Human leptospirosis in Croatia: current status of epidemiology and clinical characteristics

This study presents the current status of human leptospirosis in Croatia from an epidemiological and clinical viewpoint. Data from annual reports of the Croatian Institute for Public Health as well as archives of the University Hospital for Infectious Diseases 'Dr Fran Mihaljevic' (UHID) in Zagreb were used in this retrospective cohort analysis. The mean yearly incidence of leptospirosis from 1990 to 2007 was 1.83/100 000 inhabitants, with an incidence >2.5/100 000 inhabitants recorded approximately every 3-4 years, making Croatia one of the countries with the highest incidence of human leptospirosis in Europe. In addition to the majority of sporadic cases, two minor outbreaks were recorded. The clinical burden and more detailed epidemiology of 130 patients hospitalised at UHID in the period 1997-2007 were also studied. Clinical presentations were as expected, with an overall case fatality rate (CFR) of 0.77%. The most commonly established infective serovars were Australis followed by Saxkoebing and Grippotyphosa. In comparison with previous periods, the mean yearly number of patients with leptospirosis hospitalised at UHID decreased, but among them a rather higher rate of patients with Weil's disease and a higher CFR was observed.