Characterization of a Streptococcus equi ssp. equi Isolate From a Strangles Outbreak in Thailand

Strangles, which is caused by Streptococcus equi ssp. equi, is one of the major infectious respiratory diseases in horses. Knowledge of isolates from different areas of the world is important for investigating the different strains of the disease. In contrast to many other countries, currently little is known about S. equi ssp. equi isolates in Thailand. In 2014, a farm in Thailand imported 20 horses from Europe. Approximately 1 month after arrival, 50% of the horses had developed pyrexia, mucopurulent nasal discharge, and abscesses of the mandibular lymph nodes. Nasal swabs of mucopurulent discharge were sent to a diagnostic laboratory, and two isolates of S. equi ssp. equi were identified. One of the isolates was further characterized using seM gene polymerase chain reaction and sequence analysis. The seM sequence was then compared to the database of PubMLST-seM. It was found to contain SeM allele 48, an allele isolated from horses in the United Kingdom in 2006 and 2010. This result demonstrates the usefulness of SeM allele identification as a tool for investigating the source of related strains and for the epidemiologic study of strangles. To the best of the authors' knowledge, this is the first report of the identification of an SeM allele of the S. equi ssp. equi isolate in Thailand.     

First Report of Molecular Characterization of Argentine Isolates of Streptococcus equi subsp. equi by Pulsed-Field Gel Electrophoresis

Strangles is one of the most frequently diagnosed equine respiratory infectious diseases in the world. It is caused by Streptococcus equi subsp. equi (S. equi), and it is an acute infection characterized by pyrexia, nasal discharge, pharyngitis, and abscessation of lymph nodes. Frequently, healthy horses might continue to harbor S. equi after clinical recovery. Although the genetic distance between S. equi isolates is short, strains can be differentiated by pulsed-field gel electrophoresis (PFGE) and single locus sequence typing for epidemiological studies. The aim of this study was to characterize by PFGE Argentine isolates of S. equi obtained from horses with acute strangles and those that had recovered. Bacterial isolation and identification of 80 S. equi isolates by phenotypic and genotypic tests were performed using samples from 29 horses with acute strangles and 95 from healthy animals. Also, the isolates were characterized by PFGE using Bsp120I and SmaI. Visual comparison of macrorestriction patterns generated with both enzymes revealed three different DNA fragment profiles with variations of one or two bands. Interestingly, an identical profile was found in isolates from the same horse and from horses that were infected at the same time, and the horses recovered from strangles continue to carry the same strain. Some vaccinated horses have been mild infected for a different strain from that of carriers suggesting other source of infection. This is the first molecular characterization of Argentine isolates of S. equi, which shows the presence of three strains between 2010 and 2013 in Buenos Aires.     

Lineages of Streptococcus equi ssp. equi in the Irish equine industry

Background

Streptococcus equi ssp. equi is the causative agent of ‘Strangles’ in horses. This is a debilitating condition leading to economic loss, yard closures and cancellation of equestrian events. There are multiple genotypes of S. equi ssp. equi which can cause disease, but to date there has been no systematic study of strains which are prevalent in Ireland. This study identified and classified Streptococcus equi ssp. equi strains isolated from within the Irish equine industry.

Results

Two hundred veterinary isolates were subjected to SLST (single locus sequence typing) based on an internal sequence from the seM gene of Streptococcus equi ssp equi. Of the 171 samples which successfully gave an amplicon, 162 samples (137 Irish and 24 UK strains) gave robust DNA sequence information. Analysis of the sequences allowed division of the isolates into 19 groups, 13 of which contain at least 2 isolates and 6 groups containing single isolates. There were 19 positions where a DNA SNP (single nucleotide polymorphism) occurs, and one 3 bp insertion. All groups had multiple (2–8) SNPs. Of the SNPs 17 would result in an amino acid change in the encoded protein. Interestingly, the single isolate EI8, which has 6 SNPs, has the three base pair insertion which is not seen in any other isolate, this would result in the insertion of an Ile residue at position 62 in that protein sequence. Comparison of the relevant region in the determined sequences with the UK Streptococcus equi seM MLST database showed that Group B (15 isolates) and Group I (2 isolates), as well as the individual isolates EI3 and EI8, are unique to Ireland, and some groups are most likely of UK origin (Groups F and M), but many more probably passed back and forth between the two countries.

Conclusions

The strains occurring in Ireland are not clonal and there is a considerable degree of sequence variation seen in the seM gene. There are two major clades causing infection in Ireland and these strains are also common in the UK.     

Equine Performance and Autonomic Nervous System Improvement After Joint Manipulation: A Case Study

A nine-year-old gelding quarter horse, whose discipline is barrel racing, was experiencing difficulty performing tight turns around the barrels for 8 months prior to treatment. He demonstrated tail swishing as if aggravated when under the saddle, which would escalate to bucking for 3 weeks prior to treatment. This gelding had no previous history of bucking under the saddle. Static and motion palpation findings indicated multiple segmental joint fixations located throughout the spine and extremities. High-velocity low-amplitude adjustments were performed to address the joint fixations found during examination. A comparison of pre and post-treatment thermographic images showed a temperature change indicative of autonomic nervous system improvement caused by joint manipulation. A follow-up at two weeks revealed subjective long term improvements. Subjective, objective, and thermographic evidence indicated that segmental joint dysfunction was causing increased nociception and autonomic dysregulation, most notably over the sacroiliac joints, lateral front left cannon bone and right carpus. Previous research has indicated causative effects of joint manipulation on the autonomic nervous system and nociceptive processes. This case shows the positive thermographic effects post-adjustment on the nervous system, and a two week follow-up indicated that the gelding no longer showed signs or symptoms of pain. This case demonstrates how joint manipulation can affect the autonomic and nociceptive nervous systems in the equine patient.     

Streptococcus equi Infections in Horses: Guidelines for Treatment,Control, and Prevention of Strangles—Revised Consensus Statement

This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the “gold standard” for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the importance of judicious use of antibiotics in horses with strangles. This updated consensus statement reviews current vaccine technology and the importance of linking vaccination with currently advocated disease control and prevention programs to facilitate the eradication of endemic infections while safely maintaining herd immunity. Differentiation between immune responses to primary and repeated exposure of subclinically infected animals and responses induced by vaccination is also addressed.     

Bisphosphonates: Pharmacology and Clinical Approach to Their Use in Equine Osteoarticular Diseases

Bisphosphonates (BPs) are drugs widely used in various bone diseases, mainly for their skeletal antiresorptive effect. Nowadays, they are also used to treat degenerative pathologies such as arthritis because of their particular anti-inflammatory and analgesic properties. Since the sixties, BPs with different characteristics and biological activity profiles have been studied, although most of the pharmacologic and clinical trials have been carried out in humans. By 2002, however, tiludronate was granted a marketing license in France for use in horses. The objective of this article is to review the literature available on BPs and apply this knowledge, either experimentally or clinically, to equine osteoarticular disease therapy.     

Equine Mandibular Fibrosarcoma in Two Horses: Clinical,Diagnostic, and Therapeutic Considerations

A 25 year old Arabian gelding (case 1) presented for a large mandibular swelling involving the caudal aspect of the left horizontal mandible and a 14 year old Quarter Horse gelding (case 2) presented for a soft tissue swelling on the labial mucosa adjacent to 304. Both horses were bright and alert on presentation. Computed tomography allowed for further characterization regarding the extent of bone penetration within the lesions. This facilitated surgical planning and resection in Case 2. Histopathology of both masses diagnosed fibrosarcomas. Case 1 was humanely euthanized due to the severity of bone involvement and the grave prognosis. Case 2 underwent a left subtotal rostral hemimandibulectomy that proved to be successful in complete resection of the fibrosarcoma with a comfortable and cosmetic post-operative outcome. Surgeries that were once deemed radical should be considered for the treatment of neoplastic masses involving the soft tissues and bony structures of the oral cavity. With the aid of computed tomography, assessment of tumor penetration into deeper tissues can be achieved, thus facilitating complete surgical excision.     

马病毒性动脉炎诊断技术研究进展

马病毒性动脉炎(EVA)是马属动物之间通过呼吸道或生殖器官传播的传染病,是危害养马业及赛马比赛的重要疾病之一,应用各种诊断技术对该病做出准确的诊断是预防和控制该病的前提.EVA的诊断技术包括检测病毒,检测血清抗体,涉及的技术和方法包括病毒的分离及中和试验、血凝及血凝抑制试验、免疫荧光试验以及酶联免疫吸附试验等.每种诊断技术都有其各自的优势和局限性,应根据目的及工作条件等综合情况予以选择,论文就各种诊断技术的原理、方法及特点进行了概述和比较,并对今后的应用前景和发展趋势进行了展望.