Ticks and Tick-Borne Microorganisms in Australian Wildlife: A Scoping One Health Evidence Synthesis of Reported Associations and Knowledge Gaps.

Ticks are haematophagous ectoparasites and vectors of a diverse range of pathogens, exerting substantial impacts on wildlife, domestic animals and public health. In Australia, despite the country's rich and unique biodiversity, a comprehensive understanding of ticks and tick-borne pathogens associated with wildlife remains limited. Environmental change, urban expansion and climate variability are increasingly disrupting wildlife habitats, potentially intensifying interactions between wildlife hosts, ticks and humans. A broad evidence synthesis of studies published between January 1940 and March 2024 was conducted, retrieving 133 eligible records from Web of Science, CABI Abstracts and PubMed databases. Fifty tick species parasitising 160 wildlife species were identified, predominantly from the genera Ixodes, Amblyomma and Haemaphysalis. The most commonly reported hosts included marsupials, particularly bandicoots, wallabies and possums, with notable tick species being Ixodes tasmani, Ixodes holocyclus and Amblyomma triguttatum. Microorganism records were relatively limited and mostly represented molecular detections or reported associations, including Babesia, Borrelia, Coxiella, Rickettsia and Theileria species, rather than confirmed vector competence, reservoir status or pathogenicity. Key limitations included geographic sampling biases towards eastern Australia, limited molecular identification of ticks and infrequent pathogen screening, particularly regarding the ecology, epidemiology and molecular diversity of host-vector-microorganism interactions. Improved surveillance, expanded molecular characterisation, and integrated One Health investigations are required to better understand the ecological and public health significance of these host-vector-microorganism interactions.