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Huggins LG, Koehler AV, Gasser RB, Traub RJ. Advanced approaches for the diagnosis and chemoprevention of canine vector-borne pathogens and parasites-Implications for the Asia-Pacific region and beyond. ADVANCES IN PARASITOLOGY 2023; 120:1-85. [PMID: 36948727 DOI: 10.1016/bs.apar.2022.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Vector-borne pathogens (VBPs) of canines are a diverse range of infectious agents, including viruses, bacteria, protozoa and multicellular parasites, that are pernicious and potentially lethal to their hosts. Dogs across the globe are afflicted by canine VBPs, but the range of different ectoparasites and the VBPs that they transmit predominate in tropical regions. Countries within the Asia-Pacific have had limited prior research dedicated to exploring the epidemiology of canine VBPs, whilst the few studies that have been conducted show VBP prevalence to be high, with significant impacts on dog health. Moreover, such impacts are not restricted to dogs, as some canine VBPs are zoonotic. We reviewed the status of canine VBPs in the Asia-Pacific, with particular focus on nations in the tropics, whilst also investigating the history of VBP diagnosis and examining recent progress in the field, including advanced molecular methods, such as next-generation sequencing (NGS). These tools are rapidly changing the way parasites are detected and discovered, demonstrating a sensitivity equal to, or exceeding that of, conventional molecular diagnostics. We also provide a background to the armoury of chemopreventive products available for protecting dogs from VBP. Here, field-based research within high VBP pressure environments has underscored the importance of ectoparasiticide mode of action on their overall efficacy. The future of canine VBP diagnosis and prevention at a global level is also explored, highlighting how evolving portable sequencing technologies may permit diagnosis at point-of-care, whilst further research into chemopreventives will be essential if VBP transmission is to be effectively controlled.
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Affiliation(s)
- Lucas G Huggins
- Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia.
| | - Anson V Koehler
- Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
| | - Robin B Gasser
- Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
| | - Rebecca J Traub
- Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, The University of Melbourne, Parkville, VIC, Australia
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2
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Ghafar A, Davies N, Tadepalli M, Breidahl A, Death C, Haros P, Li Y, Dann P, Cabezas-Cruz A, Moutailler S, Foucault-Simonin A, Gauci CG, Stenos J, Hufschmid J, Jabbar A. Unravelling the Diversity of Microorganisms in Ticks from Australian Wildlife. Pathogens 2023; 12:pathogens12020153. [PMID: 36839425 PMCID: PMC9967841 DOI: 10.3390/pathogens12020153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/28/2022] [Accepted: 01/02/2023] [Indexed: 01/19/2023] Open
Abstract
Ticks and tick-borne pathogens pose a significant threat to the health and welfare of humans and animals. Our knowledge about pathogens carried by ticks of Australian wildlife is limited. This study aimed to characterise ticks and tick-borne microorganisms from a range of wildlife species across six sites in Victoria, Australia. Following morphological and molecular characterisation (targeting 16S rRNA and cytochrome c oxidase I), tick DNA extracts (n = 140) were subjected to microfluidic real-time PCR-based screening for the detection of microorganisms and Rickettsia-specific real-time qPCRs. Five species of ixodid ticks were identified, including Aponomma auruginans, Ixodes (I.) antechini, I. kohlsi, I. tasmani and I. trichosuri. Phylogenetic analyses of 16S rRNA sequences of I. tasmani revealed two subclades, indicating a potential cryptic species. The microfluidic real-time PCR detected seven different microorganisms as a single (in 13/45 ticks) or multiple infections (27/45). The most common microorganisms detected were Apicomplexa (84.4%, 38/45) followed by Rickettsia sp. (55.6%, 25/45), Theileria sp. (22.2% 10/45), Bartonella sp. (17.8%, 8/45), Coxiella-like sp. (6.7%, 3/45), Hepatozoon sp. (2.2%, 1/45), and Ehrlichia sp. (2.2%, 1/45). Phylogenetic analyses of four Rickettsia loci showed that the Rickettsia isolates detected herein potentially belonged to a novel species of Rickettsia. This study demonstrated that ticks of Australian wildlife carry a diverse array of microorganisms. Given the direct and indirect human-wildlife-livestock interactions, there is a need to adopt a One Health approach for continuous surveillance of tick-associated pathogens/microorganisms to minimise the associated threats to animal and human health.
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Affiliation(s)
- Abdul Ghafar
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
- Correspondence:
| | - Nick Davies
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
| | - Mythili Tadepalli
- Australian Rickettsial Reference Laboratory, Barwon Health, Geelong, VIC 3220, Australia
| | - Amanda Breidahl
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
| | - Clare Death
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
| | - Philip Haros
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
| | - Yuting Li
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
| | - Peter Dann
- Research Department, Phillip Island Nature Park, P.O. Box 97, Cowes, VIC 3922, Australia
| | - Alejandro Cabezas-Cruz
- Anses, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Laboratoire de Santé Animale, F-94700 Maisons-Alfort, France
| | - Sara Moutailler
- Anses, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Laboratoire de Santé Animale, F-94700 Maisons-Alfort, France
| | - Angélique Foucault-Simonin
- Anses, INRAE, Ecole Nationale Vétérinaire d’Alfort, UMR BIPAR, Laboratoire de Santé Animale, F-94700 Maisons-Alfort, France
| | - Charles G. Gauci
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Barwon Health, Geelong, VIC 3220, Australia
| | - Jasmin Hufschmid
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
| | - Abdul Jabbar
- Department of Veterinary Biosciences, Melbourne Veterinary School, University of Melbourne, Werribee, VIC 3030, Australia
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Greay TL, Evasco KL, Evans ML, Oskam CL, Magni PA, Ryan UM, Irwin PJ. Illuminating the bacterial microbiome of Australian ticks with 16S and Rickettsia-specific next-generation sequencing. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2022; 1:100037. [PMID: 35284883 PMCID: PMC8906098 DOI: 10.1016/j.crpvbd.2021.100037] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/20/2021] [Accepted: 06/04/2021] [Indexed: 12/27/2022]
Abstract
Next-generation sequencing (NGS) studies show that mosquito and tick microbiomes influence the transmission of pathogens, opening new avenues for vector-borne pathogen control. Recent microbiological studies of Australian ticks highlight fundamental knowledge gaps of tick-borne agents. This investigation explored the composition, diversity and prevalence of bacteria in Australian ticks (n = 655) from companion animals (dogs, cats and horses). Bacterial 16S NGS was used to identify most bacterial taxa and a Rickettsia-specific NGS assay was developed to identify Rickettsia species that were indistinguishable at the V1-2 regions of 16S. Sanger sequencing of near full-length 16S was used to confirm whether species detected by 16S NGS were novel. The haemotropic bacterial pathogens Anaplasma platys, Bartonella clarridgeiae, “Candidatus Mycoplasma haematoparvum” and Coxiella burnetii were identified in Rhipicephalus sanguineus (s.l.) from Queensland (QLD), Western Australia, the Northern Territory (NT), and South Australia, Ixodes holocyclus from QLD, Rh. sanguineus (s.l.) from the NT, and I. holocyclus from QLD, respectively. Analysis of the control data showed that cross-talk compromises the detection of rare species as filtering thresholds for less abundant sequences had to be applied to mitigate false positives. A comparison of the taxonomic assignments made with 16S sequence databases revealed inconsistencies. The Rickettsia-specific citrate synthase gene NGS assay enabled the identification of Rickettsia co-infections with potentially novel species and genotypes most similar (97.9–99.1%) to Rickettsia raoultii and Rickettsia gravesii. “Candidatus Rickettsia jingxinensis” was identified for the first time in Australia. Phylogenetic analysis of near full-length 16S sequences confirmed a novel Coxiellaceae genus and species, two novel Francisella species, and two novel Francisella genotypes. Cross-talk raises concerns for the MiSeq platform as a diagnostic tool for clinical samples. This study provides recommendations for adjustments to Illuminaʼs 16S metagenomic sequencing protocol that help track and reduce cross-talk from cross-contamination during library preparation. The inconsistencies in taxonomic assignment emphasise the need for curated and quality-checked sequence databases. Bacterial pathogens identified in ticks from companion animals with 16S NGS. Sanger sequencing confirmed novel Coxiellaceae gen. sp. and Francisella. “Candidatus Rickettsia jingxinensis” was identified with Rickettsia-specific NGS. Comparison of taxonomic assignments in 16S sequence databases revealed errors. Modifications to the 16S metagenomic library protocol (Illumina) are provided.
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Affiliation(s)
- Telleasha L Greay
- College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia.,Western Australian State Agricultural Biotechnology Centre, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia.,Executive Consultant, EpiSeq, PO Box 357, Kwinana, Western Australia, 6966, Australia
| | - Kimberly L Evasco
- College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia.,Western Australian State Agricultural Biotechnology Centre, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia.,A/Senior Scientific Officer, Medical Entomology Unit, Department of Health, 1A Brockway Road, Mount Claremont, Western Australia, 6010, Australia
| | - Megan L Evans
- College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia.,Western Australian State Agricultural Biotechnology Centre, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia.,Cardio Respiratory Sleep, Level 1, 52-54 Monash Avenue, Nedlands, Western Australia, 6009, Australia
| | - Charlotte L Oskam
- College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia.,Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Paola A Magni
- College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia.,Murdoch University Singapore, King's Centre, 390 Havelock Road, Singapore, 169662, Republic of Singapore
| | - Una M Ryan
- College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
| | - Peter J Irwin
- College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, Western Australia, 6150, Australia
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Vásquez-Aguilar AA, Barbachano-Guerrero A, Angulo DF, Jarquín-Díaz VH. Phylogeography and population differentiation in Hepatozoon canis (Apicomplexa: Hepatozoidae) reveal expansion and gene flow in world populations. Parasit Vectors 2021; 14:467. [PMID: 34521451 PMCID: PMC8439048 DOI: 10.1186/s13071-021-04924-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hepatozoon canis is a protozoan transmitted to dogs and other wild carnivores by the ingestion of ticks containing mature oocysts and is considered the principal cause of canine hepatozoonosis in the world. Here, we examined ribosomal RNA 18S gene sequence variation to determine the genetic differences and phylogeographic diversity of H. canis from various geographical areas around the world. METHODS We used 550 publicly available sequences of H. canis from 46 countries to assess haplotype relationships, geographical structure, genetic diversity indices, and relationships among populations. We performed neutrality tests and pairwise comparisons of fixation index (FST) values between groups and pairwise comparisons of FST values between populations. To determine whether populations are structured, analyses of molecular variance (AMOVAs) and spatial analysis of molecular variance (SAMOVA) were performed. RESULTS The dataset of H. canis yielded 76 haplotypes. Differentiation among populations indicated that there is no phylogeographical structure (GST = 0.302 ± 0.0475). Moreover, when samples were grouped by continents a significant FST was obtained, meaning that populations were genetically differentiated. The AMOVA showed that 57.4% of the genetic variation was explained by differences within populations when all locations were treated as a single group and revealed that there is no population structure when populations are grouped into two, three, and four groups (FCT, p > 0.05), suggesting that dispersal between populations is high. SAMOVA revealed significant FCT values for groups K = 5. The Tajima's D and Fu's Fs show that populations have undergone recent expansion, and the mismatch distribution analysis showed population expansion (multimodal distribution). CONCLUSIONS The current molecular data confirmed that H. canis does not show phylogeographic or population structure. The haplotypes exhibit low genetic differentiation, suggesting a recent expansion due to gene flow among populations. These results provide pivotal information required for future detailed population genetic analysis or to establish control strategies of this parasite.
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Affiliation(s)
- Antonio Acini Vásquez-Aguilar
- Red de Biología Evolutiva, Instituto de Ecología, 91073 Xalapa, Veracruz Mexico
- Centro de Investigaciones Tropicales, Universidad Veracruzana, Xalapa, Veracruz 91000 México
| | | | - Diego F. Angulo
- Red de Biología Evolutiva, Instituto de Ecología, 91073 Xalapa, Veracruz Mexico
| | - Víctor Hugo Jarquín-Díaz
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association and the Charité-Universitätsmedizin Berlin, Berlin, Germany
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Experimental and Clinical Research Center, Lindenberger Weg 80, 13125 Berlin, Germany
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
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Novel High-Throughput Multiplex qPCRs for the Detection of Canine Vector-Borne Pathogens in the Asia-Pacific. Microorganisms 2021; 9:microorganisms9051092. [PMID: 34069665 PMCID: PMC8161336 DOI: 10.3390/microorganisms9051092] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 01/10/2023] Open
Abstract
The Asia-Pacific hosts a large diversity of canine vector-borne pathogens (VBPs) with some of the most common and most pathogenic, generating significant mortality as well as a spectrum of health impacts on local dog populations. The VBPs Anaplasma platys, Babesia gibsoni, Babesia vogeli, Ehrlichia canis, Hepatozoon canis and haemotropic Mycoplasma spp. are all endemic throughout the region, with many exhibiting shifting geographical distributions that warrant urgent attention. Moreover, many of these species cause similar clinical signs when parasitising canine hosts, whilst knowledge of the exact pathogen is critical to ensure treatment is effective. This is complicated by frequent coinfection that can exacerbate pathology. Here, we describe the development, optimisation and validation of two novel quadruplex Taq-Man based real-time PCRs (qPCRs) for the specific and sensitive detection of the aforementioned VBPs. To ensure accurate evaluation of diagnostic performance, results of our qPCRs were evaluated on field samples from Thai dogs and compared with both conventional PCR (cPCR) results and next-generation sequencing (NGS) metabarcoding. Our qPCRs were found to be more sensitive at detecting canine VBP than cPCR and generated results similar to those achieved by NGS. These qPCRs will provide a valuable high-throughput diagnostic tool available to epidemiologists, researchers and clinicians for the diagnosis of key canine VBPs in the Asia-Pacific and further afield.
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Egan SL, Taylor CL, Austen JM, Banks PB, Northover AS, Ahlstrom LA, Ryan UM, Irwin PJ, Oskam CL. Haemoprotozoan surveillance in peri-urban native and introduced wildlife from Australia. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2021; 1:100052. [PMID: 35284862 PMCID: PMC8906138 DOI: 10.1016/j.crpvbd.2021.100052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/30/2021] [Accepted: 09/22/2021] [Indexed: 01/15/2023]
Affiliation(s)
- Siobhon L. Egan
- Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia
- Corresponding author.
| | - Casey L. Taylor
- School of Life and Environmental Sciences, Camperdown, The University of Sydney, New South Wales, 2006, Australia
| | - Jill M. Austen
- Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Peter B. Banks
- School of Life and Environmental Sciences, Camperdown, The University of Sydney, New South Wales, 2006, Australia
| | - Amy S. Northover
- College of Veterinary Medicine, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Liisa A. Ahlstrom
- Elanco Animal Health, Macquarie Park, New South Wales, 2113, Australia
| | - Una M. Ryan
- Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Peter J. Irwin
- Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia
- College of Veterinary Medicine, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Charlotte L. Oskam
- Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia
- Corresponding author.
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Helm CS, Samson-Himmelstjerna GV, Liesner JM, Kohn B, Müller E, Schaper R, Pachnicke S, Schulze C, Krücken J. Identical 18S rRNA haplotypes of Hepatozoon canis in dogs and foxes in Brandenburg, Germany. Ticks Tick Borne Dis 2020; 11:101520. [PMID: 32993940 DOI: 10.1016/j.ttbdis.2020.101520] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/14/2020] [Accepted: 07/23/2020] [Indexed: 02/06/2023]
Abstract
Hepatozoon canis is a blood parasite of the suborder Adeleorina infecting wild and domestic canids. Transmission occurs by oral uptake of Rhipicephalus sanguineus sensu lato vector ticks infected with H. canis, but vertical transmission is also assumed to be possible. In German foxes, a high prevalence of H. canis has previously been reported despite the fact that R. sanguineus s.l. is not endemic. In the absence of knowledge about local transmission pathways, foxes should be considered to be possible reservoirs of H. canis and contribute to infection of domestic dogs. The present study aimed to determine how often foxes and dogs are infected in Brandenburg (Germany) and if identical or different H. canis 18S rRNA haplotypes are found in these host species. Hepatozoon spp. were detected by PCR in 46/1050 (4.4 %) of dog blood and 176/201 (77.6 %) of fox spleen samples from Brandenburg. Sequencing of 19 dog and 56 fox samples identified all as H. canis. For nine positive dogs, owners stated that they had never left Germany suggesting that autochthonous transmission occurs not only in foxes but also in dogs. Sequences for seven of these possible autochthonous cases were obtained and six were identical to the predominant haplotype found in the foxes. Haplotype network analysis confirmed that many dogs, including some without travel history, carried the same or very similar 18S rRNA haplotypes as the foxes suggesting that both hosts participate in the same epidemiological cycle.
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Affiliation(s)
- Christina S Helm
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | | | - Jana M Liesner
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Barbara Kohn
- Small Animal Clinic, Freie Universität Berlin, Berlin, Germany
| | | | | | | | | | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
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The brown dog tick Rhipicephalus sanguineus sensu Roberts, 1965 across Australia: Morphological and molecular identification of R. sanguineus s.l. tropical lineage. Ticks Tick Borne Dis 2019; 11:101305. [PMID: 31594688 DOI: 10.1016/j.ttbdis.2019.101305] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/13/2019] [Accepted: 09/21/2019] [Indexed: 12/14/2022]
Abstract
The brown dog tick Rhipicephalus sanguineus (Latreille, 1806) is the most widely distributed tick species globally. Throughout the world there are at least two divergent lineages on dogs that are traditionally grouped into what was known as R. sanguineus. The species R. sanguineus was recently redescribed using a neotype reported from countries with a temperate climate. The second lineage distributed in countries with primarily tropical climates is currently designated R. sanguineus s.l. tropical lineage. Here, we present a comprehensive genetic evaluation of Australian brown dog ticks from across the continent that complements the morphological study of R. sanguineus sensu Roberts (1965). A total of 294 ticks were collected from dogs around Australia - including New South Wales, Queensland, the Northern Territory and Western Australia - for morphological identification. All ticks were morphologically identified as R. sanguineus sensu Roberts (1965). DNA was isolated from a single leg from morphologically characterised individuals from New South Wales (n = 14), Queensland (n = 18), Northern Territory (n = 7) and Western Australia (n = 13), together with ticks from Fiji (n = 1) and the Seychelles (n = 1) for comparison with Australian ticks. The study revealed three cox1 haplotypes clustered only with R. sanguineus s.l. tropical lineage'. An updated distribution of R. sanguineus sensu Roberts (1965) is compared to the 1965 distribution. In the Australian context, R. sanguineus s.l. has appeared in north-western New South Wales but remains absent from coastal New South Wales. Despite both temperate and tropical climates being present in Australia, only R. sanguineus s.l. tropical lineage was found. The evidence does not support the presence of the strictly defined brown dog tick, R. sanguineus by Nava et al. (2018) in Australia, because the examined ticks are genetically and morphologically distinct. We recommend using the term brown dog tick, R. sanguineus sensu Roberts (1965) for specimens from Australia.
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