Notifications of Q fever in NSW, 2001–2010 Chris P. Lowbridge A,E , Sean Tobin B , Holly Seale C and Mark J. Ferson C,D A NSW Public Health Officer Training Program, NSW Department of Health B Communicable Diseases Branch, NSW Department of Health C School of Public Health and Community Medicine, The University of New South Wales D South Eastern Sydney Illawarra Public Health Unit, NSW Health Transitional Organisation Southern E Corresponding author. Email: clowb@doh.health.nsw.gov.au Abstract: Q fever is the most frequently notified zoonotic infection in NSW residents. The past decade has seen the introduction of a targeted national Q fever vaccination program. Methods: We undertook a descriptive analysis of Q fever notifications in NSW, for the period 2001–2010. Results: A total of 1912 cases of Q fever were notified in NSW between 2001 and 2010 (average 2.8 per 100 000 persons per annum). The majority of Q fever cases were reported in men, aged 40–59 years, living in rural NSW and working in agricul- tural related occupations. Conclusion: The results suggest changes in the epidemiology of Q fever in response to the targeted vaccination program. Q fever is an important human and veterinary disease worldwide and is most significant in areas where its primary reservoir, cattle, sheep and goats, resides in close proximity to humans. In Australia, Q fever is endemic, with between 300 and 800 cases notified annually over the past decade, primarily in the eastern states. 1 In New South Wales (NSW), the majority of Q fever notifications have occurred in the rural areas of the state’s west. 2 Q fever is caused by the pathogen Coxiella burnetii, which has recently been removed from the Rickettsiales; C. burnetii is now considered more closely related to the Legionella genus. 3 Transmitted most commonly via the airborne route, the organism is carried in dust contaminated with tissue, birth fluids or excreta from infected animals. Q fever commonly presents as a self-limiting febrile illness with malaise, weakness, headache and chills. 4 The severity and duration of illness varies greatly. In up to 50% of cases infection is asymptomatic or sub-clinical. 5 Complications of Q fever include pneumonia, endocarditis, hepatitis, osteomyelitis, aseptic meningitis and encephalitis. 6 Acute infection may be followed by Q fever fatigue syndrome, which occurs in approximately 10% of cases and may persist for as long as 5 years. 7 C. burnetii is a pathogen with the potential to cause epidemics, due to its relative ease of transmission, envi- ronmental resilience, low infective dose and airborne route of transmission. 4 Outbreaks of Q fever are commonly reported. An epidemic of Q fever has been sustained in the Netherlands since 2007, with several hundred cases in humans reported each year. 8–10 Outbreaks have occurred in NSW, commonly associated with abattoir and farm workers, 11–13 but alternative sources such as veterinary practices as well as geographical clusters with no known likely source of infection have been reported anecdotally. Immunisation is the primary protective measure against Q fever. A vaccine against Q fever has been available in Australia since 1989; however, initial uptake of the vaccine was low and mostly limited to staff of several large abattoirs. The National Q Fever Management Program, an initiative of the Australian Government, was launched in 2000 and implemented in NSW in 2002. 14 The Program included funded screening and vaccination of workers in high-risk occupations and training for immunisation pro- viders. The Program initially targeted abattoir workers and shearers, but was subsequently expanded to sheep, dairy and cattle farmers along with their families. 14 The last 2 decades have seen significant change in the management of Q fever in NSW and Australia. This study sought to determine whether the implementation of the National Q Fever Management Program has altered the epidemiology of the disease since it was introduced in NSW. Methods Q fever is notifiable by laboratories under the Public Health Act 1991 (NSW). Public health units investigate all notified cases of Q fever to: collect relevant risk information; identify the likely source of infection; and, where necessary, instigate control measures. The NSW case definition for confirmed Q fever requires laboratory definitive evidence which comprises detection of C. bur- netii by nucleic acid testing or culture, or by seroconver- sion or significant rise in titre to Phase II antigen in the absence of recent vaccination. Before 2004, the detection of IgM in the absence of recent vaccination was also accepted as evidence of infection, however, since 2004, 10.1071/NB11037 Vol. 23(1–2) 2012 NSW Public Health Bulletin | 31 EpiReview