The role of Australian native wildlife in Q fever

Abstract

Q fever is a zoonosis caused by the bacterium Coxiella burnetii, mainly affecting people in close contact with domestic ruminants, which are regarded as the main source of human disease. In Australia Q fever vaccination (QFV) is recommended for traditional at-risk groups including meat and livestock industry workers, shearers and veterinarians. Australian native wildlife (in particular kangaroos) have also been implicated as a source of Q fever for humans. This research aimed to investigate this further via three arms including: a C. burnetii seroprevalence study in Australian wildlife rehabilitators (AWR); a knowledge, attitudes and practices (KAP) online survey in AWR; and a molecular investigation of tissue samples collected opportunistically from native wildlife species for the presence of C. burnetii DNA. Results of the seroprevalence study and KAP online survey demonstrated that AWR are at increased risk of C. burnetii exposure and developing Q fever. Unvaccinated AWR were more likely to become infected with C. burnetii and develop Q fever through exposure to traditional sources such as domestic ruminants, or associations with veterinary clinics whilst rehabilitating wildlife. However substantial shortfalls in vaccine uptake in AWR were identified. A low C. burnetii DNA prevalence was observed in the wildlife examined in this study who resided mostly in New South Wales. Two animals (koala and kangaroo) were classified as positive for the presence of C. burnetii DNA which amplified at relatively low concentrations. These findings suggest that macropods and other Australian native wildlife species may not be a major source of C. burnetii for humans in comparison to domestic ruminants. However given the low infectious dose and environmental stability of C. burnetii, and the potentially severe consequences of C. burnetii infection, QFV is strongly recommended for AWR, as is the implementation of measures to educate and improve vaccine uptake in this population.