Q fever in an endemic region of North Queensland, Australia: A 10 year review

BACKGROUND: Q fever is a zoonotic infection caused by Coxiella burnetii. Endemic Q fever has long been recognised in north Queensland, with north Queensland previously acknowledged to have the highest rate of notification in Australia. In this retrospective study, we reviewed the demographics and exposure of patients diagnosed with Q fever in an endemic region of north Queensland, to identify trends and exposure factors for the acquisition of Q fever. METHODS: A retrospective study looking at patients in the region that had tested positive for Q fever by case ascertainment between 2004 and 2014. This involved both a chart review and the completion of a patient questionnaire targeting demographics, clinical presentation, risk factors and outcomes. RESULTS: There were 101 patients with a positive Q fever serology and/or PCR that were identified in the region of north Queensland that was studied, between 2004 and 2014. The cohort was residents of Mackay Hospital and Health Service. Of these, 4 patients were excluded and 63 patients successfully completed a questionnaire on demographic and risk factors. Out of the 63 patients, the highest prevalence was in the patients residing in the coastal region of Proserpine (42/100,000 people per year) followed by the Whitsundays region (14.8/100,000 people per year). A significantly higher proportion of patients were reportedly exposed to macropods (69.8%) and possums (66.7%) as compared to cattle (23.8%). A trend between increased cases of Q fever infection and high seasonal rainfall was noted. CONCLUSIONS: In this endemic region of north Queensland, exposure to wildlife and seasonal rainfall may be substantial exposure factors for the development of Q fever. The region studied is a popular tourist destination. An understanding of risk factors involved can help practitioners who see residents or returned travelers from the region, with an undifferentiated fever.