Use of an experimental chicks model for paratuberculosis enteritis (Johne's disease).

Developments in the diagnosis and treatment of paratuberculosis is constrained by the lack of an experimental animal model. To investigate this problem conventional chicks immunodepressed by a Cyclophosphamide injection and concurrent inoculation of Infectious Bursal Disease Virus (IBDV) were infected with Mycobacterium paratuberculosis and kept for 4 months. The immunodepressed chicks eliminated mycobacteria with their faces from the first month until the third month and developed typical intestinal lesions of mycobacterial infection characterized by aggregation of macrophages with monocytes and lymphocytes. Diarrhoea was absent. The number of lymphocytes decreased by about 80%. The serological tests carried out with Complement Fixation test were negative. For the positive bacteriology and typical granulomatous lesions, the conventionally reared chicks proved to be a useful laboratory model for reproduction of Johne's disease.