Retrovirus-associated neoplasms of the respiratory system of sheep and goats. Ovine pulmonary carcinoma and enzootic nasal tumor.

As retrovirus-induced neoplasms of the respiratory epithelium of sheep and goats, OPC and ENT rank as economically important diseases in many countries of the world. They are also important as models of retroviral carcinogenesis of the secretory epithelium of the respiratory system. Control of both diseases is dependent on development and application of sensitive and specific assays for identification of carrier animals infected with the causative agents of these diseases. Recent progress in characterization of type D/B retroviruses associated with the diseases and development of new reagents for the immunologic or molecular detection of antiviral antibodies, viral proteins, or viral nucleic acids bodes well for improved control or prevention of these diseases.