In this study, immunohistochemistry was used to clarify the early stages of viral kinetics and cycliccourse of IBDV, IR499, which has been described earlier as a very virulent strain (vvIBDV). Fifteen, 4-week-old SPF chickens were inoculated with 10³ EID50 of vvIBDV, IR499, via oculo/nasal route. Five birdsserved as controls, and inoculated with phosphate buffered saline (PBS). The birds were t...