Candida rugosa: experimental mastitis in a dairy cow

Candida rugosa was isolated from the milk of 70% of the cows in a dairy herd with mastitis problems. An experimental C. rugosa infection of the udder of a healthy cow resulted in a prolonged fever and an inflammatory reaction in the mammary gland and associated lymph nodes. Milk secretion in the 2 infected quarters was reduced from 8.51 to 1.51 per day. Histological examination revealed alveolar destruction with interstitial fibrosis accompanied by lymphocyte and macrophage accumulation. C. rugosa was cultured form the cisternal mammary tissue of the infected quarters but not from the alveolar tissue or associated lymph nodes. There was no evidence of tissue invasion. The signs described were probably due to toxic components in the fungal cell walls combined with the adverse effects of lowered pH in the milk during the proliferation of the yeast.