Prevalence

• IBD was first described as a specific new disease by Cosgrove in 1962 in the town of Gumboro, Delaware, USA.
• Variant IBDV strains were first reported in the USA in 1986/87.
• Hyper or very virulent IBDV strains were first reported in Belgium and The Netherlands in 1987.
• Currently IBDV has a worldwide distribution, occurring in all major poultry producing areas.
• The classical and hyper virulent forms of IBD are predominant in all countries with the exception of North America and Australia.
• In the USA the variant strains of IBDV predominate.

Peer Reviewed by Dr J J (Sjaak) de Wit and William Baxendale.