[Weil's disease, milker's fever and other leptospiroses, 1981-1987].

In The Netherlands, human leptospirosis is mainly caused by the serovars icterohaemorrhagiae and copenhageni, both of which belong to the Icterohaemorrhagiae group and originate from rats, serovars hardjo from cattle and grippotyphosa from voles. In 1981-1987, 175 cases of leptospirosis were registered. In 17 of these cases the infection was acquired outside The Netherlands. Infections caused by serovars from the Icterohaemorrhagiae group were mainly observed in the province of Zuid-Holland, hardjo infections in the province of Friesland. The number of hardjo infections increased. Hardjo also causes problems in cattle. Infections caused by serovars icterohaemorrhagiae and copenhageni were mainly associated with exposure to inland surface waters in relation with recreational or professional activities or accidents. Hardjo infections were characteristically associated with dairy farming. The incidences of all types of leptospirosis were highest in late summer and early autumn.