Science Bite (3 minute oral presentation with PPT in live session and poster) - Students, ECRs and EMCRs only 15th Lorne Infection and Immunity 2025

Evaluation of the effectiveness of a newly developed formaldehyde-inactivated Coxiella burnetii autogenous vaccine for the control of coxiellosis (Q fever) in dairy goats on an intensively managed coxiellosis-endemic farm in Australia (#316)

Charuni Dunuke Arachchilage 1 , Tarka Bhatta 2 , Eugene Athan 1 , Simon Firestone 3 , Alyssa Barry 1 , John Stenos 2 , Stephen Graves 2
  1. Deakin University, Geelong, VICTORIA, Australia
  2. Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
  3. The University of Melbourne, Melbourne, Victoria, Australia

Coxiella burnetii is the causative agent of the zoonotic disease Q fever. In Australia, dairy goat farming is associated with a higher number of Q fever infections in humans3 in which the disease manifests as a subclinical or chronic infection. In goats, the disease causes abortions, stillbirths, deformed offspring, and reduced milk production, resulting in large-scale economic losses1,2,4. This study aims to evaluate the effectiveness of the first Australian-developed formaldehyde-inactivated Coxiella burnetii autogenous vaccine in reducing the prevalence of C. burnetii shedding during parturition (birthing) in an endemically infected dairy goat farm enterprise in Victoria, which has never been documented before. The study consists of a cross-sectional study to assess C. burnetii shedding dynamics on the farm, followed by a vaccine surveillance study to evaluate the vaccine’s efficacy in reducing C. burnetii shedding during parturition. Conducted on two different farms over two birthing seasons, with vaginal, rectal swabs, blood, and milk samples collected at three time points: one month before parturition, within 24 hours of parturition, and one month after parturition. Quantitative polymerase chain reaction (qPCR) is used to quantify C. burnetii shedding, while indirect immunofluorescence assay (IFA) detects phase I and phase II IgG and IgM antibodies in plasma. Preliminary results from vaginal swabs showed that the highest levels of shedding occurred within 24 hours after parturition (Farm A, n = 87: 31.03%, 95% CI: 21.11% to 40.95%; Farm B, n = 51: 7.84%, 95% CI: 0.21% to 15.48%). The study will further investigate parity-specific prevalence and high shedders using molecular biomarkers and serological analysis. The outcomes of the study are expected to demonstrate the current prevalence of C. burnetii shedding and the ability of the vaccine to reduce the prevalence of C. burnetii shedding during parturition in vaccinated does compared to unvaccinated does.

 

  1. Álvarez-Alonso R, Basterretxea M, Barandika JF, Hurtado A, Idiazabal J, Jado I, Beraza X, Montes M, Liendo P and García-Pérez AL (2018) 'A Q fever outbreak with a high rate of abortions at a dairy goat farm: Coxiella burnetii shedding, environmental contamination, and viability', Applied and environmental microbiology, 84(20): e01650-01618.
  2. Bauer B, Prüfer L, Walter M, Ganter I, Frangoulidis D, Runge M and Ganter M (2020) 'Comparison of Coxiella burnetii excretion between sheep and goats naturally infected with one cattle-associated genotype', Pathogens, 9(8):652.
  3. Bond K, Vincent G, Wilks C, Franklin L, Sutton B, Stenos J, Cowan R, Lim K, Athan E and Harris O (2016) 'One Health approach to controlling a Q fever outbreak on an Australian goat farm', Epidemiology & Infection, 144(6):1129-1141.
  4. Palmer N, Kierstead M, Key D, Williams J, Peacock M and Vellend H (1983) 'Placentitis and abortion in goats and sheep in Ontario caused by Coxiella burnetii', The Canadian veterinary journal, 24(2):60.