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March 2, 1935

Current Comment

JAMA. 1935;104(9):746. doi:10.1001/jama.1935.02760090050019

EVIDENCE OF LATENT BRUCELLA INFECTION  The method of spread of undulant fever has been the subject of discussion for a number of years. Hardy1 and Thomsen2 maintain that direct contact with the tissues of animals harboring some form of Brucella is perhaps the most frequent source of undulant fever in man. Opportunity for detailed investigation of this problem is offered by the packing plants in which workers are exposed to possible sources of infection over long periods. In the survey by Heathman3 in Minnesota, agglutination and allergic responses as observed by a delayed type of skin reaction were used as indexes of the extent of Brucella infection. A wide discrepancy was encountered between these two criteria, the skin test showing a strikingly high percentage of positive reactions among the workers in the packing plants while agglutination decreased with the length of service in the plant; that is,