Trends and risk factors for human Q fever in Australia, 1991-2014

Abstract

Australian abattoir workers, farmers, veterinarians and people handling animal birthing products or slaughtering animals continue to be at high risk of Q fever despite an effective vaccine being available. National Notifiable Diseases Surveillance System data were analysed for the period 1991-2014, along with enhanced risk factor data from notified cases in the states of New South Wales and Queensland, to examine changes in the epidemiology of Q fever in Australia. The national Q fever notification rate reduced by 20% [incident rate ratio (IRR) 0·82] following the end of the National Q fever Management Program in 2006, and has increased since 2009 (IRR 1·01-1·34). Highest rates were in males aged 40-59 years (5·9/100 000) and 87% of Q fever cases occurred in New South Wales and Queensland. The age of Q fever cases and proportion of females increased over the study period. Based on the enhanced risk factor data, the most frequently listed occupation for Q fever cases involved contact with livestock, followed by 'no known risk' occupations. More complete and comparable enhanced risk factor data, at the State/Territory and national levels, would aid in further understanding of the epidemiology of Q fever.

Keywords: Australia; Q fever; public health surveillance; risk factors; vaccination.

Fig. 1.

Q fever notification rates by gender and age group*, Australia 1991–2014, National Notifiable Diseases Surveillance System. [* (n = 11 915) 27 cases missing gender, 218 missing date of birth so no age group could be calculated and four missing both gender and date of birth.]

Fig. 2.

Q fever notification rates for Australia (National), Queensland (Qld) and New South Wales (NSW) by year, 1991–2014, National Notifiable Diseases Surveillance System.