Changes in the white blood cells and specific phagocytosis in chicken with experimental acute fowl typhoid

The study was performed on Salmonella-free, five-month-old Plymouth Rock chickens infected orally with a strain of Salmonella gallinanum. The dynamics of the number and structure of white blood cells and phagocytosis of the leukocytes in healthy and infected chickens were tested. The experimental typhoid infection caused a leukocytosis oil the 3(rd) day after infection, followed by leukopenia front the 4(th) day until the 14(th) day inclusive, and reversed as late as the 21(st) day. The results demonstrated that chickens with S. gallinarum infection produced an initial rise followed by fall in the percentage of circulating mature leukocytes in the recovery period and a percentage rise in immature myelocytes and bandnuclear cells. Heterophilia was associated with a relative lymphopenia. This study is the first report of enhancement of the specific phagocytic function (phagocytic activity and phagocyte number) of the leukocytes during 3 - 7 days post infection. All of these changes were found to precede the onset of the first clinical signs of the disease and they may improve early diagnosis of acute fowl typhoid in a clinical situation.