 95% CI 0.97–0.99). Cell type-specific performance varied, with stronger correlations for B cells and dendritic cells and weaker performance for neutrophils, T cells and monocytes/macrophages. Recovery of cell type-specific differential expression was inconsistent, frequently showing cross-lineage signal spillover. Although both approaches detected a Th17 signature in SEA, most deconvolution-derived differentially expressed genes overlapped with conventional bulk RNA-seq results. Conclusions: Deconvolution of bulk RNA-seq did not reliably estimate cell counts or provide substantial biological insight beyond conventional bulk analysis, highlighting the value of scRNA-seq for resolving cell type-specific disease mechanisms in equine asthma.

Hay quality is a key factor in equine respiratory health, with microbiological contaminants in inhaled organic dust posing significant risks. Sensory assessment has been used to evaluate hay hygiene, but its value to identify deficiencies remains unclear. This study aimed to explore the potential of sensory assessment to predict both particulate matter (PM) dust concentrations and microbiological contamination. Fifty hay samples were collected from horse owners and evaluated using a structured sensory examination, microbiological analyses, and dust concentration measurements obtained with the Hay-Shaker device and a DustTrak DRX 8534. Sensory examination rated only 28% of samples as adequate, with 52% showing minor and 20% major deficiencies. Microbiological analysis found that 46% of samples met acceptable standards. Regression analysis showed that abnormal musty odor was the strongest predictor of increased dust concentrations, including the respirable fraction (PM4, <4 µm), while visible impurities were associated with microbial contamination. These findings suggest that sensory attributes such as odor and impurity are valuable indicators of hay hygiene. Structured protocols for sensory examination may offer a simple and cost-effective tool for assessing hay quality in equine environments.

Hypertriglyceridemia (HTG) may be inherited and caused by variants in genes encoding enzymes of lipid metabolism. This study was prompted by the observation of eight Franches-Montagnes (FM) foals showing elevated plasma triglyceride levels and episodes of fatal acute pancreatitis. We termed this phenotype hypertriglyceridemia-induced pancreatitis (HIP). The affected foals were distantly related and inbred to a prominent stallion suggesting autosomal recessive inheritance. Whole genome sequencing of an affected foal identified a homozygous loss of function variant in LMF1 encoding lipase maturation factor 1. The variant, XM_023616679.1:c.369_373delinsTCT, leads to an early frameshift and is predicted to alter or truncate 78% of the LMF1 coding sequence. We genotyped the variant in a cohort of 2122 FM horses and identified 11 homozygous mutant animals including all eight foals that had initially been identified based on their clinical presentation. The three additional homozygous mutant animals had a comparable phenotype and were inbred to the same stallion. We concluded that all 11 had been affected by the same disease. Thus, we found perfect genotype-phenotype association in the tested cohort. The carrier frequency in the 2111 unaffected FM horses was 15.0%. Our findings enable genetic testing to prevent the unintentional breeding of further HIP-affected foals.

Background: Organic dust from hay is a primary trigger of equine asthma.Objectives: (1) To introduce a novel hay‐shaker (HS) device for standardised hay dust generation, enabling simultaneous measurements of various particulate matter (PM) size fractions. (2) To compare these measurements with those in the horse's breathing zone (BZ) to assess the influence of environmental and individual factors.Study Design: Comparative experimental study.Methods: A HS generating dust was developed. Total dust (PMT) and size fractions (PM1, PM2.5, PM4 and PM10, representing particle size in μm) were measured from 50 hay samples provided by clients using an aerosol monitor (DustTrak DRX 8534) in the HS (HS‐PMx) and the BZ (BZ‐PMx) of 50 horses (26 healthy, 24 asthmatic) during hay feeding. Linear regression analysis evaluated the relationship between HS‐PMx and ln BZ‐PMx for each fraction, accounting for environmental (humidity, temperature) and individual factors (horse characteristics and feeding behaviour, assessed with the Hay Contact Score).Results: The HS generated measurable dust across all PM sizes. Regression models explained 69% to 73% of ln BZ‐PMx variance, showing a weak positive association between HS‐PMx and ln BZ‐PMx across all size fractions. Hay Contact Score had the strongest positive association with ln BZ‐PMx. Cohort, ambient temperature and humidity were negatively associated with ln BZ‐PMx for certain particle sizes. The final model, incorporating HS‐PM4, Hay Contact Score, cohort, temperature, and humidity as predictors, demonstrated robust predictive accuracy for BZ‐PM4 (adjusted R² = 0.73).Main Limitations: Clinical impact of hay dust and poor‐quality hay was not assessed.Conclusions: The HS reliably generates hay dust for measuring standard PM fractions, particularly respirable PM4, critical to equine respiratory health. BZ dust concentrations are significantly influenced by feeding behaviour. The HS offers a standardised method for assessing hay quality, enabling informed decisions on hay selection to support respiratory health in stabled horses.

Equine asthma is a common cause of poor performance, but little is known about its impact on submaximal exercise. The aim of the present study was to evaluate the effects of equine asthma and potential confounding factors on recovery of respiratory rate (RR) and heart rate (HR) after a lunging exercise test. Thirty-seven horses completed a standardized 15 min lunging exercise including HR and RR recording pre- and up to 30 min post-exercise and venous blood lactate measurement. Endoscopy was performed and bronchoalveolar lavage fluid cytology was used to categorize horses as controls or asthmatics. In the univariate analyses, asthmatic horses (n = 21) showed prolonged RR recovery (OR 52.25, 95% CI 5.17–528.28, p = 0.001) and took more than 15 min to return to pre-exercise levels. Prolonged recovery was associated with bronchoalveolar lavage fluid neutrophilia (OR 1.14, 95% CI 1.01–1.29, p = 0.04) and also with trot velocity (OR 17.32, 95% CI 1.23–244.15, p = 0.03). HR recovery increased with higher training level (OR 0.14, 95% CI 0.02–0.83, p = 0.03) and decreased with age (OR 1.20, 95% CI 1.03–1.40, p = 0.02). RR recovery after the submaximal lunging exercise could offer a practical test for functional deficits associated with equine asthma.

This report describes a multicentric intermediate‐size B‐cell lymphoma with epitheliotropism in a Freiberger mare affecting multiple mucous membranes, skin and internal organs. The clonal neoplastic B‐cell population was accompanied by numerous reactive polyclonal small T cells. Differential diagnoses for these unusual findings are discussed.