A retrospective review of notified human leptospirosis cases in the Waikato region of New Zealand, 2004 to 2010.

AIM: To retrospectively review notified human leptospirosis cases in the Waikato region of New Zealand between 2004 and 2010 and to identify risk factors for human leptospirosis infection.

METHOD: Waikato leptospirosis notification data for the period 1 January 2004 to 31 December 2010 were analysed to identify any trends in the rates and distribution of key variables.

RESULTS

Annual Waikato leptospirosis notification rates were consistently higher than national rates. Infection was associated with males (93%) of working age (97%) who had exposure to animals through their occupation. Most cases were employed in dry stock farming, dairy farming or in the meat processing industry.

CONCLUSION

Those who work with cattle continue to be at risk of infection from Leptospira. The data suggests that dry stock cattle farmers are at the highest risk. It is speculated that the immunisation of all cattle herds may further reduce the incidence of leptospirosis, although more accurate collection of work exposure data and further analysis is needed to determine this.