Antigen-specific antibodies in cerebrospinal fluid after intramuscular injection of ovalbumin in horses

Eighteen normal horses were assigned to 1 of 3 treatment groups to investigate the effects of IM or intrathecal (IT) administration of ovalbumin on serum and cerebrospinal fluid (CSF) antibody production. Horses of group 1 were injected intramuscularly with ovalbumin and adjuvant, while horses in treatment groups 2 and 3 received ovalbumin intrathecally or intravenously, followed by IM injection as in group 1. Serum and CSF antibody titers were tested in group I every 30 days for 4 months, while serum and CSF were collected in group 2 and 3 horses at postvaccination day 60. Horses of group 1 (IM) developed a serum antibody titer that peaked at postadministration day 60 (1:24,320 +/- 7,680) (mean +/- I SEM). Anti-ovalbumin antibodies were detected in CSF, and titers paralleled that of the serum, although at a much lower concentration (peak, 1:166 +/- 87). Horses of groups 2 and 3 developed significantly (P = .02) lower serum titers (1:720 and 1:2,067, respectively), but the difference in CSF titers did not achieve statistical significance (P = .06). The results confirm that antigen-specific antibody can be found in the CSF of horses in which antigen is not administered intrathecally. This may affect the interpretation of CSF analysis in diseases such as equine protozoal myeloencephalitis. Further, the findings suggest that IT injection of the soluble antigen ovalbumin induces a state of antigenic tolerance in the horse. The clinical significance of this finding remains unknown at this time.     

Lack of Detectable Equine Herpesviruses 1 and 2 in Paraffin-Embedded Specimens of Equine Sarcoidosis

Background: Equine sarcoidosis is a rare, multisystemic, noncaseating, granulomatous and lymphoplasmacytic disease of unknown etiology. A recent report described a horse with granulomatous skin disease displaying histologic, electron microscopic, and polymerase chain reaction (PCR) findings consistent with equine herpesvirus 2 (EHV-2).
Objective: To investigate the presence of EHV-2 and equine herpesvirus 1 (EHV-1) in 8 horses with sarcoidosis.
Animals: Eight horses with sarcoidosis, reported previously.
Methods: Retrospective study. PCR assays of the tissues were performed to detect DNA associated with EHV-1 and EHV-2. For both herpesviruses the target was their respective glycoprotein B gene. Positive controls consisted of DNA from viral cultures of culturettes from naturally occurring respiratory infections of EHV-1 and EHV-2.
Results: The PCR analyses for both equine herpesviruses' DNA were negative in all 8 horses.
Conclusion: The failure to detect DNA from EHV-1 and EHV-2 in paraffin-embedded skin of these 8 horses does not discount EHV-1 or EHV-2 as causing some cases of ES, but lends support to the presumably multifactorial etiologic nature of the disease.     

Incomplete Oblique Sagittal Fractures of the Dorsal Cortex of the Third Metacarpal Bone in Six Horses

Objective —To describe incomplete oblique sagittal dorsal cortical fractures of the equine third metacarpal bone, their surgical repair, and subsequent performance of the horses.
Study Design —Retrospective examination of medical records and racing performance.
Animal Population —Six Thoroughbred race horses, 2 to 4 years of age.
Methods —Radiographic confirmation of all fractures preceded general anesthesia and surgical correction. Three fractures were treated by intracortical compression using screws placed in lag fashion, and five fractures were treated by osteostixis. Race records were reviewed for each horse to determine performance after surgery.
Results —Fractures were best observed on palmarodorsal radiographic projections. Three horses treated by intracortical compression returned to racing, but fracture recurred in one horse and was treated by osteostixis. This horse and the other three horses treated by osteostixis raced after surgery.
Conclusions —Horses with incomplete oblique sagittal fractures of the dorsal cortex of the third metacarpal bone can race after surgical management of the fracture by screws placed in lag fashion or osteostixis. The authors' preferred surgical procedure for managing this fracture is osteostixis.
Clinical Relevance —Palmarodorsal radiographic projections of the third metacarpal bone are recommended in young Thoroughbred race horses suspected of having dorsal metacarpal stress fractures.     

Antibodies against equine herpesvirus 1 in the cerebrospinal fluid in the horse

Neutralizing antibodies against equine herpesvirus 1 were measured in serum and cerebrospinal fluid of 16 horses and ponies from a closed herd both before and after vaccination with modified live equine herpesvirus 1. These titers were also measured in 22 neurologically normal and 15 neurologically abnormal horses at a teaching hospital. Animals from the closed herd had prevaccination serum titers up to 1:8 and postvaccination serum titers up to 1:128. Horses from the teaching hospital had serum titers up to 1:64. Cerebrospinal fluid titers were not detected in the vaccinated horses or the neurologically normal horses but a low titer (1:8) was noted in one neurologically abnormal horse. This titer probably resulted from hemorrhage into the cerebrospinal fluid following trauma.     

Equine viral arteritis control scheme: a brief review with emphasis on laboratory aspects of the scheme in New Zealand

AIM: To review laboratory aspects of the equine viral arteritis (EVA) control scheme in New Zealand between 1989 and 2002. METHODS: The optimisation and performance of the virus neutralisation test (VNT) for equine arteritis virus (EAV) antibody, and the cell culture test to detect EAV in semen were analysed. Laboratory data and control scheme results were reviewed. RESULTS: Using optimised tests, it has been shown that antibody prevalence in Standardbred horses has steadily declined from 54% to <20%. Prevalences in Thoroughbred horses have remained at a low level of around 3%. The number of horses shedding EAV (all Standardbreds) has steadily declined from a maximum at any one time of 20 to the current figure of three. CONCLUSION: Eradication of EVA from the horse population in New Zealand is achievable in the near future.     

Serum and plasma cardiac troponin I concentrations in clinically normal Thoroughbreds in training in Australia

Cardiac troponin I is a potentially useful test to identify cardiac muscle damage in the horse. Measurements of cardiac troponin I from serum or heparinised plasma samples from 23 clinically normal Thoroughbred horses in race training were analysed through a standard Australian commercial laboratory using the ADVIA Centaur Assay. The cardiac troponin I concentrations were < 0.15 microg/L from all samples. The test was then validated using macerated equine myocardium. Cardiac troponin I concentration may be useful in determining whether poor performance in Thoroughbred horses is related to active myocardial disease.     

Responses of horses vaccinated with avirulent modified-live equine arteritis virus propagated in the E. Derm (NBL-6) cell line to nasal inoculation with virulent virus

Nineteen horses with no prior experience with equine arteritis virus (EAV) were inoculated IM with an avirulent live-virus vaccine against equine viral arteritis; the vaccinal virus had been passaged serially 131 times in primary cell cultures of equine kidney, 111 times in primary cell cultures of rabbit kidney, and 16 times in an equine dermis cell line (EAV HK-131/RK-111/ED-16). Three or 4 of the vaccinated horses each, along with appropriate nonvaccinated controls, were inoculated nasally with virulent EAV at each of months 3, 6, 9, 12, 18, and 24 after they were vaccinated. The following was concluded: Vaccination did not induce clinical signs of disease in any horse and, thus, seemed safe for use in the field. All vaccinated horses (n = 19) developed serum-neutralizing antibodies to EAV. Fourteen of the vaccinated horses were completely protected from clinical arteritis when exposed to large doses of virulent EAV. Four were partially protected, and one had little or no protection. Six of 13 nonvaccinated horses died of acute arteritis, and the remaining 7 horses experienced severe signs of disease, but survived the infection. All horses (n = 32), whether vaccinated or not, became infected when inoculated nasally with virulent EAV. Virus was recovered from 17 of the 19 vaccinated horses, and all 19 had a secondary humoral immune response. The duration and severity of thermal reaction and persistence of virus were more transitory in vaccinated horses than in the nonvaccinated controls. Protection afforded by this vaccine can persist for at least 24 months, the maximal time after horses were vaccinated that immunity was challenged in the present study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transpalpebral eye enucleation in 40 standing horses

Objective— To report a technique for eye enucleation in standing sedated horses and to report outcome in 40 horses.
Study Design— Retrospective study.
Animals— Horses (n=40) requiring eye enucleation.
Methods— The eye was enucleated using a transpalpebral technique in 40 horses restrained in stocks and sedated. Anesthesia of orbital structures was provided by local nerve blocks and infiltration of the surgical site with local anesthetic solution.
Results— Affected eyes were successfully enucleated with the horse standing. Short-term complications included moderate swelling (5 horses) and wound discharge (1). Long-term complications were not observed.
Conclusions— A diseased eye can be safely enucleated with a horse standing.
Clinical Relevance— Enucleating an equine eye in the standing position eliminates the risks and costs of general anesthesia.     

马鼻肺炎诊断方法研究进展

马鼻肺炎的病原是马疱疹病毒l型和马疱疹病毒4型,属于疱疹病毒目,疱疹病毒科,a疱疹病毒亚科,通常会引起呼吸道疾病和病毒性流产,严重时引发神经性疾病。该病毒在世界范围内流行,对养马业和赛马业的危害很大。本文总结国内外近些年关于马疱疹病毒的病原学和血清学诊断方法的研究成果,了解国际上关于马鼻肺炎检测诊断方法的研究进展,为出入境赛马的马鼻肺炎的检验检疫提供可靠的检测方法。     

Artificial Insemination in Horses—More than a Century of Practice and Research

Important early studies on mammalian artificial insemination (AI) were carried out in equids, and at the end of the 19th century, the first AI programs were set up in horses. At that time, the most systematic research on equine AI was performed in Russia. After World War I, AI research shifted to cattle and sheep. This time saw major advances such as the development of artificial vaginas and phantoms for semen collection. Semen dilution counteracted the detrimental effect of seminal plasma, allowed semen storage, and increased the volume of an ejaculate for insemination of more mares. In the late 1930s, techniques for cooled semen AI as used today were in principle available. After World War II, the number of mares inseminated decreased, but with a new role of the horse as a partner in equestrian sports, new interest in equine AI was raised. In contrast to the situation in cattle, frozen semen has not replaced cooled semen AI in the horse. Recent advances in insemination of horses are the sexing of sperm, low-dose deep intrauterine insemination, and intracytoplasmic sperm injection.     

Antibody Responses Against Equine Influenza Virus Induced by Concurrent and by Consecutive Use of an Inactivated Equine Influenza Virus Vaccine and a Modified Live Equine Herpesvirus Type 1 Vaccine in Thoroughbred Racehorses

An inactivated equine influenza virus (EIV) vaccine and a live equine herpesvirus type 1 (EHV-1) vaccine are usually administered concurrently to Thoroughbred racehorses in Japan. The objective of this study was to evaluate whether concurrent administration of an inactivated EIV vaccine and a live EHV-1 vaccine in Thoroughbred racehorses influences the antibody response against EIV. We compared the antibody response against EIV in horses administered both vaccines on the same day (Group A; n = 27) and the response in horses administered an inactivated EIV vaccine first and then a live EHV-1 vaccine 1–2 weeks later (Group B; n = 20). In both groups, geometric mean hemagglutination inhibition (HI) titers against A/equine/Ibaraki/1/2007 and A/equine/Yokohama/aq13/2010 increased significantly after EIV vaccination. However, the percentage of horses that showed a twofold increase or greater in HI titers against A/equine/Yokohama/aq13/2010 was significantly higher in Group B (75%) than in Group A (37%; P = .02). These results suggest that the concurrent use of an inactivated EIV vaccine and a live EHV-1 vaccine reduced the immune response against EIV to some extent, and it would be better to use these vaccines consecutively, especially for naïve horses or horses whose vaccination history is incomplete.     

The horse-racetrack interface: a preliminary study on the effect of shoeing on impact trauma using a novel wireless data acquisition system

REASONS FOR PERFORMING STUDY: There is a need to determine accelerations acting on the equine hoof under field conditions in order to better assess the risks for orthopaedic health associated with shoeing practices and/or surface conditions. OBJECTIVES: To measure the acceleration profiles generated in Thoroughbred racehorses exercising at high speeds over dirt racetracks and specifically to evaluate the effect of a toe grab shoe compared to a flat racing plate, using a newly developed wireless data acquisition system (WDAS). METHODS: Four Thoroughbred racehorses in training and racing were used. Based on previous trials, each horse served as its own control for speed trials, with shoe type as variable. Horses were evaluated at speeds ranging from 12.0-17.3 m/sec. Impact accelerations, acceleration on break over and take-off, and temporal stride parameters were calculated. Impact injury scores were also determined, using peak accelerations and the time over which they occurred. RESULTS: Recorded accelerations for the resultant vector (all horses all speeds) calculated from triaxial accelerometers ranged 96.3-251.1 g, depending on the phase of the impact event. An association was observed between shoe type and change in acceleration in individual horses, with 2 horses having increased g on initial impact with toe grab shoes in place. In the final impact phase, one horse had an increase of 110 g while wearing toe grab shoes. Increased accelerations were also observed on break over in 2 horses while wearing toe grab shoes. CONCLUSIONS: Shoe type may change impact accelerations significantly in an individual horse and could represent increased risk for injury. Further work is needed to determine if trends exist across a population. POTENTIAL RELEVANCE: The WDAS could be used for performance evaluation in individual horses to evaluate any component of the horse-performance surface interface, with the goal of minimising risk and optimising performance.     

Effects of two large doses of equine recombinant growth hormone on clinical, haematological and serum biochemical variables in adult horses

Objective To evaluate the clinical, haematological, and serum biochemical effects of two large doses of recombinant equine growth hormone.
Design Duplicated Latin square.
Sample population
Three Thoroughbred and three Standardbred mares aged between 12 and 17 years.
Procedure Two horses were randomly assigned into one of three groups. On each of three successive days, each horse pair received one of two dosages of growth hormone or a saline placebo so that by the end of the experiment all three horse pairs had received both dosages and the saline placebo. Dose rates selected were 50 μg/kg, and 100 μg/kg. A clinical examination was performed and a venous blood sample drawn for a complete blood count and serum biochemical analysis before administration of growth hormone and at 1, 2, 3, 4, 6, 8 and 24 h after injection. Data were analysed by a repeated measures analysis of variance assessing the effects of dose and time.
Results There was an effect of time on a number of clinical, haematological, and serum biochemical variables. There were significant effects of growth hormone on heart rate and serum glucose concentration but values for both variables remained within the reference range.
Conclusion The results of the present study suggest that equine recombinant growth hormone has a wide margin of safety and show that the single administration of up to five times the recommended dose rate has no significant effects on clinical, haematological, or serum biochemical variables.     

Equine Viral Respiratory Pathogen Surveillance at Horse Shows and Sales

Equine respiratory viral infections cause significant worldwide disease and economic loss. Common causes include equine influenza virus (EIV) and equine herpesviruses-1 and -4 (EHV-1 and -4), and risk of exposure to these agents may be highest in young horses commingling at sales and competitive events. A surveillance study was conducted at two horse shows and two Thoroughbred sales to determine whether horses shed EHV-1, EHV-4, or EIV on arrival, or 2-4 days later, and whether shedding was associated with identifiable risk factors. Real-time polymerase chain reaction assays were used to detect EHV-1, EHV-4, and EIV nucleic acid in nasal swabs obtained from 369 horses at the four events. In response to evidence of clinical disease, 82 additional horses were sampled at two farms providing horses for one of the sales. On arrival at the events, shedding of EHV-1 was detected in 3.3%, EHV-4 in 1.1%, and EIV in 0.8% of horses. EHV-1 was detected at low levels, and EHV-1 and EHV-4 detection was not associated with clinical disease. EIV was detected only in horses at a Thoroughbred sale, in association with an outbreak of respiratory disease traced back to regional farms. On arrival at events, horses younger than 2 years had a significantly greater risk of shedding EHV-1 compared with older horses; no other significant risk factors associated with viral shedding were identified. Thus, there is a risk of exposure to EIV, EHV-1, and EHV-4 at equine events, and horses and events should be managed to mitigate this risk.     

Epidemiology of equine upper respiratory tract disease on standardbred racetracks.

The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly susceptible to upper respiratory disease and showed the greatest rate of seroconversion to influenza viruses. Major outbreaks of respiratory disease occurred when the proportion of young horses which had not previously been exposed to epidemics of respiratory disease reached 30 to 40% of the population at the track. Most horses over four years of age appeared to develop resistance to the infections.     

The structure and regulation of the Irish equine industries: Links to considerations of equine welfare

The equine industries in Ireland are vibrant and growing. They are broadly classified into two sectors: Thoroughbred racing, and sports and leisure. This paper describes these sectors in terms of governance, education and training in equine welfare, and available data concerning horse numbers, identification, traceability and disposal. Animal welfare, and specifically equine welfare, has received increasing attention internationally. There is general acceptance of concepts such as animal needs and persons' responsibilities toward animals in their care, as expressed in the 'Five Freedoms'. As yet, little has been published on standards of equine welfare pertaining to Ireland, or on measures to address welfare issues here. This paper highlights the central role of horse identification and legal registration of ownership to safeguard the health and welfare of horses.     

Concurrent T cell leukaemia and equine multinodular pulmonary fibrosis in a Hanoverian Warmblood mare

Equine multinodular pulmonary fibrosis (EMPF) and primary leukaemia are uncommon diseases in horses. This case report describes a horse with both diseases which might be linked via the equine γ‐herpesvirus EHV‐5. In man Epstein Barr Virus (EBV), also a γ‐herpesvirus, is associated with idiopathic pulmonary fibrosis as is EHV‐5 with EMPF. Furthermore, EBV is also associated with lymphoproliferative disease. Similarly in horses, primary leukaemia might be associated with EHV‐5. This is the first report associating EHV‐5 with primary leukaemia in horses.     

Photodynamic therapy for the treatment of periocular squamous cell carcinoma in horses: a pilot study

Objective  Local photodynamic therapy (PDT) is a novel cancer therapy in veterinary ophthalmology. A prospective pilot study seeking to demonstrate proof of principle and safety for the treatment of equine periocular squamous cell carcinoma (PSCC) was therefore conducted. We hypothesized that surgical excision with adjunctive local PDT is an effective and safe treatment for equine PSCC.
Procedures  Nine horses (10 eyes) with PSCC were treated with surgical resection, local infiltration of resulting wound beds with 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and irradiation with 665-nm wavelength diode laser. Regular follow-up ophthalmic examinations were performed.
Results  Surgical resection and PDT yielded disease-free intervals of 25–68 months in our study horses as of January, 2008. These results were obtained following a single treatment in seven horses and two treatments in one horse. In one horse, carcinoma in situ developed 2.5 months after partial surgical excision and PDT, requiring local excision under standing sedation.
Conclusions  Preliminary results suggest that surgical resection and adjunctive local PDT is a safe and effective novel treatment for PSCC in horses. More research is needed before PDT for the treatment of equine PSCC can be adequately compared with other current modalities. Important to future investigations regarding PDT, tumor recurrence rate, length of hospitalization, number of treatment episodes required to effect tumor remission, and total treatment costs should be examined in a controlled manner. Our present results and experiences suggest that this treatment may be useful in the treatment of equine PSCC.     

Tendonitis of the branches of insertion of the superficial digital flexor tendon in horses

Objective To describe clinical findings, ultrasonographic features and outcome of injury to the branches of insertion of the superficial digital flexor (SDF) tendon in horses.
Design Retrospective study of 14 cases.
Procedure Fourteen Thoroughbred horses with tendonitis affecting the branches of insertion of the SDF tendon were examined for lameness, location and amount of swelling, and the presence of other musculoskeletal abnormalities. The flexor tendons were assessed by ultrasonographic examination, and recommendations were made for management of the cases. Outcome was assessed by re-examination of some horses, direct communication with the owner or trainer, and examination of race records.
Results The lateral SDF branch was affected in 10 horses; the medial branch in three, and both branches in one horse. Two horses had concurrent injuries to the SDF tendon in the metacarpal region of the contralateral limb. Ultrasonographic findings included swelling of the affected SDF branch, peritendinous fluid accumulation, disruption of normal fibre alignment on sagittal scan, and variable loss of echogenicity. As healing occurred, there was return of normal echogenicity, but normal fibre alignment did not return completely and apparent adhesions formed between the affected SDF branch and adjacent structures. Seven of 10 horses which returned to their previous use were able to compete without further tendon injury. Recurrence of injury occurred in one case, and another two horses developed tendonitis in the metacarpal region. One horse was retired from racing but was able to compete at dressage without recurrence of injury. Two horses were retired for breeding without returning to training, and one horse was sold and lost to follow up but did not race.
Conclusion The prognosis is fair for return to previous use following injury to the branches of insertion of the SDF tendon in athletic horses.