1Hussein, HA., 2Youssef, MM., 3Osman, A., 2El-Ebiary, EA and 1MA Shalaby
1Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt 2Central Laboratory for Evaluation of Veterinary Biologics, Cairo, Egypt and 3Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
In the present study, the immunopathogenicity of chicken anemia virus (CAV) vaccinal strain was studied in one-day-old specific-pathogen-free (SPF) chicks. Hematocrit values, histopathological changes in haemopioetic and lymphoid organs, ELISA for CAV antibodies and PCR for CAV genome were used as testing assays for the study. Vaccinated chicks showed signs of anemia, lower hematocrit values and histopathological lesions in liver in the form of hepatocytes swelling to Centro lobular necrosis and apoptosis. Histopathology change in spleen (depletion of lymphocytes and apoptosis) and thymus (depletion of thymocytes and apoptosis) together with variable degrees of seroconversion rate were observed along the 10 weeks of the experiment indicating 2 waves of immune response in vaccinated chicks compared to the control non-vaccinated group. Detection of CAV-DNA in the liver of vaccinated chicks indicated the presence of the virus, when the antibody levels were decreased in some chicks. There was a consistent correlation between the 4 parameters used. It is concluded that the attenuated CAV vaccine strain induces anemia and lesions in the lymphoid organs. The histopathology and PCR are useful tools for evaluation and quality assurance of CAV vaccines.