EPIDEMIOLOGY OF LEPTOSPIROSIS IN NEW-CALEDONIA (SOUTH-PACIFIC) - A ONE-YEAR SURVEY

We describe a series of 144 cases of leptospirosis diagnosed in 1989 i n New Caledonia. The incidence rate was 90 per 100,000 person-years, w ith a specific mortality rate of 4% patients. Those affected (100 male s, 44 females) were mainly aged 20 to 40 years. Incidence in rural are as (112 per 100,000 person-years) was seven times higher than in urban settlements. Two periods with higher incidence were noticed correspon ding to highest rainfall; Twenty-nine of the cases occurred in individ uals with professions commonly associated with leptospirosis. Contacts with rats, dogs and ditch or river water were the most frequently men tioned. The clinical expression of the disease was polymorphic: 60% of the patients had mild symptoms, 40% were acute forms including Well's disease. Of 57 hospitalized, 23% were admitted with an initial diagno sis of dengue, and 37% with leptospirosis. Main clinical syndromes wer e: icterus and/or renal syndrome in 50% of patients, cardiac syndrome in 65%, acute myalgies in 58% and pulmonary syndrome in 50%. Although hemorrhages were uncommon (17%), 40% of the cases demonstrated thrombo cytopenia (< 50,000/m(3)). Pancreatic involvement with hyperamylasemia was evidenced in 50% of cases. Twelve serogroups of Leptospira were i mplicated, Icterohaemorragiae predominated (41%), but was not associat ed with severe forms. In New Caledonia, like in all tropics, leptospir osis must be considered as an environmental disease, professional acti vities being just an additional risk factor. Use of serology as a reli able tool for confirmation of cases in areas of high environmental con tamination is discussed.