Abstract
Klebsiella aerogenes was identified as the pathogen in an epizootic of single and multiple abscesses in the cervical, axillary and inguinal regions in laboratory rats. Involvement of the salivary glands in the inflammatory tissue in some cases produced interlobular and interacinar fibrosis resembling 'fibro-adenosis', Similar lesions were reproduced with a strain of Klebsiella aerogenes isolated from a diseased rat. Oral carriage of the same strain was detected in the diseased rats, and in normal rats of the same stock. Lymphadenitis appears to have been the primary lesion.