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Bovine Viral Diarrhoea - Surveillance, Diagnostics and Immunopathogenesis - OD0345

Description
Bovine viral diarrhoea (BVD) is a widespread viral infection of cattle, which may cause mild to severe, including lethal acute disease with a diverse spectrum of clinical signs. In the UK and continental Europe, 60-90% of domestic cattle undergo infection. During the last decade, typing of field virus isolates has shown that BVDVs genetically are very diverse. The greatest diversity has been seen in Europe, where more than 10 subtypes of two BVDV species have been found. The prevalence is different from that in the UK, where one subtype dominates. BVDVs differ also in other properties, such as virulence.
To ensure our diagnostic assays perform satisfactory, monitoring for emergence of BVDV types new to the UK cattle is necessary. Based on updated information on the diversity of BVDV, we will refine the current BVDV detection assays. This includes looking at the ability of currently used serological assays to detect antibody responses after infection with BVDV-2. We will also analyse the relative contribution of individual viral antigens to the development of immunity after natural infection and vaccination.
In the UK, vaccination against BVDV has been limited to use of inactivated vaccines. These are safer than modified live vaccines, but provide less effective immunity. Despite use of vaccines against BVD for more than four decades, it is not known what role nonstructural viral proteins play in the development of immunity. The basis for successful immunoprotection will be investigated by studying a broader range of viral proteins for potential contibution to development of protective immunity, as seen after natural infection, whilst aiming at approaches that allow discrimination between natural infection and vaccination.
Objective
1) diagnostic test development
a) validation of a real time short-target TaqMan RT-PCR for detection of BVDV in general and selected clinical sample materials (blood, semen, milk)
b) development of strand specific real time RT-PCRs
c) assessment of ability of routine serological tests to detect humoral immunity derived from acute infection with BVDV-2
d exploring possibilities for discrimination of immunity from vaccination and natural immunity

2) monitoring for emerging virus strains
a) continued surveillance for novel ruminant pestiviruses in the UK and abroad
b) prevalence monitoring, of BVD in general and of BVDV-2 in the UK in special
c) following BVD control approaches in other European countries

3) analysis of the cell mediated immune response ex vivo
a) detect and quantify the number of BVDV-specific CTL

4) identify immunogens required for protection
a) analyse inactivated viral preparations for potential immune inhibition
b) stimulate an antigen specific immune response
c) delivery of a vaccine-line formulation at the site of antigen presentation
d) induction of a BVDV-specific immune response in vivo
Time-Scale and Cost
From: 2006

To: 2011

Cost: £545,267
Contractor / Funded Organisations
Veterinary Laboratories Agency
Keywords
Animal Diseases              
Animal Health              
BVDV              
Plants and Animals              
Fields of Study
Animal Health