Epidemiological trend of human leptospirosis in Italy between 1994 and 1996

In the three-year period 1994-1996, 222 reports on human cases of leptospir osis were received by the Italian Ministry of Health. The average annual nu mber of reports was 29.2% lower than in the preceding eight years. In all c ases but two the infections were thought to have been acquired in Italy. As in previous years, the majority of cases was observed in the northern regi ons of the country (83.8%), mostly in males (88.9%). Cases occurred in all age groups, but were more common in the working-age population (15-64 years ). There was no common-source outbreaks. The typical leptospiral seasonal c ourse, with a peak in August, was observed. During 1994, leptospirosis was the reported cause of death in 19 patients. Mortality was higher among male s than females. The overall fatality rate was 22.6%. During the study perio d, a total of 126 cases of leptospirosis were confirmed by the National Cen tre for Leptospirosis or one of the 12 Regional Leptospira Laboratories. Of the 103 patients for whom information on place of residence, contact with animals, occupational and recreational activities was available, 98 (95.1%) were people who live in rural areas or devote themselves to occupational o r recreational activities at risk. The likely source of infection and the m ode of exposure were known for 55 patients. Forty-five patients (81.8%) wer e likely infected by contaminating water (43 cases) or soil (2 cases), ten (18.2%) by direct contact with animals or animal urine. Both running (51.2% ) and stagnant water (27.9%) have been reported as a source of infection. R odents were implicated in 50.0% of the 10 cases involving animals. In compa rison with the preceding eight-year period, the risk of contracting leptosp irosis was found to have increased for recreational activities (from 34.7 t o 38.2%) and decreased for occupational activities (from 45.8 to 32.7%). A large number of infections, however, was ascribed to accidental events (25. 5%). As in the previous period, besides fever, the involvement of the liver was the most frequent clinical manifestation (70.8%). Influenza-like sympt oms were the only signs of illness in 15.1% of cases. Infections by 9 diffe rent serogroups were detected. The most frequent antibodies were those agai nst serovars icterohaemorrhagiae, poi, copenhageni and bratislava. The pres ence of co-agglutinins against serovars belonging to different serogroups p revented the identification of the presumptive infecting serogroup in 19.8% of subjects.