Comparison of challenge methods for experimental infection with MDV: intra-abdominal injection of cell cultured MDV versus exposure to infectious dust.

The aim of this study was to investigate whether infection of chickens with MDV1 byexposure to small amounts of infective dust (500 mg) under defined conditions is suitable asan alternative challenge method to intra-abdominal injection with infective cellular material.The infection via intra-abdominal injection induced 100% infection in chickens at 14 dpi andhigher mortality with gross MD lesions (32-49%) whereas exposure to infective dust resultedin 67-83% infectivity and (13-14%) mortality. The body weight and immune organ data at 14dpi revealed that infection by injection induced an earlier onset of immune responses andrelated changes to MDV infection in these organs compared to infection by exposure.