Q fever: How common is it and how can we best prevent it?

9 November 2012

NHMRC Grant Application: APP1049558

Amount: $721,150.51 over 3 years

Dr Katrina Bosward
Dr Katrina Bosward

This is a collaborative project between veterinary and medical colleagues from NSW and Queensland to determine the importance of Q fever in the veterinary community as well as the broader Australian population. It brings together veterinarians from the University of Sydney (Assoc. Prof. Jacqui Norris, Dr Katrina Bosward, Dr Navneet Dhand), Charles Sturt University (Dr Jane Heller), the University of Queensland (Dr Rowland Cobbold) and James Cook University as well as medical colleagues from Sydney (Dr Nicholas Wood, Professor Peter McIntyre, Dr Heather Gidding, Professor Dominic Dwyer), the New England/Hunter region (Prof David Durrheim, Assoc. Prof. Stephen Graves), Brisbane (Professor Michael Nissen, Mrs Sarah Tozer, Dr Theo Sloots) and north east Queensland (Townsville, Dr Peter Massey).

Q fever is a ubiquitous zoonotic disease of worldwide importance caused by the bacterium Coxiella burnetii. It is classified as a category B bioterrorism agent and is a significant cause of acute and chronic illness in humans when identified. Traditional thinking is that domestic livestock (cattle, goats and sheep) are the main reservoir of infection however this bacterium is also found in a range of wild and domestic species including mammals, birds, and arthropods. Infected animals shed large quantities of C. burnetii into the environment through their products of conception but also via urine, milk and faeces. Humans are the species most significantly clinically affected by infection although reproductive failure is reported in cattle, sheep and goats.

Q fever has special significance for Australia because it is where the causative organism C. burnetii was discovered in the 1930s and because it is where the only available vaccine for humans (which was licensed in 1989) is used. Q fever has recently gained attention internationally due to an extensive outbreak in the Netherlands. The reluctance of the Netherlands to vaccinate humans during this outbreak highlighted the lack of knowledge about the Australian vaccine, which more than 20 years after its introduction, is used in no other country.

Australia's veterinary workforce is an ideal subset of the population to act as sentinels to the relative risk of transmission of Q fever by different animal species. They are a diverse group with variable exposures to different animal species from the traditional high risk livestock vet, to zoo vets, to jobs with minimal animal exposure. In addition, there are more than 20,000 veterinary nurses, a predominantly unvaccinated group, whose knowledge and attitudes to Q fever and barriers to vaccine uptake have never been explored. Information gained from Australian veterinary personnel on their knowledge, attitudes and assessment of risk, is essential to inform future vaccination practices for veterinarians and allied veterinary staff and the community at large.

The aims of the study are to:

a) To measure the national seroprevalence (seropositive to Q fever antibody) in purposely selected representative samples of the Australian population and describe seroprevalence by exposure and occupation risk groups.

b) To perform detailed studies of antibody and cell mediated immunity in a recurrently exposed population - veterinarians (vets), vet students and vet nurses - among whom these results can be accurately correlated with exposure history, verified Q fever related illnesses and vaccine history.

c) To perform detailed studies relevant to the use of Q fever vaccine in this sentinel population of veterinary workers - including their attitudes, knowledge, infection control practices and adverse events following Q fever vaccination.