Pregnancy status determination in mares using a rapid lateral flow test for measuring serum oestrone sulphate

AIMS: To develop a means of determining pregnancy status in horses based on measuring serum oestrone sulphate (OS) concentrations using a rapid lateral flow immunoassay, and to determine the assay's effectiveness using a visual end-point. METHODS: Serum samples from mares >100 days post-mating (n=701) were assayed using a nitrocellulose membrane-based lateral flow immunoassay device. The device was developed using membrane-bound 1,3,5 (10)-estratrien-3-ol-17-one conjugated to bovine serum albumin as the capture antigen, and an OS-detection monoclonal antibody coupled to colloidal gold as the visible detection reagent. Concentrations of the coating antigen and OS monoclonal antibody were optimised so that the working range would allow pregnancy status to be determined from a visual end-point. The test was run by adding 0.1 ml serum to the sample well of a plastic cassette encasing the test membrane. As the serum migrated along the membrane, a test dot and control line were generated on it within 5-10 min. The intensity of the test dot was inversely proportional to the concentration of OS in the serum sample being tested. Results were compared with those from a validated OS enzyme immunoassay (EIA) and subsequent foaling or return to oestrus of the mares. RESULTS: Serum samples with OS concentrations <10 ng/ml, indicative of non-pregnancy in mares >100 days post-mating, generated a test end-point consisting of a highly visible test dot and control line, whereas serum OS concentrations >50 ng/ml, indicative of pregnancy, generated a control line only. The test correctly identified 384/389 (98.7%) non-pregnant mares tested, and 303/312 (97.1%) pregnant mares tested that were >100 days post-mating. The lateral flow test devices were stable for at least 12 months when stored at 4 degrees C, sealed in aluminium pouches with desiccant. CONCLUSION: This novel, rapid, easy-to-use, lateral flow immunoassay offers a practical alternative to traditional laboratory- based immunoassays for measuring serum OS concentrations in mares for determining their pregnancy status.     

A practitioner's primer on foot-and-mouth disease

Foot-and-mouth disease (FMD) is caused by an RNA virus of the genus Aphthovirus; 7 immunologically distinct serotypes of the virus have been identified. Susceptible species are mainly domestic and wild even-toed ungulates, such as cattle, sheep, goats, pigs, bison, and deer. All body fluids of infected animals can contain the virus and are considered infective. The primary mode of transmission is animal-to-animal transmission through inhalation or ingestion of aerosols containing the virus. The virus can also be spread mechanically by contaminated organic debris and fomites and can survive for 48 hours on human oral and nasal mucosa and be spread to uninfected animals in this manner. There is a rapid progression of clinical signs after an animal becomes infected, and the virus spreads rapidly throughout a herd. Clinical signs include excessive salivation; fever; vesicles and erosions of the oral and nasal mucosa, coronary band, interdigital area, and teats; lameness; sloughing of claws; reluctance to move; anorexia; mastitis; decreased milk production; and abortion or weak newborns. In mature animals, FMD has high morbidity and low mortality rates. Infected animals can become inapparent carriers of the virus.     

Serum insulin concentrations in horses with equine Cushing's syndrome: response to a cortisol inhibitor and prognostic value

REASONS FOR PERFORMING STUDY: Serum insulin concentration and its use as a prognostic indicator in horses with equine Cushing's syndrome (ECS) have been poorly documented. OBJECTIVES: To examine daily insulin variations in horses with ECS and the effect of treatment using trilostane, a competitive inhibitor of 3beta-hydroxysteroid dehydrogenase. Further, we aimed to examine the relationship between baseline serum insulin concentration and survival in horses with ECS. METHODS: Basal serum insulin concentrations were measured in 20 confirmed ECS cases by taking blood at regular 4 h intervals for 24 h (1200, 1600, 2000, 2400, 0400 and 0800 h) before treatment (Day 0) and 10 days, and 30 days and 1-2 years after the onset of trilostane therapy. The temporal pattern of insulin was analysed using a linear mixed model approach, and the prognostic value of measurements on Day 0 assessed using receiver-operating characteristic analysis. RESULTS: Horses with ECS showed a diurnal pattern of serum insulin concentration, highest value at 1200 h, and this pattern was not altered by treatment with trilostane. Furthermore, despite a mild increase of serum insulin concentrations after 10 days of trilostane therapy, insulin concentration was unaffected in the long-term. Low serum insulin concentrations at the beginning of the trial were significantly associated with improved survival to 1-2 years. The 1200 h sampling before treatment had the highest prognostic value for prediction of survival with a sensitivity and specificity of at least 90% for serum insulin at < 62 and > 188 microu/ml to predict survival and nonsurvival, respectively. CONCLUSIONS AND POTENTIAL RELEVANCE: Insulin is a useful prognostic indicator for ECS, but potentially large variations can occur throughout a 24 h period, indicating a single sample may not be representative. Serum insulin concentration did not increase over 1-2 years in horses receiving trilostane therapy.     

Equine ocular anatomy and ophthalmic examination.

This article is intended to provide the practitioner with a succinct but complete source regarding equine orbital and ocular anatomy,instrumentation available for ophthalmic examination, a methodical examination technique, sedation and regional nerve blocks, and diagnostic procedures involving the eye. Such knowledge of orbital and ocular anatomy is essential to allow recognition of normal,normal variations, or an abnormality of the equine eye and orbit.     

Incidence of post-anaesthetic arrhythmias in dogs

OBJECTIVES: To assess the use of Holter monitoring for evaluating the incidence of post-anaesthetic cardiac arrhythmias and associated anaesthetic risk for two different anaesthetic protocols. METHODS: Patients undergoing orthopaedic surgery were randomly divided into two groups with different anaesthetic regimens (group A, isoflurane n = 30; group B, propofol n = 30). Two 24-hour Holter recordings were performed for each patient: the first directly following anaesthesia and the second, as a comparison, on the fifth postoperative day. RESULTS: Although all dogs were healthy on pre-anaesthetic cardiac evaluation, 56 dogs showed arrhythmias in the two 24-hour (Holter) electrocardiograms performed. However, the number of arrhythmias recorded was low in most cases (less than 10 supraventricular extrasystoles and less than 100 ventricular extrasystoles). One patient in group A showed 94 supraventricular extrasystoles during the second monitoring period. Three patients in each group developed more than 100 ventricular extrasystoles during both Holter recordings. There were no statistically significant differences between the two anaesthetic regimens or between the two recordings in both groups. CLINICAL SIGNIFICANCE: The two anaesthetic protocols investigated in this study did not induce an increased incidence of severe arrhythmias in healthy dogs in the post-anaesthetic phase.     

Retrospective study of bacterial infective arthritis in 31 dogs

OBJECTIVES: To characterise the presenting signs and pathological changes of canine bacterial infective arthritis in 31 dogs, and to document the response to different treatment regimens. Risk factors that may predispose joints to bacterial infective arthritis and influence the success of treatment were also investigated. METHODS: A retrospective review of cases of bacterial infective arthritis that were presented to three university veterinary referral hospitals over a five-year period (January 1997 to January 2002) was performed. RESULTS: The elbow joint (38 per cent) and stifle joint (44 per cent) were most commonly affected. Radiographic changes consistent with pre-existing osteoarthritis were identified in 14 joints, which had no history of previous surgery (articular or periarticular) or penetrating wound. No significant difference (P = 0.78) was identified between the outcome of combined surgical and medical management, and medical management alone. There were trends for poorer outcomes with increased bodyweight of the dog, longer duration of lameness and a higher nucleated cell count of the affected joint fluid at presentation. The overall infection rate for articular surgical procedures at one institution was 1-3 per cent. CLINICAL SIGNIFICANCE: Medical and/or surgical management were usually successful in resolving infection (94 per cent). However, they were frequently unsuccessful in restoring full joint function; this may in part have been due to the nature of the underlying joint     

A novel subgroup among genotypes of equine arteritis virus: genetic comparison of 40 strains

The authors determined partial nucleic sequences of the variable regions of open-reading frame (ORF5) from 151 nucleotide to 668 nucleotide and deduced amino acid sequences of 518 nucleotide respectively of 20 equine arteritis virus (EAV) isolates. About 19 Hungarian and one Austrian EAV strains were subjected to sequence analysis, the further data of 20 EAV strains: six North American and 14 European were obtained from the GenBank. Comparative sequence analysis of the Hungarian EAV strains indicated that among the three variable regions the first has been affected mostly by point mutations. Genetic comparison of the Hungarian strains with other EAV isolates from western Europe and North America (including the Bucyrus reference strain) has been performed on the aforementioned genome region. Besides the already known genetic subgroups of EAV; phylogenetic analysis revealed a novel subgroup comprising mainly Hungarian strains. Compared with the Bucyrus virus, the overall sequence divergencies of the examined Hungarian strains ranged from 81.47 to 90.73% at nucleotide and from 84.88 to 91.86% at amino acid level. Epizootiological studies have shown that the significant part of the EAV strains having been existed in Hungary before and in 2000 belong to this unique cluster (II.D) which was not indicated in former phylogenetic studies. After 2000 new EAV strains emerged in Hungary, one of them causing abortions or neonatal death. The previously dominant 'Hungarian' EAV genotypes were replaced by these new strains belonging to North American and European subgroups (I.A, I.B, II.A, II.B). The anamnesis of these cases revealed connections with persistent virus shedder stallions, those were imported to the country after 2000 or have been infected abroad. One of these Hungarian stallions became the source of abortion storms in Hungarian studs.