Streptococcus equi subspecies equi (S. equi) is the causative organism of the upper respiratory disease of equids, strangles, characterised by pyrexia, lymphadenopathy, and mucopurulent nasal discharge. Strangles was first reported over 750 years ago and continues to be of significance in equine populations across the globe. This review discusses how S. equi has adapted, the clinical manifestation of strangles, and how clinicians and caregivers can tackle the disease in the future. S. equi evolved from the commensal, and occasionally opportunistic pathogen, Streptococcus equi subspecies zooepidemicus refining its capabilities as it became host restricted. The success of S. equi can be attributed to its ability to cause both acute and persistent infection, the latter occurring in about 10% of those infected. In this carrier state, S. equi persists in the guttural pouch without causing clinical signs, intermittently shedding into the environment, and encountering naïve animals. Insight into the S. equi genome and lifestyle has led to advances in diagnostic assays and the development of a safe and efficacious recombinant-fusion vaccine, giving clinicians and caregivers the tools to better combat this infection. Alongside rigorous biosecurity protocols and pragmatic control measures such as screening new arrivals for exposure and carrier status, these new technologies demonstrate that strangles can be an increasingly preventable infection.

Septicemia can be a tragic illness in neonatal and young foals. Sick foals may manifest a variety of clinical symptoms all related to a common infection and its systemic effects. While the pathogenesis of this disease is the same as for adult equids, the clinical signs seen can be very different. The rapid changes seen in foal are reflective of their low endogenous reserves of glucose and innate immune mediators as well as the poor ability to self-regulate their metabolism. The neonatal immune system is reliant on maternal antibodies at birth and development of the foal's own system takes a significant amount of time. This non-competent immune system changes how the foal responds to infection when compared to the adult. Clinical signs in septic foals include tachycardia, tachypnea, depression, anorexia, colitis, and fever. Less commonly, foals may show petechiation, swollen joints, anterior uveitis, and coma. This article is the first of a two part series on neonatal sepsis and will present a review on the neonatal immune system, the pathophysiology of sepsis, and the range of clinical signs seen in foals.

Bladder prolapse is a rare condition in mares and may occur as a result of excessive straining during the parturition or in the postpartum period. We report a case of dystocia associated prolapse and incarceration of the small colon through the external urethral opening into a prolapsed urinary bladder. No previous reports of this condition were found. An 11-year-old Thoroughbred mare was presented to The Equine Hospital at the Jockey Club of Saudi Arabia for evaluation and treatment of dystocia. Prolapse of the urinary bladder was concomitantly diagnosed. Initial assessment deemed replacement of the urinary bladder in the normal position and vaginal delivery not possible. The mare was immediately prepared for caesarean section. The foal was successfully delivered and resuscitated. Detailed assessment of the bladder during the surgery revealed that the small colon had prolapsed through the external urethral opening and was inside the bladder. The urinary bladder was opened. The small colon was replaced into the abdominal cavity; a first surgeon gently replaced the small colon through the external urethral sphincter and a second surgeon retrieved the small colon by gentle traction. The mare recovered uneventfully from general anaesthesia. The mare and the foal were discharged from the hospital seventeen days post-operatively.

This case report describes the clinical and diagnostic imaging findings, treatment, and outcome of a three-month-old Thoroughbred foal referred for the evaluation of severe left forelimb lameness and presents the acquisition of a novel radiographic projection of the scapula used to achieve the diagnosis. No abnormalities were found with the standard radiographic examination of the left shoulder. Ultrasound and a dorsal 45° lateral‐ventral lateral oblique radiographic view were performed to evaluate the body of the left scapula. A longitudinal, minimally displaced fracture of the infraspinous fossa was diagnosed with this projection that was not detected in the routine projections. Ultrasound was used in conjunction to confirm the diagnosis, assess the displacement of the fracture in the frontal plane, and evaluate soft tissue damage. The foal was treated conservatively with anti-inflammatory drugs and stall rest. A radiographic follow-up and clinical reassessment were performed, and the horse appeared sound, no atrophy of the region was appreciated, and no radiographic abnormalities were found.

Amidst discourse surrounding the racing industry’s social license to operate, the welfare of racehorses and jockeys is often at the forefront of discussions. Specifically, catastrophic events and the sudden death (SD) of horses on race days tend to capture media attention and often place the racing industry under public scrutiny. While such occurrences are not frequent, they have negative ramifications on the welfare of both racehorses and jockeys. The development of advanced diagnostic technology is therefore paramount to bettering the safety and welfare of horses and jockeys, as well as maintaining the integrity of the racing industry. Most importantly, the application of such technology could reduce the prevalence of avoidable injuries and SD. This review discusses the relevance of monitoring horses’ cardiovascular, respiratory, and thermometry biometrics and examines the currently available commercial devices capable of doing so. The review also explores the relevance and application of such devices within the racing industry and suggests how they may fit in with currently-available tools for monitoring the musculoskeletal health of racehorses.

Thoracic hemivertebra is one of the rare congenital vertebral anomalies in horses resulting in vertebral column deformity with or without neurological signs. A nine-month-old Racking filly was presented with a distinct bump over the back region. This bump was apparent at birth and has been increasing in size. Clinical examination revealed a painless kyphoscoliosis over the thoracic vertebrae with mild ataxia and abnormal gait of hindlimbs. In plain lateral radiographs of thoracic vertebrae, hemivertebrae were seen in the 13th-15th thoracic vertebrae. At myelography performed under general anaesthesia, the ventral and dorsal aspects of the contrast medium column were narrowing at the level of the 13th-14th thoracic vertebrae, and no sign of contrast medium after the 14th thoracic vertebra that represents spinal cord compression. Little information about hemivertebra in horses exists and a better understanding of hemivertebra etiology is required.

The case report by Navarro-Lopez et al., (2023) in this issue describes a thorough differential diagnosis in an equine with acute neurological disease. Rabies was confirmed by direct fluorescent antibody test (DFA). Rabies virus (RABV) was isolated from brain tissue of the ill mare by intracerebral inoculation in sucking mice. Sequencing and phylogenetic inference allowed the identification of the rabies virus variant (RVV) associated with this case. Thus, Navarro-Lopez et al., reported that the rabid mare got infected with a rabies virus variant associated with skunks. This clinical commentary elaborates on the seemingly rare skunk rabies across North America (NA) highlighting its relevance in human and animal health that have remained somehow neglected

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.

A 2-year-old racing Thoroughbred gelding in training was presented with moderate (6/10) right hindlimb lameness unresponsive to regional anaesthesia of the right hind limb. Gamma scintigraphic examination revealed severe, focal, increased radio-pharmaceutical uptake over the dorsal aspect of the right 18th rib, which had an abnormal contour. Ultrasonographic examination of this area confirmed the presence of a complete, displaced fracture of the proximal aspect of the right 18th rib. Local infiltration with local anaesthetic around the 18th right rib (10ml cranial and 10ml caudal to the fracture site) abolished the right hindlimb lameness. A diagnosis of rib fracture causing moderate ipsilateral hindlimb lameness was made. The horse returned to walking exercise after 12 weeks of rest and was reported to be sound on the same limb 12 months after presentation. Caudal rib fractures should be considered as possible cause of hind limb lameness. Local diagnostic anaesthesia around the fracture site can aid localise the origin of lameness.

A document by Callum Haseler. Click on the document to view its contents.

Ticks pose a significant threat to horses, as they can cause harm and transmit diseases. This study aimed to assess the experiences, knowledge, and practices of equine veterinarians regarding ticks and tick-borne diseases (TBDs) in the United States. A survey was conducted, covering topics such as tick biology, identification, prevention, and veterinary education. The results revealed variations in veterinarians’ knowledge on ticks and TBDs, highlighting the need for improved tick control options, enhanced education, and comprehensive resources for tick and TBD prevention. The study emphasizes the importance of accurate tick identification for effective diagnosis and treatment of TBDs in horses. The limitations of the study include potential response bias and a limited sample size. To address these issues, collaborations between academia, industry, and the human medicine community are recommended to strengthen veterinarian training and education on ticks and TBDs. This research provides valuable insights for developing continuing education programs that focus on tick-borne illness prevention in horses.

Simple dilution of semen is the oldest method to process semen for artificial insemination with either fresh or cooled. This was developed prior to the optimization centrifugation techniques for semen through a combination of trial and error and research. Simple dilution and is a faster method to process semen, is easy to use and works in many circumstances. For on farm semen use a 1:1 (v/v) semen to extender ratio is used. A variety of other techniques have been developed, such as cushion centrifugation, density gradient centrifugation and sperm filtration. Cushion centrifugation is used to concentrate the sperm and allows higher centrifugation speeds than centrifugation alone. This allows for improved recovery rates of sperm. Density gradient centrifugation has been used to select for morphologically normal sperm but suffers from low recovery rates. Processing sperm with this technique can result in improved motility and improved DNA integrity of sperm. Sperm filtration is another method to concentrate sperm without the use of centrifugation; however, this technique has lower recovery rates compared to cushion centrifugation. This review will discuss these techniques in the application of processing equine semen for either fresh or cooled-shipped use.

Background: A reduction in the Egg Reappearance Period (ERP) has been suggested to be an early indication of emerging anthelmintic resistance in strongyles. Objective:To measure the strongyle ERP following moxidectin treatment of horses in the southeast of England. Study Design: Prospective study. Methods: Horses with a faecal egg count (FEC) of > 400 strongyle eggs per gram (EPG) in a routine screening sample were enrolled into the study. Moxidectin (400 mcg/kg) was administered per os and FEC tests repeated every 2 weeks for 16 weeks. Results: Forty-eight horses completed the study. The mean EPG prior to treatment was 1047 (range 375 – 2137 EPG). In all but two horses, FEC was 0 EPG 2 weeks after moxidectin administration. In the remaining two, the FECs were 12.5 EPG (97.8-98.3% reductions compared to pre-treatment FEC). At 4 weeks post-treatment, 6 horses had positive FECs (96.6-99.2% reductions). At 6 weeks, 11 horses had positive FECs (83.8% reduction in one horse; >90% reduction in 10). At 8 weeks, 21 horses exhibited positive FECs (<90% reduction in 2). At 10 weeks, 27 horses had positive FECs (<90% in 6). At 12 weeks, 31 horses had positive FECs (<90% reduction in 11). At 14 weeks, 34 horses had positive FECs (<90% reduction in 13). At 16 weeks, 38 horses had positive FECs (<90% reduction in 17). Limitations: Weights of some horses were estimated using weigh tapes rather than a weighbridge. Dosing of the horses with moxidectin was carried out by owners. Conclusions: The results indicated acceptable efficacy of moxidectin at 14 days after treatment; however, the ERP pattern measured across the group suggest that this anthelmintic has a considerably shorter suppressive effect on strongyle egg shedding than measured when it was first introduced ( >13 weeks and up to 24 weeks).

Urethral diverticula have been described in other species. Congenital anomalies of the urinary tract in horses are rare. A 26-year-old gelding presented with complaints of abdominal discomfort and dysuria. Urine dribbling was reported since several years. General clinical examination was within normal limits. Rectal palpation showed a distended bladder, which was emptied spontaneously after manipulation. Urine cytology showed an increased white blood cell count and presence of bacteria. Bacterial culture however remained sterile. Cystoscopy identified two symmetrical urethral diverticula dorsal to the entrance of the bladder, lined with normal epithelium. Mucosa of the bladder, urethra and two diverticula were hyperemic with evidence of urine accumulation in both diverticula. Ultrasound, abdominal and transrectal, did not identify the diverticula. Treatment included trimethoprim-sulfamides and meloxicam. After 2 weeks, the owner reported resolution of clinical signs. It is unclear if the diverticula in this case were congenital or acquired. In humans it is described that urethral diverticula can be asymptomatic and incidental findings. Surgical intervention has been described in small animal and human medicine with complete resolution of clinical signs, however in this case was not possible due to financial restraints.

Caudal cervical spine pathologic lesions are a common cause of pain, lameness, ataxia, poor performance, or any mixture of these clinical signs. Combined radiographic and computed tomography myelography imaging of the caudal cervical spine is imperative when spinal cord compression, nerve root compression, and/or intervertebral disc disease is suspected. Surgical arthrodesis (ventral interbody fusion) of the C7-T1 articulation can be performed successfully and it is important for veterinarians to be aware that treatment at this level is possible.

Adipose tissue is not only required for energy storage but is an essential endocrine organ with a central role in the pathology of obesity. The understanding of its role, both in human and equine medicine, is continually evolving. With obesity being an ever-growing problem in the equine population, gaining owner compliance is critical when implementing management plans. The aim of this review is to encourage the inclusion of the concept of adiposity in discussions with horse owners on obesity and metabolic syndrome. In doing this, we hope to improve clients understanding and therefore maximise the impact of diagnostic tests, monitoring tools and management.

Objective: To report clinical characteristics, surgical management, and medium-term outcomes of 3 Arabian neonatal foals with meniscal disruption associated with septic arthritis of the lateral femorotibial joint. Methods: Three neonatal Arabian foals with septic arthritis of the lateral femorotibial joint (LFTJ), were diagnosed with lateral meniscal (LM) tears, based on persistent lameness despite improving synovial parameters, ultrasound (US) findings (protrusion of meniscal tissue beyond the level of the condyles, with hypoechoic regions), contrast Computed Tomography findings, and confirmed on arthroscopy. Treatment included arthroscopic debridement and lavage of the joint with debridement of the meniscal tear. Postoperative care included systemic and intra-articular antimicrobials, based on culture and sensitivity results. Two of the foals received intra-articular injections of autologous mesenchymal stem cells. Results: Grade III meniscal tears were observed in the LFTJ of the affected joints of all foals, involving the meniscal body (n=3) and caudal horn (n=1). Purulent material within the torn tissue, was debrided with a synovial resector. Foal 1 was lame-free as a yearling. Foal 2 was lame at walk at 7.5 months and euthanatized due to poor prognosis. Foal 3 showed mild lameness at trot in a straight line at 6 months. Disruption of the LM continued to be visible on US in both foals at these time-points. Conclusion: Meniscal disruption and infection should be considered a differential in neonatal foals with persistent femorotibial septic arthritis. In such cases, the LM could be the primary nidus of infection.

Background: Neonatal foals are born essentially agammaglobulinemic and therefore must ingest colostrum or receive immunoglobulins to maintain health. Failure of passive transfer treatment involves administration of equine colostrum, plasma or commercial powdered colostrum (CPC). Anecdotal reports suggest a risk of anaphylaxis associated with plasma transfusion in neonates that received CPC prior to gut closure. Bovine serum albumin (BSA) in CPC may serve as a target for BSA-specific immunoglobulin E (IgE) in donor equine plasma. Objectives: To determine presence of BSA-specific IgE in samples collected post-routine vaccination in healthy horses, horses experiencing adverse vaccine reactions and commercial equine plasma. Study Design: Prospective Observational Methods: Serum was collected from 65 healthy horses at day 0, 14, 28, 90, 180, 270 and 365 post-vaccination, 26 horses after vaccine reaction at day 1, 180 or 270 post-vaccination, 4 horses not vaccinated and 10 horses from a commercial plasma donor herd. BSA-specific IgE was determined using enzyme-linked immunosorbent assay (ELISA). Results: BSA-specific IgE was not detected in non-vaccinated horses and was identified in all vaccinated horses. Younger horses demonstrated higher fold changes in post-vaccination BSA-specific IgE expression compared to older horses. No significant difference in BSA-specific IgE levels between commercial plasma donors and healthy horses was identified. No significant difference in post-vaccination anti-BSA IgE levels between reactor and healthy horses at day 180 and 270 post-vaccination were identified. Main Limitations: Small number of reactor horses at day 180 and 270 post-vaccination with most samples being collected 24 hours. There were no healthy horse samples for 24 hours post-vaccination; therefore, it was not possible to compare the two groups at this timepoint. Conclusions: Horses may express BSA specific IgE following vaccination. There may be risk of hypersensitivity type reaction when veterinarians administer commercial plasma to neonatal foals that have consumed CPC prior to gut closure.