Attenuation of infectious bursal disease virus and vaccination trials under laboratory and field conditions.
Adaptation to the chicken embryo of a virus strain of infectious bursal disease resulted in a reduction in virulence. After 60 passages the strain was attenuated enough to be used as a vaccine. The attenuation proved adequately stable. If given orally in the drinking water, the strain induced the development of neutralising and precipiting antibodies and a strong resistance against the disease. Promising results have also been obtained in the field.
Rinaldi
A
A
Istituto Zooprofilattico Sperimentale della Lombardia a dell'Emilia, BRESCIA, Italia.
Cessi
D
D
Cervio
G
G
Lodetti
E
E