One Health approach to controlling a Q fever outbreak on an Australian goat farm

Abstract

SUMMARYA recent outbreak of Q fever was linked to an intensive goat and sheep dairy farm in Victoria, Australia, 2012-2014. Seventeen employees and one family member were confirmed with Q fever over a 28-month period, including two culture-positive cases. The outbreak investigation and management involved a One Health approach with representation from human, animal, environmental and public health. Seroprevalence in non-pregnant milking goats was 15% [95% confidence interval (CI) 7–27]; active infection was confirmed by positive quantitative PCR on several animal specimens. Genotyping of Coxiella burnetii DNA obtained from goat and human specimens was identical by two typing methods. A number of farming practices probably contributed to the outbreak, with similar precipitating factors to the Netherlands outbreak, 2007-2012. Compared to workers in a high-efficiency particulate arrestance (HEPA) filtered factory, administrative staff in an unfiltered adjoining office and those regularly handling goats and kids had 5·49 (95% CI 1·29–23·4) and 5·65 (95% CI 1·09–29·3) times the risk of infection, respectively; suggesting factory workers were protected from windborne spread of organisms. Reduction in the incidence of human cases was achieved through an intensive human vaccination programme plus environmental and biosecurity interventions. Subsequent non-occupational acquisition of Q fever in the spouse of an employee, indicates that infection remains endemic in the goat herd, and remains a challenge to manage without source control.

Seroprevalence and Factors Associated with Coxiella burnetii Infection in Small Ruminants in Baringo County, Kenya

“…Although a direct link between the human C. burnetii cases previously reported in the study region, and the C. burnetii seropositive domestic small ruminants in the current study could not be established, there is a plausible zoonotic public health risk link of animal to human transmission which may need further investigation (Chang et al., ; Dean et al., ; De Lange et al., ; Bond et al., ).…”

Bayesian Validation of the Indirect Immunofluorescence Assay and Its Superiority to the Enzyme-Linked Immunosorbent Assay and the Complement Fixation Test for Detecting Antibodies against Coxiella burnetii in Goat Serum

“…All procedures performed in studies involving animals were in accordance with the ethical standards of the University of Melbourne [University of Melbourne Animal Ethics Committee approval number 1413118].) The herd had previously tested positive for C. burnetii antibodies in serum using CFT testing and had also tested positive for C. burnetii DNA in air samples, vaginal swabs, and placenta samples using PCR (42). There were also 22 laboratory-confirmed human cases of acute Q fever associated with the farm (42).…”

“…The herd had previously tested positive for C. burnetii antibodies in serum using CFT testing and had also tested positive for C. burnetii DNA in air samples, vaginal swabs, and placenta samples using PCR (42). There were also 22 laboratory-confirmed human cases of acute Q fever associated with the farm (42). Two-fold serial dilutions of the serum samples, from 1:40 to 1:40,960, were prepared and tested in duplicate using the IFA to determine the endpoint titer above which no antibodies to C. burnetii were detected in each of the samples.…”

One Health research and training in Australia and New Zealand

“…The majority of research in Australia tends to focus on analysis of notified cases (35), unusual outbreaks, (36, 37), or animal and environmental sources (38). However, a recent study by Bond et al (39) demonstrated the application and outcomes of taking a One Health approach to an outbreak associated with a goat farm. The outbreak investigation and its management involved a team representing animal, environmental, and public health professionals.…”

“…The outbreak investigation and its management involved a team representing animal, environmental, and public health professionals. Activities included serological and molecular studies to characterise transmission followed by an evaluation of farming practices to identify points of intervention (39). An intensive human vaccination programme plus environmental and biosecurity interventions was credited with resolving the outbreak (39).…”