Infectious bursal disease virus
Infectious bursal disease virus (IBDV) is the etiologic agent of Infectious bursal disease (IBD), which is an acute, highly contagious, and immunosuppressive viral disease of young chickens. IBDV is a single-shelled, non-enveloped, double stranded RNA virus of the Birnaviridae family. There are several different types of serotypes of IBDV distributed worldwide. IBDV causes acute infection and depletion of B cells in the bursa of Fabricius (cloacal bursa) and other organs of the chicken, leading to severe and prolonged immunosuppression.
The IBD virus genome is segmented and is susceptible to genetic mutations through random recombination of its gene segments. The very virulent strains of IBDV (vvIBDV) have mutations that allow the virus to replicate faster and cause more severe disease.
Diagnosis: Laboratory confirmation of the disease is by identification of the virus in affected tissues from dead birds. The "very virulent" IBDV strains have higher flock mortality than "classic" IBD and laboratory analysis would identify IBDV with specific gene mutations compared to "classic" IBDV.
Environmental Contamination: IBDV is a very stable virus, and is able to remain in contaminated environments and on equipment for several months, resisting most common disinfectants, temperature variations and sunlight.