title: Novel Chlamydiales genotypes identified in ticks from Australian wildlife.
abstract: Members of the order Chlamydiales are known for their potential as human and veterinary bacterial pathogens. Despite this recognition, epidemiological factors such as routes of transmission are yet to be fully defined. Ticks are well known vectors for many other infections with several reports recently describing the presence of bacteria in the order Chlamydiales in these arthropods. Australian wildlife are hosts to an extensive range of tick species. Evidence is also growing that the marsupial hosts these ticks parasitise can also be infected by a number of bacteria in the order Chlamydiales, with at least one species, Chlamydia pecorum, posing a significant conservation threat. In the current study, we investigated the presence and identity of Chlamydiales in 438 ixodid ticks parasitizing wildlife in Australia by screening with a pan-Chlamydiales specific targeting the 16S rRNA gene.
  
  
  
  Pan-Chlamydiales specific PCR assays confirmed the common presence of Chlamydiales in Australian ticks parasitising a range of native wildlife. Interestingly, we did not detect any Chlamydiaceae, including C. pecorum, the ubiquitous pathogen of the koala. Instead, the Chlamydiales diversity that could be resolved indicated that Australian ticks carry at least six novel Chlamydiales genotypes. Phylogenetic analysis of the 16S rRNA sequences (663 bp) of these novel Chlamydiales suggests that three of these genotypes are associated with the Simkaniaceae and putatively belong to three distinct novel strains of Fritschea spp. and three genotypes are related to the "Ca. Rhabdochlamydiaceae" and putatively belong to a novel genus, Rhabdochlamydia species and strain, respectively.
  
  
  
  Sequence results suggest Australian wildlife ticks harbour a range of unique Chlamydiales bacteria that belong to families previously identified in a range of arthropod species. The results of this work also suggest that it is unlikely that arthropods act as vectors of pathogenic members of the family Chlamydiaceae, including C. pecorum, in Australian wildlife. The biology of novel Chlamydiales identified in arthropods remain unknown. The pathogenic role of the novel Chlamydiales identified in this study and the role that ticks may play in their transmission needs to be explored further.
authors.affiliation: Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4556, Australia.
authors.forename: Delaney
authors.initials: D
authors.lastname: Burnard
authors.affiliation: Australian Government, Department of Environment and Energy, Australian Biological Resources Study, GPO Box 787, Canberra, ACT, 2601, Australia.
authors.forename: Haylee
authors.initials: H
authors.lastname: Weaver
authors.affiliation: Australia Zoo Wildlife Hospital, Steve Irwin Way, Beerwah, QLD, 4519, Australia.
authors.forename: Amber
authors.initials: A
authors.lastname: Gillett
authors.affiliation: Endeavour Veterinary Ecology Pty Ltd, 1695 Pumicestone Rd, Toorbul, QLD, 4510, Australia.
authors.forename: Joanne
authors.initials: J
authors.lastname: Loader
authors.affiliation: Port Macquarie Koala Hospital, Roto House Historic Site, Cnr Lord Street and Roto Place, Port Macquarie, 2444, NSW, Australia.
authors.forename: Cheyne
authors.initials: C
authors.lastname: Flanagan
authors.affiliation: Centre for Animal Health Innovation, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4556, Australia. apolking@usc.edu.au.
authors.forename: Adam
authors.initials: A
authors.lastname: Polkinghorne
mesh_terms: D000818:Animals; D000835:Animals, Wild; D001315:Australia / Q000453:epidemiology; D002695:Chlamydiales / Q000235:genetics*; D005260:Female; D005838:Genotype; D026863:Ixodidae / Q000382:microbiology*; D008394:Marsupialia / Q000469:parasitology*; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013984:Tick Infestations / Q000453:epidemiology / Q000662:veterinary
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Australia; Chlamydia; Chlamydia-like organisms; Marsupials; Ticks; Transmission; Vector; Wildlife