An outbreak of a lethal disease was reported in 4–6-month-old Holstein calves in a feedlot around Tehran. The signs of central nervous system and gastrointestinal system (GI) involvement were observed in the diseased animals. Necropsy samples of GI, liver, kidney, spleen and lung from 3 died animals were prepared for histopathological examination. Blood and formalin-fixed ear notch samples of 6...
