Leptospirosis in Hawaii: shifting trends in exposure, 1907-1984.

Leptospirosis was first recognized as an occupational disease of sugar plantation workers in Hawaii in 1907. Since then, shifts have been noted in the animal transmission cycles, the occupational groups at risk, and an increasing recognition of cases associated with avocational exposure. Surveys of the small mammal populations indicate rats, mice, and mongooses are the most important vectors in Hawaii. Serologic surveys of workers in high-risk occupations show antibody prevalence rates ranging from 12 to 82 percent. The epidemiology of leptospirosis in Hawaii is described, based on 182 cases reported to the Hawaii Department of Health from 1970-1984. The most common infecting serovar was mankarso in the Icterohaemorrhagiae serogroup; other serovars in the Icterohaemorrhagiae group were also frequently implicated as causing disease. The manifestations of disease noted by physicians in Hawaii are similar to those observed in the continental U.S. Fever, myalgia, and headache were the most common symptoms reported in the majority of cases in Hawaii; jaundice was noted in the records of 24 percent. Recommendations made to interrupt the cycle of transmission and reduce the chances of exposure in occupational settings include the control of rodent populations and vaccination of domestic animals. Personal hygiene among workers is to be encouraged, and the development of prophylactic measures is suggested either by immunization or by chemoprophylaxis.