Loss of virulence in a small plaque mutant of the infectious bursal disease virus

Area of Science:

• Veterinary Virology
• Immunology

Background:

• Infectious bursal disease virus (IBDV) causes significant economic losses in the poultry industry.
• Development of safe and effective vaccines is crucial for controlling IBDV outbreaks.

Purpose of the Study:

• To characterize a newly established variant strain of IBDV, designated Cu-1 M.
• To evaluate the potential of this variant strain as a live vaccine candidate.

Main Methods:

• Isolation and characterization of the IBDV Cu-1 M variant strain.
• Assessment of pathogenicity in chickens, including plaque formation, growth rate, and lesion development.
• Evaluation of protective immunity induced by the variant strain against virulent IBDV challenge.

Main Results:

• The IBDV Cu-1 M variant exhibited smaller plaque formation and a reduced growth rate compared to the wild-type strain.
• The variant strain did not cause overt disease or significant lesions in the bursa of Fabricius in chickens.
• Infection with the Cu-1 M variant successfully induced solid protective immunity against challenge with virulent IBDV.

Conclusions:

• The IBDV Cu-1 M variant strain is attenuated and possesses desirable characteristics for a live vaccine.
• This variant strain offers a promising strategy for protecting poultry against infectious bursal disease without adverse clinical effects.