Arch. Inst. Pasteur de l'Afrique du Nord, 3, 48-66.

Castellani, Aldo, and Chalmers, Albert J. (1919): Manual of tropical medicine. 3d ed., 2436 pp. London.

Durham, Herbert E. (1898): Some observations on the Micrococcus melitensis (of Bruce). J. Path. & Bacteriol., 5, 377-388.

Evans, Alice C. (1918): Further studies on Bacterium abortus and related bacteria. II. A comparison of Bacterium abortus with Bacterium bronchisepticus and with the organism which causes Malta fever. III. Bacterium abortus and related bacteria in cow's milk. J. Infect. Dis., 22, 580-593; 23, 354–372.

Eyre, J. W. H. (1912): Mittelmeerfieber. In Kolle und Wassermann. Handbuch der pathogenen Mikroorganismen. 2. Aufl., Bd. 4, 423, 424.

Fleischner, E. C., Meyer, K. F., and Shaw, E. B. (1919): A résumé of some experimental studies on cutaneous hypersensitiveness. Am. J. Dis. of Children, 18, 577-590.

Jordan, Edwin O. (1912): A textbook of general bacteriology. 3d ed., 623 pp. Philadelphia and London.

Khaled, Z. (1921): A comparative study of bovine abortion and undulant fever, from the bacteriological point of view. J. Hyg., Cambridge, Eng., 20, 319–329. Meyer, K. F., and Shaw, E. B. (1920): A comparison of the morphologic, cultural, and biochemical characteristics of B. abortus and B. melitensis. Studies on the genus Brucella nov. gen. I. J. Infect. Dis., 27, 173–184. Royal Society (London) Advisory Committee (1905-1907): Reports of the Commission appointed by the Admiralty, the War Office, and the Civil Government of Malta, for the investigation of Mediterranean fever. Pts. 1-7. London.

Winslow, C.-E. A., Broadhurst, Jean, Buchanan, R. E., Krumwiede, Chas., jr., Rogers, L. A., and Smith, George H.:

(1917) The families and genera of the bacteria. Preliminary report of the Committee of the Society of American Bacteriologists on Characterization and Classification of Bacterial Types. J. Bacteriol., 2, 505–566. (1920)—The families and genera of the bacteria. Final report of 5, 191-229.

* #

Ibid.,

THE SEROLOGICAL CLASSIFICATION OF BRUCELLA MELITENSIS FROM HUMAN, BOVINE, CAPRINE, PORCINE, AND EQUINE SOURCES.

By ALICE C. EVANS, Associate Bacteriologist, Hygienic Laboratory, United States Public Health Service.

REVIEW OF THE LITERATURE.

The observation that the causative organism of Malta fever and that of contagious abortion in cattle are closely related in their morphological, cultural, biochemical, serological, and pathogenic characteristics (Evans, 1918) was confirmed by Meyer and his associates in this country, by Zeller, Jaffé and Skarić in Europe, by Khaled in Egypt, and by Burnet in Tunisia. Fleischner, Meyer, and Shaw found, further, that the test for cutaneous hypersensitiveness, which they regard as highly specific, can not differentiate between experimental infections in guinea pigs, caused by Brucella melitensis varieties abortus and melitensis. Burnet subjected four

1 See the preceding paper (pp. 1943-1948 of this issue) for a discussion of the nomenclature of this bacterial species.

Malta fever patients to the intradermal test with three Br. melitensis antigens, one prepared with the melitensis variety and two with the abortus variety—a bovine and a porcine strain, respectively. The three reactions were positive at the same time in all four cases, and in all four cases the porcine strain provoked the strongest reaction.

Fleischner, Vecki, Shaw, and Meyer compared the pathogenicity for monkeys of strains of Br. melitensis from human and from bovine sources. By feeding large doses of virulent strains of the abortus variety they were able to infect monkeys as demonstrated by isolation of the organism from the viscera and heart blood at necropsy. Br. melitensis melitensis was far more invasive, however, causing infection in comparatively small doses.

Meyer and his associates also studied the pathogenicity of the abortus and melitensis varieties of Br. melitensis for guinea pigs. They found the abortus variety slightly more invasive and virulent, as a rule, than the melitensis variety. The gross anatomic and the histologic changes were so nearly alike for the two infections, however, that they could sometimes be differentiated only by careful serologic cross absorption tests with the isolated organisms. Jaffé also found that the inflammatory changes in the case of Br. melitensis varieties abortus and melitensis infections in guinea pigs were qualitatively alike, with more pronounced changes in the case of the abortus infections. Burnet also states that he is of the impression that the abortus variety is more virulent than the melitensis variety for guinea pigs. On the contrary, Khaled found the melitensis variety much more virulent than the abortus variety for guinea pigs.

Huddleson found that the tissue changes produced in guinea pigs by virulent strains of the melitensis variety could not be distinguished from those changes produced by virulent strains of the abortus variety. Certain strains of both varieties failed, however, to produce the characteristic lesions in guinea pigs. The author attributes the lack of virulence to long cultivation in an artificial medium. It is well recognized that pathogenic bacteria lose their virulence when grown on artificial media, and this loss in virulence has been commonly noted in the organism of contagious abortion. Hence a fair comparison of the virulence of the varieties of Br. melitensis can not be made with strains whose histories differ greatly.

Khaled immunized a monkey by treating with the abortus variety and found a mild reaction to an infecting dose of the melitensis variety as compared with an untreated control monkey. This was the only record of a cross immunization experiment found in the literature.

Feusier and Meyer made a study of the agglutinin absorption reactions of 1 bovine and 11 human strains of Br. melitensis and 2 strains of paramelitensis. The strains fell into groups as follows:

Group 1: One human strain of Br. melitensis, and the one bovine strain.

Group 2: Nine human strains of Br. melitensis.

Group 3: One human strain of Br. melitensis.

Group 4: Two strains of Br. paramelitensis.

Groups 1 and 2 were so closely related that they could not be differentiated by simple agglutination tests, although certain differences were manifest in agglutinin absorption tests. Thirty-two strains isolated from aborted fetuses or pathologic discharges or milk of cattle and hogs in this country or in England all fell into group 1, according to the tests that were made. The authors state, however, that the complete absorption technique was carried out with only one strain of the abortus variety.

A review of the literature, therefore, leaves no question about the close relationship between strains of Br. melitensis from bovine and human sources.

SCOPE OF THIS STUDY,

The epidemic of Malta fever which occurred in Arizona in 1922, (reported by Lake) and a few sporadic cases which have come to our attention have renewed an interest in the causal organism of this disease. It appeared important that a larger series of human strains than that of Feusier and Meyer should be serologically classified and compared with caprine strains and with the organism causing contagious abortion in cattle and other species of domestic animals.

Accordingly, a collection of strains has been made. The sources of the strains and the date of isolation, as far as the information could be obtained, are recorded in tabular form (Table I). The writer is indebted to the many investigators whose names appear in the table for generous response when requests for cultures were made. Altogether 49 strains have been received and serologically classified.

STRAINS FROM BOVINE SOURCES.

September, 1917... Laurel, Md......

Prior to Decem- (?)....
ber, 1918.

Prior to Decem- (?)......
ber, 1918.

January, 1917..... Gambrills, Md.... Bureau of Animal Industry, U. S.

February, 1922.... Gilbert, Iowa..... Dr. S. H. McNutt, Iowa State Col

January, 1918..... Logansport, Ind.. Dr. Edgar B. Carter, Swan-Myers

485 (?).

(?).

Zurich, Switzer-
land.

497 (?).

Prior

to April, (?).

1916.

498 (?)...

Prior to May, 1920. (?)..

Co., Indianapolis, Ind. Labeled "B. abortus 101.3."

Dr. Edgar B. Carter, Swan-Myers Co., Indianapolis, Ind. Labeled "B. abortus 101.4."

Dr. Edgar B. Carter, Swan-Myers Co., Indianapolis, Ind. Labeled "B. abortus 101.5."

Dr. Edgar B. Carter, Swan-Myers Co., Indianapolis, Ind. Labeled "B. abortus 101.6."

Dr. Edgar B. Carter, Swan-Myers Co., Indianapolis, Ind. Labeled "B. abortus 101.7."

As the work progressed, new information was obtained which revealed advantages to be gained by changes in method. Such changes were made. The following description applies to the methods found to be most efficient and practicable.