Does the Uterine Ozone Therapy Alter the Transcript Profile of Anti- and Proinflammatory Genes in Mares With Endometritis?

This study aimed to evaluate the localised effects of intrauterine ozone therapy on endometrial recovery in mares with endometritis. Our investigation assessed changes in gene expression profiles of anti-inflammatory (IL-1RA and IL-10), proinflammatory (IL-R1B3i and TNFα) and pleiotropic (IL-6) cytokines, along with detailed histological measurements of epithelial and endometrial thickness and the glandular area ratio. Twenty mares were assigned to a 2 × 2 factorial design based on endometritis diagnosis and treatment (control or 42 µg/mL ozone insufflation), resulting in four groups: NC (negative for endometritis/control), NO (negative/ozone), PC (positive/control) and PO (positive/ozone). Oestrus was induced with 2 mg of oestradiol benzoate on Days -1, 1 and 3, plus 1 mg on Day 5. Day 0 marked the initial uterine treatment, followed by insufflations on Days 1 and 2 with O3 (ozone) or O2 (control). Uterine biopsies were taken before treatment on Day 0 and Day 6 for histological analysis and gene expression assessment. Data were analysed using a statistical model that included endometritis status, treatment type, biopsy times (D0 and D6) and their interactions, analysed with Proc Glimmix. Regardless of treatment or endometritis status, significant biopsy effects (p < 0.01) indicated increased epithelial height and endometrial thickness in Day 6 samples. Analysis of IL-1 and TNFα revealed a significant interaction (p < 0.05) among endometritis, treatment and biopsy, with higher IL-1B3i expression on Day 6 in the PC group. The treatment effect (p < 0.04) showed a higher frequency (p < 0.01) of animals with positive modulation in the PC group (66.7%) versus the PO group (0.0%). An interaction effect (p = 0.08) between endometritis and treatment resulted from higher IL-1RA expression on Day 6 in the PC group compared to the PO group. Biopsy effect was significant for IL-10 (p < 0.01), indicating higher values in the second sample associated with tissue repair. In the short-term evaluation, ozone therapy did not influence endometrial morphology and may modulate cytokine expression, specifically the reduction in IL-1 and TNFα levels. Therefore, this therapy appears to be a safe and potentially effective treatment for modulating the inflammatory response in mares with endometritis.

Serological and molecular detection of Toxoplasma gondii infection in apparently healthy horses in eastern of Spain.

Toxoplasmosis is one of the most common parasitic zoonoses and represents a significant health risk for humans, especially for immunodeficient patients. The main transmission route is by oral uptake of oocysts and consumption of undercooked meat of infected animals. Different species have been evaluated as possible reservoirs of the parasite, but few studies have been carried out to examine the role of horses in transmission of the disease. Given the proximity of these animals to humans and the widespread consumption of their meat in many countries, including the Mediterranean basin, it is important to determine the prevalence of T. gondii infection in this species. In this study, blood samples from 105 horses were collected and the presence of T. gondii was evaluated by serological and molecular methods. Antibodies against T. gondii of 12 horses (11.43%) were detected by enzyme-linked immunosorbent assay (ELISA), whereas 29 horses (27.62%) showed positive for PCR. Seroprevalence was related to use of the animals, being higher in horses used for dressage than in others. Purebreds had higher seroprevalence than crossbred animals. No differences between breed, sex or age were found. The results of this study confirm the presence of T. gondii infection in horses, highlighting the need to analyse the meat of this species before human consumption and to control of this infection in horses, as they could be an important reservoir of this zoonotic parasite.

Association between equine asthma and fungal elements in the tracheal wash: An environment-matched case-control study.

The presence of fungi in tracheal wash (TW) of horses was recently linked to mild-moderate equine asthma, indicating a possible causal role; however, increased numbers of fungi may also stem from asthma-related alteration of tracheal mucus clearance or from environmental exposure. Our objective was to elucidate the association between the presence of fungi in TW and asthma status while controlling for relevant confounders. We conducted a retrospective case-control study involving 73 horses, including 34 controls and 39 asthmatic cases. Each asthmatic horse was matched with a control from the same barn to account for the influence of environmental exposure. All horses underwent respiratory clinical scoring, endoscopy, TW, and bronchoalveolar lavage (BAL). The association between asthma status and presence of TW fungi was tested with multivariable logistic regression modelling, accounting for selected management factors, tracheal mucus accumulation, and selected TW and BAL cytological characteristics, including multinucleated giant cells (MGCs) in the TW. Given the variability in MGC definitions in the literature, particularly concerning their morphology and number of nuclei, we constructed two distinct models for each outcome (asthma status or presence of fungi in TW): one considering MGCs as cells with ≥ 3 nuclei, and another using a criterion of ≥ 10 nuclei. Horses with a tracheal mucus score ≥ 2 exhibited 3.6 to 4.3 higher odds of being asthmatic, depending on the MGC definition. None of the other variables examined were associated with either asthma status or TW fungi detection. Notably, the presence of fungal elements in the TW was not associated with equine asthma.

Prevalence, risk factors, and characterisation of extended-spectrum ß-lactamase -producing Enterobacterales (ESBL-E) in horses entering an equine hospital and description of longitudinal excretion.

BACKGROUND: Extended-spectrum ß-lactamase -producing Enterobacterales (ESBL-E) are important zoonotic pathogens that can cause serious clinical infections, also in horses. Preventing the spread of ESBL-E, especially in the equine hospital environment, is key to reducing the number of difficult-to-treat infections. Estimating the local prevalence of ESBL-E in horses is crucial to establish targeted infection control programs at equine hospitals. We conducted a prevalence and risk factor study in equine patients on admission to an equine teaching hospital in Finland through a rectal ESBL-E screening specimen of the horse and a questionnaire. RESULTS: The prevalence of ESBL-E in admitted horses was 3% (5/161, 95% CI 1-7%); none of the tested factors remained statistically significant in multivariate analysis, although antimicrobial treatment within three months was borderline significant (p = 0.052). Extended-spectrum ß-lactamase -producing Klebsiella pneumoniae ST6179:CTX-M-15 was detected in three horses using whole-genome sequencing, which in combination with patient records suggested nosocomial transmission. Escherichia coli isolates were ST1250:CTX-M-1 (n = 1), ST1079:CTX-M-1 (n = 1), and ST1245:CTX-M-14 (n = 1). Multiple virulence genes were detected in the ESBL-E isolates. In the ESBL-E positive horses enrolled in a one-year follow-up study, ESBL-E were unlikely to be isolated in rectal screening specimens after the initial positive specimen. CONCLUSIONS: The prevalence of ESBL-E in horses visiting a veterinary teaching hospital in Finland is low, indicating an overall low prevalence estimate in the country's equine population. No statistically significant risk factors were identified, likely due to the low number of cases. The duration of ESBL-E carriage is likely to be very short in horses.

Technique description and outcome evaluation of Thoroughbred racehorses following soft palate thermocautery performed under standing sedation.

BACKGROUND: Palatal dysfunction (PD), which encompasses palatal instability (PI) and intermittent dorsal displacement of the soft palate, is the most common performance-limiting upper respiratory tract obstruction in young Thoroughbred racehorses. Soft palate thermocautery (SPT) performed under general anaesthesia is a routinely performed procedure for PD in some countries, but the procedure for and outcome of SPT performed under standing sedation has not been published. OBJECTIVES: (1) To describe a technique for SPT performed under standing sedation; and (2) to assess post-operative performance in horses compared to controls using the Racing Post rating (RPR), British Horseracing Authority official rating (OR), Performance Index and Earnings. STUDY DESIGN: Retrospective case series. METHODS: Medical records were reviewed for all horses that had SPT performed under standing sedation following topical and local infusion of lidocaine hydrochloride into the rostral soft palate, and that were identified to have PI by overground endoscopy. Two matched controls were identified for each case. The median RPR, OR, Performance Index and Earnings for the three pre-operative and three post-operative races were compared. RESULTS: No significant differences were identified between the SPT (n = 23) and Control groups (n = 46) for baseline characteristics or outcomes. MAIN LIMITATIONS: Retrospective study design, small sample size. CONCLUSIONS: No significant differences in racing performance were identified between horses that had SPT performed under standing sedation and controls.

Aspergillus fumigatus antigen-reactive Th17 cells are enriched in bronchoalveolar lavage fluid in severe equine asthma.

Introduction: Equine asthma (EA) is a common disease of adult horses with chronic respiratory pathology and common neutrophilic airway inflammation. It presents with hyperreactivity to hay dust components such as molds, and underlying dysregulated T cell responses have been suggested. Thus far, T cells have been analysed in EA with conflicting results and the antigen reactivity of T cells has not been demonstrated. Serological and epidemiological data point to the relevance of Aspergillus fumigatus as an antigen source in EA. Here, we aimed to identify and characterise Aspergillus antigen-reactive T cells in EA. Methods: Cryopreserved bronchoalveolar lavage cells (BALC) and peripheral blood mononuclear cells (PBMC) from healthy horses (HE, n=9) and those with mild-moderate (MEA, n=3) or severe asthma (SEA, n=8) were stimulated in vitro with the recombinant A. fumigatus antigens Asp f 1, or Asp f 7 combined with Asp f 8, to assess antigen reactivity, and with phorbol-12-myristat-13-acetate and ionomycin (P/i) to assess overall T cell reactivity. Stimulated cells were analysed by flow cytometry for CD4, CD8, IL-17, IL-4, and IFN-γ. Cytokine expression in all lymphocytes, and in CD4+ or CD8+ T cells, was quantified and compared between the groups. In BAL fluid (BALF), soluble cytokines and chemokines were quantified by bead-based assays. Results: Antigen restimulation of BALC with Asp f 1 or Asp f 7/8 provoked higher frequencies of IL-17+ lymphocytes, CD4+IL-17+ Th17 cells, and CD4+IL-4+ Th2 cells in SEA than in HE, whereas MEA and HE were similar. Antigen stimulation of PBMC did not result in group differences. P/i stimulation of BALC resulted in increased IL-17+ lymphocyte and CD4+IL-17+ Th17 cell frequencies in MEA compared with HE but the limited number of horses with MEA must be considered. P/i-stimulated PBMC from MEA or SEA contained more IL-17+ lymphocytes compared with HE. Cytokines were hardly detected in BALF and similar between the groups but CCL2 and CCL5 concentrations were increased in BALF from SEA or MEA, respectively, compared with HE. Conclusion: Horses with SEA have increased Aspergillus antigen-reactive Th17 cells in their airways, emphasising local T cell responses to this mold, which were quantified in EA for the first time here.

Cutaneous and conjunctival habronemosis in horses treated at the Veterinary Hospital of the Santa Catarina State University, Brazil.

Habronemosis, also known as habronemiasis or habronematidosis, is a parasitic disease of equids caused by the larval stages of Habronematidae nematodes (Habronema muscae, Habronema microstoma, and Draschia megastoma) that are transmitted by muscid flies. The presence of aberrant infective larvae in the cutaneous and conjunctival tissues of these hosts results in granulomatous, exudative, and ulcerated lesions, also known as "summer sores." In this study, we present a retrospective analysis of habronemosis cases in horses from the municipality of Lages, located on the Santa Catarina Plateau, a region with high altitudes and a temperate climate that differs from regions of Brazil where such parasitosis usually occurs. The equids were examined from 2008 to 2020 at the Veterinary Hospital of Santa Catarina State University. Sixteen patients were diagnosed and treated using macrocyclic lactones and wound cleaning. Most cases were recorded in autumn in horses (10/16, 62.5%) over 15 years of age (11/16, 68.8%), and the lesions were more frequently located in the conjunctiva (11/16, 68.8%). In scientific dissemination media, this is the first report of habronemosis on the Santa Catarina Plateau, Brazil. This information will contribute to the diagnosis, treatment and prevention of skin diseases in horses in this region.

Nineteen years of radiographic screening: Impact of sepsis and evolution of osteochondrosis dissecans prevalence in Walloon sport horses born between 2004 and 2022.

Osteochondrosis dissecans is a particularly common developmental orthopaedic disorder in equines. Among its causes, the hereditary component is no longer a matter of debate, and, for several decades, the various studbooks for sport horses have been selecting stallions in order to limit the prevalence of this condition in the population. However, to our knowledge, no study has evaluated changes in the prevalence of osteochondrosis dissecans over time through longitudinal monitoring of a population of sport horses. The study presented here is part of a large screening programme for developmental orthopaedic pathologies in Wallonia (Belgium) and assessed the presence of these lesions over a period of 19 years in the Walloon sport horse population according to constant and standardised sampling and diagnostic criteria. The effects of breeding conditions and infection in foals were also assessed by means of questionnaires. The results showed no significant change in the prevalence of osteochondrosis dissecans in a population of 1099 individuals born between 2004 and 2022. Furthermore, individuals who had suffered from sepsis during their growing period were very significantly predisposed (p < 0.001) to the development of osteochondrosis dissecans compared to a control group, with respectively 14/21 (67%) and 103/364 (28%) of individuals affected. This study suggests that the selection programmes applied to the population studied are not sufficiently strong or adapted to reduce the prevalence of osteochondrosis dissecans in the population over a period of 19 years. Moreover, this study confirms that foals with sepsis and concurrent osteochondrosis dissecans lesions should not necessarily be excluded from breeding programmes on this basis.

Prevalence and risk factors associated with nasal carriage of methicillin-resistant staphylococci in horses and their caregivers.

Antimicrobial resistance is a global threat, and pet-associated strains may pose a risk to human health. Equine veterinarians are at high risk of carrying methicillin-resistant staphylococci (MRS), but specific risk factors remain elusive, and few data are available for other personnel involved in the horse industry. The prevalence, characteristics, and risk factors for nasal carriage of MRS in horses and their caregivers were studied in northwestern Italy. Nasal swabs from 110 asymptomatic horses housed at 21 barns and 34 human caregivers were collected. Data on barns, horses, and personnel were acquired through questionnaires. The samples were incubated in selective media, and the bacterial isolates were identified by mass spectrometry. Risk factors were investigated by Poisson regression. MRS were isolated from 33 horses (30%), 11 humans (32.4%) and 3 environmental samples (14.2%). Most isolates were multidrug resistant (MDRS). The prevalence of MRS and MDRS was greater in racehorses and their personnel than in pleasurable and jumping/dressing horses. MRS carriage in caregivers was associated with an increased prevalence of MRS carriage in horses. The frequency of antimicrobial treatments administered in the barn during the last 12 months was a risk factor for MRS carriage in horses [prevalence ratio (PR) 3.97, 95% CI 1.11, 14.13] and caregivers (PR 2.00, 95% CI 1.05, 3.82), whereas a good ventilation index of the horse tabling environment was a protective factor (PR 0.43, 95% CI 0.20, 0.92). Our data reveal relevant interactions occurring between bacterial communities of horses and humans that share the same environment, suggesting that One Health surveillance programs should be implemented.

Diagnostic utility of acute phase proteins and their ability to guide antibiotic usage in pigs, horses, and cattle: a mapping review.

To mitigate the use of antibiotics for many of the multifactorial diseases seen in pigs, horses and cattle, new diagnostic tools are needed. Acute phase protein (APP) measurements can, in humans, be used to guide antibiotic treatment initiation, evaluate treatment efficacy, and make a prognosis. The aim of this review is to collect evidence on the clinical functionality of APP measurements as a tool to guide antibiotic treatment in pigs, horses, and cattle. Literature was retrieved using Medline, CAB Abstracts and Google Scholar. The acute phase response has been investigated for a plethora of diseases and clinical signs and the major acute phase proteins are elevated in diseased compared to healthy animals. Few studies correlated acute phase response with aetiology, antibiotic treatment efficacy, prognosis, or severity of disease. The existing research does not support that APP can be used to guide antibiotic treatment, but the reported studies indicate that C-reactive protein (CRP) might be able to differentiate between bacterial and non-bacterial causes of disease in pigs. Serum amyloid A (SAA) might reflect underlying aetiology in horses and infectious or non-infectious cases of mastitis in cows.

Methicillin-resistant Staphylococcus aureus outbreak in a Dutch equine referral clinic.

In 2020 and 2022, nine cases of surgical site infections with a methicillin-resistant Staphylococcus aureus (MRSA) were diagnosed in horses in an equine referral clinic. Sixteen isolates (horses, n=9; environment, n=3; and staff members, n=4) were analysed retrospectively using Nanopore whole-genome sequencing to investigate the relatedness of two suspected MRSA outbreaks (2020 and 2022). The MRSA isolates belonged to ST398 and ST612. ST398 genomes from 2020 and 2022 formed three phylogenetic clusters. The first ST398 cluster from 2020 consisted of isolates from five horses and one staff member, and we suspected within clinic transmission. The second cluster of ST398 isolates from 2022 originated from two horses and two staff members but showed higher single nucleotide polymorphism (SNP) distances. One ST398 isolate from an individual staff member was not related to the other two clusters. The ST612 isolates were isolated in 2022 from two horses and three environmental samples and showed very low SNP distances (<7 SNPs), indicating the transmission of MRSA ST612 in this clinic in 2022. Molecular characterization revealed an abundant set of virulence genes and plasmids in the ST612 isolates in comparison to ST398 isolates. Phenotypic antimicrobial susceptibility showed that differences between the two sequence types were consistent with the genetic characteristics. MRSA ST612 has not been reported in Europe before, but it is a dominant clone in African hospitals and has been described in horses and people working with horses in Australia, indicating the importance of surveillance.

"How long is life worth living for the horse?" A focus group study on how Austrian equine stakeholders assess quality of life for chronically ill or old horses.

BACKGROUND: Quality of life (QoL) provides a comprehensive concept underpinning veterinary decision-making that encompasses factors beyond physical health. It becomes particularly pertinent when seeking responsible choices for chronically ill or old horses that emphasise their well-being and a good QoL over the extension of life. How different stakeholders use the concept of QoL is highly relevant when considering the complexity of these decisions in real-life situations. METHODS: Seven focus group discussions (N = 39) were conducted to gain insights into how stakeholders assess and use equine QoL in veterinary care decisions for chronically ill and/or old horses. The discussions included horse owners (n = 17), equine veterinarians (n = 7), veterinary officers (n = 6), farriers (n = 4), and horse caregivers (n = 5). The combination of deductive and inductive qualitative content analysis of the group discussions focused on identifying both similarities and differences in the views of these groups regarding QoL for old and/or chronically ill horses. RESULTS: Findings show agreement about two issues: the importance of the individuality of the horse for assessing QoL and the relevance of QoL in making decisions about veterinary interventions. We identified differences between the groups with respect to three issues: the time required to assess QoL, stakeholders' contributions to QoL assessments, and challenges resulting from those contributions. While owners and caregivers of horses emphasised their knowledge of a horse and the relevance of the time they spend with their horse, the veterinarians in the study focused on the differences between their own QoL assessments and those of horse owners. In response to challenges regarding QoL assessments and decision-making, stakeholders described different strategies such as drawing comparisons to human experiences. CONCLUSIONS: Differences between stakeholders regarding equine QoL assessments contribute to challenges when making decisions about the care of chronically ill or old horses. The results of this study suggest that individual and collaborative reflection about a horse's QoL should be encouraged, for example by developing practicable QoL assessment tools that support relevant stakeholders in this process.

Early-life gut bacterial community structure predicts disease risk and athletic performance in horses bred for racing.

Gut bacterial communities have a profound influence on the health of humans and animals. Early-life gut microbial community structure influences the development of immunological competence and susceptibility to disease. For the Thoroughbred racehorse, the significance of early-life microbial colonisation events on subsequent health and athletic performance is unknown. Here we present data from a three-year cohort study of horses bred for racing designed to explore interactions between early-life gut bacterial community structure, health events in later life and athletic performance on the racetrack. Our data show that gut bacterial community structure in the first months of life predicts the risk of specific diseases and athletic performance up to three years old. Foals with lower faecal bacterial diversity at one month old had a significantly increased risk of respiratory disease in later life which was also associated with higher relative abundance of faecal Pseudomonadaceae. Surprisingly, athletic performance up to three years old, measured by three different metrics, was positively associated with higher faecal bacterial diversity at one month old and with the relative abundance of specific bacterial families. We also present data on the impact of antibiotic exposure of foals during the first month of life. This resulted in significantly lower faecal bacterial diversity at 28 days old, a significantly increased risk of respiratory disease in later life and a significant reduction in average prize money earnings, a proxy for athletic performance. Our study reveals associations between early-life bacterial community profiles and health events in later life and it provides evidence of the detrimental impact of antimicrobial treatment in the first month of life on health and performance outcomes in later life. For the first time, this study demonstrates a relationship between early-life gut bacterial communities and subsequent athletic performance that has implications for athletes of all species including humans.

Spatial and seasonal distribution of Leptospira spp. seropositive horses in the Northeast region of Brazil.

Leptospirosis is an anthropozoonosis of economic and public health importance, caused by bacteria of the genus Leptospira. Horses are deemed important in its transmission chain due to their proximity to humans, and because the species is often asymptomatic, making these animals potential silent reservoirs. In this context, the objectives of this study were to determine the prevalence of seropositive horses for Leptospira spp., and to identify the presence of Leptospira spp. serogroups and antibody titers, the occurrence of areas with higher density of infection cases and demographic characteristics associated with seropositivity in the states of Paraíba (PB), Pernambuco (PE), Rio Grande do Norte (RN) and Ceará (CE), in the Northeast region of Brazil, during rainy (May and June) and dry (October and November) seasons from 2017 to 2019. Using the microscopic agglutination test (MAT), 1152 equine serum samples from 225 municipalities were analyzed. Anti-Leptospira antibodies were detected in 23.9 % (95 % CI= 21.4 - 26.3 %) of the samples in the three-year period, with a frequency of 30.4 % (95 % CI= 26.7 - 34.2 %) during the rainy period (with greater emphasis on the Ballum serogroup) and 17.4 % (95 % CI= 14.3 - 20.5 %) in the dry period (with greater emphasis on the Sejroe serogroup). Age of horses ≥ 6 years (6-10 years, 11-15 years and ≥ 16 years), rainy season, and animal belonging to Pernambuco state were factors with higher seropositivities. Regarding spatial distribution, a higher percentage of seropositive animals was observed in Pernambuco (P < 0.05), in interstate border areas, and large urban centers, with a spatial cluster detected in the dry season of 2018 with relative risk of 2.8 (P = 0.049) times higher in municipalities within the cluster. It is suggested that measures for controlling rodents and contact with wild animals in equine farming, both in rainy and dry periods, combined with care regarding the use of pastures shared with cattle and the adoption of immunoprophylaxis are important in preventing and controlling leptospirosis in horses in the Northeast region of Brazil.

Application of blood parameters for the early diagnosis of natural ascending placentitis in pregnant mares.

Placental infection is an important cause of late-term pregnancy loss and neonatal diseases in horses. Detection of changes in blood parameters especially during early placentitis could improve the diagnostic accuracy, treatment decision, and potential outcomes. The objectives of this 2-part study were to identify differences in circulating immunological, inflammatory, and hormonal parameters between mares with natural ascending placentitis and control mares; evaluate each and combination of parameters as predictors of placentitis; and determine how these parameters indicate severity of placentitis. Reproductive examination and blood sampling were prospectively performed on pregnant mares in a natural setting. Study 1 enrolled mares diagnosed with early stage of ascending placentitis based on ultrasonographic findings (n = 12), and gestationally age-matched mares with healthy pregnancies as controls (n = 12). Blood samples were classified as pre-onset (before) and early onset (at the time of ultrasonographic changes) of placentitis. There were no detected statistically significant differences between groups and timepoints in immunological and inflammatory parameters, including peripheral lymphocyte subpopulations, cytokine, and serum amyloid A concentrations. The placentitis group showed a reduced (P = 0.01) DHP/20α-DHP ratio when compared to the control group at the early onset timepoint. Plasma estradiol-17ß concentration <359 pg/mL predicted ascending placentitis with acceptable accuracy (area under the curve, AUC = 0.71). Combined albumin <3.7 g/dL, estradiol-17ß < 499 ng/mL, and DHP <33 ng/mL predicted 100 % of cases of ascending placentitis. In study 2, samples were classified according to the presence and severity of the abnormal ultrasonographic findings as mild (n = 11) and moderate-severe (n = 23), and gestationally age-matched with samples from control mares (n = 34). Mares with moderate-severe ascending placentitis had increased (P = 0.03) plasma 20α-DHP concentration and reduced (P = 0.03) DHP/20α-DHP ratio when compared to control mares. Our results suggest that the early events of ascending placentitis detected by ultrasonographic findings include hormonal alterations of feto-placental metabolism measurable in the mare's circulation, yet without obvious systemic immunological and inflammatory changes. Additional studies are warranted to further assess how hormonal markers and cutoff values could guide decisions for timely therapeutic intervention.