Avian Leukosis in Brahma Chicken Raised in Al-Qurnah Town,Southern Iraq

The current study was conducted to diagnose avian leukosis in naturally infected Brahma backyard chickens in southern parts of Iraq, on the basis of clincopathological findings and serological detection by using antigen-capture enzyme-linked immunosorbent assay (AC-ELISA) in suspected tumor cases in field conditions. In this study the avian leukosis was mostly observed in birds from 16 to 22 weeks of age, as well as the infected flocks showed a low mortality rate ranging from 5–6%. Typical variable sized grey to yellow obvious tumor-like nodular lesion was demonstrated on the surface of enlarged visceral organs such as liver, spleen, kidney and duodenum, as in white meat-type chickens. The histopathological features revealed massive infiltration of monomorphic lymphocytes in which the lymphoblasts were predominant in the liver, kidney, spleen and duodenum. In this study, a total of 40 sera were tested for ALV P27 antigen by ELISA technique. Thirty-five out of forty sera (87.5%) obtained from Brahma chickens tested positive to ALV P27 antigen and a higher percentage (88.58%) of the chicken sera were strongly positive and had (EUs > 75%). Based on these findings, avian leukosis was concluded to be associated with this pathological condition in Iraqi backyard flocks. This is the first report of the presence of the avian leukosis in visceral samples of Brahma breed. It seems that commercial poultry population in Iraq is not far from the threat of the avian leukosis, and surveillance for avian leukosis is needed.