Aspects of the pathogenesis and molecular epidemiology of Marek's disease in chickens

Abstract

Marek's disease virus (MDV) is the causative agent of Marek's disease (MD) in the chicken. MDV is an important oncogenic avian pathogen that leads to world-wide economic costs to the poultry industry estimated at more than $US1 billion. Natural infection is via inhalation of feather dander containing the virus then infects lymphocytes and feather follicle epithelial cells from which virus is shed in dander subsequently. Infection of lymphocytes causes lysis and immunosuppression followed by either latent infection or transformation and induction of neoplastic lymphomas in various organs. MDV is still a major concern for the poultry industry in spite of widespread vaccine use, partly because of isolation of very virulent strains from vaccinated chickens. This thesis investigates aspects of the pathogenesis and molecular epidemiology of MD in chickens relevant to the current MD situations in Iraq and Australia.