Influence of inflammation on the expression of microRNA-140 in extracellular vesicles from 2D and 3D culture models of synovial-membrane-derived stem cells.

Background: In osteoarthritis (OA), articular homeostasis is regulated by microRNA-140 that inhibits ADAMTS-5, an enzyme that cleaves aggrecan and stimulates the synthesis of other inflammatory mediators. This study aims to evaluate the expression of microRNA-140 in extracellular vesicles (EVs) derived from equine synovial-membrane-derived mesenchymal stem cells (eqSMMSCs) cultured in monolayer (2D) and three-dimensional (3D) culture models under an in vitro inflammatory environment. Methods: Four experimental groups of eqSMMSC cultures were defined for isolation of the EVs. The 2D and 3D control groups were cultured in a conventional cell culture medium, while the 2D-OA and 3D-OA treatment groups were exposed to an OA-like medium containing IL-1ß and TNFα. The culture media samples were collected at 24 h, 72 h, and 120 h time points for EV isolation and characterization using nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). Reverse transcription quantitative polymerase chain reaction was employed to assess the expressions of microRNA-140 in both the cells and EVs. All statistical analyses were conducted at the 5% significance level. Results: Encapsulation of the eqSMMSCs protected the cells from the inflammatory media compared to the monolayer cultures. EVs were found in higher concentrations in the 3D-OA cultures. Additionally, higher expressions of microRNA-140 were observed in the cells of the 3D-OA group at 24 and 72 h, whereas microRNA-140 expressions in the EVs were higher in the 3D group at 72 h and in the 2D-OA group at 120 h (p < 0.001). However, the 3D-OA culture showed higher expression of the mRNA Adamts5 in the EVs at 120 h. Conclusion: The responses of the eqSMMSCs to inflammatory stimuli involve intracellular expression of microRNA-140 and its subsequent transportation via the EVs, with quicker responses observed in the 3D than 2D cultures. This study sheds light on the behaviors of stem cells in restoring homeostasis in osteoarthritic joints.

Long-term use of an implantable loop recorder for ECG recording in horses.

Potential arrhythmias recorded by cardiac monitors using the built-in human algorithm are as follows: total number of episodes, ventricular tachycardia, asystole, bradycardia, atrial tachycardia, atrial fibrillation and the percentage of time spent in atrial tachycardia or atrial fibrillation. Long-term use of an insertable cardiac monitor (loop recorder) has been reported in one horse earlier, but its accurate role as a diagnostic tool is still unclear. The aim of the present study was to investigate the long-term applicability of the Reveal XT cardiac monitor for recording cardiac arrhythmias in adult horses. The Reveal XT cardiac monitor was implanted in 12 horses under sedation in standing position. Median duration of data recording calculated for the population was 1,169 days. The number of false positive detections of asystole and bradycardia was extremely high in all horses. For atrial fibrillation, false positive detection occurred in five and false negative detection occurred in one horse. The present study showed that the long-term use of the Reveal XT cardiac monitor is feasible, well-tolerated and the devices work reliably, without complications. The human algorithm could not be used for automatic detection of arrhythmic episodes in the study population. The device could detect atrial fibrillation in horses, but the recorded AF burden was inaccurate and the stored ECGs had to be manually interpreted. Because the human analyser algorithm of this cardiac monitor fails to identify bradyarrhythmias in horses based on our results, this instrument is not capable for accurately determining the aetiology of episodic collapse in this species.

Explainable machine learning for assessing upper respiratory tract of racehorses from endoscopy videos.

Laryngeal hemiplegia (LH) is a major upper respiratory tract (URT) complication in racehorses. Endoscopy imaging of horse throat is a gold standard for URT assessment. However, current manual assessment faces several challenges, stemming from the poor quality of endoscopy videos and subjectivity of manual grading. To overcome such limitations, we propose an explainable machine learning (ML)-based solution for efficient URT assessment. Specifically, a cascaded YOLOv8 architecture is utilized to segment the key semantic regions and landmarks per frame. Several spatiotemporal features are then extracted from key landmarks points and fed to a decision tree (DT) model to classify LH as Grade 1,2,3 or 4 denoting absence of LH, mild, moderate, and severe LH, respectively. The proposed method, validated through 5-fold cross-validation on 107 videos, showed promising performance in classifying different LH grades with 100%, 91.18%, 94.74% and 100% sensitivity values for Grade 1 to 4, respectively. Further validation on an external dataset of 72 cases confirmed its generalization capability with 90%, 80.95%, 100%, and 100% sensitivity values for Grade 1 to 4, respectively. We introduced several explainability related assessment functions, including: (i) visualization of YOLOv8 output to detect landmark estimation errors which can affect the final classification, (ii) time-series visualization to assess video quality, and (iii) backtracking of the DT output to identify borderline cases. We incorporated domain knowledge (e.g., veterinarian diagnostic procedures) into the proposed ML framework. This provides an assistive tool with clinical-relevance and explainability that can ease and speed up the URT assessment by veterinarians.

Molecular Epidemiology of Western Equine Encephalitis Virus, South America, 2023-2024.

Western equine encephalitis virus (WEEV) is a mosquitoborne virus that reemerged in December 2023 in Argentina and Uruguay, causing a major outbreak. We investigated the outbreak using epidemiologic, entomological, and genomic analyses, focusing on WEEV circulation near the Argentina‒Uruguay border in Rio Grande do Sul state, Brazil. During November 2023‒April 2024, the outbreak in Argentina and Uruguay resulted in 217 human cases, 12 of which were fatal, and 2,548 equine cases. We determined cases on the basis of laboratory and clinical epidemiologic criteria. We characterized 3 fatal equine cases caused by a novel WEEV lineage identified through a nearly complete coding sequence analysis, which we propose as lineage C. Our findings highlight the importance of continued surveillance and equine vaccination to control future WEEV outbreaks in South America.

Enhancing the Horse Grimace Scale (HGS): Proposed updates and anatomical descriptors for pain assessment.

The use of grimace scales enables the clinical identification of changes in the facial expressions of animals caused by pain. The Horse Grimace Scale (HGS) is one such tool, comprising a pain coding system based on facial expressions and assessing six Facial Action Units (FAUs). Each FAU is accompanied by descriptions and anatomical details to assist the evaluator. However, the morphological descriptions for certain FAUs in the HGS are not sufficiently detailed, potentially hindering accurate interpretation. This study is an analytical investigation aimed at enhancing the morphoanatomical details in the HGS and providing raters with more comprehensive materials for pain evaluation in horses using this scale. To achieve this, detailed anatomical analyses were conducted using established references in veterinary anatomy. Initially, we propose substituting the term 'ear' with 'auricle' or 'pinna' and replacing 'area above the eye' with 'supraorbital region' for anatomical accuracy. Additionally, we introduce detailed morphoanatomical descriptions that identify specific landmarks, with the goal of ensuring more consistent application of the HGS and reducing interpretation variability. Furthermore, this study provides an explanation of the muscles involved in the investigated FAUs. These adjustments on the descriptions and evaluations remain unverified, however it is anticipated that the descriptive enhancements lead us to understand that higher interobserver reliability can be achieved for each of the FAUs.

Foal sex in Thoroughbred horses: related factors.

Reproductive biotechniques in the equine species have advanced in the last decade and horse breeders have started to question the possibilities of interfering in the determination of foal sex. The aim of the present study was to verify whether the variables mares and stallion's age, side of the ovary containing the preovulatory follicle, preovulatory follicle diameter, time between breeding and ovulation, and ovulation inducing hormones influence the sex of the foal. A total of 259 reproductive cycles of 160 mares and 22 Thoroughbred stallions were used. Statistical analysis was performed using R software, including Pearson's chi-square test and logistic regression. Of the total foals born, 136 were males (52.51%) and 123 were females (47.49%). In mares that ovulated with -24h after ovulation induction, 104 foals (54.74%) were males and 86 (45.26%) were females, while in mares that ovulated with +24h, 32 foals (46.38%) were males and 37 (53.62%) were females. Stallions up to 15 years old had 44.14% (n=49) females and those over 15 years had 49.66% (n=73) females. The simple logistic regression model showed that mares and stallions under 15 years old, mares with ovulation time less than 24 hours and treated with Deslorelin had a higher probability of having male foals, but the Pearson's chi-square test showed that foals gender were not influenced by the variables studied.

Digital video analysis reveals gait parameters that predict performance in the jumping test phase of three-day eventing.

In international equestrian sport, visual inspections assess gait and lameness to protect the welfare of performance horses during competition. Horses competing internationally in three-day eventing must pass two mandatory inspections (pre-competition and post-cross country) before attempting the final phase: the jumping test (JT). We hypothesized that digitally quantifying objective gait parameters captured during the two mandatory inspections will identify locomotor characteristics that predict success during the jumping test. Utilizing the DeepLabCut (DLC) software package for labeling of anatomical landmarks and a custom analysis pipeline we calculated gait parameters for 194 competition horses at the trot. During the pre-competition inspection, relative trot speed was significantly associated (P = 0.0060, GLMM), and the forelimb travel trended towards significance (P =0.0800, GLMM), with achieving a clear round in the later jumping test. Post-cross country, the forelimb travel significantly predicted JT results (P = 0.0188, GLMM). As our parameters are scaled for body size, these parameters may indicate conformational characteristics for superior jumping ability and overall athletic fitness. Within each competitive effort, comparisons of the post-cross country and pre-competition observations revealed that the change in speed and duty factor were significantly different in the group that accrued jumping faults (P = 0.00376 and P = 0.02430, GLMM), perhaps capturing locomotor signs of exercise fatigue. Further work employing these approaches to better understand competition performance will encourage the use of objective measures to protect sport horse welfare, as well as provide an advantageous tool for gait evaluation in the horse.

Temperature has a greater effect than salinity on microbial survival in saltwater from a single equine hydrotherapy unit.

OBJECTIVE: To determine the ability of bacteria commonly isolated from equine limb wounds to survive in saltwater obtained from an equine hydrotherapy unit at different salinity concentrations and temperatures. METHODS: Saltwater samples were obtained over a 2-week period (January 22, 2024 to February 2, 2024) from an equine hydrotherapy unit used for clinical patients, kept at either full salinity per manufacturer recommendations or diluted to half salinity to mimic the dilution that likely occurs in the clinical setting between cases when holding tanks are replenished with tap water only. Samples were then autoclaved to eliminate preexisting bacterial contamination before individual inoculation with Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus zooepidemicus. Each inoculated sample was maintained at 2, 22, or 44 °C to represent typical holding tank conditions. The bacterial concentration was determined at each condition every 24 hours up to and including 96 hours. The lower limit of detection was set at 1 CFU/mL. RESULTS: Salinity did not affect bacterial survival. Bacterial concentrations generally decreased with increasing temperature over time. Escherichia coli, S aureus, and S zooepidemicus concentrations decreased to the lower limit of detection at 44 °C by 24 to 48 hours, while P aeruginosa concentrations significantly decreased over 24 hours but remained well above the lower limit of detection. CONCLUSIONS: Common bacterial isolates of equine limb wounds can survive in typical saltwater hydrotherapy conditions. CLINICAL RELEVANCE: Further investigation is warranted to determine the clinical relevance of these findings including protocols for hydrotherapy unit disinfection, wastage of treatment water, and case inclusion/exclusion criteria.

Western equine encephalitis, a report of two cases in pediatric patients. / Encefalitis equina del oeste, reporte de dos casos en pacientes pediátricos.

Western equine encephalitis (WEE) is vector-borne infection caused by an RNA virus of the genus Alphavirus, disseminated by mosquitoes that can cause WEE in humans. There are two cycles of transmission, a maintenance cycle and an occasional amplification with vector augmentation, where equines and humans are terminal hosts. In Argentina, no human cases had been reported since 1983. Here we describe 2 pediatric patients with brain symptoms and serological diagnosis of WEE. Both samples of cerebrospinal fluid (CSF) showed pleocytosis, while the neuroimaging test showed alterations in the basal ganglia. The serological diagnosis was based on the detection of specific IgM in serum and CSF and neutralizing antibodies 14 days after symptom onset. The patients were managed with supportive treatment. One patient recovered his normal neurological status without seizures before discharge, while the other was discharged with right hemiparesis, which resolved after 2 months, and continued with anticonvulsants due to a pathological EEG.

La encefalitis equina del oeste (EEO) es una infección causada por un virus ARN del género Alphavirus, de transmisión vectorial por mosquitos que pueden causar la enfermedad en humanos. Hay dos ciclos de transmisión, de mantenimiento y de amplificación ocasional con aumento de vectores, donde equinos y seres humanos son huéspedes terminales. En Argentina no se reportaban casos humanos desde 1983. Se presentan dos pacientes pediátricos con síntomas encefálicos y diagnóstico por serología de EEO. Ambos líquidos cefalorraquídeos (LCR) evidenciaron pleocitosis y las neuroimágenes, alteraciones en ganglios de la base. Se arribó al diagnóstico por serología con detección de IgM específica en suero y LCR, y anticuerpos neutralizantes 14 días después del inicio de síntomas. El tratamiento fue de sostén. Un paciente recuperó el estado neurológico habitual previo al alta sin crisis comiciales y el otro egresó con hemiparesia derecha, que se resolvió luego de dos meses, y continuó con anticonvulsivantes por EEG patológico.

Transient efficacy of buparvaquone against Theileria haneyi in chronically infected horses.

BACKGROUND: Theileria haneyi is one of the three known causative agents of equine piroplasmosis. While imidocarb is generally effective in the clearance of the highly pathogenic Theileria equi, it is ineffective in the treatment of T. haneyi. Moreover, co-infection with T. haneyi has been shown to impede the successful treatment of T. equi. Furthermore, tulathromycin and diclazuril have demonstrated inefficacy in eradicating T. haneyi. The absence of an effective therapeutic agent against this parasite represents a significant obstacle in managing equine piroplasmosis. METHODS: To address this issue, we evaluated the efficacy of buparvaquone in the treatment of T. haneyi in chronically infected horses. RESULTS: Our findings showed that treatment of horses with the recommended dose of 2.5 mg/kg of buparvaquone led to a rapid abatement of T. haneyi levels, to a level where the parasites were not detectable by nested PCR. Following treatment, the horses remained PCR negative for a minimum of seven weeks until recrudescence occurred. Subsequent re-administration of buparvaquone at an increased dosage of 6 mg/kg upon recrudescence failed to exert a theilericidal effect on T. haneyi. Throughout the treatment regimen, the hematological parameters of the horses and most components of the chemistry panel remained within the normal range, except for blood urea nitrogen levels, which fell below the normal range in certain instances. CONCLUSIONS: BPQ at 2.5 mg/kg and 6 mg/kg had a robust theilericidal effect but was ineffective in the clearance of the T. haneyi infection in persistently infected animals.

Influence of haematological parameters on size of the advanced platelet-rich fibrin+ (A-PRF+) in the horse.

The advanced-PRF+ (A-PRF+) is a platelet concentrate, showing a higher concentration of growth factors, an increased number of cells and looser structure of the fibrin clot than leukocyte-PRF. A high variability in the size of PRF associated with patients, haematological features and centrifugation protocols was reported. The aims of this study were to evaluate the feasibility of A-PRF+ production in the field and the correlation between haematological parameters, macroscopic and microscopic features in equine A-PRF+. Samples from twenty Standardbred horses (3-7 years) were harvested with glass tubes without anticoagulants, previously heated at 37 °C. Blood samples were centrifugated at 1300 rpm for 8 min with a fixed-angle centrifuge and a horizontal centrifuge in the field, at a temperature of 15-17 °C. Clots were measured and placed on the Wound Box® for a 2-min compression. Membranes were measured and fixed in 10% formalin for histological examination. Clot and membrane surface did not differ between sex and centrifuge. Haematological parameters did not show a significant correlation to clot and membrane size. Membranes obtained from both centrifugation protocols showed a loose fibrin structure and cells evenly distributed throughout the clot. Tubes' warming was effective to obtain A-PRF+ clots from all samples, regardless the environmental temperature. Further studies are needed to evaluate the influence of other blood molecules on the A-PRF+ structure and size.

Comparative analysis of breeding patterns and reproductive efficiency of mares in subtropical conditions of Pakistan.

BACKGROUND AND AIM: The present study aimed to evaluate and compare the overall and breed-specific seasonal breeding patterns, fertility rates, cyclicity, and follicular dynamics of Arab, Thoroughbred, and Percheron mares under the subtropical conditions of Pakistan. MATERIALS AND METHODS: A retrospective analysis of climatic data and breeding records of eleven breeding studs spanning four years (2020-2023) was made to find out the overall seasonality in the breeding pattern of mares. Fifty mares of each breed (n = 150 in total) were scanned by ultrasonography for a calendar year to find the cyclicity pattern and follicular dynamics (follicular growth rate, size of ovulatory follicle, and days from estrus till ovulation). RESULTS AND DISCUSSION: The statistical analysis of breeding records demonstrated a clear pattern of seasonal breeding (p< 0.05). The highest monthly foalings were noted in March (247 ± 45.37), and overall breeding activities peaked in Spring season (p< 0.05). Breed-specific results of Arab, Thoroughbred, and Percheron mares revealed that Arab mares maintained stable breeding activity throughout the year, with the highest activity in spring and peak conception rate in winter (56.25% ± 32.78; p > 0.05). Thoroughbred mares experienced significant seasonal declines from spring to winter with a peak conception rate in winter (63.89% ± 27.37, p > 0.05). Percherons showed the most pronounced seasonal effects, especially with a high fall conception rate (73.04% ± 19.61) and a sharp decrease in winter breeding metrics (p< 0.05). Furthermore, Thoroughbred and Percheron mares displayed the most pronounced seasonal effects on the percentage of cyclic mares 77.3% and 56% in winters (p< 0.05). Moreover, the follicular dynamics of the three breeds also exhibited significant differences (p< 0.05). CONCLUSION: The current study concludes that seasonal and breed-specific variability exists among the reproductive parameters of Arab, Thoroughbred, and Percheron mares in subtropics, necessitating breed-specific reproductive management measures to maximize mare breeding efficiency.

Return to sport activity following ultrasonographic diagnosis and conservative management of spontaneous injuries of the serratus cervicis ventralis and serratus thoracis ventralis muscles in 11 endurance horses.

OBJECTIVE: To describe the clinical diagnosis, ultrasound findings, and outcome of 11 endurance horses with injuries to the serratus ventralis thoracis (SVT) or serratus ventralis cervicis (SVC) muscle. ANIMALS: 11 endurance horses competing in medium- to high-level competitions and presenting with lameness caused by injuries to the SVT or SVC muscle, as confirmed by ultrasonography. CLINICAL PRESENTATION: Physical examinations revealed swelling caudal to the shoulder region associated with dorsocranial displacement of the scapula and edema of the ventral thorax for horses with SVT injuries. Swelling cranial to the scapula and edema of the pectoral area were identified among horses with injuries to the SVC. RESULTS: Dynamic examinations revealed moderate-to-severe reduction of the cranial phase of the stride at the walk; at the trot, a lameness score of 2 to 3/5 was assigned (modified American Association of Equine Practitioners Lameness Scale). Ultrasonography revealed moderate-to-severe increases in size of the muscle body, heterogeneous echogenicity, loss of the striated muscle pattern, and varying degrees of perimuscular edema. All horses were able to resume full training and competition in an average of 216 days (range, 74 to 362 days) and 148 days (range, 112 to 309 days) for injuries of the SVT and SVC, respectively. CLINICAL RELEVANCE: This case series is the first to describe the clinical and ultrasonographic features of spontaneous injuries to the SVT or SVC. Ultrasonography for diagnosis was simple and well tolerated by the horses.

Real-time in vivo confocal laser endomicroscopic imaging of equine endometrium: preliminary observations and feasibility study.

Endometrial health is vital for the reproductive efficiency of broodmares and accurate diagnostic testing is crucial for directing the best treatment options and outcomes. Confocal laser endomicroscopy (CLE) is an endoscopic technique for obtaining in-vivo, real-time microscopic imaging of tissues using a fiber optic probe. CLE relies on induced tissue fluorescence and fluorescein sodium, given intravenously, is the contrast agent most used in human medicine. This study aimed to determine the feasibility of CLE for imaging equine endometrium and determine a standard dose of fluorescein sodium to achieve optimal cellular imaging. In-vivo CLE was performed on 44 mares, and the images were compared with routine histopathological analysis of endometrial biopsies. No adverse reactions occurred after IV fluorescein sodium administration and a dose of 4mg/kg was established (0.04mL/kg of 10% fluorescein sodium solution) to achieve optimal image contrast. CLE enabled multiple regions of the endometrium to be assessed quickly. Distinct tissue architecture patterns could be appreciated using CLE, and the luminal epithelium could be assessed for integrity (ulceration) and exocytosed inflammatory cells. Endometrial gland distribution, density, shape, and epithelial height were evaluated. Blood vessels were clearly outlined, and inflammatory cells and fibrosis were discernable within the interstitium. Image quality varied between mares, and the stage of oestrous cycle may have been a factor of influence. This novel imaging modality enables collection of "virtual" biopsies and facilitates critical assessment of multiple regions of the uterus compared with the standard histopathologic assessment of a single random tissue biopsy.

Platelet lysate does not have an anti-inflammatory effect on monoiodoacetic acid-induced equine persistent synovitis.

OBJECTIVE: To clarify the anti-inflammatory effect of platelet lysate (PL) on equine persistent synovitis by using a model of synovitis induced by monoiodoacetic acid (MIA). METHODS: Nonseptic synovitis was induced by administering MIA into both antebrachiocarpal joints of 6 clinically healthy horses on day 0. On days 23, 30, and 37, carpal circumference measurement and synovial fluid collection for assays (leucocytes, LDH, tumor necrosis factor-α, and TGF-ß1) were performed, after which PL was injected into 1 antebrachiocarpal joint and saline into the contralateral joint. Synovium and synovial fluid were obtained on day 44 for histological analysis and quantification of inflammation-related genes (matrix metalloproteinase-13, a disintegrin and metalloproteinase with thrombospondin motifs 4, receptor activator of nuclear factor κ-Β ligand, and collagen type I α2 chain) and the abovementioned proteins. RESULTS: The LDH level on day 44 was significantly lower in the PL-injected joint than in the saline-treated one. However, no significant differences were found in the other indices quantified, including osteoclast counts on the synovium. CONCLUSIONS: Multiple IA administration of PL does not exert anti-inflammatory effects on the equine persistent synovitis induced by MIA. CLINICAL RELEVANCE: Intra-articular PL administration did not alter many inflammatory biomarkers, suggesting that PL does not have a direct anti-inflammatory effect. However, the reduction in synovial LDH levels suggests that PL promoted joint tissue repair and may consequently alleviate inflammation at the site of administration.

Immune horses rapidly increase antileukoproteinase and lack type I interferon secretion during mucosal innate immune responses against equine herpesvirus type 1.

Equine herpesvirus type 1 (EHV-1) is one of the most prevalent respiratory pathogens in horses with a high impact on animal health worldwide. Entry of the virus into epithelial cells of the upper respiratory tract and rapid local viral replication is followed by infection of local lymphoid tissues leading to cell-associated viremia and disease progression. Pre-existing mucosal immunity has previously been shown to reduce viral shedding and prevent viremia, consequently limiting severe disease manifestations. Here, nasopharyngeal transcriptomic profiling was used to identify differentially expressed genes following EHV-1 challenge in horses with different EHV-1 immune statuses. Immune horses (n = 4) did neither develop clinical disease nor viremia and did not shed virus after experimental infection, while non-immune horses (n = 4) did all the above. RNA sequencing was performed on nasopharyngeal samples pre- and 24 hours post-infection (24hpi). At 24hpi, 109 and 44 genes were upregulated in immune horses and non-immune horses, respectively, and three genes were explored in further detail. Antileukoproteinase (SLPI) gene expression increased 2.1-fold within 24 hours in immune horses in concert with protein secretion. Interferon (IFN)-induced proteins with tetratricopeptide repeats 2 (IFIT2) and 3 (IFIT3) were upregulated in non-immune horses, corresponding with nasal IFN-α secretion and viral replication. By contrast, neither IFIT expression nor IFN-α secretion was induced by EHV-1 infection of immune horses. Transcriptomic profiling offered a tool to identify, for the first time, the role of SLPI in innate immunity against EHV-1, and further emphasized the central role of the type I IFN response in the anti-viral defense of non-immune horses. IMPORTANCE: Equine herpesvirus type 1 (EHV-1) remains a considerable concern in the equine industry, with yearly outbreaks resulting in morbidity, mortality, and economic losses. In addition to its importance in equine health, EHV-1 is a respiratory pathogen and an alphaherpesvirus, and it may serve as a model for other viruses with similar pathogenicity or phylogeny. Large animal models allow the collection of high-volume samples longitudinally, permitting in-depth investigation of immunological processes. This study was performed on bio-banked nasopharyngeal samples from an EHV-1 infection experiment, where clinical outcomes had previously been determined. Matched nucleic acid and protein samples throughout infection permitted longitudinal quantification of the protein or related proteins of selected differentially expressed genes detected during the transcriptomic screen. The results of this manuscript identified novel innate immune pathways of the upper respiratory tract during the first 24 hours of EHV-1 infection, offering a first look at the components of early mucosal immunity that are indicative of protection.

An overview of various stages and morphology of Histoplasma capsulatum var. farciminosum in the horse.

This article describes the development of the pathogenic dimorphic fungus Histoplasma capsulatum var. farciminosum (HCF), which is the causative agent of Equine epizootic lymphangitis (EEL), from the mycelial form in the soil to the yeast form in the horse. In this study, the stages and morphology of HCF were identified through histopathological analysis and culture with various samples collected in Ethiopia from 15 horses showing clinical signs of EEL. In equids, especially cart horses in Ethiopia, poor-quality harnesses cause cutaneous wounds, which often attract flies facilitating the transmission of the fungus. Also, HCF infection occurs through open wounds or ocular mucous membranes when horses roll on contaminated damp soil. Respiratory histoplasmosis can occur through inhaling fungal spores, which is rare. HCF microconidia enter the lungs and skin wounds and are phagocytized by tissue-resident macrophages. The spores undergo intracellular replication within the macrophages transitioning into yeasts. The infected macrophages undergo lysis releasing pathogenic yeast cells into the surrounding tissue. Consequently, yeast-rich purulent exudate is produced, contaminating the soil in stables where yeast cells germinate into the mycelial form, and the entire process starts from the beginning.

Environmental Conditions in Equine Indoor Arenas: A Descriptive Study.

Indoor arenas do not always include mechanical ventilation or stirring fans and occupancy by horses and humans can be sporadic and inconsistent, which creates a challenging space for understanding and predicting variations in temperature, moisture, and airflow. To understand the interior environment within indoor arenas, monitoring was conducted at 15 facilities within 200 kilometres of Lexington, KY. Environmental monitoring of dry bulb temperature, relative humidity, dew point temperature, air speeds, and solar radiation took place over 7 days in the winter and summer to examine temporal variability. Environmental data was collected every 5 minutes using the HOBO RX3000 Remote Monitoring Station with the HOBOnet Temp/RH Sensor, HOBOnet Solar Radiation (Silicon Pyranometer) Sensor, and HOBOnet Ultrasonic Wind Speed and Direction Sensor. Clear seasonal differences and diurnal patterns were evident in all environmental conditions, but the relative humidity. The relative humidity and dew point temperatures indicated moisture could be an issue in many of the indoor arenas. High relative humidity and excess moisture can negatively impact horse and human health as well as the lifespan of the facility. Similar results to previous spatial variability indoor arena characterizations were observed during the environmental monitoring with air speeds being below the threshold for still air in livestock facilities (0.51 m/s). Sensor technology and implementation provides a better understanding of the interior environment and how indoor arena design can impact it.

Prevalence and antimicrobial susceptibility of Streptococcus equi isolated from horses in Santa Catarina state, Southern Brazil.

The objective of this study was to determine the prevalence of Streptococcus equi (S. equi subsp equi and S. equi subsp zooepidemicus) in the state of Santa Catarina and evaluate the antimicrobial susceptibility of the isolates. For this, 420 nasal swab samples were collected from randomly selected horses. Isolation and phenotypic characterization of the bacteria were performed by sowing on 5% sheep blood agar, followed by analysis of morphotinctorial characteristics and biochemical analysis. To differentiate the main beta-hemolytic Streptococcus in horses, the fermentation profiles of the sugar's lactose, maltose, sorbitol, and trehalose were used, which were confirmed at the subspecies level by the PCR technique. The antimicrobial susceptibility panel was defined by the disk diffusion method, testing 13 antimicrobials from ten different classes, all regularly used in equine medical clinics, followed by the calculation of the multiple antimicrobial resistance index. Ten strains of S. equi were isolated, with a prevalence of 2.38% (10/420). Of the total positive samples, 3% (3/10) were confirmed as belonging to S. equi subsp equi and 70% (7/10) were confirmed as belonging to S. zooepidemicus. Multidrug resistance was observed in 60% (6/10) of isolates. The antimicrobial with the greatest resistance was clindamycin with 70% (7/10), followed by beta-lactams, with 40% (4/10) resistance to penicillin and 30% (3/10) to ceftiofur. The isolates were 100% (10/10) sensitive to gentamicin, chloramphenicol, levofloxacin, and vancomycin. This was the first study carried out in the state, and based on these data, it can be said that Santa Catarina has a low prevalence of S. equi and the presence of multi-resistant strains of S. equi was confirmed in the equine herd in Santa Catarina.

Genetic and antigenic characterization of two diarrhoeicdominant rotavirus A genotypes G3P[12] and G14P[12] circulating in the global equine population.

Equine rotavirus species A (ERVA) G3P[12] and G14P[12] are two dominant genotypes that cause foal diarrhoea with a significant economic impact on the global equine industry. ERVA can also serve as a source of novel (equine-like) rotavirus species A (RVA) reassortants with zoonotic potential as those identified previously in 2013-2019 when equine G3-like RVA was responsible for worldwide outbreaks of severe gastroenteritis and hospitalizations in children. One hurdle to ERVA research is that the standard cell culture system optimized for human rotavirus replication is not efficient for isolating ERVA. Here, using an engineered cell line defective in antiviral innate immunity, we showed that both equine G3P[12] and G14P[12] strains can be rapidly isolated from diarrhoeic foals. The genome sequence analysis revealed that both G3P[12] and G14P[12] strains share the identical genotypic constellation except for VP7 and VP6 segments in which G3P[12] possessed VP7 of genotype G3 and VP6 of genotype I6 and G14P[12] had the combination of VP7 of genotype G14 and VP6 of genotype I2. Further characterization demonstrated that two ERVA genotypes have a limited cross-neutralization. The lack of an in vitro broad cross-protection between both genotypes supported the increased recent diarrhoea outbreaks due to equine G14P[12] in foals born to dams immunized with the inactivated monovalent equine G3P[12] vaccine. Finally, using the structural modelling approach, we provided the genetic basis of the antigenic divergence between ERVA G3P[12] and G14P[12] strains. The results of this study will provide a framework for further investigation of infection biology, pathogenesis and cross-protection of equine rotaviruses.