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Taylor CL, Egan SL, Gofton AW, Irwin PJ, Oskam CL, Hochuli DF, Banks PB. An invasive human commensal and a native marsupial maintain tick populations at the urban fringe. MEDICAL AND VETERINARY ENTOMOLOGY 2023; 37:460-471. [PMID: 36718907 DOI: 10.1111/mve.12643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
Ticks (Acari: Ixodidae) are major disease vectors globally making it increasingly important to understand how altered vertebrate communities in urban areas shape tick population dynamics. In urban landscapes of Australia, little is known about which native and introduced small mammals maintain tick populations preventing host-targeted tick management and leading to human-wildlife conflict. Here, we determined (1) larval, nymphal, and adult tick burdens on host species and potential drivers, (2) the number of ticks supported by the different host populations, and (3) the proportion of medically significant tick species feeding on the different host species in Northern Sydney. We counted 3551 ticks on 241 mammals at 15 sites and found that long-nosed bandicoots (Perameles nasuta) hosted more ticks of all life stages than other small mammals but introduced black rats (Rattus rattus) were more abundant at most sites (33%-100%) and therefore important in supporting larval and nymphal ticks in our study areas. Black rats and bandicoots hosted a greater proportion of medically significant tick species including Ixodes holocyclus than other hosts. Our results show that an introduced human commensal contributes to maintaining urban tick populations and suggests ticks could be managed by controlling rat populations on urban fringes.
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Affiliation(s)
- Casey L Taylor
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, New South Wales, Australia
| | - Siobhon L Egan
- Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, Murdoch, Western Australia, Australia
| | | | - Peter J Irwin
- Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, Murdoch, Western Australia, Australia
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
| | - Charlotte L Oskam
- Centre for Biosecurity and One Health, Harry Butler Institute, Murdoch University, Murdoch, Western Australia, Australia
| | - Dieter F Hochuli
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, New South Wales, Australia
| | - Peter B Banks
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, New South Wales, Australia
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Egan SL, Taylor CL, Banks PB, Northover AS, Ahlstrom LA, Ryan UM, Irwin PJ, Oskam CL. The bacterial biome of ticks and their wildlife hosts at the urban-wildland interface. Microb Genom 2021; 7. [PMID: 34913864 PMCID: PMC8767321 DOI: 10.1099/mgen.0.000730] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Advances in sequencing technologies have revealed the complex and diverse microbial communities present in ticks (Ixodida). As obligate blood-feeding arthropods, ticks are responsible for a number of infectious diseases that can affect humans, livestock, domestic animals and wildlife. While cases of human tick-borne diseases continue to increase in the northern hemisphere, there has been relatively little recognition of zoonotic tick-borne pathogens in Australia. Over the past 5 years, studies using high-throughput sequencing technologies have shown that Australian ticks harbour unique and diverse bacterial communities. In the present study, free-ranging wildlife (n=203), representing ten mammal species, were sampled from urban and peri-urban areas in New South Wales (NSW), Queensland (QLD) and Western Australia (WA). Bacterial metabarcoding targeting the 16S rRNA locus was used to characterize the microbiomes of three sample types collected from wildlife: blood, ticks and tissue samples. Further sequence information was obtained for selected taxa of interest. Six tick species were identified from wildlife: Amblyomma triguttatum, Ixodes antechini, Ixodes australiensis, Ixodes holocyclus, Ixodes tasmani and Ixodes trichosuri. Bacterial 16S rRNA metabarcoding was performed on 536 samples and 65 controls, generating over 100 million sequences. Alpha diversity was significantly different between the three sample types, with tissue samples displaying the highest alpha diversity (P<0.001). Proteobacteria was the most abundant taxon identified across all sample types (37.3 %). Beta diversity analysis and ordination revealed little overlap between the three sample types (P<0.001). Taxa of interest included Anaplasmataceae, Bartonella, Borrelia, Coxiellaceae, Francisella, Midichloria, Mycoplasma and Rickettsia. Anaplasmataceae bacteria were detected in 17.7% (95/536) of samples and included Anaplasma, Ehrlichia and Neoehrlichia species. In samples from NSW, 'Ca. Neoehrlichia australis', 'Ca. Neoehrlichia arcana', Neoehrlichia sp. and Ehrlichia sp. were identified. A putative novel Ehrlichia sp. was identified from WA and Anaplasma platys was identified from QLD. Nine rodent tissue samples were positive for a novel Borrelia sp. that formed a phylogenetically distinct clade separate from the Lyme Borrelia and relapsing fever groups. This novel clade included recently identified rodent-associated Borrelia genotypes, which were described from Spain and North America. Bartonella was identified in 12.9% (69/536) of samples. Over half of these positive samples were obtained from black rats (Rattus rattus), and the dominant bacterial species identified were Bartonella coopersplainsensis and Bartonella queenslandensis. The results from the present study show the value of using unbiased high-throughput sequencing applied to samples collected from wildlife. In addition to understanding the sylvatic cycle of known vector-associated pathogens, surveillance work is important to ensure preparedness for potential zoonotic spillover events.
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Affiliation(s)
- Siobhon L Egan
- Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Casey L Taylor
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, New South Wales, 2006, Australia
| | - Peter B Banks
- School of Life and Environmental Sciences, The University of Sydney, Camperdown, New South Wales, 2006, Australia
| | - Amy S Northover
- School 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.,School of Veterinary Medicine, Murdoch University, Murdoch, Western Australia, 6150, Australia
| | - Charlotte L Oskam
- Harry Butler Institute, Murdoch University, Murdoch, Western Australia, 6150, Australia
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Estrada-Peña A, Cevidanes A, Sprong H, Millán J. Pitfalls in Tick and Tick-Borne Pathogens Research, Some Recommendations and a Call for Data Sharing. Pathogens 2021; 10:pathogens10060712. [PMID: 34200175 PMCID: PMC8229135 DOI: 10.3390/pathogens10060712] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 11/20/2022] Open
Abstract
An understanding of the relationships of ticks and tick-borne pathogens can only be achieved by integrating data from multiple studies. The publication of raw material is a necessary step for wide-area meta-analyses and study design, data collection and reporting require harmonization. This is an opinion paper, not a consensus position, and is open to debate. This work reflects our view about how data should be communicated in mainstream journals. We indicate rules that should be observed in recording weather data, to avoid serendipitous correlations between the density of ticks and climate variables and recommend the inclusion of raw data in reports. We stress the need for standardized methods to collect ticks that cannot be obtained by standard flagging. The reporting of infection rates of pathogens in ticks should avoid conclusions based on pure molecular findings in feeding ticks. Studies demonstrating the vectorial capacity of ticks should not be supported only by molecular surveys of feeding ticks. Vacuous conclusions about vectorial or reservoir status based solely on the finding of genomic material of a pathogen should be discouraged. We stress that phylogenetic studies based on random selection of sequences from GenBank are unsuitable. We firmly support the development of a dedicated server of curated sequences of ticks and pathogens as a standard for future studies.
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Affiliation(s)
- Agustín Estrada-Peña
- Department of Animal Health. Faculty of Veterinary Medicine. University of Zaragoza, 50013 Zaragoza, Spain
- Research Group in Emerging Zoonoses, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain;
- Correspondence:
| | - Aitor Cevidanes
- Department of Animal Health, NEIKER-Basque Institute for Agricultural Research and Development, Basque Research and Technology Alliance (BRTA), Parque Científico y Tecnológico de Bizkaia P812, 48160 Derio, Spain;
| | - Hein Sprong
- Center for Infectious Disease Control, National Institute for Public Health and the Environment, Mailbox 63, Room V353, Antonie van Leeuwenhoeklaan 9, P.O. Box 1, 3720 BA Bilthoven, The Netherlands;
| | - Javier Millán
- Research Group in Emerging Zoonoses, Instituto Agroalimentario de Aragón-IA2 (Universidad de Zaragoza-CITA), 50013 Zaragoza, Spain;
- Fundación ARAID, 50018 Zaragoza, Spain
- Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile
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