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Sustainable Livestock Production LINK Programme
OVERVIEW
Project LK0699/OD0720: Development of rationally attenuated live vaccines for
effective control of infectious bronchitis
Start Date: 08/10/2009
End Date: 07/10/2013
Background
Control of infectious diseases and a reduction in the use of therapeutic antibiotics
are two major challenges faced by the UK poultry industry. The avian coronavirus,
IBV, is a highly contagious poultry pathogen prevalent in all types of poultry flocks
worldwide. IBV is the causal agent of infectious bronchitis (IB) and continues to be
responsible for economic loss, welfare problems in chickens and a potential risk to
food security. IBV preferentially causes respiratory disease, but can also infect other
organs such as the kidneys (resulting in kidney disease) or the reproductive tract
(resulting in loss of egg production and/or egg quality). IBV has been reported to be
responsible for more economic loss to the UK poultry industry than any other
infectious disease. Although live attenuated vaccines and inactivated vaccines are
universally used in the control of IBV, the protection gained by use of vaccination can
be lost either due to vaccine breakdown or the introduction of a new IBV serotype
that is not related to the vaccine used, posing a risk to the poultry industry.
It is important that new and safer vaccines are developed for the control of IBV.
Relaxation of IBV vaccination strategies or the breakdown of vaccination, due to new
IBV strains, would have a profound and devastating effect on the UK poultry industry
in terms of bird welfare and production costs, with associated risks to food security.
Objective
The overall aim of this project is to attenuate the pathogenicity of infectious
bronchitis virus (IBV) of poultry in a non-reversible way, whilst maintaining
immunogenicity for both vaccination of chickens and for in ovo application. The work
seeks to develop an infectious clone system for the generation of rationally
attenuated IBV vaccines, identifying two spatially distant regions of the genome that
can be modified for attenuation. The project is divided into four sub-objectives:1. To produce an IBV reverse genetics system based on the pathogenic M41
strain of IBV.
2. To remove the M41 accessory non-structural genes to identify whether they
play a role in pathogenicity.
3. To study the role of the M41 essential (replicase) non-structural protein genes
in pathogenicity.
4. To investigate the attenuation of IBV for in ovo vaccination.
This work will pave the way for new rationally modified and safer vaccines, as they
will be less likely to revert. A further expected benefit from the development of safer
vaccines, is a reduction in the amount of antibiotics used to counteract secondary
bacterial infections associated with IB.
CONTACT
Dr Paul Britton
Institute for Animal Health
Compton Laboratory
Compton, Newbury
Berkshire, RG20 7NN
[email protected]
PARTNERS
Pfizer Animal Health
British Poultry Council
British Egg Industry Council.
GOVERNMENT SPONSORS
Defra/BBSRC