It is well known that immunity acquired through vaccination can be impaired by ingestion of mycotoxins. An Egyptian study revealed that mycotoxicosis might be the cause of vaccination failure against Avian Influenza virus. Mycotoxin induced immunosuppression may be manifested as depressed T- or B-lymphocyte activity and suppressed production and impaired macrophage/neutrophil-effector functions. Mycotoxins reduce the level of antibodies following infection or vaccination and reduce the activity of phagocytic cells. Suppressed immune function by mycotoxins can eventually decrease resistance to infectious diseases, reactivate chronic infections and/or decrease vaccines efficacy11. The presence of mycotoxins in poultry rations could therefore lead to a breakdown in vaccinal immunity and to a consequent increase in the occurrence of diseases such as infectious bursal disease virus (IBDV) or Adenovirus