Is there a Lyme-like disease in Australia? Summary of the findings to date

Chalada, Melissa Judith; Stenos, John; Bradbury, Richard S.

doi:10.1016/j.onehlt.2016.03.003

Cited by 37 publications

(51 citation statements)

References 138 publications

(251 reference statements)

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“…Currently in Australia, the ecology, epidemiology, and incidence of human tick-borne diseases remains largely a matter of conjecture, having received little scientific study compared with many other parts of the world (Graves and Stenos, 2017). Despite significant national interest, including a federal government senate inquiry (Radcliffe et al, 2016), the prevailing scientific opinion concludes that Lyme borreliosis (caused by B. burgdorferi sensu lato), for example, is absent from Australia (Chalada et al, 2016;Irwin et al, 2017). In the unique Australian environment, long isolated in geological terms, it is likely that unidentified tick-host life cycles have evolved that may contribute to zoonotic illness when humans encroach these sylvatic ecologies and become exposed to native ticks.…”

Section: Discussionmentioning

confidence: 99%

Bacterial community profiling highlights complex diversity and novel organisms in wildlife ticks

Egan

Loh

Banks

et al. 2019

Preprint

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Ticks (Acari: Ixodida) transmit a greater variety of pathogens than any other blood-feeding 1 2 arthropod. While numerous microbes have been identified inhabiting Australian Ixodidae, some of which are related to globally important tick-borne pathogens, little is known about the bacterial communities within ticks collected from Australian wildlife. In this study, 1,019 ticks were identified on 221 hosts spanning 27 wildlife species. Next-generation sequencing was used to amplify the V1-2 hypervariable region of the bacterial 16S rRNA gene from 238 ticks; Amblyomma triguttatum (n=6), Bothriocroton auruginans (n=11), Bothriocroton concolor (n=20), Haemaphysalis bancrofti (n=10), Haemaphysalis bremneri (n=4), Haemaphysalis humerosa (n=13), Haemaphysalis longicornis (n=4), Ixodes antechini (n=29), Ixodes australiensis (n=26), Ixodes fecialis (n=13), Ixodes holocyclus (n=37), Ixodes myrmecobii (n=1), Ixodes ornithorhynchi (n=10), Ixodes tasmani (n=51) and Ixodes trichosuri (n=3). After bioinformatic analyses, over 14 million assigned bacterial sequences revealed the presence of newly described bacteria 'Ca. Borrelia tachyglossi', 'Ca. Neoehrlichia australis', 'Ca. Neoehrlichia arcana' and 'Ca. Ehrlichia ornithorhynchi'. Furthermore, three novel Anaplasmataceae species were identified including; a Neoehrlichia sp. in I. australiensis and I. fecialis ex quenda (Isoodon fusciventer) (Western Australia), an Anaplasma sp. from one B. concolor ex echidna (Tachyglossus aculeatus) (New SouthWales), and an Ehrlichia sp. from a single I. fecialis parasitising a quenda (WA). This study highlights the diversity of bacterial genera harboured within wildlife ticks, which may prove to be of medical and/or veterinary importance in the future.

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Section: Discussionmentioning

confidence: 99%

Bacterial community profiling highlights complex diversity and novel organisms in wildlife ticks

Egan

Loh

Banks

et al. 2019

Preprint

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“…and Babesia spp. [21], and the geographical distribution of I. holocyclus appears to largely coincide with that of the LD-like cases reported in the scientific literature in Australia [12]. Although there are another 18 species of Ixodes tick species described in Australia [22], all are confined to the Australian continent; most of these have highly restricted host ranges and/or enzootic distributions, and rarely bite humans [22].…”

Section: Discussionmentioning

confidence: 79%

Searching for Lyme borreliosis in Australia: results of a canine sentinel study

et al. 2017

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BackgroundLyme borreliosis is a common tick-borne disease of the northern hemisphere that is caused by bacterial spirochaetes of the Borrelia burgdorferi (sensu lato) (Bbsl) complex. To date, there has been no convincing evidence for locally-acquired Lyme borreliosis on the Australian continent and there is currently a national debate concerning the nature and distributions of zoonotic tick-transmitted infectious disease in Australia. In studies conducted in Europe and the United States, dogs have been used as sentinels for tick-associated illness in people since they readily contact ticks that may harbour zoonotic pathogens. Applying this principle, we used a combination of serological assays to test dogs living in tick ‘hot spots’ and exposed to the Australian paralysis tick, Ixodes holocyclus, for evidence of exposure to B. burgdorferi (s.l.) antigens and other vector-borne pathogens.ResultsAltogether, 555 dogs from four demographic groups were recruited into this study. One dog had evidence of exposure to Anaplasma spp. but no other dog was positive in screening tests. A total of 122 dogs (22.0%) had a kinetic ELISA (KELA) unit value > 100, and one dog with a high titre (399.9 KELA units) had been vaccinated against B. burgdorferi (sensu stricto) before travelling to Australia. Older dogs and those with a history of tick paralysis were significantly more likely to have a KELA unit value > 100. Line immunoassay analysis revealed moderate-to-weak (equivocal) bands in 27 (4.9%) dogs.ConclusionsExcept for a single dog presumed to have been exposed to Anaplasma platys, infection with Anaplasma spp. B. burgdorferi (s.l.), Ehrlichia spp., and Dirofilaria immitis, was not detected in the cohort of Australian dogs evaluated in this study. These results provide further evidence that Lyme borreliosis does not exist in Australia but that cross-reacting antibodies (false positive results) are common and may be caused by the transmission of other tick-associated organisms.

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“…Previous meta-transcriptomic studies targeting arthropod viromes have revealed an abundance of novel and often highly divergent viruses (14, 23-25, 32). To date, however, there has been no study of the diversity of tick-associated viruses in Australia, nor of whether any of these viruses might play a role in tick-borne disease, despite the controversy surrounding tick-borne disease in this country (6, 7). Importantly, we also used the RNA-Seq meta-transcriptomic data generated here to search for the presence of known tick-associated pathogens, particularly the bacteria B. burgdorferi s.l.…”

Section: Discussionmentioning

confidence: 99%

“…For example, cases of tick-borne bacterial infection, particularly Lyme disease, are becoming increasingly frequent across parts of North America and Europe (4, 5). In Australia, Lyme disease is not recognized as endemic by the scientific nor medical communities, although controversy over its presence along the eastern coast of Australia has raged since the mid-1980s (6-8). Importantly, the species of ticks known to act as a vector of the disease are not found in Australia, and detailed studies involving microscopy, culturing, PCR, and metagenomic techniques indicate that the causative bacterial agent, Borrelia burgdorferi senso lato, is not present in Australian ticks (6, 7).…”

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confidence: 99%

“…In Australia, Lyme disease is not recognized as endemic by the scientific nor medical communities, although controversy over its presence along the eastern coast of Australia has raged since the mid-1980s (6-8). Importantly, the species of ticks known to act as a vector of the disease are not found in Australia, and detailed studies involving microscopy, culturing, PCR, and metagenomic techniques indicate that the causative bacterial agent, Borrelia burgdorferi senso lato, is not present in Australian ticks (6, 7). In addition, a North American strain of B. burgdorferi could not be transmitted by the Australian paralysis tick, Ixodes holocyclus , following experimental infection (9).…”

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confidence: 99%

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Extensive Diversity of RNA Viruses in Australian Ticks

Harvey

Rose

Eden

et al. 2018

Preprint

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Understanding the microbiome of ticks in Australia is of considerable interest given the ongoing debate over whether Lyme disease, and its causative agent the bacteriumBorrelia burgdorferisenso lato, are present in Australia. The diversity of bacteria infecting Australian ticks has been the subject of a number of studies using both culture and metagenomics based techniques. However, little is known about the virome of Australian ticks, including those that may have the potential to infect mammalian species. We used a meta-transcriptomics approach to reveal the viral diversity within Australian ticks collected from two locations on the central-east coast of Australia, including metropolitan Sydney. From this we identified 19 novel species of RNA virus belonging to 10 families, as well as one previously described RNA virus. The majority of these viruses clustered phylogenetically with arthropod-associated viruses suggesting that they do not utilize mammalian hosts. However, two novel viruses discovered in ticks feeding on bandicoot marsupials clustered closely within the mammalian associatedHepacivirusandPestivirusgenera (Flaviviridae). Notably, another bandicoot tick yielded a novelColtivirus(Reoviridae) – a group of largely tick-associated viruses containing the known human pathogen Colorado tick fever virus and its relative Eyach virus. Importantly, our transcriptomic data provided no evidence for the presence ofB. burgdorferis.l.. in any tick sample, providing further evidence against the presence of Lyme Disease in Australia. In sum, this study reveals that Australian ticks harbor a diverse virome, including some viruses that merit additional screening in the context of emerging infectious disease.IMPORTANCEEach year a growing number of individuals along the east coast of Australia experience debilitating disease following tick bites. As there is no evidence for the presence of the causative agent of Lyme disease,Borrelia Burgdorferiseno lato, in Australian ticks, the etiological basis of this disease syndrome remains controversial. To characterize the viruses associated with Australian ticks, particularly those that might be associated with mammalian infection, we performed unbiased RNA sequencing on 146 ticks collected across two locations along the coast of New South Wales, Australia. This revealed 19 novel RNA viruses from a diverse set of families. Notably, three of these viruses were related to known mammalian viruses, including one that fell within the genusColtivirusand related to the human pathogen, Colorado tick fever virus.

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Is there a Lyme-like disease in Australia? Summary of the findings to date

Cited by 37 publications

References 138 publications

Bacterial community profiling highlights complex diversity and novel organisms in wildlife ticks

Bacterial community profiling highlights complex diversity and novel organisms in wildlife ticks

Searching for Lyme borreliosis in Australia: results of a canine sentinel study

Extensive Diversity of RNA Viruses in Australian Ticks

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