Does the Bacillus Abortus (Bang) Infect Man?

Abstract

The frequent presence in milk of Bacillus abortus, the causative agent of contagious abortion of cattle and its pathogenicity for, or at least its ability to cause abortion in, many species of animals, raises the question whether it may not be infectious for man. Mohler and Traum1 tested the serum of forty-two persons by the agglutination and complement-fixation reaction with negative results. Fifty-six adenoids and tonsils from milk-consuming children were injected into guinea-pigs. The material from one case produced nodular areas in the liver, but cultures remained sterile. The injection of tonsils from another patient produced typical lesions in guinea-pigs and B. abortus was isolated. More recently Larson and Sedgwick2 presented further evidence of the possible infection of man. They found that some women giving a history of abortion gave a positive complement-fixation reaction using B. abortus as antigen. They also examined the blood of 425 children, and 73, or 17 per cent., gave positive reactions. These results were checked by the agglutination reaction, which gave parallel results. The positive reactions were among children having bone lesions, mostly diagnosed as tuberculosis and rickets. As they point out, inoculation of cultures into guinea-pigs produces bone lesions, which may be epiphyseal enlargements, as well as lesions of the lymphatic nodes, spleen, liver, kidney, testicle and lungs.As noted, the B. abortus has been isolated only once from human tissues. As this was a tonsil, the bacillus may have come from the milk ingested and is of no value as evidence of infection. The presence of serum reactions are suggestive, but they again are not conclusive, failing the isolation of the bacillus from the lesions. That the ingestion of bacilli in large doses may be followed by the presence of antibodies in the blood has been demonstrated by several investigators. We have had similar results in feeding guinea-pigs with typhoid bacilli.Because of these findings of Larson and Sedgwick, we have tested a large number of serums, using the agglutination reaction. This method was selected as simpler to carry out and because of the con-

The Incidence of Undulant Fever in Children

“…some authors have gone so far as to argue that Brucella infection is not caused by drinking milk because children seem to contract the disease so infrequently in spite of drinking large quantities of milk. 4 years. and 8 in children between the ages of 3 and 9 vears.…”