Canine leptospirosis: Improving diagnostics and understanding of the epidemiology of disease in UK dogs

在与默沙东动物健康和动植物卫生署（APHA）的合作中，我们将采取跨学科的方法来研究犬钩端螺旋体病，重点是开发改进的诊断方法，并增加我们对英国犬群中疾病的流行病学了解。我们将通过重新测序和比较目前在英国鉴定的疫苗株和田间株，评估脂多糖（LPS）合成基因和外膜蛋白（OMP，包括LipL 21、LipL 32、LipL 41、LigA/B/C）的遗传多样性。我们假设遗传变异会影响这些表面抗原的B细胞表位。选定的蛋白质和肽将用于生产血清型特异性抗原，并将在血清学试验中进行评估。我们将开发用于测量针对血清型特异性LPS和OMP的血清IgM（更可能在感染急性期）和IgG（更可能在疫苗接种后）的技术。我们假设，这种方法将是更有效的诊断测试和区分急性感染和疫苗免疫。将从最常见的钩端螺旋体血清型中纯化LPS，并合并或单独用于ELISA。重组OMP将作为具有纳米荧光素酶标签的融合蛋白产生。这些将用于液相荧光素酶免疫沉淀（LIPS）试验。之前已由APHA通过MAT检测且已知钩端螺旋体抗体状态的残留血清样本将可用于本研究部分。我们将访问VetCompass临床病例数据库和APHA犬钩端螺旋体病血清学结果数据库，以估计参加第一意见兽医实践的犬的钩端螺旋体病频率和相关风险因素，探索钩端螺旋体病临床病例的地理和时间分布，并量化趋势英国犬钩端螺旋体病疫苗接种率。

In partnership with MSD Animal Health and the Animal & Plant Health Agency (APHA), we will take an interdisciplinary approach to studying canine leptospirosis, with a focus on developing improved diagnostics and increasing our epidemiological understanding of the disease in the UK dog population. We will evaluate the genetic diversity in lipopolysaccharide (LPS) synthesis genes and outer membrane proteins (OMPs including LipL21, LipL32, LipL41, LigA/B/C), by resequencing and comparing vaccine and field strains currently identified in the UK. We hypothesise that genetic variation will impact on B cell epitopes of these surface antigens. Selected proteins and peptides will be taken forward for production of serovar specific antigens, which will be assessed in serological assays. We will develop techniques for measuring serum IgM (more likely during the acute phase of infection) and IgG (more likely following vaccination) against serovar specific LPS and OMPs. We hypothesise that this approach will be more effective for diagnostic testing and discriminating between acute infection and vaccine immunity. LPS will be purified from the most common Leptospira serovars and pooled or used individually in ELISA. Recombinant OMPs will be produced as fusion proteins with a nanoluciferase tag. These will be used in a liquid-phase luciferase immunoprecipitation (LIPS) assay. Residual serum samples that have previously been tested by MAT by APHA and of known leptospira antibody status will be made available for this part of the study. We will access the VetCompass database of clinical cases and APHA database of canine leptospirosis serology results to estimate the frequency of leptospirosis in dogs attending first opinion veterinary practices and the associated risk factors, explore the geographical and temporal distribution of clinical cases of leptospirosis and quantify trends in vaccination uptake for canine leptospirosis in the UK.