Detection and phylogenetic characterisation of novel Anaplasma and Ehrlichia species in Amblyomma triguttatum subsp. from four allopatric populations in Australia

Opening the Black Box of Host Range, Vectorial Diversity, and Genetic Variants of Genus Anaplasma: The Contributing Factors Toward Its Zoonosis

Background: Genus Anaplasma of the family Anaplasmataceae possesses bacteria of hematopoietic origin, which are obligate intracellular Gram-negative bacteria transmitted mainly by tick vectors. The members of this group of infectious agents are not new as etiological agents of animal diseases worldwide. However, now, reports of their zoonotic potential have gained currency to study these pathogens. The emergence of new species of Anaplasma and the spread of existing species to new areas and hosts highlight the importance of monitoring and improving diagnostic and treatment options for zoonotic diseases caused by Anaplasma. Conclusion: This review focuses on the general and distinctive characteristics of Anaplasma spp., with particular emphasis on the novel species and their diverse spectrum of hosts as potential risk factors impacting its emerging zoonosis.

Great genetic diversity of vector-borne bacteria and protozoan in wild rodents from Guangxi, China

BACKGROUND

Rodents are recognized as the hosts of many vector-borne bacteria and protozoan parasites and play an important role in their transmission and maintenance. Intensive studies have focused on their infections in vectors, especially in ticks, however, vector-borne bacterial and protozoan infections in rodents are poorly understood although human cases presenting with fever may due to their infection have been found.

METHODS

From May to October 2019, 192 wild rodents were trapped in wild environment of Guangxi Province, and the spleen samples were collected to reveal the presence of vector-borne bacterial and protozoan infections in them. The microorganisms in rodents were identified by detecting their DNA using (semi-)nested PCR. All the PCR products of the expected size were subjected to sequencing, and then analyzed by BLASTn. Furthermore, all the recovered sequences were subjected to nucleotide identity and phylogenetic analyses.

RESULTS

As a result, 192 rodents representing seven species were captured, and Bandicota indica were the dominant species, followed by Rattus andamanensis. Based on the (semi-)nested PCR, our results suggested that Anaplasma bovis, Anaplasma capra, Anaplasma ovis, Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis", "Candidatus E. hainanensis", "Candidatus E. zunyiensis", three uncultured Ehrlichia spp., Bartonella coopersplainsensis, Bartonella tribocorum, Bartonella rattimassiliensis, Bartonella silvatica, two uncultured Bartonella spp., Babesia microti and diverse Hepatozoon were identified in six rodent species. More importantly, six species (including two Anaplasma, two Bartonella, "Ca. N. mikurensis" and Bab. microti) are zoonotic pathogens except Anaplasma bovis and Anaplasma ovis with zoonotic potential. Furthermore, dual infection was observed between different microorganisms, and the most common type of co-infection is between "Ca. N. mikurensis" and other microorganisms. Additionally, potential novel Bartonella species and Hepatozoon species demonstrated the presence of more diverse rodent-associated Bartonella and Hepatozoon.

CONCLUSIONS

The results in this work indicated great genetic diversity of vector-borne infections in wild rodents, and highlighted the potential risk of human pathogens transmitted from rodents to humans through vectors.

RPA-CRISPR/Cas12a assay for the diagnosis of bovine Anaplasma marginale infection

Anaplasma marginale infection is one of the most common tick-borne diseases, causing a substantial loss in the beef and dairy production industries. Once infected, the pathogen remains in the cattle for life, allowing the parasites to spread to healthy animals. Since clinical manifestations of anaplasmosis occur late in the disease, a sensitive, accurate, and affordable pathogen identification is crucial in preventing and controlling the infection. To this end, we developed an RPA-CRISPR/Cas12a assay specific to A. marginale infection in bovines targeting the msp4 gene. Our assay is performed at one moderately high temperature, producing fluorescent signals or positive readout of a lateral flow dipstick, which is as sensitive as conventional PCR-based DNA amplification. This RPA-CRISPR/Cas12a assay can detect as few as 4 copies/μl of Anaplasma using msp4 marker without cross-reactivity to other common bovine pathogens. Lyophilized components of the assay can be stored at room temperature for an extended period, indicating its potential for field diagnosis and low-resource settings of anaplasmosis in bovines.

Occurrence of Anaplasma spp. in wild lagomorphs from Southern Spain: Molecular detection of new Anaplasma bovis lineages

Wild lagomorphs can act as reservoirs of several pathogens of public and animal health concern. However, the number of studies assessing the presence of Anaplasma spp. in these species is scarce. The aim of the present study was to molecularly identify Anaplasma spp. in wild rabbits (Oryctolagus cuniculus) and Iberian hares (Lepus granatensis) from Southern Spain and assess their epidemiological role in the maintenance of the bacterium. During 2017-2021, spleen samples of 394 wild rabbits and 145 Iberian hares were collected. Anaplasma DNA was detected using different PCR assays (16S rRNA and groEL) and phylogenetic analyses were carried out by Bayesian approach. The possible influence of lagomorph species, age and sex on the prevalence of Anaplasma spp. was evaluated by a multiple logistic regression model. The 9.4% of the rabbits were positive to Anaplasma bovis, but all the hares were negative. No significant differences were found in Anaplasma spp. prevalence regarding to age or sex. This is the first report of A. bovis in lagomorphs from Europe. The phylogenetic analysis of A. bovis confirms the existence of different clusters suggesting the existence of several lineages. In addition, a high divergence of nucleotide identity was observed within the lineage 4, which could result in the under-detection of some strains when using A. bovis-specific PCR, hindering its detection and characterization. Since this analysis is based on a limited number of nucleotide bases and sequences, more studies are needed for further characterize A. bovis, as well as its relationship with other Anaplasma spp.

Unravelling the Diversity of Microorganisms in Ticks from Australian Wildlife

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.

The Troublesome Ticks Research Protocol: Developing a Comprehensive, Multidiscipline Research Plan for Investigating Human Tick-Associated Disease in Australia

In Australia, there is a paucity of data about the extent and impact of zoonotic tick-related illnesses. Even less is understood about a multifaceted illness referred to as Debilitating Symptom Complexes Attributed to Ticks (DSCATT). Here, we describe a research plan for investigating the aetiology, pathophysiology, and clinical outcomes of human tick-associated disease in Australia. Our approach focuses on the transmission of potential pathogens and the immunological responses of the patient after a tick bite. The protocol is strengthened by prospective data collection, the recruitment of two external matched control groups, and sophisticated integrative data analysis which, collectively, will allow the robust demonstration of associations between a tick bite and the development of clinical and pathological abnormalities. Various laboratory analyses are performed including metagenomics to investigate the potential transmission of bacteria, protozoa and/or viruses during tick bite. In addition, multi-omics technology is applied to investigate links between host immune responses and potential infectious and non-infectious disease causations. Psychometric profiling is also used to investigate whether psychological attributes influence symptom development. This research will fill important knowledge gaps about tick-borne diseases. Ultimately, we hope the results will promote improved diagnostic outcomes, and inform the safe management and treatment of patients bitten by ticks in Australia.

Metatranscriptomic profiling reveals diverse tick-borne bacteria, protozoans and viruses in ticks and wildlife from Australia

Tick-borne zoonoses are emerging globally due to changes in climate and land use. While the zoonotic threats associated with ticks are well studied elsewhere, in Australia, the diversity of potentially zoonotic agents carried by ticks and their significance to human and animal health is not sufficiently understood. To this end, we used untargeted metatranscriptomics to audit the prokaryotic, eukaryotic and viral biomes of questing ticks and wildlife blood samples from two urban and rural sites in New South Wales, Australia. Ixodes holocyclus and Haemaphysalis bancrofti were the main tick species collected, and blood samples from Rattus rattus, Rattus fuscipes, Perameles nasuta and Trichosurus vulpecula were also collected and screened for tick-borne microorganisms using metatranscriptomics followed by conventional targeted PCR to identify important microbial taxa to the species level. Our analyses identified 32 unique tick-borne taxa, including 10 novel putative species. Overall, a wide range of tick-borne microorganisms were found in questing ticks including haemoprotozoa such as Babesia, Theileria, Hepatozoon and Trypanosoma spp., bacteria such as Borrelia, Rickettsia, Ehrlichia, Neoehrlichia and Anaplasma spp., and numerous viral taxa including Reoviridiae (including two coltiviruses) and a novel Flaviviridae-like jingmenvirus. Of note, a novel hard tick-borne relapsing fever Borrelia sp. was identified in questing H. bancrofti ticks which is closely related to, but distinct from, cervid-associated Borrelia spp. found throughout Asia. Notably, all tick-borne microorganisms were phylogenetically unique compared to their relatives found outside Australia, and no foreign tick-borne human pathogens such as Borrelia burgdorferi s.l. or Babesia microti were found. This work adds to the growing literature demonstrating that Australian ticks harbour a unique and endemic microbial fauna, including potentially zoonotic agents which should be further studied to determine their relative risk to human and animal health.

Molecular Characterization of Rickettsial Agents in Ticks (Acari: Ixodidae) from Sri Lanka

Because the majority of spotted fever group rickettsiae are transmitted to humans by tick bites, it is important to understand which ticks might play a role in transmission of rickettsial pathogens in Sri Lanka. The purpose of our study was to conduct molecular surveillance of 847 ticks collected in different locations in central Sri Lanka to determine which were infected with Rickettsia and Anaplasmataceae. Molecular methods were used to identify the ticks and the agents detected. Most ticks (Amblyomma, Haemaphysalis, and Rhipicephalus) were collected by flagging, and lower number was collected from dogs, cattle, pigs, a pangolin, and tortoises. Five spotted fever genotypes were identified: a Rickettsia africae-like agent in Amblyomma larvae, Rhipicephalus massiliae and a related genotype identified in association with the tropical type of Rhipicephalus sanguineus from dogs and Rhipicephalus haemaphysaloides from dogs and cattle, and Candidatus R. kellyi and another novel genotype (SL94) in R. haemaphysaloides. Twenty-three ticks were positive for Anaplasmataceae, including one Anaplasma and two Ehrlichia genotypes. Because the sequence database for both ticks and rickettsial agents from Sri Lanka and southern India is not extensive, additional molecular characterization of the tick species of Sri Lanka and their rickettsial agents is required to understand their pathogenic potential more completely. However, several of the agents we identified in this survey may well be pathogenic for humans and domestic animals, and should be considered as a part of epidemiological surveillance and patient management.

Illuminating the bacterial microbiome of Australian ticks with 16S and Rickettsia-specific next-generation sequencing

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.

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Bacterial pathogens identified in ticks from companion animals with 16S NGS.

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Sanger sequencing confirmed novel Coxiellaceae gen. sp. and Francisella.

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“Candidatus Rickettsia jingxinensis” was identified with Rickettsia-specific NGS.

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Comparison of taxonomic assignments in 16S sequence databases revealed errors.

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Modifications to the 16S metagenomic library protocol (Illumina) are provided.

The bacterial biome of ticks and their wildlife hosts at the urban-wildland interface

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.

Genetic diversity of Anaplasma bacteria: Twenty years later

The genus Anaplasma (family Anaplasmataceae, order Rickettsiales) includes obligate intracellular alphaproteobacteria that multiply within membrane-bound vacuoles and are transmitted by Ixodidae ticks to vertebrate hosts. Since the last reclassification of Anaplasmataceae twenty years ago, two new Anaplasma species have been identified. To date, the genus includes eight Anaplasma species (A. phagocytophilum, A. marginale, A. centrale, A. ovis, A. bovis, A. platys, A. odocoilei, and A. capra) and a large number of unclassified genovariants that cannot be assigned to known species. Members of the genus can cause infection in humans and a wide range of domestic animals with different degrees of severity. Long-term persistence which, in some cases, is manifested as cyclic bacteremia has been demonstrated for several Anaplasma species. Zoonotic potential has been shown for A. phagocytophilum, the agent of human granulocytic anaplasmosis, and for some other Anaplasma spp. that suggests a broader medical relevance of this genus. Genetic diversity of Anaplasma spp. has been intensively studied in recent years, and it has been shown that some Anaplasma spp. can be considered as a complex of genetically distinct lineages differing by geography, vectors, and host tropism. The aim of this review was to summarize the current knowledge concerning the natural history, pathogenic properties, and genetic diversity of Anaplasma spp. and some unclassified genovariants with particular attention to their genetic characteristics. The high genetic variability of Anaplasma spp. prompted us to conduct a detailed phylogenetic analysis for different Anaplasma species and unclassified genovariants, which were included in this review. The genotyping of unclassified genovariants has led to the identification of at least four distinct clades that might be considered in future as new candidate species.

Morphological identification of ticks and molecular detection of tick-borne pathogens from bare-nosed wombats (Vombatus ursinus)

BACKGROUND

Ticks are obligate haematophagous ectoparasites of vertebrate hosts and transmit the widest range of pathogenic organisms of any arthropod vector. Seven tick species are known to feed on bare-nosed wombats (Vombatus ursinus), in addition to the highly prevalent Sarcoptes scabiei mite which causes fatal sarcoptic mange in most bare-nosed wombat populations. Little is known about the pathogens carried by most wombat ticks or how they may impact wombats and wombat handlers.

METHODS

Wombat ticks were sourced from wildlife hospitals and sanctuaries across Australia and identified to species level using taxonomic keys. Genomic DNA was extracted from a subsample, and following the amplification of the bacterial 16S rRNA gene V3-V4 hypervariable region, next-generation sequencing (NGS) on the Illumina MiSeq platform was used to assess the microbial composition.

RESULTS

A total of 447 tick specimens were collected from 47 bare-nosed wombats between January 2019 and January 2020. Five species of ticks were identified comprising wombat tick Bothriocroton auruginans (n = 420), wallaby tick Haemaphysalis bancrofti (n = 8), bush tick Haemaphysalis longicornis (n = 3), common marsupial tick Ixodes tasmani (n = 12), and Australian paralysis tick Ixodes holocyclus (n = 4). Tick infestations ranged from one to 73 ticks per wombat. The wombat tick was the most prevalent tick species comprising 94% of the total number of samples and was present on 97.9% (46/47) of wombat hosts. NGS results revealed the 16S rRNA gene diversity profile was predominantly Proteobacteria (55.1%) followed by Firmicutes (21.9%) and Actinobacteria (18.4%). A species of Coxiella sharing closest sequence identity to Coxiella burnetii (99.07%), was detected in 72% of B. auruginans and a Rickettsiella endosymbiont dominated the bacterial profile for I. tasmani.

CONCLUSIONS

A new host record for H. longicornis is the bare-nosed wombat. One adult male and two engorged adult female specimens were found on an adult male wombat from Coolagolite in New South Wales, and more specimens should be collected to confirm this host record. The most prevalent tick found on bare-nosed wombats was B. auruginans, confirming previous records. Analysis of alpha-diversity showed high variability across both sample locations and instars, similar to previous studies. The detection of various Proteobacteria in this study highlights the high bacterial diversity in native Australian ticks.

Diversity unearthed by the estimated molecular phylogeny and ecologically quantitative characteristics of uncultured Ehrlichia bacteria in Haemaphysalis ticks, Japan

Ehrlichia species are obligatory intracellular bacteria transmitted by arthropods, and some of these species cause febrile diseases in humans and livestock. Genome sequencing has only been performed with cultured Ehrlichia species, and the taxonomic status of such ehrlichiae has been estimated by core genome-based phylogenetic analysis. However, many uncultured ehrlichiae exist in nature throughout the world, including Japan. This study aimed to conduct a molecular-based taxonomic and ecological characterization of uncultured Ehrlichia species or genotypes from ticks in Japan. We first surveyed 616 Haemaphysalis ticks by p28-PCR screening and analyzed five additional housekeeping genes (16S rRNA, groEL, gltA, ftsZ, and rpoB) from 11 p28-PCR-positive ticks. Phylogenetic analyses of the respective genes showed similar trees but with some differences. Furthermore, we found that V1 in the V1-V9 regions of Ehrlichia 16S rRNA exhibited the greatest variability. From an ecological viewpoint, the amounts of ehrlichiae in a single tick were found to equal approx. 6.3E+3 to 2.0E+6. Subsequently, core-partial-RGGFR-based phylogenetic analysis based on the concatenated sequences of the five housekeeping loci revealed six Ehrlichia genotypes, which included potentially new Ehrlichia species. Thus, our approach contributes to the taxonomic profiling and ecological quantitative analysis of uncultured or unidentified Ehrlichia species or genotypes worldwide.

Parasites of wombats (family Vombatidae), with a focus on ticks and tick-borne pathogens

Ticks (Arachnida: Acari) are vectors for pathogens and the biggest threat to animal health. Many Australian ticks are associated with pathogens that impact humans, domestic animals and livestock. However, little is known about the presence or impact of tick-borne pathogens in native Australian wildlife. Wombats are particularly susceptible to the effects of the ectoparasite Sarcoptes scabiei which causes sarcoptic mange, the reason for which is unknown. Factors such as other ectoparasites and their associated pathogens may play a role. A critical understanding of the species of ectoparasites that parasitise wombats and their pathogens, and particularly ticks, is therefore warranted. This review describes the ectoparasites of wombats, pathogens known to be associated with those ectoparasites, and related literature gaps. Pathogens have been isolated in most tick species that typically feed on wombats; however, there are minimal molecular studies to determine the presence of pathogens in any other wombat ectoparasites. The development of next-generation sequencing (NGS) technologies allows us to explore entire microbial communities in ectoparasite samples, allowing fast and accurate identification of potential pathogens in many samples at once. These new techniques have highlighted the diversity and uniqueness of native ticks and their microbiomes, including pathogens of potential medical and veterinary importance. An increased understanding of all ectoparasites that parasitise wombats, and their associated pathogens, requires further investigation.

Anaplasmosis in Animals

Anaplasmosis is a vector-borne, infectious and non-contagious disease. The disease is caused by various pathogens of the genus Anaplasma. The different species cause different types of anaplasmosis depending on which cells that are infected in the mammalian host. Anaplasmosis has a wide host range, including humans, and it is distributed worldwide. The zoonotic potential of some species is of great importance in regards to public health concerns. This review presents information about anaplasmosis in animals and its prevalence in Europe, and other countries in the world.

Rickettsia spp. and Ehrlichia spp. in Amblyomma ticks parasitizing wild amphibious sea kraits and yellow-margined box turtles in Okinawa, Japan

Recently, several tick-borne pathogens were detected in reptile-associated ticks. However, studies on the microorganisms in reptile-associated ticks in Japan are limited. This molecular survey thus aimed to identify and characterize tick-borne pathogens (Rickettsiaceae and Anaplasmataceae) in reptile-associated ticks in Japan. In total, 77 Amblyomma nitidum and 104 Amblyomma geoemydae were collected from wild amphibious sea kraits (Laticauda semifasciata, Laticauda colubrina, and Laticauda laticaudata) and from yellow-margined box turtles (Cuora flavomarginata evelynae), respectively. Conventional polymerase chain reaction was performed using the DNA extracted from the ticks to detect the selected pathogens. Sequencing analysis of four Rickettsia genes (gltA, ompA, ompB, and sca4) led to the identification of a putative novel Rickettsia sp. and Rickettsia aeschlimannii-like rickettsia in A. nitidum and A. geoemydae, respectively. Sequencing analysis of gltA and groEL of Anaplasmataceae revealed that the Ehrlichia spp. in these ticks were novel and related to Candidatus Ehrlichia occidentalis. This is the first study on the microorganisms in A. nitidium and the first record of Rickettsia and Ehrlichia in A. geoemydae. Further studies are required to understand their pathogenicity to humans and animals and their life cycle in the wild.

Extensive genetic diversity of Anaplasma bovis in ruminants in Xi'an, China

Anaplasma bovis is an organism significant to cattle and buffalo since it is one of the causative agents of bovine anaplasmosis. Previous studies have shown the worldwide distribution of A. bovis. However, most of these studies about its genetic diversity only focused on the rrs gene. In this study, DNA of A. bovis was detected in blood samples of cattle and goats in Xi'an city, China by nested-PCR. Near full-length rrs, groEL, and gltA genes were amplified successfully from the positive samples. Genetic analysis showed that specific genetic marker (an insertion and a deletion) was found in the rrs sequences in some strains, as well as clone 88 from monkeys in previous study. Phylogenetic analysis based on the rrs, groEL, and gltA genes revealed that A. bovis circulating in Xi'an exhibited great genetic diversity. Our results also indicated that variants outside China presented geographic clustering, and all A. bovis isolates based on the groEL or gltA gene also showed a host origin clustering. Also of note was that the phylogenetic analyses of the groEL and gltA genes suggested that both frequent dispersals over long distances in recent years and local adaptation over long evolutionary timescales played important roles in the distribution and evolution of A. bovis in China. Finally, a potential recombination event in the genome of Zhouzhi-cattle-10 based on inconsistent positions in the groEL and gltA trees was also observed. These results also reinforce the need for assessing the pathogenicity to humans of A. bovis variants with specific marker in the rrs gene.

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

Ticks Acari:Ixodida transmit a greater variety of pathogens than any other blood-feeding group of arthropods. 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 recently described bacteria 'Candidatus Borrelia tachyglossi', 'Candidatus Neoehrlichia australis', 'Candidatus Neoehrlichia arcana' and 'Candidatus Ehrlichia ornithorhynchi'. Furthermore, three novel Anaplasmataceae species were identified in the present study including; a Neoehrlichia sp. in I. australiensis and I. fecialis collected from quenda (Isoodon fusciventer) (Western Australia), an Anaplasma sp. from one B. concolor from echidna (Tachyglossus aculeatus) (New South Wales), 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.

A putative novel strain of Ehrlichia infecting Amblyomma tigrinum associated with Pampas fox (Lycalopex gymnocercus) in Esteros del Iberá ecoregion, Argentina

The current work evaluated road-killed Pampas foxes (Lycalopex gymnocercus) and their ticks for the presence of vector-borne agents in the ecoregion Esteros del Iberá in northeastern Argentina. Spleen, lung and blood samples and Amblyomma tigrinum adult ticks collected from the foxes were tested by polymerase chain reaction (PCR) assays targeting bacteria of the genera Ehrlichia, Anaplasma, and Rickettsia. All foxes tested were negative for the three genera, but evidence of Ehrlichia and Rickettsia infection was detected in the ticks. One A. tigrinum (out of 12 tested) was infected by an ehrlichial agent, here named Ehrlichia sp. strain Iberá, related to ehrlichial agents recently detected in platypuses in Tasmania (Ornithorhynchus anatinus) and in voles (Myodes rutilus and Myodes rufocanus) and shrews (Sorex araneus) in the Russian Far East. Regarding Rickettsia, all A. tigrinum ticks (100%) were infected by ´Candidatus Rickettsia andeanae´, a member of the spotted fever group rickettsia of unknown pathogenicity. Further research is necessary to unveil the ecology of Ehrlichia sp. strain Iberá as well as its zoonotic relevance. The species of the genus Ehrlichia are known to be pathogenic to mammals, including humans and domestic animals, thus the presence of this ehrlichial agent in A. tigrinum is a potential risk for veterinary and public health, as the adults of A. tigrinum are common parasites of dogs in rural and peri-urban environments, and humans are also frequently bitten by this tick species.

Novel Ehrlichia sp. detected in Magellanic penguins (Sphenicus magellanicus) and in the seabird tick Ixodes uriae from Magdalena Island, southern Chile

Ehrlichia spp. are obligatory intracellular microorganisms that infect hematopoietic, endothelial or blood cells of mammals. Ticks are the only vectors of these agents in nature. To date, the role of birds and their associated ticks as reservoirs of ehrlichiae remains almost unexplored. In this study, we performed a molecular screening for bacteria of Anaplasmataceae family in samples of spleen (n = 72) and lung (n = 17), recovered from 72 carcasses of Magellanic penguins (Spheniscus magellanicus) in Brazil and Chile. One apparently unengorged tick (Ixodes uriae) was also collected while wandering upon one of the carcasses and submitted to molecular analyses as well. Through conventional and nested PCR protocols three genes (16S rRNA, dsb and groEL) of a new Ehrlichia sp. were partially characterized upon organs of three penguins and in the tick coming from Magdalena Island (Chile). First matches after BLASTn comparisons showed that our sequences share 99.4% (16S rRNA), 94.6% (groEL) and 79.3% (dsb) of identity with "Candidatus Ehrlichia ornithorhynchi", Ehrlichia sp. NS101 and Ehrlichia canis CCZ, respectively. Matrixes of genetic distance including other representatives of the Ehrlichia genus point a 99.4%, 94.0%, and 80.0% of identity with 16S rRNA, groEL and dsb genes from Ehrlichia sp. It25, Ehrlichia sp. NS101, and Ehrlichia chaffeensis San Louis, respectively. A Bayesian phylogenetic analysis of Anaplasmataceae 16S rRNA gene places the detected Ehrlichia sp. into a group with Ehrlichia sp. BAT and Ehrlichia sp. Natal. Although depicting different topologies, Bayesian unrooted phylogenetic trees constructed for groEL and dsb genes position this Ehrlichia sp. into well-supported branches, which reinforces the finding of a new taxon. For the moment, any pathogenic effect of this new Ehrlichia sp. on penguins is still unknown. However, this fact becomes important to assess from a conservation point of view since populations of Magellanic penguins are currently threatened and in an ongoing decrease.

Investigation of ticks and red blood cell parasites of a population of reintroduced mainland tammar wallabies (Notamacropus eugenii eugenii)

Ticks and blood smears were collected from a reintroduced population of threatened tammar wallabies (Notamacropus eugenii eugenii). Ixodes hirsti was common during autumn/winter, and Amblyomma spp. in spring/summer, reflecting the seasonal density of questing A. triguttatum triguttatum. Red blood cell parasites were not detected in the 90 smears analysed.

Bacterial tick-associated infections in Australia: current studies and future directions

It may seem perplexing that there is any uncertainty in Australia about the existence of zoonotic tick-associated infections1–3. Outside this country, particularly in the northern hemisphere, tick-borne diseases such as human granulocytic anaplasmosis, babesiosis, Boutonneuse fever, ehrlichiosis, Lyme borreliosis, and tick-borne encephalitis, have well documented aetiologies, epidemiology, diagnostic methods, and treatments. Why is Australia different and what research is being conducted to address this issue? This article briefly addresses these questions and explains how high-throughput metagenomic analysis has started to shed light on bacterial microbiomes in Australian ticks, providing new data on the presence and distribution of potentially zoonotic microbial taxa.

A novel Ehrlichia species in blood and Ixodes ornithorhynchi ticks from platypuses (Ornithorhynchus anatinus) in Queensland and Tasmania, Australia

Worldwide, Ehrlichia spp. are emerging infectious organisms of domestic animals and people, however, most Ehrlichia spp. naturally infect wildlife reservoirs causing mainly asymptomatic infections. Australian ecosystems have been under-explored for these potentially pathogenic organisms, and recent studies have identified a range of novel Ehrlichia, and their sister genera, Anaplasma and 'Candidatus Neoehrlichia' species, from native Australian ticks. We used bacterial 16S rRNA (16S) next-generation sequencing and genus-specific PCR to profile the bacterial communities in platypus (Ornithorhynchus anatinus) blood samples and platypus ticks (Ixodes ornithorhynchi), and identified a high prevalence of Ehrlichia sequences. We also observed Ehrlichia-like intra-neutrophilic inclusions (morulae) in PCR-positive stained platypus blood films that were consistent in morphology with other Ehrlichia spp. Bayesian phylogenetic analysis of 16S (1343 bp), gltA (1004 bp), and groEL (1074 bp) gene sequences group the platypus Ehrlichia with 'Candidatus Ehrlichia khabarensis' from far-eastern Russia, and demonstrate that the platypus Ehrlichia is clearly distinct from all other Ehrlichia spp. Enough genetic divergence exists to delineate this platypus Ehrlichia as a separate species that we propose to designate 'Candidatus Ehrlichia ornithorhynchi'. There is no evidence that 'Candidatus Ehrlichia ornithorhynchi' causes disease in wild platypuses, however, the organism does seem to be widespread in Australia, being found in both Queensland and Tasmania. 'Candidatus Ehrlichia ornithorhynchi' is the second native Australian Ehrlichia described and adds to the rapidly growing diversity of recently described native Australian tick-borne bacteria.