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.
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.
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.
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.
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
This report describes the evisceration of the jejunum following acute dehiscence of the abdominal wall in an 18 year old gelding which had undergone treatment for suspected sarcoids on the ventral abdomen with a topical caustic/chemotherapy agent 6 weeks previously. The sarcoid lesions appeared to be responding appropriately to the topical therapy until the day of presentation. The jejunum was safely contained in an abdominal bandage and the horse underwent emergency referral before immediate anaesthesia and further assessment. The horse was euthanased at the owners’ request following a guarded prognosis.
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).
Equine primary hyperparathyroidism is rare compared with the condition in human medicine where it is often encountered and represents the most common explanation for hypercalcemia in the outpatient setting. Primary hyperparathyroidism results from a hyperfunctioning parathyroid gland and surgical treatment (parathyroidectomy) is typically curative. Successful surgical removal of a diseased parathyroid gland can be challenging in horses as both normal and hyperfunctioning glands are difficult to localize. Identification of surgical targets using ultrasonography and/or Technetium-99m sestimibi scintigraphy are useful for this purpose in both the human and equine contexts. However, these localization approaches are not aways effective. Moreover, not all patients are candidates for general anesthesia and surgery and the costs associated with diagnostic localization and parathyroidectomy may be prohibitive for some owners. This commentary presents information about primary hyperparathyroidism in the event that it is not treated and strives to review aspects of the disease when left untreated from the human medical context.
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.
A one-year-old Belgian warmblood with a previously known history of successfully repaired temporal and parietal bone fracture sustained at 14 days of age was presented for investigation of a recent, acute, and progressive four limbs ataxia. The owner reported a lack of coordination and difficulty getting up with progressing paresis two weeks prior to the presentation. Neurological examination revealed pronounced hypermetria/dysmetria in walk and trot in all four limbs. No evidence of cranial nerve deficit was observed. The horse was in good general condition with unremarkable clinical parameters. Survey lateral radiographs of the cervical spine showed moderate to severe signs of cervical malformation of the vertebral canal and articular process joints, indicating cervical stenotic myelopathy. Cervical computed tomographic (CT) myelography revealed the presence of a dorsal subarachnoid diverticulum causing significant spinal cord compression at multiple locations, with associated osteoarthrosis of the cervical articular process joints. Due to a poor prognosis and warranted surgical outcome, the owner declined further treatment, and the horse was discharged with conservative corticosteroid treatment. The patient was euthanised shortly after the initial presentation due to progressive worsening. To the author’s knowledge, CT myelography findings in a yearling with cervical subarachnoid diverticulum have not been previously published. This case illustrates the usefulness of advanced imaging techniques, such as CT myelography, in combination with static and dynamic radiography to provide a better and more accurate diagnosis.
Due to the length of the reserve crown and roots of equine cheek teeth, especially in younger horses, their extraction (exodontia) can be a challenging procedure with the potential for many types of post-extraction complications to develop. The prevalence of post-extraction complications is greatly influenced by the exodontia technique used, with unacceptably high levels of complications with the traditional repulsion technique and conversely, low levels of complications with oral extraction performed by skilled operators. Recent objective studies on post-exodontia problems in horses have also highlighted some risk factors for the development of post-extraction problems including exodontia of rostral mandibular teeth in young horses, and exodontia of teeth with apical infections The recent recognition that some non-healing post-extraction equine alveoli suffer from a disorder very similar to dry socket in humans, may help clinicians to recognise, treat and possibly help prevent this disorder.
Background: Analgesic protocols related to orchiectomy or castration of young horses vary widely depending on geographic location, educational background of the veterinarian, and other demographic factors. Specific practices of equine veterinarians in the United States (US) have not been reported. Objectives: To determine perioperative pain management practices of equine veterinarians in the US as they relate to castration of young male horses. Study Design: Cross-sectional survey Methods: An internet-based questionnaire included items related to analgesic drugs used in association with castration of healthy yearling colts. Demographic and educational factors associated with routine recommendation of analgesic medications after castration were analyzed using logistic regression. Results: Responses from 146 equine veterinarians in the US revealed that 112/146 (76.7%) administered a nonsteroidal anti-inflammatory drug (NSAID) at the time of castration. Routine recommendation of post-castration analgesia was associated with veterinarians who were employed in a multi-veterinarian practice, completed their veterinary education after 2000, and provided a higher pain severity score for horses at 24 hours after a routine castration. Main Limitations: Possible distribution, self-selection, response, and recall biases as a result of convenience sampling methodology. Conclusions: Perioperative pain management practices vary widely among US veterinarians but the majority of veterinarians, especially more recent graduates, recommend administration of an NSAID.
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.