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

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.