Respiratory disease(trachea-bronchitis) caused by adenovirus in turkey poults

During the period between 2001 and 2010, the authors observed respiratory diseases relating to adenovirus infection in eight large flocks (6,500-17,000) of young turkeys. The disease occurred at 6-10 weeks of age of the birds and lasted for 2-3 weeks in the flocks. The clinical signs included malaise, anorexia, sneezing and hampered respiration (dyspnoe). The mortality attributable to the disease was around 2-5.5%. At necropsy, gross pathology findings consisted of acute mucous-fibrinous tracheitis, multifocal catarrhal pneumonia, as well as mucous-fibrinous air-sacculitis and pericardititis. By histopathology, mucous-fibrinous tracheo-bronchitis with deciliation of epithelium in the respiratory tract, accompanied by epithelial proliferation and metaplasia, and catarrhal pneumonia were revealed. In the epithelial cells of the respiratory tract, basophil and/or acidophil nuclear inclusion bodies could be observed. In samples from the affected organs, the presence of aviadenoviruses was demonstrated by PCR. The viruses were also isolated in cell culture. The detected viruses, determined as turkey adenovirus 5, differed from every previously known adenovirus but seemed to be identical with each other. The novel virus was found to be a close relative of fowl adenoviruses, but different from turkey adenovirus 1, sequenced recently. Most likely, turkey adenovirus 5 represents a novel adenovirus species. Bacteria, that can be considered as primary pathogen such as Bordetella, Riemerella, Ornithobacterium, Pasteurella, etc., or Mycoplasma were not found. By virological and serological tests (with paired serum samples), the etiological role of the Newcastle disease virus (NDV), avian influenza virus (AIV) and the turkey rhinotracheitis (TRT) virus could be excluded except one flock where also a low pathogenic H9N2 A1V strain was isolated.