Leptospirosis in Western Australia, 1983-1984

The diagnosis of leptospirosis is often difficult to make because of vague and mild symptoms. Patients who present with a "flu-like" illness and who have had either direct or indirect contact with infected animals should be investigated by serological examination. In Western Australia during 1983 and 1984, the sera of 937 patients were tested for the presence of leptospiral antibodies. Of these, 131 gave positive results; in 45, these were consistent with recently acquired infection. Apart from one veterinary worker, all the cases that were diagnosed serologically occurred in farmers and meatworkers. Farmers were most often infected with serovar hardjo. Meatworkers demonstrated a high degree of cross-reactivity among serovars pomona, hardjo, and to a lesser extent, icterohaemorrhagiae. However, in cases in which the infecting serovar was identifiable serologically, serovar pomona predominated.