US: New pathogenic Gumboro viruses characterised

In recent years the very virulent infectious bursal disease virus (Gumboro virus) has appeared in the US poultry industry for the first time.

The virus has since recombined with infectious bursal disease viruses that have been common in the US for years.

In a recently completed research project funded by the USPOULTRY Foundation, researchers at the Ohio State University, led by Dr. Daral Jackwood, have isolated and characterized these new recombined viruses and found that they are less virulent than the parent very virulent viruses but break through maternal antibodies earlier than our native viruses. This may require adjustments in breeder vaccination programs in areas of the country where these viruses have been found.

In summarising the findings the researchers stated that “Genome reassorted IBDV appear to be less pathogenic than vvIBDV. However, these viruses can still cause morbidity and mortality in SPF chickens, and they were able to break through maternal immunity produced using commercial classic and variant vaccines. This suggests that current breeder vaccination programs may not adequately protect against the reassorted vv/serotype 2 and vv/cv IBDV strains.”