Two cases, one acute and one chronic (or subacute) type, of pigeon breeder's disease were reported. The precipitating antibody possibly against X-PGG was demonstrated in both cases. Positive inhalation test to sterilized pigeon dropping extract (500μg/5ml for 15 minutes) was shown in the acute type, and excerbation of clinical signs upon exposure to the pigeon breeding conditions was noted in the chronic type case. The development of cell-mediated immunity to pigeon dropping extracts was also demonstrated in the acute case. Immunological examinations of pigeon fanciers and their families might be necessary in the preclinical stage.
