Molecular Detection and Characterisation of Coxiella burnetii in Koala (Phascolarctos cinereus) Urogenital Tract Swabs

Karen O Mathews; David Phalen; Paul A Sheehy; Jacqueline M Norris; Damien P Higgins; Katrina L Bosward

doi:10.3390/pathogens13100873

Molecular Detection and Characterisation of Coxiella burnetii in Koala (Phascolarctos cinereus) Urogenital Tract Swabs

Pathogens. 2024 Oct 4;13(10):873. doi: 10.3390/pathogens13100873.

Authors

Karen O Mathews¹, David Phalen^{1

2}, Paul A Sheehy¹, Jacqueline M Norris^{1

3}, Damien P Higgins^{1

2}, Katrina L Bosward^{1

3}

Affiliations

¹ Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia.
² Koala Health Hub, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia.
³ Sydney Infectious Diseases Institute, The University of Sydney, Sydney, NSW 2006, Australia.

Abstract

Q fever is a zoonosis caused by Coxiella burnetii, primarily affecting those in close contact with domestic ruminants, the main source of human infection. Coxiella burnetii has also been detected in various wildlife species globally. In Australia, serological and molecular studies have shown exposure to and infection by C. burnetii in macropods, bandicoots, and koalas. However, the extent to which these species contribute to human infection remains unclear. An unpublished public health investigation into a Q fever case in a person involved in koala care could not conclusively link the infection to koalas due to the patient's broad animal exposure. This study aimed to explore the potential role of koalas in transmitting C. burnetii to humans by investigating the presence of C. burnetii DNA in urogenital tract (UGT) swabs from koalas. DNA was extracted from UGT swabs from koalas in three regions in New South Wales, Australia. An optimised multiplex qPCR assay detected C. burnetii DNA in 2 out of 225 samples (0.89%) at approximately 10 genome equivalents per reaction. Both positive samples amplified all three gene targets. MLVA genotyping identified two distinct C. burnetii genotypes previously isolated from Australian Q fever cases. These findings highlight the need for vaccination against Q fever for those in close contact with koalas.

Keywords: Australia; Coxiella burnetii; Q fever; koalas; urogenital swabs; wildlife rehabilitators.

Grants and funding

This research was funded by a Sydney Infectious Diseases (formerly Marie Bashir) Institute 2017 Zoonoses Node Seed Funding Grant. We would like to offer our sincere thanks and appreciation to Ramune “Rami” Cobb and Pfizer International Inc. for their support of our research into understanding Q fever. The koala specimen archive and Andrea Casteriano, who curates it, were supported financially by Koala Conservation Australia andthe Wildlife Information Rescue and Education Service (WIRES NSW).