Marek's disease in chickens: development of viral antigen in feather follicles and of circulating antibodies.

The infection of young chickens with Marek's disease herpesvirus (MDHV) leads to the early appearance of viral antigen in the bursa Fabricii, in the kidney tubular epithelium, and particularly in the epithelial cells of growing feather follicles (Calnek and Hitchner, 1969; Purchase, 1970). Viral antigen may persist in feather follicles over several months, whereas in neural lesions or in lymphoid tumors induced by MDHV viral antigen is either lacking or present only in a few cells (Calnek and Hitchner, 1969; Spencer and Calnek, 1970; Purchase, 1970). Haider et al. (1976) have pointed out the high diagnostic value of the double-diffusion agar-gel participitation test (Chubb and Churchill, 1968) using growing feathers of MDHV-infected chickens as antigen.