January 8, 2007

UK develops new in-ovo vaccine for IBV

A pre-hatching prototype vaccine virus for providing immunity to chicks against infectious bronchitis virus (IBV) has been developed by scientists at the Institute for Animal Health (IAH) and vaccine company Intervet UK.

The disease causes losses of GBP 23.6 million (US$ 45.52 million) a year to the UK poultry industry.

The vaccine could be delivered to the to chicks still in the egg (in-ovo) using robotic 'vaccinators'.

IBV is the worst infectious disease in terms of economic loss to the UK poultry industry. Infection could lead to severe respiratory disease, dramatically reduce egg production and affect the quality and hatchability of eggs.

The researchers, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), Department of the Environment, Food and Rural Affairs (Defra) and Intervet UK, used a 'reverse genetic' system to produce new vaccine strains. Existing strains, which are usually delivered by less efficient spray or drinking water dosage, can prevent chicks hatching if delivered in the egg.

The scientists have extracted a so-called spike protein from a pathogenic virus strain which triggers an immune response, and incorporated it into a harmless non-pathogenic strain.

The hybrid virus was able to induce immunity when inoculated before hatching. When hatched chicks were exposed to the virulent M41 strain, scientists observed protection rates of up to 100 percent, pointed out Dr Paul Britton, head of the Coronavirus Group at IAH Compton.