Seroprevalence of antibodies toRickettsia typhiin the Waikato region of New Zealand
SUMMARYThe first reported New Zealand-acquired case of murine typhus occurred near Auckland in 1989. Since then, 72 locally acquired cases have been recorded from northern New Zealand. By 2008, on the basis of the timing and distribution of cases, it appeared that murine typhus was escalating and spreading southwards. To explore the presence ofRickettsia typhiin the Waikato region, we conducted a seroprevalence study, using indirect immunofluorescence, Western blot, and cross-adsorption assays of blood donor samples. Of 950 human sera from Waikato, 12 (1·3%) hadR. typhiantibodies. The seroprevalence forR. typhiwas slightly higher in northern Waikato (1·4%) compared to the south (1·2%; no significant difference,χ2P= 0·768 atP< 0·05). Our results extend the reported southern range ofR. typhiby 140 km and indicate it is endemic in Waikato. Evidence of pastRickettsia felisinfections was also detected in six sera. Globally,R. felisis an emerging disease of concern and this pathogen should also be considered when locally acquired rickettsiosis is suspected. If public health interventions are to be implemented to reduce the risk of rickettsioses as a significant public health problem, improvements in rickettsial diagnostics and surveillance will be necessary.