Experimental Bovine Mastitis Produced with Hemolytic Streptococci of Human Origin

Abstract

The Chicago epidemic of septic sore throat reported by Capps and Miller1 was traced to a contaminated milk-supply at Batavia, Ill. It was found that on a number of farms supplying milk to Dairy X, sore throat occurred in the milkers, and mastitis appeared in the cows; in some instances the sore throat appeared first, and in other instances the mastitis preceded the throat infections. These facts bring up the question whether or not it is possible for milkers suffering with sore throat to infect the teats or udders of cows by contaminated hands or otherwise during the process of milking. The question of the susceptibility of the cow to human streptococci is also involved. In an attempt to clear up these points some experiments were designed to test the pathogenicity of human streptococci for cows, and to determine possible avenues of udder infection through the teats. For this purpose a healthy milch cow was obtained, giving at the time about 16 quarts of milk in twenty-four hours. Examination of the udder revealed no lesions, and examination of the milk from each quarter after proper cleansing of the teats showed no hemolytic streptococci on blood agar plates. Leukocytes in the milk from the quarters numbered from 10,000 to 30,000.2