Serologic evidence of L. australis A in a Georgia patient.

T HE SEROTYPE Leptospira australis A Ballico was first isolated by Cotter and Sawers (1) in 1934 in northern Queensland, Australia. It was reported recently by Derrick and others (2) as the second most common serotype in Australia and accounted for 87 percent of the leptospirosis cases that occurred in canefield workers. The principal animal carrier was found to be a native rat, Rattus conatus (3). In addition, this serotype was isolated from the kidney of a dog in Makasar by Mochtar (4) and from hedgehogs and yellowthroated mice, Apodeinus flavicollis, in Czechoslovakia by Kmety (5). No evidence of L. australis A infection was found in the United States until 1955, when two cultures isolated from raccoons in Decatur County, Ga. (6), were identified in the Communicable Disease Center's Leptospira Research Laboratory (7). Subsequently, presumptive identification has been made of 3 other isolations from raccoons and 1 from an opossum in southwestern Georgia. In August 1956 a macroscopic slide agglutination test antigen was prepared from the first L. australis A strain isolated in southwestern Georgia. The antigen was incorporated into the battery of leptospiral antigens used to screen all human and animal serums examined in the laboratory. Routine use of this antigen led to the detection of L. australis A antibodies in serum from a patient in October 1957. The history of the patient's illness and the subsequent epidemiological investigation are described in this report.