Changes

They contain a deleted protein or gene; vaccinated animals cannot make antibody to the missing protein whereas infected animals can and this helps immunosurveillance for animals infected by an organism in countries that vaccinate against that disease.

They contain a deleted protein or gene; vaccinated animals cannot make antibody to the missing protein whereas infected animals can and this helps immunosurveillance for animals infected by an organism in countries that vaccinate against that disease.

==Which type of vaccine is used for each disease?==

==Tailoring Vaccines for Specific Diseases==

 

*The life-cycle of infectious organisms needs to be understood to ascertain the best type of immune response for fighting that particular infection

*The life-cycle of the organisms needs to be understood to ascertain the best type of immune response for fighting the particular infection

*A vaccine can be created to provide the specific immunity best suited for fighting the associated infection

 

*A vaccine can be created to provide specific immunity which is best suited for fighting the specific infection

===Immunity to Virus Infection===

===Immunity to Virus Infection===

[[Image:Virus Life Cycle.jpg|thumb|right|150px|Virus Life Cycle - Copyright Dr Brian Catchpole BVetMed PhD MRCVS]]

[[Image:Virus Life Cycle.jpg|thumb|right|200px|Virus Life Cycle - Copyright Dr Brian Catchpole BVetMed PhD MRCVS]]

*The virus life cycle consists of an extracellular phase, a replicative intracellular phase and another extracellular phase spreading viral particles to other cells to begin the life cycle again

*The virus life cycle consists of an extracellular phase, a replicative intracellular phase and another extracellular phase spreading viral particles to other cells to begin the life cycle again