Pathological and Immunopathological Studies on Broiler Chicks Infected with Chicken Anemia Virus

Chicken anemia virus (CAV) has become a significant worldwide problem in the broiler industry due to its economic losses. The aim of this work was, investigation of the hematological, clinicobiochemical, pathological, and immunohistochemical changes associated with Chicken Anemia Virus (CAV) infection using processed tissue homogenates positive for CAV. CAV isolated from clinically infected broiler chickens (100 samples from 10 flocks) at Sharkia governorate Egypt. Ten samples representing the 10 flocks were done by PCR test to determine the presence of CAV-DNA in tissue samples (spleen, thymus, bone marrow, and bursa fabricius of suspected cases). Supernatant (0.2 ml) of tissue homogenates was inoculated intramuscular into one-day-old chicks; control group received only phosphate-buffered saline. Blood and tissue samples were collected at 7, 14, and 21 days old. Positive presence of CAV-DNA genome in the PCR products (583 bp in size) of amplified CAV-DNA was extracted from the tissues of diseased chicks. The infected group with displayed signs of growth retardation; normocytic normochromic anemia with PCV <22%; significant decreases in the levels of total protein, albumin, globulin and triglycerides that were detected at 7 days post infection and persisted till 21 days, in addition to a significant increase in Alanine aminotransferase and Alkaline phosphatase activities; and decrease in serum calcium level with a significant increase in serum inorganic phosphorus level throughout the experimental period. The deviation in liver enzymes revealed the presence of liver disorder consistent with the histopathological changes demonstrating marked depletion in lymphocyte cells in the bone marrow, thymus and bursa of fabricius with liver damage.