Q fever risk significantly higher on regional and remote farms

By Bianca Nogrady 
Adults living on farms in regional and remote areas of Australia are at significantly greater risk of contracting Q fever, research suggests.

Data from a large Australian population-based cohort study (the 45 and Up Study) of 266,906 adults living across New South Wales found participants living on a farm in an outer regional or remote area had an 11-fold greater risk of contracting Q fever compared with those living in inner regional areas but not on farms.

The incidence of Q fever was also significantly lower in individuals aged over 65 years and women, according to the study findings published in the Medical Journal of Australia.

Overall, the study found an incidence of notified Q fever of 3.6 cases per 100,000 person-years.

Q fever, a highly infectious disease caused by Coxiella burnetii, with domestic and wild animals being the main reservoirs of infection, most often presents as an acute flu-like illness but can also present as pneumonia or hepatitis, or can even be asymptomatic. About 5% of symptomatic patients present with endocarditis, and Q fever fatigue is the most frequently reported consequence of acute infection, occurring in 10 to 20% of cases, the researchers wrote.

Lead author Dr Surendra Karki said previous studies of Q fever incidence looked at specific occupational groups known to be at risk, whereas this study was a broader, population-based analysis.

‘There is a big problem of Q fever in animal farms and in recent years we have been seeing a slight rise in the number of cases,’ said Dr Karki, research fellow at the School of Public Health at UNSW, Sydney.

Dr Karki told Medicine Today that the finding of an increased risk in people living on farms had implications for targeting vaccination campaigns against the disease, given that an earlier campaign only achieved around a 40% uptake in farmers.

‘Our recommendation is that there should be broader targeting of people living in outer regional and remote areas, and doctors who work in rural areas should be made more aware of possible Q fever infections,’ Dr Karki said.

He noted that we should also be educating people in the community in regional areas about Q fever so that they are more likely to attend for screening or vaccination. 

Med J Aust 2015; 203, doi: 10.5694/mja15.00391.

Picture credit: © NIAID/CDC/SPL. Coxiella burnetii (TEM).