Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2020 Investigation of the antibody response and nasal shedding after EHV-1/4 vaccination and nasal shedding of gamma herpesviruses Scheurer, Laura Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-200797 Dissertation Published Version Originally published at: Scheurer, Laura. Investigation of the antibody response and nasal shedding after EHV-1/4 vaccination and nasal shedding of gamma herpesviruses. 2020, University of Zurich, Vetsuisse Faculty. Departement für Pferde, Klinik für Pferdemedizin der Vetsuisse-Fakultät Universität Zürich Vorsteher: Prof. Dr. med. vet. Colin Schwarzwald Arbeit unter wissenschaftlicher Betreuung von PD Dr. med. vet. Angelika Schoster Investigation of the antibody response and nasal shedding after EHV-1/4 vaccination and nasal shedding of gamma herpesviruses Inaugural-Dissertation zur Erlangung der Doktorwürde der Vetsuisse-Fakultät Universität Zürich vorgelegt von Laura Scheurer Tierärztin von Schnottwil, Solothurn genehmigt auf Antrag von PD Dr. med. vet. Angelika Schoster, Referentin PD Dr. med. vet. Claudia Bachofen, Korreferentin 2020 3 Content Zusammenfassung ............................................................................................................... 6 Abstract ................................................................................................................................... 7 Glossary .................................................................................................................................. 8 1 Introduction ....................................................................................................................... 9 1.1 Herpesviruses .................................................................................................................. 9 1.1.1 Equine Herpesviruses ......................................................................................... 9 1.1.2 Equine Alpha Herpesviruses ............................................................................ 10 1.1.2.1 Virion ........................................................................................ 10 1.1.2.2 Epidemiology ............................................................................ 13 1.1.2.3 Seroprevalence .......................................................................... 13 1.1.2.4 Antigen (virus) prevalence ........................................................ 15 1.1.2.5 Latency ...................................................................................... 16 1.1.2.6 Transmission ............................................................................. 17 1.1.2.7 Pathogenesis of EHV-1 and -4 in general ................................ 19 1.1.2.8 Respiratory Disease .................................................................. 20 1.1.2.9 Abortion, Neonatal and Perinatal Disease ............................... 21 1.1.2.10 Myeloencephalopathy ............................................................. 21 1.1.2.11 Occular Disease ...................................................................... 22 1.1.2.12 Diagnosis of EHV-1 and -4 ..................................................... 22 1.1.2.13 Immunity against EHV ............................................................ 23 1.1.2.14 Vaccination ............................................................................. 24 1.1.3 Equine Gamma Herpesviruses ......................................................................... 30 1.1.3.1 Genomic structure ..................................................................... 30 1.1.3.2 Epidemiology ............................................................................ 31 1.1.3.3 Pathogenesis and Clinical signs ............................................... 31 1.1.3.4 Diagnosis of infection ............................................................... 33 1.1.4 Aims and Hypothesis of the Study ................................................................... 33 2 Material and Methods .................................................................................................. 34 2.1 PART – A EHV-1 and EHV-4 shedding and antibody response after vaccination 34 2.1.1 Farms and animals ............................................................................................ 34 4 2.1.2 Vaccination ....................................................................................................... 35 2.1.3 Sampling ........................................................................................................... 36 2.1.3.1 Sampling procedure .................................................................. 38 2.1.4 DNA detection EHV-1 and EHV-4 (real - time PCR) ..................................... 39 2.1.5 EHV-1 and EHV-4 antibody detection (ELISA) ............................................. 41 2.1.6 Statistical analysis ............................................................................................ 42 2.2 PART – B Screening for equine herpesviruses in healthy horses ........................... 43 2.2.1 Farms and animals ............................................................................................ 43 2.2.2 Panherpes nested PCR ...................................................................................... 44 2.2.3 Statistical analysis ............................................................................................ 46 3 Results ................................................................................................................................ 47 3.1 PART – A EHV-1 and EHV-4 shedding and antibody response after vaccination 47 3.1.1 Animals ............................................................................................................ 47 3.1.2 Adverse reaction to the vaccine ........................................................................ 49 3.1.3 EHV outbreak in Control Group D .................................................................. 49 3.1.4 Serological EHV-1 response after vaccination................................................. 49 3.1.4.1 Pre-study antibody status .......................................................... 49 3.1.4.2 Serological results of sample groups ........................................ 49 3.1.4.3 Serological results of single animals ........................................ 52 3.1.4.4 Group A – Basic immunization > 4 years ago with boosters every 6 months .......................................................................... 53 3.1.4.5 Group B – no vaccination history, vaccinated twice 6 months apart .......................................................................................... 54 3.1.4.6 Group C – no vaccination history, vaccinated with BI followed by a booster 6 months later ....................................................... 55 3.1.4.7 Group D – No vaccination history, natural exposure............... 56 3.1.5 Serological EHV-4 response after vaccination................................................. 57 3.1.5.1 Serologic results of single animals ........................................... 57 3.1.5.2 Group A – Basic immunization > 4 years ago with boosters every 6 months........................................................................... 58 3.1.5.3 Group B – no vaccination history, vaccinated twice 6 months apart .......................................................................................... 59 3.1.5.4 Group C – no vaccination history, vaccinated with BI followed by a booster 6 months later ....................................................... 60 3.1.5.5 Group D – No vaccination history, natural exposure............... 61 3.1.6 Viral shedding at pre-study status .................................................................... 62 5 3.1.6.1 EHV-1 Contamination of pre-vaccination samples by vaccine vials ........................................................................................... 62 3.1.7 EHV-1 viral shedding after vaccination ........................................................... 63 3.1.7.1 Viral shedding results of sample groups ................................... 63 3.1.7.2 Viral shedding results of single animals ................................... 65 3.1.7.3 Group A – Basic immunization > 4 years ago with boosters every 6 months........................................................................... 66 3.1.7.4 Group B – no vaccination history, vaccinated twice 6 months apart .......................................................................................... 67 3.1.7.5 Group C – no vaccination history, vaccinated with BI followed by a booster 6 months later ....................................................... 68 3.1.7.6 Group D – No vaccination history, natural exposure............... 69 3.1.8 EHV-4 viral shedding after vaccination ........................................................... 70 3.1.8.1 Viral shedding results of sample groups ................................... 70 3.1.8.2 Viral shedding results of single animals ................................... 72 3.1.8.3 Group A – Basic immunization > 4 years ago with boosters every 6 months........................................................................... 73 3.1.8.4 Group B – no vaccination history, vaccinated twice 6 months apart .........................................................................................