Strain of Vaccine
A vaccine is a biological preparation that provides active acquired immunity to a particular disease in the host after applying via orally or parenteral route
Virus for used for preparation of vaccine called strain of vaccine. Either its parts of virus or whole body uses this purpose to produce immunuty in the body.
The Intracerebral pathogenicity index is a test to see how virulent a virus is
Its define as a determination of virulency of vaccine virus which ability to causing diseases in day old chicks.
he most virulent Ndv viruses will give a maximum score of 2.0 in this test, whereas whereas lentogenic and asymptomatic enteric strains will give values close to 0.0 which indicates NDV unable to produce disease into host.
Commonly used live lentogenic (loNDV) vaccine strains, mesogenic vaccine strains, and virulent challenge virus strains and their genotype and pathogenicity indices for chickens :
|Varus strain||Pathotypes||Genotypes||ICPI value|
Reference diseases of poultry, 13th edition