Nine-year seroepidemiological study of severe fever with thrombocytopenia syndrome virus infection in feral horses in Cape Toi, Japan.

Severe fever with thrombocytopenia syndrome (SFTS) is a fatal zoonosis caused by ticks in East Asia. As SFTS virus (SFTSV) is maintained between wildlife and ticks, seroepidemiological studies in wildlife are important to understand the behavior of SFTSV in the environment. Miyazaki Prefecture, Japan, is an SFTS-endemic area, and approximately 100 feral horses, called Misaki horses (Equus caballus), inhabit Cape Toi in Miyazaki Prefecture. While these animals are managed in a wild-like manner, their ages are ascertainable due to individual identification. In the present study, we conducted a seroepidemiological survey of SFTSV in Misaki horses between 2015 and 2023. This study aimed to understand SFTSV infection in horses and its transmission to wildlife. A total of 707 samples from 180 feral horses were used to determine the seroprevalence of SFTSV using enzyme-linked immunosorbent assay (ELISA). Neutralization testing was performed on 118 samples. In addition, SFTS viral RNA was detected in ticks from Cape Toi and feral horses. The overall seroprevalence between 2015 and 2023 was 78.5% (555/707). The lowest seroprevalence was 55% (44/80) in 2016 and the highest was 92% (76/83) in 2018. Seroprevalence was significantly affected by age, with 11% (8/71) in those less than one year of age and 96.7% (435/450) in those four years of age and older (p < 0.0001). The concordance between ELISA and neutralization test results was 88.9% (105/118). SFTS viral RNA was not detected in ticks (n = 516) or feral horses. This study demonstrated that horses can be infected with SFTSV and that age is a significant factor in seroprevalence in wildlife. This study provides insights into SFTSV infection not only in horses but also in wildlife in SFTS-endemic areas.

Extensive intraocular melanoma with secondary glaucoma in a 15-month-old Thoroughbred filly.

A 15-month-old, grey, Thoroughbred filly presented for investigation of a 6-week history of corneal oedema and blepharospasm on the right eye (OD). The filly was otherwise healthy. Following ophthalmic examination, glaucoma on the OD was diagnosed. A space occupying mass within the anterior chamber was documented on transpalpebral ultrasonographic examination. This mass obliterated most of the anterior intraocular structures on the peripheral nasal side (corneal endothelium and drainage angle), leading to secondary glaucoma. After systemic and topical treatment addressing secondary glaucoma, the corneal oedema reduced. The mass was visualised as an irregularly rounded brown structure associated with the iris on the peripheral nasal side of the anterior chamber. Given the filly's signalment, location and appearance of the mass, a tentative diagnosis of intraocular melanoma was made and enucleation was performed. Histopathological evaluation of the globe revealed solid sheets of heavily pigmented melanocytic cells, disrupting the normal ciliary body architecture and extending into the iris and subretinal. The cells were pleomorphic, polyhedral to round with occasional spindle-shaped cells, and contained moderate to large amounts of granular black-brown pigment (melanin). The iridal component expanded into the anterior chamber, with cells directly opposed to Descemet's membrane, with loss of the endothelium and expanding and occluding the filtration angle in this area. The lesion infiltrated locally into the edge of the sclera, but did not extend through the sclera, though occasional perivascular clusters of melanophages were observed within the scleral stroma adjacent to the optic nerve. Diagnosis of a uveal melanocytic neoplasm was confirmed, with characteristics similar to only one reported case . This is a unique case of a rapidly growing, invasive, uveal melanoma in a young horse. Intraocular melanoma should be considered as a differential diagnoses for glaucoma in grey horses, regardless of the age and absence of melanocytic skin lesions.

Impact of the host immune response on the development of equine herpesvirus myeloencephalopathy in horses.

Herpesviruses establish a well-adapted balance with their host's immune system. Despite this co-evolutionary balance, infections can lead to severe disease including neurological disorders in their natural host. In horses, equine herpesvirus 1 (EHV-1) causes respiratory disease, abortions, neonatal foal death and myeloencephalopathy (EHM) in ~10 % of acute infections worldwide. Many aspects of EHM pathogenesis and protection from EHM are still poorly understood. However, it has been shown that the incidence of EHM increases to >70 % in female horses >20 years of age. In this study we used old mares as an experimental equine EHV-1 model of EHM to identify host-specific factors contributing to EHM. Following experimental infection with the neuropathogenic strain EHV-1 Ab4, old mares and yearling horses were studied for 21 days post-infection. Nasal viral shedding and cell-associated viremia were assessed by quantitative PCR. Cytokine/chemokine responses were evaluated in nasal secretions and cerebrospinal fluid (CSF) by Luminex assay and in whole blood by quantitative real-time PCR. EHV-1-specific IgG sub-isotype responses were measured by ELISA. All young horses developed respiratory disease and a bi-phasic fever post-infection, but only 1/9 horses exhibited ataxia. In contrast, respiratory disease was absent in old mares, but all old mares developed EHM that resulted in euthanasia in 6/9 old mares. Old mares also presented significantly decreased nasal viral shedding but higher viremia coinciding with a single fever peak at the onset of viremia. According to clinical disease manifestation, horses were sorted into an EHM group (nine old horses and one young horse) and a non-EHM group (eight young horses) for assessment of host immune responses. Non-EHM horses showed an early upregulation of IFN-α (nasal secretions), IRF7/IRF9, IL-1ß, CXCL10 and TBET (blood) in addition to an IFN-γ upregulation during viremia (blood). In contrast, IFN-α levels in nasal secretions of EHM horses were low and peak levels of IRF7, IRF9, CXCL10 and TGF-ß (blood) coincided with viremia. Moreover, EHM horses showed significantly higher IL-10 levels in nasal secretions, peripheral blood mononuclear cells and CSF and higher serum IgG3/5 antibody titres compared to non-EHM horses. These results suggest that protection from EHM depends on timely induction of type 1 IFN and upregulation cytokines and chemokines that are representative of cellular immunity. In contrast, induction of regulatory or TH-2 type immunity appeared to correlate with an increased risk for EHM. It is likely that future vaccine development for protection from EHM must target shifting this 'at-risk' immunophenotype.

Detection of tick-borne pathogens in Rhipicephalus bursa ticks collected from the autochthonous Garrano breed of horses in Portugal.

The Garrano is a semi-feral horse breed native to several mountains in the northern Iberian Peninsula. Despite being endangered, this unique breed of pony has managed to survive in the wild and continues to be selectively bred, highlighting their remarkable resilience and adaptability to harsh environments. Wildlife plays a critical role in the survival of tick vectors in their natural habitats and the transfer of tick-borne pathogens, as they can serve as reservoir hosts for many agents and amplifiers for these vectors. The semi-feral lifestyle of the Garrano horses makes them particularly vulnerable to exposure to numerous tick species throughout the year. Therefore, the aim of this study was to investigate the occurrence of Anaplasma, Ehrlichia, Babesia, Theileria, and spotted fever rickettsiae in the Garrano horse ticks to obtain a knowledge of circulating agents in this host population. The collected ticks (n = 455) were identified as Rhipicephalus bursa. DNA specimens were organized in pools of 5 ticks, for molecular screening. Pools PCR results confirmed the presence of Candidatus Rickettsia barbariae (n = 12 for the ompB gene, n = 11 for the ompA gene and n = 6 for the gltA gene), Babesia bigemina (n = 1), Babesia caballi (n = 3), Theileria equi (n = 15) and Theileria haneyi (n = 1).These results confirm the circulation of an emerging rickettsial spotted fever group member, Candidatus R. barbariae, in R. bursa ticks. Our findings demonstrated that Candidatus R. barbariae co-circulates with B. bigemina and T. equi, which are vectored by R. bursa. We are reporting for the first time, the detection of T. haneyi among R. bursa ticks feeding in the Garrano horses in Portugal. Surveillance studies for tick-borne infections are essential to provide information that can facilitate the implementation of preventive and control strategies.

Sensory nerve conduction stimulus threshold measurements of the infraorbital nerve and its applicability as a diagnostic tool in horses with trigeminal-mediated headshaking.

BACKGROUND: To determine whether sensory nerve conduction stimulus threshold measurements of the infraorbital nerve are able to differentiate horses with idiopathic trigeminal-mediated headshaking (i-TMHS) from healthy horses and from horses with secondary trigeminal-mediated headshaking (s-TMHS). In a prospective trial, headshaking horses were examined using a standardized diagnostic protocol, including advanced diagnostics such as computed tomography and 3-Tesla-magnetic resonance imaging (MRI), to differentiate s-TMHS from i-TMHS. Clinically healthy horses served as controls. Within this process, patients underwent general anesthesia, and the minimal sensory nerve conduction stimulus threshold (SNCT) of the infraorbital nerve was measured using a bipolar concentric needle electrode. Sensory nerve action potentials (SNAP) were assessed in 2.5-5 mA intervals. Minimal SNCT as well as additional measurements were calculated. RESULTS: In 60 horses, SNAP could be recorded, of which 43 horses had i-TMHS, six had suspected s-TMHS, three horses had non-facial headshaking, and eight healthy horses served as controls. Controls had a minimal SNCT ≥ 15 mA, whereas 14/43 horses with i-TMHS and 2/6 horses with s-TMHS showed a minimal SNCT ≤ 10 mA. Minimal SNCT ≤ 10 mA showed 100% specificity to distinguish TMHS from controls, but the sensitivity was only 41%. CONCLUSION: A minimal SNCT of the infraorbital nerve ≤ 10 mA was able to differentiate healthy horses from horses with TMHS. Nevertheless, a higher minimal SNCT did not exclude i-TMHS or s-TMHS and minimal SNCT does not distinguish s-TMHS from i-TMHS.

Prevalence and risk factors of gastrointestinal helminths infection in Brazilian horses: A retrospective study of a 12-year (2008-2019) diagnostic data.

Understanding gastrointestinal parasite distribution is crucial for effective control programs in horses. This study reports the prevalence of helminth infections in horses and selected risk factors (i.e., breed, age, climate, season) by analyzing 19,276 fecal samples from the Laboratory of Veterinary Clinical Parasitology, in Curitiba, Southern Brazil. The analyses were carried out from 2008 to 2019, coming from 153 stud farms located in 60 municipalities of nine Brazilian states. The parasite prevalence was 73.3%, with 72.1% present in the adult population and 80.6% in young horses. Strongyles were present in 100% horse farms. Strongyles had a prevalence of 72.1% with a mean FEC of 453.53 (+/- 717.6). Parascaris spp. had a prevalence of 5.8% and a FEC of 17.11 (+/- 149.2). The tropical wet/monsoon climate (Am) showed the lowest FEC for strongyles and Parascaris spp. when compared to the other climates. In the logistic regression analysis, young horses exhibited 4.6 times higher odds ratio (OR) (3.9-5.5) of Parascaris spp. and 1.2 (1.1-1.4) times higher OR of strongyles egg shedding when compared to adults (P < 0.001). Summer presented a higher risk for Parascaris spp. and Strongyles eggs when compared to the other seasons (P < 0.001). Mangalarga Marchador, Criollo, and Crossbred breeds were identified with higher OR of Parascaris spp. egg shedding than Thoroughbred. The extensive prevalence of strongyles across ages, seasons, breeds, and climates alerts for the risk of clinical manifestations in equines raised on pastures designing optimal health management and parasite control strategies worldwide.

Serum concentrations of selenium, copper, and zinc in neonatal foals: Influence of failure of passive transfer and age-related changes.

Background: An adequate supply of trace elements is very important for equine neonates, as deficiencies can lead to health problems and even death. Objective: This study investigated serum concentrations of selenium (Se), copper (Cu), and zinc (Zn) in neonatal foals up to the 8th day of life. The influences of disease, age, and failure of passive transfer (FPT) on these concentrations were analyzed. Animals and procedure: Serum concentrations of Se, Cu, and Zn were determined from blood samples of 93 foals by means of inductively coupled plasma mass spectrometry. The foals were divided into 2 groups based on health status: clinically sick (n = 51) and clinically healthy (n = 42). The latter group was further divided into foals with FPT (n = 20) and those without (n = 22). Results: Mean serum concentrations for Se, Cu, and Zn were 60 ± 40 µg/L, 0.25 ± 0.22 mg/L, and 605 ± 285 µg/L, respectively. A significant influence of age on serum Cu concentration was observed (P < 0.0001). No differences were observed between any of the serum concentrations in clinically sick and clinically healthy foals on the 1st day of life. The FPT status was not associated with reduced serum concentrations of Se, Cu, or Zn. Conclusion and clinical relevance: It is not necessary to supplement trace elements in all foals with FPT.

Concentrations sériques de sélénium, de cuivre et de zinc chez les poulains nouveau-nés : influence de l'échec du transfert passif et des changements liés à l'âge. Contexte: Un apport suffisant en oligo-éléments est très important pour les nouveau-nés équins, car des carences peuvent entraîner des problèmes de santé, voire la mort. Objectif: Cette étude a examiné les concentrations sériques de sélénium (Se), de cuivre (Cu) et de zinc (Zn) chez les poulains nouveau-nés jusqu'au 8ème jour de vie. Les influences de maladies, de l'âge et de l'échec du transfert passif (FPT) sur ces concentrations ont été analysées. Animaux et procédure: Les concentrations sériques de Se, Cu et Zn ont été déterminées à partir d'échantillons de sang de 93 poulains au moyen d'une spectrométrie de masse à plasma à couplage inductif. Les poulains ont été divisés en 2 groupes en fonction de leur état de santé: cliniquement malades (n = 51) et cliniquement sains (n = 42). Ce dernier groupe a été divisé en poulains avec FPT (n = 20) et ceux sans (n = 22). Résultats: Les concentrations sériques moyennes de Se, Cu et Zn étaient respectivement de 60 ± 40 µg/L, 0,25 ± 0,22 mg/L et 605 ± 285 µg/L. Une influence significative de l'âge sur la concentration sérique de Cu a été observée (P < 0,0001). Aucune différence n'a été observée entre les concentrations sériques chez les poulains cliniquement malades et cliniquement sains au premier jour de leur vie. Le statut FPT n'était pas associé à une réduction des concentrations sériques de Se, Cu ou Zn. Conclusion et pertinence clinique: Il n'est pas nécessaire de supplémenter tous les poulains en oligo-éléments avec FPT.(Traduit par Dr Serge Messier).

Is it pain, or is it behaviour?

This year BVA Live will, for the first time, feature farm animal and equine CPD. Among the varied topics on offer, Gemma Pearson will be presenting an introduction to equine behavioural medicine, examining the link between emotional and physical health in horses.

Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions improves insulin sensitivity and reduces systemic inflammation in equine metabolic affected horses.

Equine metabolic syndrome (EMS) is a critical endocrine condition in horses, characterized by hyperinsulinemia, hyperlipidemia, and insulin resistance, posing a significant threat to their health. This study investigates the efficacy of supplementing EMS-affected horses with Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions using biosorption process in improving insulin sensitivity and glucose tolerance, reducing inflammation, and mitigating obesity-related fat accumulation. Our results demonstrate that Arthrospira supplementation reduces baseline insulin and glucose levels, contributing to decreased adipose tissue inflammation. Furthermore, Arthrospira supplementation results in a decrease in body weight and improvements in overall body condition scores and cresty neck scores. Additionally, administration of Arthrospira leads to reduced levels of triglycerides and aspartate aminotransferase, indicating a decrease in hepatic adiposity and inflammation. These findings suggest that Arthrospira, enriched with essential micro- and macroelements, can be an advanced feed additive to enhance insulin sensitivity, promote weight reduction, and alleviate inflammatory processes, thereby improving the overall condition of horses affected by EMS. The use of Arthrospira as a feed additive has the potential to complement conventional management strategies for EMS.

Adjunctive bevacizumab therapy in an equine corneal stromal invasive squamous cell carcinoma with a 53-months follow-up.

A 17-year-old Appaloosa mare was referred for evaluation of presumed refractory keratitis of the left eye. Gross examination revealed ocular discomfort and corneal neovascularization with a nasal focal opacification affecting approximately 40% of the corneal surface. On ophthalmic examination, extensive subepithelial to mid-stromal vascular branching accompanied by a homogeneous white, dense opacification, which affected up to 80% of the total corneal thickness, were apparent. Signs of concurrent uveitis were absent. Deep-stromal lamellar keratectomy with a conjunctival pedicle graft was performed under general anesthesia. Histopathology confirmed a poorly differentiated corneal stromal invasive squamous cell carcinoma (SI-SCC) with neoplastic cell extension to the surgical margins. Postoperatively, 4 topical mitomycin C 0.04% chemotherapy cycles combined with oral firocoxib therapy were initiated. Seven months after surgery, regrowth of the SI-SCC was clinically suspected. A total volume of 1 ml bevacizumab 2.5% was administered in the standing sedated horse via 3 mid-stromal corneal injections. Four weeks later, intrastromal bevacizumab injections (ISBIs) were repeated, however, this time the solution was injected directly into the main corneal vessel branches.Seven weeks after the second ISBIs, the left eye was comfortable and significant remission of corneal vascularization and opacity was recognized. No recurrence has been noted for a follow-up period of more than 53 months.Equine SI-SCC usually has a very poor prognosis for globe maintenance. To the authors' knowledge this is the first report of well-tolerated intrastromal antivascular endothelial growth factor adjunctive therapy with bevazicumab 2.5% and SI-SCC resolution after a multimodal treatment approach.

Development of novel Streptococcus equi vaccines with an assessment of their immunizing potentials and protective efficacies.

Strangles is a highly contagious disease of the equine upper respiratory tract caused by Streptococcus equi subspecies. Streptococcus equi subsp. equi (S. equi) and Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) was isolated, as local, hot, and field strains, from horses clinically suffering from respiratory distress. The isolated Streptococci were identified using bacteriological and molecular techniques. Four formulations of inactivated S. equi vaccines were developed and evaluated. The first formulation was prepared using the S. equi isolates, adjuvanted with MONTANIDE GEL adjuvant, while the second formulation was adjuvanted with MONTANIDE ISA-70 adjuvant. The other 2 formulations were inactivated combined vaccines prepared from both S. equi and S. zooepidemicus isolates. The 3rd formulation was the combined isolates adjuvanted with MONTANIDE GEL while the 4th formulation was the combined isolates adjuvanted with MONTANIDE ISA-70. The developed vaccines' physical properties, purity, sterility, safety, and potency were ensured. The immunizing efficacy was determined in isogenic BALB/c mice and white New Zealand rabbits using the passive hemagglutination test. Also, the antibodies' titer of the combined S. equi and S. zooepidemicus vaccine adjuvanted with MONTANIDE ISA-70 in foals was tracked using an indirect enzyme-linked immunosorbent assay. The protective efficacy of the developed vaccines was determined using a challenge test in both laboratory and field animal models, where a 75% protection rate was achieved. The combined vaccine proved to be more efficacious than the monovalent vaccine. Also, the MONTANIDE ISA-70 adjuvant provided significant protective efficacy than the MONTANIDE GEL. The current work is introducing a very promising mitigative and strategic controlling solution for strangles.

Effect of video angle on detection of induced front limb lameness in horses.

BACKGROUND: Lameness examinations are commonly performed in equine medicine. Advancements in digital technology have increased the use of video recordings for lameness assessment, however, standardization of ideal video angle is not available yielding videos of poor diagnostic quality. The objective of this study was to evaluate the effect of video angle on the subjective assessment of front limb lameness. A randomized, blinded, crossover study was performed. Six horses with and without mechanically induced forelimb solar pain were recorded using 9 video angles including horses trotting directly away and towards the video camera, horses trotting away and towards a video camera placed to the left and right side of midline, and horses trotting in a circle with the video camera placed on the inside and outside of the circle. Videos were randomized and assessed by three expert equine veterinarians using a 0-5 point scoring system. Objective lameness parameters were collected using a body-mounted inertial sensor system (Lameness Locator®, Equinosis LLC). Interobserver agreement for subjective lameness scores and ease of grading scores were determined. RESULTS: Induction of lameness was successful in all horses. There was excellent agreement between objective lameness parameters and subjective lameness scores (AUC of the ROC = 0.87). For horses in the "lame" trials, interobserver agreement was moderate for video angle 2 when degree of lameness was considered and perfect for video angle 2 and 9 when lameness was considered as a binary outcome. All other angles had no to fair agreement. For horses in the "sound" trials, interobserver agreement was perfect for video angle 5. All other video angles had slight to moderate agreement. CONCLUSIONS: When video assessment of forelimb lameness is required, a video of the horse trotting directly towards the video camera at a minimum is recommended. Other video angles may provide supportive information regarding lameness characteristics.

Potent drug delivery enhancement of betulinic acid and NVX-207 into equine skin in vitro - a comparison between a novel oxygen flow-assisted transdermal application device and microemulsion gels.

BACKGROUND: Gray horses are predisposed to equine malignant melanoma (EMM) with advancing age. Depending on the tumor's location and size, they can cause severe problems (e.g., defaecation, urination, feeding). A feasible therapy for EMM has not yet been established and surgical excision can be difficult depending on the location of the melanoma. Thus, an effective and safe therapy is needed. Naturally occurring betulinic acid (BA), a pentacyclic triterpene and its synthetic derivate, NVX-207 (3-acetyl-betulinic acid-2-amino-3-hydroxy-2-hydroxymethyl-propanoate) are known for their cytotoxic properties against melanomas and other tumors and have already shown good safety and tolerability in vivo. In this study, BA and NVX-207 were tested for their permeation potential into equine skin in vitro in Franz-type diffusion cell (FDC) experiments after incubation of 5 min, 30 min and 24 h, aiming to use these formulations for prospective in vivo studies as a treatment for early melanoma stages. Potent permeation was defined as reaching or exceeding the half maximal inhibitory concentrations (IC50) of BA or NVX-207 for equine melanoma cells in equine skin samples. The active ingredients were either dissolved in a microemulsion (ME) or in a microemulsion gel (MEG). All of the formulations were transdermally applied but the oil-in-water microemulsion was administered with a novel oxygen flow-assisted (OFA) applicator (DERMADROP TDA). RESULTS: All tested formulations exceeded the IC50 values for equine melanoma cells for BA and NVX-207 in equine skin samples, independently of the incubation time NVX-207 applied with the OFA applicator showed a significant time-dependent accumulation and depot-effect in the skin after 30 min and 24 h (P < 0.05). CONCLUSIONS: All tested substances showed promising results. Additionally, OFA administration showed a significant accumulation of NVX-207 after 30 min and 24 h of incubation. Further in vivo trials with OFA application are recommended.

Severe orbital hematoma with third eyelid swelling and prolapse following a blind maxillary nerve block in a horse.

A 20-year-old quarter horse gelding was presented for routine dental examination. Periodontal disease and luxation of tooth 108 was diagnosed and oral extraction was planned. After an unsuccessful blind maxillary nerve block, it was elected to perform the procedure under total intravenous anesthesia. Following recovery, a focal superficial corneal ulcer, severe retrobulbar swelling, mild exophthalmos, and marked swelling and prolapse of the third eyelid (nictitating membrane) were observed. Clinical signs persisted beyond 48 h despite the use of systemic anti-inflammatories and topical ocular anti-inflammatories and antibiotics. A temporary tarsorrhaphy was subsequently done at 48 h and the horse was discharged after 5 d of hospitalization and regression of clinical signs. Although it is very useful for easing dental extractions, the blind maxillary nerve block is associated with potential complications due to inadvertent vascular puncture. This case report describes a rare complication of prolapse of the third eyelid in a horse after a maxillary nerve block and successful treatment with a temporary tarsorrhaphy. Key clinical message: This case report explains how nictitating membrane swelling and prolapse can occur following a blind maxillary nerve block in the horse and describes treatment with a temporary tarsorrhaphy.

Hématome orbitaire sévère avec gonflement de la troisième paupière et prolapsus à la suite d'un bloc du nerf maxillaire à l'aveugle chez un cheval. Un hongre quarter horse de 20 ans a été présenté pour un examen dentaire de routine. Une maladie parodontale et une luxation de la dent 108 ont été diagnostiquées et une extraction orale a été planifiée. Après l'échec d'un bloc du nerf maxillaire à l'aveugle, il a été décidé d'effectuer la procédure sous anesthésie intraveineuse. Après la guérison, un ulcère cornéen superficiel focal, un gonflement rétrobulbaire sévère, une légère exophtalmie ainsi qu'un gonflement et un prolapsus marqués de la troisième paupière (membrane nictitante) ont été observés. Les signes cliniques ont persisté au-delà de 48 heures malgré l'utilisation d'anti-inflammatoires systémiques et d'anti-inflammatoires oculaires topiques et d'antibiotiques. Une tarsorraphie temporaire a ensuite été réalisée à 48 heures et le cheval est sorti après 5 jours d'hospitalisation et de régression des signes cliniques. Bien qu'il soit très utile pour faciliter les extractions dentaires, le bloc du nerf maxillaire à l'aveugle est associé à des complications potentielles dues à une ponction vasculaire involontaire. Ce rapport de cas décrit une complication rare de prolapsus de la troisième paupière chez un cheval après un bloc nerveux maxillaire et un traitement réussi par tarsorraphie temporaire.Message clinique clé:Ce rapport de cas explique comment un gonflement et un prolapsus de la membrane nictitante peuvent survenir à la suite d'un bloc du nerf maxillaire à l'aveugle chez le cheval et décrit le traitement par tarsorraphie temporaire.(Traduit par Dr Serge Messier).

Gross, organoleptic and histologic assessment of cadaveric equine heads preserved using chemical methods for veterinary surgical teaching.

BACKGROUND: Preservation of biological tissues has been used since ancient times. Regardless of the method employed, tissue preservation is thought to be a vital step in veterinary surgery teaching and learning. OBJECTIVES: This study was designed to determine the usability of chemically preserved cadaveric equine heads for surgical teaching in veterinary medicine. METHODS: Six cadaveric equine heads were collected immediately after death or euthanasia and frozen until fixation. Fixation was achieved by using a hypertonic solution consisting of sodium chloride, sodium nitrite and sodium nitrate, and an alcoholic solution containing ethanol and glycerin. Chemically preserved specimens were stored at low temperatures (2°C to 6°C) in a conventional refrigerator. The specimens were submitted to gross and organoleptic assessment right after fixative solution injection (D0) and within 10, 20, and 30 days of fixation (D10, D20, and D30, respectively). Samples of tissue from skin, tongue, oral vestibule, and masseter muscle were collected for histological evaluation at the same time points. RESULTS: Physical and organoleptic assessments revealed excellent specimen quality (mean scores higher than 4 on a 5-point scale) in most cases. In some specimens, lower scores (3) were assigned to the range of mouth opening, particularly on D0 and D10. A reduced the range of mouth opening may be a limiting factor in teaching activities involving structures located in the oral cavity. CONCLUSIONS: The excellent physical, histologic, and organoleptic characteristics of the specimens in this sample support their usability in teaching within the time frame considered. Appropriate physical and organoleptic characteristics (color, texture, odor, and flexibility) of the specimens in this study support the use of the method described for preparation of reusable anatomical specimens.

Expression pattern of germ cell markers in cryptorchid stallion testes.

Cryptorchidism affects spermatogenesis and testis development, often resulting in stallion subfertility/infertility. This study aims to identify the specific germ cells impacted by cryptorchism in stallions. In a previous study, we found that PGP9.5 and VASA are molecular markers expressed in different germ cells within stallions. Herein, we assessed the heat stress-induced response of spermatogonial stem cells (SSCs) in the seminiferous tubules (ST) of cryptorchid stallion testes (CST) and normal stallion testes (NST). This goal was accomplished by comparing PGP9.5 and VASA expression patterns through reverse transcription quantitative PCR and immunofluorescence assays. We also compared the cross-sectional ST area between groups. Six post-pubertal Thoroughbred unilateral cryptorchid stallions were used. The relative abundance of the mRNA transcripts of PGP9.5 and VASA was significantly upregulated in the NST group than in the CST group. Additionally, the cross-sectional ST area and localization of PGP9.5 and VASA in germ cells were significantly higher in the NST group than in the CST group. Regarding Leydig cells, PGP9.5 staining was observed in both groups. Spermatogonia, primary spermatocytes and secondary spermatocytes were immunostained with VASA in the NST group, while immunostaining was only observed in spermatogonia in the CST group. These results indicate long-term exposure to heat stress conditions, such as cryptorchidism, directly impacts germ cell proliferation and differentiation, leading to impaired spermatogenesis and compromised fertility in stallions.

Streptococcus equi subsp. zooepidemicus: High molecular diversity of Argentinian strains isolated from mares with endometritis.

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is a mucosal commensal of the lower genital tract in horses and is the most isolated bacterium causing endometritis in mares. The aim of this study was to determine the molecular diversity of S. zooepidemicus obtained from endometritis in mares in Buenos Aires province, Argentina. Thirty isolates obtained from the uterus of mares in 2005 and 2017 were studied. The MLST scheme was applied to identify the Argentinian genotypes and the clonal relationships and patterns of evolutionary descent were identified using the eBURST algorithm - goeBURST. Twenty six different Sequence types (STs) were identified, being only 11 of them previously reported in horses and also, from several host species and tissues. The other 15 STs were reported in Argentinian reproductive strains of mares in our study for the first time. The genotypes obtained from uterus in Argentina were not evenly distributed when all the published S. zooepidemicus STs were analysed, thus, it was not possible to establish that the same lineage circulates in our equine population. The fact that the identified genotypes were also reported in other countries, diverse samples and host species suggest that there is not a host, and an anatomical niche adaptation. Finally, the isolation of the same genotype in the vagina/clitoris and the uterus of the same mare highlights the versatility of S. zooepidemicus and its role as an opportunistic pathogen.

Molecular detection and characterization of prevailing Theileria equi genotype in equine from northern India.

Equine piroplasmosis caused by Theileria equi is a febrile, tick-borne disease of equids. However, there is limited literature about the genotyping of T. equi in India. Blood samples were collected from 202 horses and subjected to microscopy and PCR to detect T. equi. Initially, a universal screening primer pair targeting 18S ribosomal RNA genes common for Babesia caballi and T. equi was employed to amplify the DNA of both parasites. Thereafter additional primers were employed for species-specific detection resulting in amplification of approximately 435 bp specific for T. equi. T.equi was detected in 9.9% and 20.79% of horses screened by microscopy and PCR, respectively. The representative samples confirmed positive by PCR were sequenced, submitted to NCBI (OR651254, OR687254, OR685656, OR650830, OR650834), and used for genotype characterization and phylogenetic analysis. Employing Genetool and MEGA X software, the T. equi Indian isolates and across the globe were compared, and the results demonstrated 99.05-100% and 95.86-100% homologies, respectively. All the T. equi Indian isolates belonged to genotype A. Phylogeny based on the EMA-1 gene of five isolates (OR731831, OR731833, OR731829, OR731830, OR731832) were also characterized by sequencing and support the previous findings. Genotypes C and D, as well as genotypes B and E, exhibited lower levels of evolutionary divergence compared to other genotypes. The EMA-1 gene exhibited limited diversity and might not be the most suitable target for assessing variability within T. equi populations. The findings also reveal a significant association (p < 0.01) between T. equi infection and the presence of ticks.

Ivermectin performance in horses diagnosed with equine endocrine disorders.

Anthelmintic performance against equine cyathostomins can be evaluated by two different non-terminal measures; the Fecal Egg Count Reduction Test (FECRT) and the Egg Reappearance Period (ERP). Most available FECRT and ERP data have been determined in populations of young horses, and very little information is available from mature and senior horses. Furthermore, it is unknown how commonly occurring equine endocrine disorders such as Insulin dysregulation (ID) and Pituitary pars intermedia dysfunction (PPID) may interfere with these measurements, but it has been suggested that horses with these conditions could be more susceptible to parasitic infections. A research population of senior horses and horses with or without PPID, ID, or both were enrolled in this study. All strongylid egg count positive horses were included in an ivermectin (200 µg/kg) efficacy study. These were distributed among the following groups: ID: six, PPID: three, PPID and ID: seven, and healthy controls: three. Strongylid fecal egg counts were determined on the day of ivermectin administration, at two weeks post deworming, and on weekly intervals until eight weeks post treatment. Determination of FECRT and ERP were carried out following World Association for the Advancement of Veterinary Parasitology guidelines. Results revealed high ivermectin efficacy with mean egg count reduction at 99.7% or above in all groups at two weeks post treatment. Egg reappearance was documented at six and seven weeks in the ID and PPID/ID groups, respectively, whereas the PPID and healthy control groups both had ERP at 8 weeks. Statistical analysis found no significant differences in egg count levels between groups during the study. The expected ERP for ivermectin is 8-10 weeks, meaning that two of the groups displayed shortened ERPs. However, due to the small group sizes, these data should be interpreted with caution. Nonetheless, results do indicate a need for further investigation of the possible influence of endocrine disorders on anthelmintic performance in horses.

Strongyle egg shedding and egg reappearance periods in horses with pituitary pars intermedia dysfunction.

Pituitary pars intermedia dysfunction (PPID) is the most common endocrine disorder of older horses. Immune dysfunction in horses with PPID could increase susceptibility to infectious diseases, including strongyle infections; however, few data are available. The aim of this study was to determine if horses with PPID had increased strongyle faecal egg counts (FEC) compared with control horses, over a fourteen-week period in Victoria, Australia. Clinical signs and plasma adrenocorticotropic hormone (ACTH) concentrations were used to categorise horses into PPID (n=14) or control (n=31) groups. Faecal samples were collected for FEC determination prior to anthelmintic treatment, and fortnightly post-treatment for each horse. Generalised linear mixed modelling, using a gamma distribution, was used to compare differences between groups in the repeated measures study. The confounding variable of age was controlled for as a fixed effect. Following anthelmintic treatment, mean FEC was greater for the PPID group compared to the control group on day 56 (405 ± 756 eggs per gram [EPG] vs 40 ± 85 EPG, p=0.05) and day 70 (753 ±1598 EPG vs 82 ±141 EPG, p=0.04). There were no differences in mean FEC between groups on days 84 and 98. Cumulative FEC (day 14 to day 98) was significantly greater for the PPID horses than control horses (2118 ± 4016 EPG vs 798 ± 768 EPG, p<0.0001). Group egg reappearance period was shorter for PPID horses (day 56 post-anthelmintic treatment) compared to control horses (day 70) and 30% of the PPID horses reached a FEC threshold of >200 EPG on day 42, compared to 0% of control horses (p=0.02). These results suggest that the rate of a re-established patent infection between groups could be different due to a comprised immune response in PPID horses or differences in the host-parasite relationship regarding encysted stage larvae. However, despite differences between groups, some horses with PPID consistently had no detectable or low FEC (<200 EPG) during the study period. These findings highlight the importance of individual FEC monitoring to determine if anthelmintic treatment is required, in line with sustainable parasite management practices.