Irish Equine Centre

BackgroundImpingement of spinous processes (SPs) is commonly diagnosed in the equine athlete. For diagnostic and therapeutic purposes, local injections are performed at the level of the space between adjacent spinous processes in affected horses.ObjectivesTo assess the accuracy of different techniques for the local injection of the interspinal space in the equine thoracolumbar spine.Study DesignEx vivo experimental study.MethodsEquine thoracolumbar spine specimens were used to compare three techniques for needle insertion (midline; bilateral abaxial; unilateral oblique), two needles (20G—1½″; 20G—3½″) and two volumes (5 mL; 20 mL) for local injection of the interspinal space. Additionally, needle insertion based on radiographic, ultrasonographic guidance, or palpation was assessed. Computed tomographic analysis and anatomical dissection were performed to evaluate the distribution of the injected volume.ResultsThe most accurate injection of the interspinous ligament was achieved when the midline injection method using a 20G—1½″ short needle and a volume of 5 mL was used. Wide distribution of the injected volume was observed when the bilateral abaxial injection technique was utilised. The unilateral oblique injection technique led to significantly asymmetrical unilateral distribution of the injectate. Radiographic guidance did not increase the accuracy of the injection.ConclusionThe midline injection method is the most reliable technique for the targeted injection of the thoracolumbar interspinal space.

Equine rotavirus A (RVA) is a major cause of debilitating diarrhoea in neonatal foals globally. The aim of this study was to characterise RVA viruses currently circulating in Ireland and to identify risk factors associated with disease outbreaks. Of the 377 samples submitted during 2023 and 2024, 48 foals from 36 outbreaks were confirmed to be RVA-positive by real-time PCR. The viruses detected were genotyped by VP7 and VP4 gene sequencing. In 2024, the attending veterinary surgeon was contacted, and epidemiological data were collected. These included the vaccination status of the foal's dam and the clinician's opinion of the hygiene standard and stocking density on the farm. During the study period, 37 G3 RVAs were detected on 26 premises and 7 G14 RVAs were detected on 6 premises. Phylogenetic analysis indicated that all the viruses characterised were of the G3A subtype and the P[12]genotype and were closely related to viruses previously identified in Europe and Japan. Farm hygiene standards and stocking rates, with some exceptions, were considered satisfactory by the clinicians. However, vaccination coverage needs to be improved as the dams of the affected foals were unvaccinated on 68% of farms.

This study describes a comparison of the detection of rotavirus in clinical samples from foals using two commercially available rapid antigen detection (RAD) kits, with the detection of rotavirus nucleic acid via a laboratory-based, in-house, real-time reverse transcription polymerase chain reaction (RT-PCR) assay. One hundred and forty freeze-thawed samples (70 that were RT-PCR-positive and 70 that were RT-PCR-negative on original tests) submitted to the diagnostic laboratory over a seven-year period were tested in addition to 123 fresh samples (15 RT-PCR-positive and 108 RT-PCR-negative) submitted over a four- month period in 2024. The analyst performing the RAD tests was blinded to the RT-PCR result as were the two individuals who read the results. Samples with discordant results were re-tested in duplicate using RT-PCR and the two RAD kits. Both kits demonstrated a high level of concordance with the RT-PCR (>95%). However, testing of serial dilutions of RT-PCR positive faeces samples indicated that the RADs failed to detect the virus at the higher dilutions. In conclusion, the RADs evaluated are potentially useful for screening individual foals and for the determination of the urgency of the appropriate treatment and isolation. Negative samples from suspect cases and weak positives should always be submitted to a specialist laboratory for real-time RT-PCR testing.

Simple SummaryThe association between poor performance and respiratory disease in Thoroughbred racehorses that do not have a structural abnormality of the respiratory tract is often based on anecdotal evidence. We examined peer reviewed publications to determine if there was scientific evidence to link conditions such as inflammation of the airways, asthma, tracheal mucous, and exercise-induced pulmonary haemorrhage (EIPH) with decreased athletic performance. This is a complex field and studies have yielded conflicting results as to the impact of such conditions on performance. For example, some investigators found a significant association between poor racing performance and low-grade EIPH and mild to moderate asthma. In contrast, others have suggested that they may represent a normal response to training and the stabling environment. The key outcome of the review was that there is a dearth of studies unequivocally linking non-structural airway disease with poor performance, and there is a lack of an internationally harmonised approach to the assessment of racehorse performance. Improved investigations providing better quality evidence would facilitate comparison across studies, increase our understanding of the conditions associated with poor performance, safeguard horse welfare, and assist trainers to achieve their goals.The association between poor performance and respiratory disease in Thoroughbred racehorses that do not have a structural abnormality of the respiratory tract, is often based on anecdotal evidence. The objective of this scoping review was to examine the scientific evidence for such associations. Publications were selected based on a search of three databases (PubMed, Scopus, and CAB Direct), in English and without date restriction, followed by a screening process to exclude non-relevant papers, duplicates, and reviews. This process identified 996 publications of which 20 were analysed using the Quality in Prognosis Studies (QUIPS) tool. The results indicated that the evidence supporting the relationship between proposed diagnostic indicators and poor performance is variable. There is a need for better quality evidence. In particular, there are conflicting reports relating to the impact of equine asthma and EIPH on athletic performance. Furthermore, a lack of standardisation in the measurement of racehorse performance makes it difficult to compare findings from different studies. The industry would benefit from high-level guidance concerning the design of controlled performance studies in Thoroughbred racehorses to collect comprehensive data and facilitate targeted interventions.

Reproduction, Fertility and Development is an international journal publishing original research , review and comment in the fields of reproduction and developmental biology in humans, domestic animals and wildlife

Equine septic fungal arthritis is poorly documented in the literature. There is absence of efficacy and safety data for anti-fungal medications, highlighting the importance of documenting this case. A 15-year-old Irish sport horse gelding presented moderately lame at the walk on the left hindlimb 13 days after intra-articular medication of the left tarso-crural joint with triamcinolone and hyaluronic acid. Radiography revealed an osteochondral fragment at the distal intermediate ridge of the tibia and shallow subchondral bone defect on the medial trochlear ridge. Synoviocentesis yielded a turbid sample with an elevated total nucleated cell count (49x109cells/L; total neutrophil count of 62.8%). Arthroscopic lavage of the tarsocrural joint (TCJ) was performed. Ceftriaxone was administered and systemic antimicrobials initiated. The fungus Wickerhamomyces anomalus was identified on culture. The horse was subsequently intensively treated with antimicrobial and anti-fungal medications, both systemically and intra-articularly over the following 60 plus days. Multiple subsequent synovial cultures revealed the persistence of the fungal organism, until a negative culture on day 55. However, on day 113, a non-weight bearing lameness at trot was present, and a further positive synovial fungal culture. Radiographs revealed a lytic lesion at the distal tibia with marked progression. The horse was euthanised on day 126.

Incisional complications are a common cause of morbidity following laparotomy. Although uncommon, acute abdominal dehiscence (AAD) is a potentially fatal post-operative complication. However, few AAD cases are described in the literature. To describe common features of cases of AAD following ventral midline laparotomy, management and outcomes. Retrospective case series. Hospital records of horses that underwent a ventral midline laparotomy at nine hospitals in the UK, Ireland and USA over a 10-year period (2009-2019) were reviewed. Data were collected for pre-, intra- and post-operative factors that were considered relevant. Descriptive statistical analysis was performed. A total of 63 cases of AAD were identified. AAD occurred due to tearing of sutures through the linea alba or rupture of the body wall adjacent to the suture line in 46 horses (73%). AAD occurred at a median of 5days (0.5-70days) post-operatively and broodmares accounted for 25% of the cases (n=16). Surgical site infection developed prior to AAD in 28 horses (44%); leakage of peritoneal fluid occurred in 5% of horses prior to AAD being identified. Surgical repair was performed in 27 horses (43%), 10 (16%) were treated conservatively and 26 (41%) were euthanised immediately. Repair was most frequently performed using suture (n=14), wire (n=5) or a combination (n=5). Overall survival to hospital discharge was 39% (24/63). Where surgical repair was performed, 15 horses (56%) survived to hospital discharge; 9 horses (90%) managed conservatively survived to hospital discharge. Follow-up was not performed for all cases following hospital discharge and some data were incompletely recorded in hospital files. Previously stated causative factors for AAD were not consistent features in the present study. Surgical site infection following laparotomy and pregnant or early post-partum mares may be important risk factors for AAD and warrant further investigation.

Background: Equine herpesvirus type-1 (EHV-1) is an important threat to the equine industry, as illustrated by the ongoing outbreak of neurological disease that was initially reported during a large equestrian event in Valencia, Spain in 2021. Horses returning from this event to their training yards have contributed to the spread of the virus to nine other European countries and to Qatar. Objectives: To design a “tracking” marker in order to specifically follow the dissemination of the Valencia strain, in EHV-1 infected horses with no known epidemiological link with the Valencia outbreak. Study design: Strain isolation and genome sequences’ comparison. Methods: 67 nasopharyngeal swab samples from horses stationed in Valencia were analysed by EHV-1 qPCR and a rapid A/G/C2254 (ORF30) typing test. Positive samples were used for strain isolation in vitro, and Multilocus Sequence Typing (MLST). Results: 19/67 (28%) samples were EHV-1 positive (all 19 typed as A2254). Two strains (FR/Valencia1/2021 and FR/Valencia2/2021) were successfully isolated and characterised by MLST as belonging to clade 10. Analysis of the MLST ORF sequences revealed a mutation at position 713 of the ORF11 (A713G) in FR/Valencia1/2021 and FR/Valencia2/2021, when compared with reference strains Ab4 and V592. This A713G mutation was not present in 104 ORF11 sequences obtained from Genbank (strains from the UK, USA, China, Australia, Belgium, New-Zealand, Japan or India), or 131 and 14 ORF11 sequences from strains isolated in Ireland or France, respectively. This marker allowed subsequent confirmation of suspicious epidemiological links in EHV-1 cases. Main limitation: The limited number of ORF11 sequences available in some countries. Conclusions: Although the existence of this mutation in other field strains cannot be excluded, its absence in the 249 ORF11 sequences analysed, suggests that this SNP constitutes an interesting epidemiological marker to identify horses infected with the EHV-1 strain which was associated with the outbreak in Valencia.

Elephant endotheliotropic herpesvirus (EEHV) causes a disease that primarily affects juvenile Asian (Elephas maximus) elephants, causing acute hemorrhage and death. Due to the severity of the disease, many zoos have developed EEHV active surveillance programs. Currently, trunk washes are the standard for testing elephants for shedding of EEHV, but it has also been detected from other mucosal surfaces. This study compared the efficacy of oral swabs and trunk washes for the detection of EEHV shedding using previously validated quantitative polymerase chain reaction (qPCR) methods. Oral swab and trunk wash samples from three juvenile elephants at the Dublin Zoo in Ireland were collected in tandem and tested from April to September 2017. Of the 51 paired samples, 21 trunk wash samples were positive for EEHV1, while only 2 of the oral swab samples were positive for EEHV1, suggesting that trunk wash samples are more effective for detecting shedding of EEHV in Asian elephants compared with oral swabs.