Borrelia turcica sp. nov., isolated from the hard tick Hyalomma aegyptium in Turkey

Characterization of the family-level Borreliaceae pan-genome and development of an episomal typing protocol

Background

The Borreliaceae family includes many obligate parasitic bacterial species which are etiologically associated with a myriad of zoonotic borrelioses including Lyme disease and vector-borne relapsing fevers. Infections by the Borreliaceae are difficult to detect by both direct and indirect methods, often leading to delayed and missed diagnoses. Efforts to improve diagnoses center around the development of molecular diagnostics (MDx), but due to deep tissue sequestration of the causative spirochaetes and the lack of persistent bacteremias, even MDx assays suffer from a lack of sensitivity. Additionally, the highly extensive genomic heterogeneity among isolates, even within the same species, contributes to the lack of assay sensitivity as single target assays cannot provide universal coverage. This within-species heterogeneity is partly due to differences in replicon repertoires and genomic structures that have likely arisen to support the complex Borreliaceae lifecycle in which these parasites have to survive in multiple hosts each with unique immune responses.

Results

We constructed a Borreliaceae family-level pangenome and characterized the phylogenetic relationships among the constituent taxa which supports the recent taxonomy of splitting the family into at least two genera. Gene content pro les were created for the majority of the Borreliaceae replicons, providing for the first time their unambiguous molecular typing.

Conclusion

Our characterization of the Borreliaceae pan-genome supports the splitting of the former Borrelia genus into two genera and provides for the phylogenetic placement of several non-species designated isolates. Mining this family-level pangenome will enable precision diagnostics corresponding to gene content-driven clinical outcomes while also providing targets for interventions.

Borrelia miyamotoi in wild rodents from four different regions of Turkey

Borrelia miyamotoi is a tick-borne zoonotic agent that causes hard tick-borne relapsing fever, an emerging disease in humans. Some small mammalian and bird species are reported to be reservoirs of B. miyamotoi. This study aims to examine Borrelia species present in rodents captured from rural areas of Turkey. Blood samples of rodents were initially screened with Borrelia 16S rRNA qPCR. The Borrelia flaB gene was subsequently amplified by conventional PCR, after which all positive samples were sequenced. Borrelia miyamotoi was observed in nine out of 536 blood samples (1.7%) collected from wild rodents. Phylogenetic analysis showed that all positive samples belonged to the European genotype clade of B. miyamotoi. PCR positivity was 5.3%, 3.7%, and 1.8% in Apodemus uralensis, Apodemus flavicollis, and Myodes glareolus, respectively. Borrelia burgdorferi sensu lato that causes Lyme borreliosis in humans could not be detected in the rodents. In this study, presence of B. miyamotoi DNA is reported for the first time in rodents in Turkey.

Genetic Diversity of Borreliaceae Species Detected in Natural Populations of Ixodes ricinus Ticks in Northern Poland

In Europe, Ixodes ricinus tick is the vector of Lyme disease spirochetes and their relatives (Borreliella genus) and Borrelia miyamotoi. However, a newly described tick I. inopinatus with similar biological features and separated from I. ricinus may act as a vector for different Borrelia species. To date, eleven Borreliella species were detected in the natural populations of I. ricinus. Recently, two North American species have been detected in ticks parasitizing bats and red foxes in Europe, i.e., B. lanei and B. californiensis pointing to the necessity for searching for them in natural tick populations. In this study, using the coxI molecular marker only I. ricinus was identified in field-collected ticks with the exception of individual specimens of Haemaphysalis concinna. Using the flaB gene and mag-trnI intergenic spacer as molecular markers 14 Borreliaceae species have been detected with various frequencies in different parts of northern Poland. Among infected ticks, the most frequent were Borreliella (Bl.) afzelii (29.4%) and Bl. garinii (20.0%), followed by Bl. spielmanii, Bl. valaisiana, Bl. lanei, Bl. californiensis, B. miyamotoi, Bl. burgdorferi, Bl. carolinensis, Bl. americana, B. turcica, Bl. lusitaniae, Bl. bissettiae and Bl. finlandensis. Three of the above-mentioned species, i.e., Bl. lanei, Bl. californiensis and B. turcica were detected in this study for the first time in the natural ixodid tick population in Europe. The existence of the newly detected spirochetes increases their total diversity in Europe and points to the necessity of careful identification and establishment of the actual distribution of all Borreliaceae species transmitted by I. ricinus.

New records of Amblyomma gervaisi from Pakistan, with detection of a reptile-associated Borrelia sp

Ticks are hematophagous ectoparasites of terrestrial and semi-aquatic vertebrates that may transmit microorganisms to their hosts. Spirochetes of the genus Borrelia are common in ticks and an incipient group has been identified in association with reptiles and their tick parasites. To overcome the knowledge deficit, this study aimed to morphologically and molecularly identify ticks infesting wild lizards and to molecularly assess Borrelia spp. associated with these ticks in Pakistan. For this purpose, free-ranging monitor lizards (Varanus bengalensis) from Khyber Pakhtunkhwa province, Pakistan, were examined for tick infestations. A total of 776 ticks were collected from 36/63 lizards, resulting in a prevalence of 57% (95% CI 44.7-69.3%), overall mean intensity of 21.5 (95% CI 18.9-24.1) ticks per infested lizard, and overall mean abundance of 12.3 (95% CI 9.25-15.4) ticks per examined lizard. All ticks were morphologically identified as Amblyomma gervaisi. The morphological identification of the ticks was molecularly confirmed through sequencing fragments of the mitochondrial 16S rRNA gene. In addition, a fragment of nuclear second internal transcribed spacer (ITS2) was generated for the first time for A. gervaisi. Phylogenetic analysis inferred from tick 16S rRNA gene partial sequences predicted a close evolutionary relationship of the collected A. gervaisi ticks with conspecific sequences from India, which shared 94.5% identity. Through two PCR assays targeting fragments of the borrelial genes, 16S rRNA and flaB, 19 (18%) out of 108 ticks yielded borrelial DNA. Phylogenetic analyses inferred from DNA sequences of the two borrelial genes revealed that the Borrelia sp. from A. gervaisi detected in this study belonged to the reptile-associated Borrelia group (REP). This is the first molecular report of ticks infesting monitor lizards and associated Borrelia sp. in Pakistan. The preliminary phylogenetic analyses of A. gervaisi may assist in understanding the molecular epidemiology of Amblyomma spp.

Red Foxes (Vulpes vulpes) Are Exposed to High Diversity of Borrelia burgdorferi Sensu Lato Species Infecting Fox-Derived Ixodes Ticks in West-Central Poland

The role of red fox, Vulpes vulpes, and its associated ticks in maintaining Borrelia burgdorferi sensu lato (s.l.) was studied. A total of 1583 ticks were removed from ears of 120 infested animals and were identified as species using a nested PCR targeting the ITS2 and coxI fragments of Ixodes DNA. Ixodes kaiseri prevailed (76%), followed by I. canisuga, I. ricinus, and I. hexagonus. In total, 32.4% of 943 ticks revealed Borrelia DNA and 10 species of B. burgdorferi s.l. complex were identified. Borrelia garinii and B. afzelii comprised 70% of all infections. The other eight species included B. americana, B. bissettiae, B. burgdorferi sensu stricto (s.s.), B. californiensis, B. carolinensis, B. lanei, B. spielmanii, and B. valaisiana. Analysis of tissues from 243 foxes showed that 23.5% were infected with B. burgdorferi s.l. Borrelia garinii was detected in 91% of the infected animals, including 31% of mixed infections with B. afzelii, the second most prevalent species, followed by B. spielmanii. The predominance of B. garinii in PCR-positive animals and infected larval ticks (38.1%), suggests that this spirochete and B. afzelii are preferentially associated with foxes. Although red foxes are exposed to a high diversity of B. burgdorferi s.l. species found in engorged Ixodes ticks, their reservoir competence for most of them appears to be low.

Detection and molecular identification of Anaplasma phagocytophilum and Babesia spp. infections in Hyalomma aegyptium ticks in Tunisia

Tortoises of the genus Testudo are the main hosts of Hyalomma aegyptium ticks. This species serves as a vector of several zoonotic pathogens. Therefore, the present study aimed to investigate the presence of four pathogens associated with H. aegyptium ticks obtained from tortoises from Tunisia. Conventional, multiplex and nested PCRs were used for Aanaplasma phagocytophilum, Ehrlichia canis, Coxiella burnetii and Babesia spp. screening. The molecular analyses revealed the presence of A. phagocytophilum and Babesia spp. None of the ticks, were infected by E. canis or C. burnetii species. Co-infection was detected in four ticks. As a conclusion, this is the first detection of A. phagocytophilum and Babesia spp. in H. aegyptium ticks collected from tortoises, in Tunisia. Thus, considering these results, the spur-thighed tortoise constitute a potential host of H. aegyptium which plays an important role in the transmission of pathogenic agents affecting both human and animals. In term of public health, a strict control and surveillance should be carried to reduce the circulation of such pathogens between different hosts.

Molecular and MALDI-TOF MS characterisation of Hyalomma aegyptium ticks collected from turtles and their associated microorganisms in Algeria

The identification of ticks and their associated pathogens is important for knowledge on tick-borne diseases. The objective of this study was to use morphological, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and/or molecular biology tools to identify ticks collected from turtles in north-eastern Algeria, as well as to investigate the microorganisms associated with these ticks. A total of 471 adult ticks were collected and identified morphologically as Hyalomma aegyptium, of which 248 (52.7%) were female and 223 (47.3%) were male. amongst them, 230 specimens were randomly selected for molecular and MALDI-TOF MS analysis. Molecular biology confirmed that our ticks were Hy. aegyptium. MALDI-TOF MS analysis revealed that 100% of the spectra were of excellent quality. Four spectra were selected to update our own database MALDI-TOF MS arthropod. The blind test of the 226 remaining spectra showed that all ticks were correctly identified, with scores ranging from 1.774 to 2.655 with a mean of 2.271 ± 0.16 of which, 223 (98.6%) had log score value (LSV)>1.8. Molecular biology screening showed that the ticks carried the DNA of Borrelia turcica, Rickettsia africae, Rickettsia aeschlimannii, Rickettsia sibirica mongolitimonae and with the Anaplasmataceae were close to a potentially new, undescribed Ehrlichia sp. This study confirms that MALDI-TOF MS is a reliable tool for the identification of ticks and that ticks collected from turtles in Algeria are carriers of several species of microorganisms which may be responsible for diseases in humans and animals.

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

The classification of "parasites" in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.

Borreliae Part 1: Borrelia Lyme Group and Echidna-Reptile Group

Simple Summary

Borreliae are spirochaetes, which represent a heterogeneous phylum within bacteria. Spirochaetes are indeed distinguished from other bacteria for their spiral shape, which also characterizes Borreliae. This review describes briefly the organization of the phylum Spirocheteales with a digression about its pathogenicity and historical information about bacteria isolation and characterization. Among spirochaetes, Borrelia genus is here divided into three groups, namely the Lyme group (LG), the Echidna-Reptile group (REPG) and the Relapsing Fever group (RFG). Borreliae Part 1 deals with Lyme group and Echidna-Reptile group Borreliae, while the subject of Borreliae Part 2 is Relapsing Fever group and unclassified Borreliae. Lyme group Borreliae is organized here in sections describing ecology, namely tick vectors and animal hosts, epidemiology, microbiology, and Borrelia genome organization and antigen characterization. Furthermore, the main clinical manifestations in Lyme borreliosis are also described. Although included in the Lyme group due to their particular clinical features, Borrelia causing Baggio Yoshinari syndrome and Borrelia mayonii are described in dedicated paragraphs. The Borrelia Echidna-Reptile group has been recently characterized including spirochaetes that apparently are not pathogenic to humans, but infect reptiles and amphibians. The paragraph dedicated to this group of Borreliae describes their vectors, hosts, geographical distribution and their characteristics.

Abstract

Borreliae are divided into three groups, namely the Lyme group (LG), the Echidna-Reptile group (REPG) and the Relapsing Fever group (RFG). Currently, only Borrelia of the Lyme and RF groups (not all) cause infection in humans. Borreliae of the Echidna-Reptile group represent a new monophyletic group of spirochaetes, which infect amphibians and reptiles. In addition to a general description of the phylum Spirochaetales, including a brief historical digression on spirochaetosis, in the present review Borreliae of Lyme and Echidna-Reptile groups are described, discussing the ecology with vectors and hosts as well as microbiological features and molecular characterization. Furthermore, differences between LG and RFG are discussed with respect to the clinical manifestations. In humans, LG Borreliae are organotropic and cause erythema migrans in the early phase of the disease, while RFG Borreliae give high spirochaetemia with fever, without the development of erythema migrans. With respect of LG Borreliae, recently Borrelia mayonii, with intermediate characteristics between LG and RFG, has been identified. As part of the LG, it gives erythema migrans but also high spirochaetemia with fever. Hard ticks are vectors for both LG and REPG groups, but in LG they are mostly Ixodes sp. ticks, while in REPG vectors do not belong to that genus.

Tick-Borne Pathogens and Diseases in Greece

Tick-borne diseases (TBDs) are recognized as a serious and growing public health epidemic in Europe, and are a cause of major losses in livestock production worldwide. This review is an attempt to present a summary of results from studies conducted over the last century until the end of the year 2020 regarding ticks, tick-borne pathogens, and tick-borne diseases in Greece. We provide an overview of the tick species found in Greece, as well as the most important tick-borne pathogens (viruses, bacteria, protozoa) and corresponding diseases in circulation. We also consider prevalence data, as well as geographic and climatic conditions. Knowledge of past and current situations of TBDs, as well as an awareness of (risk) factors affecting future developments will help to find approaches to integrated tick management as part of the ‘One Health Concept’; it will assist in avoiding the possibility of hotspot disease emergencies and intra- and intercontinental transmission. Increased surveillance in Greece is required to ensure clear and effective policies for TBD control.

The Family Borreliaceae (Spirochaetales), a Diverse Group in Two Genera of Tick-Borne Spirochetes of Mammals, Birds, and Reptiles

Spirochetes of the family Borreliaceae are, with one exception, tick-borne pathogens of a variety of vertebrates. The family at present comprises two genera: Borrelia (Swellengrebel), which includes the agents of relapsing fever, avian spirochetosis, and bovine borreliosis, and Borreliella (Gupta et al.), which includes the agents of Lyme disease and was formerly known as 'Borrelia burgdorferi sensulato complex'. The two genera are distinguished not only by their disease associations but also biological features in the tick vector, including tissue location in unfed ticks and transovarial transmission. Borrelia species transmitted by argasid (soft) ticks tend to have more exclusive relationships with their tick vectors than do other Borrelia species and all Borreliella species that have ixodid (hard) ticks as vectors. The division of genera is supported by phylogenomic evidence from whole genomes and by several specific molecular markers. These distinguishing phylogenetic criteria also applied to three new species or isolates of Borrelia that were discovered in ixodid ticks of reptiles, a monotreme, and birds. Although the deep branching of the family from other spirochetes has been a challenge for inferences about evolution of the family, the discovery of related microorganisms in the gut microbiota of other arachnids suggests an ancestral origin for the family as symbionts of ticks and other arachnids.

Diversity of microorganisms in Hyalomma aegyptium collected from spur-thighed tortoise (Testudo graeca) in North Africa and Anatolia

Ticks carry a diverse community of microorganisms including non-pathogenic symbionts, commensals, and pathogens, such as viruses, bacteria, protozoans, and fungi. The assessment of tick-borne microorganisms (TBM) in tortoises and their ticks is essential to understand their eco-epidemiology, and to map and monitor potential pathogens to humans and other animals. The aim of this study was to characterize the diversity of microorganisms found in ticks collected from the spur-thighed tortoise (Testudo graeca) in North Africa and Anatolia. Ticks feeding on wild T. graeca were collected, and pathogens were screened by polymerase chain reaction using group-specific primers. In total, 131 adult Hyalomma aegyptium ticks were collected from 92 T. graeca in Morocco (n = 48), Tunisia (n = 2), Algeria (n = 70), and Turkey (n = 11). Bacteria and protozoa detected included Hemolivia mauritanica (22.9%), Midichloria mitochondrii (11.4%), relapsing-fever borreliae (8.4%), Ehrlichia spp. (7.6%), Rickettsia spp. (3.4%), Borrelia burgdorferi s.l. (0.9%), Francisella spp. (0.9%), and Wolbachia spp. (0.8%). The characterization of Rickettsia included R. sibirica mongolitimonae (Algeria), R. aeschlimannii (Turkey), and R.africae (Morocco). Hemolivia mauritanica and Ehrlichia spp. prevalence varied significantly with the sampling region/country. We did not detect significant associations in microorganism presence within ticks, nor between microorganism presence and tick mitochondrial DNA haplogroups. This is the first report of Francisella persica-like, relapsing fever borreliae, M. mitochondrii, and Wolbachia spp. in H. aegyptium ticks collected from wild hosts from the South and Eastern Mediterranean region, and of R. sibirica mongolitimonae and R. africae in H. aegyptium from Algeria and Morocco, respectively. Given that T. graeca is a common species in commercial and non-commercial pet trade, the evaluation of the role of this species and its ticks as hosts for TBM is particularly relevant for public health.

Molecular Detection of Novel Borrelia Species, Candidatus Borrelia javanense, in Amblyomma javanense Ticks from Pangolins

A novel Borrelia species, Candidatus Borrelia javanense, was found in ectoparasite ticks, Amblyomma javanense, from Manis javanica pangolins seized in anti-smuggling operations in southern China. Overall, 12 tick samples in 227 (overall prevalence 5.3%) were positive for Candidatus B. javanense, 9 (5.1%) in 176 males, and 3 (5.9%) in 51 females. The phylogenetic analysis, based on the 16S rRNA gene and the flagellin gene sequences of the Borrelia sp., exhibited strong evidence that Candidatus B. javanense did not belong to the Lyme disease Borrelia group and the relapsing fever Borrelia group but another lineage of Borrelia. The discovery of the novel Borrelia species suggests that A. javanense may be the transmit vector, and the M. javanica pangolins should be considered a possible origin reservoir in the natural circulation of these new pathogens. To our knowledge, this is the first identification of a novel Borrelia species agent in A. javanense from pangolins. Whether the novel agent is pathogenic to humans is unknown and needs further research.

Molecular detection of the reptile-associated Borrelia group in Amblyomma dissimile, Mexico

Recently, the first record of Borrelia associated with reptiles in Mexico was published; however, no studies have been done to assess the role of Mexican ticks as potential vectors of this Borrelia group. Amblyomma dissimile is a hard tick mainly associated with amphibians and reptiles in this country. The aim of this study was to evaluate the presence of Borrelia in A. dissimile from Mexico. We collected 60 A. dissimile individuals attached to 16 Rhinella horribilis. DNA was extracted and all specimens were screened individually for Borrelia by amplification of a fragment of the 16S rDNA and an additional fragment of the flagellin gene. Five ticks were positive for Borrelia, DNA sequences corresponded to Borrelia sp. and group with sequences of the reptile-associated Borrelia group. This is the first report of Borrelia in A. dissimile and the second report of the reptile-associated Borrelia group in Mexico. This study also highlights the importance of this tick species as potential vector of this group.

TICKS PARASITIZING THE SPUR-THIGHED TORTOISE (TESTUDO GRAECA) POPULATION OF TUNISIA

From March to April 2017, a total of 147 free-ranging spur-thighed tortoises (Testudo graeca) was captured in different habitat types of northern Tunisia and examined for tick infestation. A total of 134 was infested, yielding an infestation prevalence of 91.2%. From these tortoises, 1,174 ticks were collected, a subsample (10%, n=120) of which was randomly selected and identified; the remaining ticks were stored at -80 C and examined for zoonotic pathogens. Only adult Hyalomma aegyptium were found among the subsample of ticks collected for spur-thighed tortoise. The prevalence of tick infestation did not vary significantly within the study area but differences in intensity were observed in relation to the size of tortoises and the vegetation coverage. Our results provide strong evidence that adult H. aegyptium is the predominant tick species found on wild spur-thighed tortoises in northern Tunisia, where the species is commonly traded illegally across the Mediterranean Basin. Considering the potential transmission of several zoonotic pathogens by H. aegyptium to humans, we highlight the need to develop a surveillance system to prevent the introduction and the spread of tick-borne pathogens in the Mediterranean Basin.

Genetic diversity of Borrelia burgdorferi sensu stricto: Novel strains from Mexican wild rodents

Borrelia burgdorferi s.s. is a Gram-negative spirochaete, the aetiological agent of Lyme disease, the most common vector-borne disease in the Northern hemisphere. Reports on the presence of B. burgdorferi in central Mexico have been strongly criticized, since these were based only on unspecific serological methods. Furthermore, the worldwide genetic diversity of B. burgdorferi s.s. has not been evaluated. For this reason, the aim of the present study was to confirm the presence of B. burgdorferi in the central area of Mexico and to evaluate its relationship with regard to the global genetic diversity of B. burgdorferi s.s. To achieve this, fragments of the flagellin and the outer surface protein A genes were amplified from ear biopsies of the arboreal wild endemic mice Habromys schmidlyi. With these sequences, a concatenated Bayesian analysis was performed to confirm the identity of B. burgdorferi s.s. Afterwards, the global genetic diversity of this bacterial species was evaluated using our sequences and those available in GenBank. A prevalence of 10.4% (5/48) of H. schmidlyi infected with Borrelia sp. was detected, and the phylogenetic analyses confirmed the identity of B. burgdorferi s.s. Using both genes, the genetic diversity was low. However, genetic structuring analyses revealed that populations of western United States and those from Mexico formed slightly different genetic groups, separated from the populations of the rest of the world. Our study not only confirms the presence of this bacterium in central Mexico, but also shows the most southern record of this bacterium so far. It also highlights the importance of H. schmidlyi as a new potential host of this bacterial species. Our study also provides first genetic data on an incipient process of divergence in B. burgdorferi s.s. populations of eastern United States and central Mexico.

The prevalence of Borrelia in Ixodes persulcatus in southeastern Kazakhstan

Borreliosis is one of the most common vector-borne zoonotic diseases in the world. Limited data are available regarding Borrelia spp. and their genotypes in Kazakhstan. The goal of this study was to investigate the prevalence of Borrelia spp. in ixodid ticks collected in the southeastern region of Kazakhstan. A total of 1907 ixodid ticks were collected by flagging vegetation at three collection areas in the Almaty oblast between 2015 and 2018. They were grouped into 407 pools and examined by qPCR for Borrelia burgdorferi sensu lato (s.l.). A conventional PCR with specific primers targeting 16S rRNA gene was used to differentiate B. burgdorferi s.l. genospecies. Sequence analysis of the PCR products was performed for sixteen samples. Lyme borreliosis agents were only detected in adult questing Ixodes persulcatus. The overall B. burgdorferi s.l. prevalence in I. persulcatus estimated as the minimum infection rate reached 10.7 %. Borrelia burgdorferi sensu stricto was not detected in any of the tick pools. Partial 16S rRNA gene sequencing revealed the presence of B. miyamotoi, B. afzelii, and B. garinii. Borrelia afzelii was the dominant genospecies in Almaty oblast. A significantly lower proportion of B. garinii positive tick pools was detected in the Zailiyskiy Alatau as compared to the Dzungarian Alatau (χ² = 16.243; p = 0.0001) and Yenbekshikazakh district (χ² = 7.4156; p = 0.0065). The obtained results indicate the epidemiological significance of B. afzelii and B. garinii in southeastern Kazakhstan. These new data aim to improve the diagnostics of Lyme borreliosis and monitoring of tick-borne infections in Kazakhstan.

Molecular Evidence of Hemolivia mauritanica, Ehrlichia spp. and the Endosymbiont Candidatus Midichloria Mitochondrii in Hyalomma aegyptium Infesting Testudo graeca Tortoises from Doha, Qatar

Simple Summary

Due to the veterinary and medical importance of pathogens transmitted by Hyalomma aegyptium, we tested ticks removed from Testudo graeca tortoises for the presence of Anaplasma, Ehrlichia, Hemolivia, Babesia and Hepatozoon. Forty-three percent of the examined adult ticks were infected with at least one agent. The most prevalent agent identified was Hemolivia mauritanica (28.6%), followed by Candidatus Midichloria mitochondrii (9.5%) and Ehrlichia spp. (4.7%). Our study reported for the first time H. mauritanica, Ehrlichia spp. and Candidatus M. mitochondrii in H. aegyptium ticks collected from pet spur-thighed tortoises, in Qatar, providing data that adds to the geographical extension of these agents.

Abstract

Tick-borne agents constitute a growing concern for human and animal health worldwide. Hyalomma aegyptium is a hard tick with a three-host life cycle, whose main hosts for adults are Palearctic tortoises of genus Testudo. Nevertheless, immature ticks can feed on a variety of hosts, representing an important eco-epidemiological issue regarding H. aegyptium pathogens circulation. Hyalomma aegyptium ticks are vectors and/or reservoirs of various pathogenic agents, such as Ehrlichia, Anaplasma, Babesia and Hepatozoon/Hemolivia. Ehrlichia and Anaplasma are emergent tick-borne bacteria with a worldwide distribution and zoonotic potential, responsible for diseases that cause clinical manifestations that grade from acute febrile illness to a fulminant disease characterized by multi-organ system failure, depending on the species. Babesia and Hepatozoon/Hemolivia are tick-borne parasites with increasing importance in multiple species. Testudo graeca tortoises acquired in a large animal market in Doha, Qatar, were screened for a panel of tick-borne pathogens by conventional PCR followed by bidirectional sequencing. The most prevalent agent identified in ticks was Hemolivia mauritanica (28.6%), followed by Candidatus Midichloria mitochondrii (9.5%) and Ehrlichia spp. (4.7%). All samples were negative for Babesia spp. and Hepatozoon spp. Overall, 43% of the examined adult ticks were infected with at least one agent. Only 4.7% of the ticks appeared to be simultaneously infected with two agents, i.e., Ehrlichia spp. and H. mauritanica. This is the first detection of H. mauritanica, Ehrlichia spp. and Candidatus M. mitochondrii in H. aegyptium ticks collected from pet spur-thighed tortoises, in Qatar, a fact which adds to the geographical extension of these agents. The international trade of Testudo tortoises carrying ticks infected with pathogens of veterinary and medical importance deserves strict control, in order to reduce potential exotic diseases.

A review on Hyalomma species infestations on human and animals and progress on management strategies

The Hyalomma species of ticks have gained additional attention due to their role in the transmission of Theileria annulata infection in animals and the Crimean-Congo Haemorrhagic Fever (CCHF) virus in humans. Apart from these, many other pathogens viz., other species of Theileria, a few species of Babesia, Rickettsia and viruses are either maintained or transmitted by this tick species. The medium to large size species with longer proboscis has inflicted additional burden on the overall impact of tick infestations. Being a multi-host species, management of the species is very challenging. Presently, the traditional method of tick management using chemical acaricides is found insufficient and unsustainable. Henceforth, the overall burden of tick infestations and tick-borne diseases are increasing gradually. After the successful development of vaccines against cattle tick, Rhipicephalus microplus, the anti-Hyalomma vaccine is considered a feasible and sustainable management option. In the recent past research on herbal acaricides and its possible application for tick control seems promising. Other eco-friendly methods are still under experimental stage. The present review is focused on impact of Hyalomma species infestation on human and animal health with special emphasis on progress on its sustainable management.

Ticks (Acari: Ixodidae) on birds migrating to the island of Ponza, Italy, and the tick-borne pathogens they carry

Seasonal migration of birds between breeding and wintering areas can facilitate the spread of tick species and tick-borne diseases. In this study, 151 birds representing 10 different bird species were captured on Ponza Island, an important migratory stopover off the western coast of Italy and screened for tick infestation. Ticks were collected and identified morphologically. Morphological identification was supported through sequencing a fragment of the 16S mitochondrial gene. In total, 16 captured birds carried ticks from four tick species: Hyalomma rufipes (n = 14), Amblyomma variegatum (n = 1), Amblyomma sp. (n = 1), and Ixodes ventalloi (n = 2). All specimens were either larvae (n = 2) or nymphs (n = 16). All ticks were investigated for tick-borne pathogens using published molecular methods. Rickettsia aeschlimannii was detected in six of the 14 collected H. rufipes ticks. Additionally, the singular A. variegatum nymph tested positive for R. africae. In all 14 H. rufipes specimens (2 larvae and 12 nymphs), Francisella-like endosymbionts were detected. Four H. rufipes ticks tested positive for Borrelia burgdorferi sensu lato in a screening PCR but did not produce sufficient amplicon amounts for species identification. All ticks tested negative for tick-borne encephalitis virus, Crimean-Congo hemorrhagic fever virus, Coxiella burnetii, Coxiella-like organisms, Babesia spp., and Theileria spp. This study confirms the role of migratory birds in the spread and establishment of both exotic tick species and tick-borne pathogens outside their endemic range.

A novel Borrelia species, intermediate between Lyme disease and relapsing fever groups, in neotropical passerine-associated ticks

Lyme disease (LD) and relapsing fevers (RF) are vector-borne diseases caused by bacteria of the Borrelia genus. Here, we report on the widespread infection by a non-described Borrelia species in passerine-associated ticks in tropical rainforests of French Guiana, South America. This novel Borrelia species is common in two tick species, Amblyomma longirostre and A. geayi, which feed on a broad variety of neotropical mammal and bird species, including migratory species moving to North America. The novel Borrelia species is divergent from the LD and RF species, and is more closely related to the reptile- and echidna-associated Borrelia group that was recently described. Genome sequencing showed that this novel Borrelia sp. has a relatively small genome consisting of a 0.9-Mb-large chromosome and an additional 0.3 Mb dispersed on plasmids. It harbors an RF-like genomic organization but with a unique mixture of LD- and RF-specific genes, including genes used by RF Borrelia for the multiphasic antigen-switching system and a number of immune-reactive protein genes used for the diagnosis of LD. Overall, our data indicate that this novel Borrelia is an intermediate taxon between the LD and RF species that may impact a large host spectrum, including American mammals. The designation "Candidatus Borrelia mahuryensis" is proposed for this species.

Molecular detection of reptile-associated Borrelia in Boa constrictor (Squamata: Boidae) from Veracruz, Mexico

The reptile-associated Borrelia represent a monophyletic group of bacteria transmitted by several species of hard ticks, which has been reported to only infect amphibians and reptiles in Eurasia and Middle East, however, this bacterial group has not been studied in North America. The aim of this study was to assess the presence of Borrelia spirochetes in blood samples of native reptiles of Mexico. Blood samples were directly obtained from individuals, DNA extractions were performed using Chelex-100. The Borrelia detection was performed by conventional PCR. From 102 reptiles tested, only five individuals of Boa constrictor were positive for the presence of DNA of the reptile-associated Borrelia group. Supported by phylogenetic analysis, this study presents the first record of these spirochetes group in Mexico, and initial evidence of B. constrictor as a host of this group.

Bacterial and protozoan agents found in Hyalomma aegyptium (L., 1758) (Ixodida: Ixodidae) collected from Testudo graeca L., 1758 (Reptilia: Testudines) in Corum Province of Turkey

Hyalomma aegyptium (L., 1758) (Ixodida: Ixodidae) is a hard tick and the main host for adults are Palearctic tortoises of the genus Testudo, while larvae and nymphs are less host-specific and nymphs also attach to humans. In the present study, a total of 261 H. aegyptium ticks were removed from 26 Testudo graeca L., 1758 in Corum Province of Turkey. The most prevalent pathogens identified molecularly in the ticks were Hemolivia mauritanica (51.9 %), followed by Rickettsia aeschlimannii (32.6 %), Ehrlichia spp. (30.2 %), and Bartonella bovis (0.8 %). All samples were negative for Coxiella burnetii, Francisella tularensis, Anaplasma phagocytophilum, Babesia spp., Hepatozoon spp. and Theileria spp. Overall, 97.4 % of the examined adult ticks and 26.3 % of nymphs were infected with at least one pathogen, while 40.9 % of all ticks were infected with only one pathogen, 27.4 % with two pathogens, and 9.9 % with three pathogens, concomitantly. Overall, 80.8 % of the examined blood smears of tortoises were H. mauritanica-positive, and the mean intensity of parasitemia was 4.8 % (1-21). As a conclusion, since the examined tortoises were sampled in gardens and vineyards close to human habitation, and as a relatively large percentage of them were infested with ticks carrying pathogenic agents affecting also humans, the importance of tortoises, their ticks and pathogens in terms of the public health should be farther examined.

Population structure of Borrelia turcica from Greece and Turkey

Borrelia turcica, a member of the reptile-associated Borrelia clade, is vectored by Hyalomma aegyptium. The only suggested reservoir hosts of B. turcica are tortoises of the genus Testudo. Borrelia turcica has been described to occur in several Southeastern European countries including Turkey, Romania, Bulgaria and Greece but so far nothing is known about the relationship of these populations and whether or how they are structured. Using multilocus sequence typing (MLST) on eight chromosomally located housekeeping loci (clpA, clpX, nifS, pepX, pyrG, recG, rplB and uvrA) we analyzed 43 B. turcica isolates from Serres, Greece (n = 15) collected in 2017 and Izmir, Turkey (n = 28) collected in 2018. To understand their relationship a maximum-likelihood phylogenetic tree and goeBURST analysis were done based on MLST sequence data and allelic profiles, respectively. The data we generated confirmed that the samples of B. turcica investigated here were divergent from Lyme disease (LD) and relapsing fever (RF) species. Within the B. turcica clade, samples of different geographic origin (Greece, Turkey) clustered together in terminal branches; no obvious differences between the Greek and Turkish samples were noticeable. A goeBURST analysis using triple-locus variants revealed very few clonal complexes with the majority of samples appearing as singletons. Minor clonal complexes (consisting of two sequence types) comprised only Greek isolates, only Turkish isolates or both, so no pattern of clustering of isolates from the two geographical regions was observed. Interestingly, very little population structure was discerned in our study. This was surprising in view of the large geographic distance between collection sites of B. turcica and raises questions about the evolution or spatial spread of this species.

First investigations on serum resistance and sensitivity of Borrelia turcica

Borrelia turcica is a reptile-associated Borrelia species that is vectored by the hard tick Hyalomma aegyptium. Tortoises of the genus Testudo represent the principal host of adult H. aegyptium, while immature stages are less host-specific and can be found on various vertebrates and even on humans. Borrelia turcica isolates were already successfully obtained from exotic tortoises suggesting that they are putative hosts. To the best of our knowledge, no further investigations on additional host association of B. turcica were conducted. Since many but not all adult Hyalomma ticks collected from tortoises are infected, questions arise about the direction of transmission between tick and tortoises for this Borrelia species. In addition, there is no information on the potential pathogenicity of B. turcica for humans. For other Borrelia species it has been shown that resistance or sensitivity to complement-active serum can be indicative of host species association(s). In this study, we explored for the first time the in vitro survival of B. turcica isolates from Turkey (IST7) and Greece (171601G) in the presence of 50% complement-active serum of different species (tortoise, turtle, human and bird). Both isolates showed resistance to tortoise serum, partial resistance to turtle serum but did not survive human and bird serum. These data suggest that indeed tortoises are reservoir host species for B. turcica while birds or humans are not. By implication these data suggest that B. turcica is not human pathogenic. Whether or not other reptile species, such as lizards, are also potential hosts, requires further investigation. However, as the life cycle of Borrelia is closely linked to that of their hosts and vectors, in vitro studies can only give clues about the actual in vivo behavior.

A cross-sectional screening by next-generation sequencing reveals Rickettsia, Coxiella, Francisella, Borrelia, Babesia, Theileria and Hemolivia species in ticks from Anatolia

Background

Ticks participate as arthropod vectors in the transmission of pathogenic microorganisms to humans. Several tick-borne infections have reemerged, along with newly described agents of unexplored pathogenicity. In an attempt to expand current information on tick-associated bacteria and protozoans, we performed a cross-sectional screening of ticks, using next-generation sequencing. Ticks seeking hosts and infesting domestic animals were collected in four provinces across the Aegean, Mediterranean and Central Anatolia regions of Turkey and analyzed by commonly used procedures and platforms.

Results

Two hundred and eighty ticks comprising 10 species were evaluated in 40 pools. Contigs from tick-associated microorganisms were detected in 22 (55%) questing and 4 feeding (10%) tick pools, with multiple microorganisms identified in 12 pools. Rickettsia 16S ribosomal RNA gene, gltA, sca1 and ompA sequences were present in 7 pools (17.5%), comprising feeding Haemaphysalis parva and questing/hunting Rhipicephalus bursa, Rhipicephalus sanguineus (sensu lato) and Hyalomma marginatum specimens. A near-complete genome and conjugative plasmid of a Rickettsia hoogstraalii strain could be characterized in questing Ha. parva. Coxiella-like endosymbionts were identified in pools of questing (12/40) as well as feeding (4/40) ticks of the genera Rhipicephalus, Haemaphysalis and Hyalomma. Francisella-like endosymbionts were also detected in 22.5% (9/40) of the pools that comprise hunting Hyalomma ticks in 8 pools. Coxiella-like and Francisella-like endosymbionts formed phylogenetically distinct clusters associated with their tick hosts. Borrelia turcica was characterized in 5% (2/40) of the pools, comprising hunting Hyalomma aegyptium ticks. Co-infection of Coxiella-like endosymbiont and Babesia was noted in a questing R. sanguineus (s.l.) specimen. Furthermore, protozoan 18S rRNA gene sequences were detected in 4 pools of questing/hunting ticks (10%) and identified as Babesia ovis, Hemolivia mauritanica, Babesia and Theileria spp.

Conclusions

Our metagenomic approach enabled identification of diverse pathogenic and non-pathogenic microorganisms in questing and feeding ticks in Anatolia.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3277-7) contains supplementary material, which is available to authorized users.

The genus Borrelia reloaded

The genus Borrelia, originally described by Swellengrebel in 1907, contains tick- or louse-transmitted spirochetes belonging to the relapsing fever (RF) group of spirochetes, the Lyme borreliosis (LB) group of spirochetes and spirochetes that form intermittent clades. In 2014 it was proposed that the genus Borrelia should be separated into two genera; Borrelia Swellengrebel 1907 emend. Adeolu and Gupta 2014 containing RF spirochetes and Borreliella Adeolu and Gupta 2014 containing LB group of spirochetes. In this study we conducted an analysis based on a method that is suitable for bacterial genus demarcation, the percentage of conserved proteins (POCP). We included RF group species, LB group species and two species belonging to intermittent clades, Borrelia turcica Güner et al. 2004 and Candidatus Borrelia tachyglossi Loh et al. 2017. These analyses convincingly showed that all groups of spirochetes belong into one genus and we propose to emend, and re-unite all groups in, the genus Borrelia.

Genome-wide analysis of Borrelia turcica and 'Candidatus Borrelia tachyglossi' shows relapsing fever-like genomes with unique genomic links to Lyme disease Borrelia

Borrelia are tick-borne bacteria that in humans are the aetiological agents of Lyme disease and relapsing fever. Here we present the first genomes of B. turcica and B. tachyglossi, members of a recently described and rapidly expanding Borrelia clade associated with reptile (B. turcica) or echidna (B. tachyglossi) hosts, transmitted by hard ticks, and of unknown pathogenicity. Borrelia tachyglossi and B. turcica genomes are similar to those of relapsing fever Borrelia species, containing a linear ~ 900 kb chromosome, a single long (> 70 kb) linear plasmid, and numerous short (< 40 kb) linear and circular plasmids, as well as a suite of housekeeping and macronutrient biosynthesis genes which are not found in Lyme disease Borrelia. Additionally, both B. tachyglossi and B. turcica contain paralogous vsp and vlp proteins homologous to those used in the multiphasic antigen-switching system used by relapsing fever Borrelia to evade vertebrate immune responses, although their number was greatly reduced compared to human-infectious species. However, B. tachyglossi and B. turcica chromosomes also contain numerous genes orthologous to Lyme disease Borrelia-specific genes, demonstrating a unique evolutionary, and potentially phenotypic link between these groups. Borrelia tachyglossi and B. turcica genomes also have unique genetic features, including degraded and deleted tRNA modification genes, and an expanded range of macronutrient salvage and biosynthesis genes compared to relapsing fever and Lyme disease Borrelia. These genomes and genomic comparisons provide an insight into the biology and evolutionary origin of these Borrelia, and provide a valuable resource for future work.

Assessment of bacterial diversity in Hyalomma aegyptium, H. marginatum and H. excavatum ticks through tag-encoded pyrosequencing

Ticks are among the most significant human-biting ectoparasites and they play a major role in transmission of many pathogenic agents to humans. In the present study, three species of Hyalomma ticks, Hyalomma aegyptium, H. marginatum and H. excavatum, were examined for the presence of zoonotic bacteria, both male and female ticks alike. Examination of microbial diversity with tag-encoded pyrosequencing indicates that H. marginatum and H. excavatum were more diversity rich than H. aegyptium. Although numerous pathogenic and non-pathogenic bacterial genera were detected, including Acidovorax, Bacillus, Bacteroides, Bdellovibrio, Clostridium, Curvibacter, Escherichia, Flavobacterium, Limnohabitans, Paenibacillus, Ralstonia, Sarcina, Sediminibacterium, Segetibacter Stenotrophomonas and Variovorax, the predominant zoonotic bacteria represented in these ticks were genera Borrelia, Francisella, and Rickettsia. To the authors' knowledge, this work represents the first detection of Yersinia enterocolitica in the tick H. excavatum, raising questions regarding the vector competency of this tick, as well as associations of different disease representations perhaps through previously unforeseen routes of pathogen introduction. Likewise, similar questions are related to the presence of Legionella pneumophila in one H. excavatum sample.

Molecular characterization of Babesia species in wild animals and their ticks in Turkey

To date, no study has investigated Babesia ecology in wild boars, hares or foxes in Turkey. This study aimed to determine and characterize Babesia spp. in wild animals and their ticks. We identified a novel Babesia genotype and four known Babesia species in wild animals and their ticks. We detected Babesia spp. molecularly in hares for the first time. In addition, we identified B. vulpes in foxes for the first time in Turkey. The presence of B. rossi, B. crassa and B. occultans was also revealed in ticks collected from wild boars and hares. This is only the second report of B. rossi in ticks outside of Africa and suggests that B. rossi is circulating in ticks in Turkey. Therefore B. rossi poses a significant threat to domestic dogs. Here we demonstrate the role of wild animals in the life cycle of Babesia species in Turkey and contribute to Babesia ecological and taxonomic information.

Molecular characterization of 'Candidatus Borrelia tachyglossi' (family Spirochaetaceae) in echidna ticks, Bothriocroton concolor

Recently, a novel species of the genus Borreliawas identified in Bothriocroton concolor and Ixodes holocyclus ticks from echidnas. Analyses of 16S rRNA and flaB genes identified three closely related genotypes of this bacterium (Borrelia sp. Aus A-C) that were unique and distinct from previously described borreliae. Phylogenetic analyses of flaB (763 bp), groEL (1537 bp), gyrB (1702 bp) and glpQ (874 bp) gene sequences and concatenated sequences (3585 bp) of three gene loci (16S rRNA, flaB and gyrB) were consistent with previous findings and confirm that this novel species of the genus Borrelia is more closely related to, yet distinct from, the Reptile-associated (REP) and Relapsing Fever (RF) groups. At the flaB locus, genotypes A, B and C shared the highest percentage sequence similarities (87.9, 88 and 87.9 %, respectively) with B.orrelia turcica (REP), whereas at the groEL and gyrB loci, these genotypes were most similar (88.2–89.4 %) to B.orrelia hermsii (RF). At the glpQ locus, genotypes A and B were most similar (85.7 and 85.4 % respectively) to Borrelia sp. Tortoise14H1 (REP). The presence of the glpQ gene, which is absent in the Lyme Borreliosis group spirochaetes, further emphasises that the novel species of the genus Borrelia characterized in the present study does not belong to this group. Phylogenetic analyses at multiple loci produced consistent topographies revealing the monophyletic grouping of this bacterium, therefore providing strong support for its species status. We propose the name ‘CandidatusBorrelia tachyglossi’, and hypothesize that this species of the genus Borrelia may be endemic to Australia. The pathogenic potential of this bacterium is not yet known.

Ixodoidea of the Western Palaearctic: A review of available literature for identification of species

We aim to produce a review of the most important literature references necessary for the identification of ticks of the families Ixodidae and Argasidae in Europe and northern Africa (i.e. the Western Palaearctic region). The purpose of this paper is to pinpoint a set of critically selected papers that contain reliable information on morphology, taxonomic keys, and comparative discussions which are critical for the identification of the ticks reported in the target region. When necessary, comments are provided on the systematic position of a species, or on suitable papers already addressing the issue. This review includes a list of 216 references which cover all Ixodoidea species reported as permanent residents of the Western Palaearctic, namely 28 species of the genus Ixodes, two Dermacentor, seven Haemaphysalis, nine Hyalomma, eight Rhipicephalus, five Argas and about seven species of Ornithodoros.

Tick-Borne Diseases in Turkey: A Review Based on One Health Perspective

The importance of tick-borne diseases is increasing all over the world, including Turkey. Global warming, environmental and ecological changes and the existence of suitable habitats increase the impact of ticks and result in frequent emergence or re-emergence of tick-borne diseases (TBDs) with zoonotic characteristics. In Turkey, almost 19 TBDs have been reported in animals and men, involving four protozoa (babesiosis, theileriosis, cytauxzoonosis, hepatozoonosis), one filarial nematode (acanthocheilonemasis), ten bacterial agents (anaplasmosis, ehrlichiosis, aegyptianellosis, tick-borne typhus, Candidatus Rickettsia vini, Lyme borreliosis, tick-borne relapsing fever [TBRF], tularaemia, bartonellosis, and hemoplasmosis), and four viral infections (tick-borne encephalitis [TBE], Crimean-Congo Haemorrhagic Fever [CCHF], louping-ill [LI], and lumpy skin disease [LSD]). The growing number of TBD cases, in particular the fatal viral epidemics in humans, have led to increased public awareness and concern against TBDs in recent years. The World Health Organization (WHO) has developed a new political concept, called the "One Health" initiative, which is especially relevant for developing strategies against tick infestations and TBD control in humans and animals. It would be beneficial for Turkey to adopt this new strategy and establish specific research and control programs in coordination with international organizations like WHO, the World Organization for Animal Health (OIE), the Food and Agriculture Organization (FAO), the Centers for Disease Control and Prevention (CDC), and the European Center for Disease Prevention and Control (ECDC) to combat TBDs based on the "One Health Initiative" concept. In this article, we review the occurrence of primary TBDs in man and animals in Turkey in light of the "One Health" perspective.

Emerging borreliae - Expanding beyond Lyme borreliosis

Lyme borreliosis (or Lyme disease) has become a virtual household term to the exclusion of other forgotten, emerging or re-emerging borreliae. We review current knowledge regarding these other borreliae, exploring their ecology, epidemiology and pathological potential, for example, for the newly described B. mayonii. These bacteria range from tick-borne, relapsing fever-inducing strains detected in some soft ticks, such as B. mvumii, to those from bat ticks resembling B. turicatae. Some of these emerging pathogens remain unnamed, such as the borrelial strains found in South African penguins and some African cattle ticks. Others, such as B. microti and unnamed Iranian strains, have not been recognised through a lack of discriminatory diagnostic methods. Technical improvements in phylogenetic methods have allowed the differentiation of B. merionesi from other borrelial species that co-circulate in the same region. Furthermore, we discuss members that challenge the existing dogma that Lyme disease-inducing strains are transmitted by hard ticks, whilst the relapsing fever-inducing spirochaetes are transmitted by soft ticks. Controversially, the genus has now been split with Lyme disease-associated members being transferred to Borreliella, whilst the relapsing fever species retain the Borrelia genus name. It took some 60 years for the correlation with clinical presentations now known as Lyme borreliosis to be attributed to their spirochaetal cause. Many of the borreliae discussed here are currently considered exotic curiosities, whilst others, such as B. miyamotoi, are emerging as significant causes of morbidity. To elucidate their role as potential pathogenic agents, we first need to recognise their presence through suitable diagnostic approaches.

Borrelia sp. phylogenetically different from Lyme disease- and relapsing fever-related Borrelia spp. in Amblyomma varanense from Python reticulatus

Background

Species of the genus Borrelia are causative agents of Lyme disease and relapsing fever. Lyme disease is the most commonly reported vector-borne disease in the northern hemisphere. However, in some parts of the world Lyme borreliosis and relapsing fever may be caused by novel Borrelia genotypes. Herein, we report the presence of a Borrelia sp. in an Amblyomma varanense collected from Python reticulatus.

Methods

Ticks were collected from snakes, identified to species level and examined by PCR for the presence of Borrelia spp. flaB and 16S rRNA genes. Phylogenetic trees were constructed using the neighbour-joining method.

Results

Three A. varanense ticks collected from P. reticulatus were positive for a unique Borrelia sp., which was phylogenetically divergent from both Lyme disease- and relapsing fever-associated Borrelia spp.

Conclusion

The results of this study suggest for the first time that there is a Borrelia sp. in A. varanense tick in the snake P. reticulatus that might be novel.

Novel Borrelia species detected in echidna ticks, Bothriocroton concolor, in Australia

BACKGROUND

To date, little has been documented about microorganisms harboured within Australian native ticks or their pathogenic potential. Recently, a Borrelia sp. related to the Relapsing Fever (RF) group was identified in a single tick removed from a wild echidna (Tachyglossus aculeatus). The present study investigated the presence of Borrelia in 97 Bothriocroton concolor ticks parasitizing echidnas in Queensland, New South Wales, and Victoria, Australia, using nested PCR with Borrelia-specific primers targeting the 16S rRNA (16S) and flaB genes.

RESULTS

Borrelia-specific PCR assays confirmed the presence of a novel Borrelia sp. related to the RF and reptile-associated (REP) spirochaetes in 38 (39 %) B. concolor ticks. This novel Borrelia sp. was identified in 41 % of the B. concolor ticks in Queensland and New South Wales, but not in any ticks from Victoria. The resulting flaB sequences (407 bp) were 88 and 86 % similar to the flaB sequences from Borrelia turcica and Borrelia hermsii, respectively. Of the ticks confirmed as Borrelia-positive following the flaB assay, 28 were positive with the 16S assay. Phylogenetic analysis of the 16S sequences (1097 bp) suggests that these sequences belong to a novel Borrelia sp., which forms a unique monophyletic clade that is similar to, but distinct from, RF Borrelia spp. and REP-associated Borrelia spp.

CONCLUSIONS

We conclude that the novel Borrelia sp. identified in this study does not belong to the Borrelia burgdorferi (sensu lato) complex, and that the phylogenetic analysis of the partial 16S gene sequences suggests it forms a unique monophyletic cluster in the genus Borrelia, potentially forming a fourth major group in this genus associated with monotremes in Australia. However, a thorough molecular characterisation will be required to confirm the phylogenetic position of this unique Borrelia sp. The zoonotic potential and pathogenic consequences of this novel Borrelia sp. are unknown at the current time.

Molecular identification of Borrelia genus in questing hard ticks from Portugal: Phylogenetic characterization of two novel Relapsing Fever-like Borrelia sp

In the last decades, several studies have reported pathogenic species of Borrelia related to those that cause Tick-borne Relapsing Fever (RF), but unexpectedly suggesting their transmission by hard ticks, known vectors of Borrelia burgdorferi sensu lato (B. burgdorferi s.l.) species, rather than by soft ticks. This study was designed to update the presence of B. burgdorferi s.l. species in ticks from several districts of mainland Portugal, where Ixodes ricinus had been previously described. Ticks (a total of 2915 specimens) were collected in seven districts throughout the country, and analyzed using molecular methods. Three nested-PCR protocols, targeting the flagellin gene (flaB), the intergenic spacer region (IGS) located between 5S and 23S rRNA, and the glpQ gene, and a conventional PCR targeting the 16S rRNA, were used for Borrelia DNA detection. Borrelia DNA was detected in 3% of the ticks from Braga, Vila Real, Lisboa, Setúbal, Évora and Faro districts. The obtained amplicons were sequenced and analyzed by BLASTn, and 15/63 (24%) matched with homologous sequences from Borrelia lusitaniae and 15/63 (24%) with B. garinii, being these the most prevalent species. DNA from B. burgdorferi sensu stricto (s.s.), B. valaisiana and B. afzelii were detected in 7/63 (11%), 6/63 (10%), and 2/63 (3%) of the specimens, respectively. Unexpectedly, DNA sequence (flaB) analysis from eight (13%) samples, two from Rhipicephalus sanguineus and six from Haemaphysalis punctata tick species, revealed high homology with RF-like Borrelia. Phylogenetic analyses obtained from three genetic markers (16S rRNA, flaB, and glpQ) confirmed their congruent inclusion in a strongly supported RF cluster, where they segregated in two subgroups which differ from the other Relapsing Fever species. Therefore, the results confirm the circulation of multiple species of B. burgdorferi s.l. over a wide geographic range, covering most of the Portuguese mainland territory. Surprisingly, the obtained data also revealed two putative Relapsing Fever-like Borrelia species in different species of hard ticks, possibly disclosing the circulation of novel RF-like Borrelia species with different associated tick vectors.

Ticks and tick-borne pathogens in wild birds in Greece

Wild birds are common hosts of ticks and can transport them for long distances, contributing to the spreading of tick-borne pathogens. The information about ticks on birds and tick-borne pathogens in Greece is limited. The present study aimed to evaluate the prevalence and species of ticks infesting wild resident birds (mostly small passerines) in Greece, and to assess Borrelia and Rickettsia infection in the collected ticks. Detection of Borrelia burgdorferi s.l. was performed by nested PCR targeting the flaB gene. Rickettsia spp. were detected by PCR targeting the gltA and ompA genes. Seven (2 %) out of 403 birds examined in northern Greece in 2013 were infested with 15 ticks, identified as Ixodes frontalis, Ixodes acuminatus, Hyalomma marginatum, Hyalomma aegyptium and Hyalomma sp. All ticks were negative for Borrelia spp. while four of them were positive for rickettsiae (Rickettsia aeschlimannii in H. aegyptium and Rickettsia sp. in I. frontalis, H. aegyptium and H. marginatum). Ixodes acuminatus is reported for the first time in Greece and Sylvia borin is reported as a new host record for I. acuminatus.

Interaction of spirochetes with the host fibrinolytic system and potential roles in pathogenesis

The pathogenic spirochetes Borrelia burgdorferi, B. hermsii, B. recurrentis, Treponema denticola and Leptospira spp. are the etiologic agents of Lyme disease, relapsing fever, periodontitis and leptospirosis, respectively. Lyme borreliosis is a multi-systemic disorder and the most prevalent tick-borne disease in the northern hemisphere. Tick-borne relapsing fever is persistent in endemic areas worldwide, representing a significant burden in some African regions. Periodontal disease, a chronic inflammatory disorder that often leads to tooth loss, is caused by several potential pathogens found in the oral cavity including T. denticola. Leptospirosis is considered the most widespread zoonosis, and the predominant human disease in tropical, undeveloped regions. What these diseases have in common is that they are a significant burden to healthcare costs in the absence of prophylactic measures. This review addresses the interaction of these spirochetes with the fibrinolytic system, plasminogen (Plg) binding to the surface of bacteria and the generation of plasmin (Pla) on their surface. The consequences on host-pathogen interactions when the spirochetes are endowed with this proteolytic activity are discussed on the basis of the results reported in the literature. Spirochetes equipped with Pla activity have been shown to degrade extracellular matrix (ECM) components, in addition to digesting fibrin, facilitating bacterial invasion and dissemination. Pla generation triggers the induction of matrix metalloproteases (MMPs) in a cascade of events that enhances the proteolytic capacity of the spirochetes. These activities in concert with the interference exerted by the Plg/Pla on the complement system - helping the bacteria to evade the immune system - should illuminate our understanding of the mechanisms involved in host infection.

Transstadial transmission of Borrelia turcica in Hyalomma aegyptium ticks

Borrelia turcica comprises the third major group of arthropod-transmitted borreliae and is phylogenetically divergent from other Borrelia groups. The novel group of Borrelia was initially isolated from Hyalomma aegyptium ticks in Turkey and it was recently found in blood and multiple organs of tortoises exported from Jordan to Japan. However, the ecology of these spirochetes and their development in ticks or the vertebrate hosts were not investigated in detail; our aims were to isolate the pathogen and to evaluate the possibility of transstadial transmission of Borrelia turcica by H. aegyptium ticks. Ticks were collected from Testudo graeca tortoises during the summer of 2013 from southeastern Romania. Engorged nymphs were successfully molted to the adult stage. Alive B. turcica was isolated from molted ticks by using Barbour-Stoenner-Kelly (BSK) II medium. Four pure cultures of spirochetes were obtained and analyzed by PCR and sequencing. Sequence analysis of glpQ, gyrB and flaB revealed 98%–100% similarities with B. turcica. H. aegyptium ticks collected from T. graeca tortoises were able to pass the infection with B. turcica via transstadial route, suggesting its vectorial capacity.

Molecular Typing of Borrelia burgdorferi

Borrelia burgdorferi sensu lato is a group of spirochetes belonging to the genus Borrelia in the family of Spirochaetaceae. The spirochete is transmitted between reservoirs and hosts by ticks of the family Ixodidae. Infection with B. burgdorferi in humans causes Lyme disease or Lyme borreliosis. Currently, 20 Lyme disease-associated Borrelia species and more than 20 relapsing fever-associated Borrelia species have been described. Identification and differentiation of different Borrelia species and strains is largely dependent on analyses of their genetic characteristics. A variety of molecular techniques have been described for Borrelia isolate speciation, molecular epidemiology, and pathogenicity studies. In this unit, we focus on three basic protocols, PCR-RFLP-based typing of the rrs-rrlA and rrfA-rrlB ribosomal spacer, ospC typing, and MLST. These protocols can be employed alone or in combination for characterization of B. burgdorferi isolates or directly on uncultivated organisms in ticks, mammalian host reservoirs, and human clinical specimens.

A look into the Medical and Veterinary Entomology crystal ball

Medical and Veterinary Entomology (MVE) represents a leading periodical in its field and covers many aspects of the biology and control of insects, ticks, mites and other arthropods of medical and veterinary importance. Since the first issue of the journal, researchers working in both developed and developing countries have published in MVE, with direct impact on current knowledge in the field. An increasing number of articles dealing with the epidemiology and transmission of vector-borne pathogens have been published in MVE, reflecting rapid changes in vector distribution, pathogen transmission and host-arthropod interactions. This article represents a gaze into the crystal ball in which we identify areas of increasing interest, discuss the main changes that have occurred in the epidemiology of parasitic arthropods since the first issue of MVE, and predict the principal scientific topics that might arise in the next 25 years for scientists working in medical and veterinary entomology.

Detection of a Borrelia species in questing Gulf Coast ticks, Amblyomma maculatum

Borrelia spp. are agents of Lyme disease and relapsing fever, diseases which use Ixodes hard ticks and Ornithodoros soft ticks, respectively, as primary vectors. Some relapsing fever spirochetes, such as B. miyamotoi, are also found in hard ticks. To date, no Borrelia sp. is known to use the hard tick, Amblyomma maculatum, as a vector. However, both B. burgdorferi and B. lonestari were recently detected in A. maculatum removed from hosts. In our study, DNA extracts from 306 questing adult A. maculatum collected in Mississippi in 2009 and 2010 were tested for Borrelia spp. DNA by PCR amplification of flaB and 16S rRNA gene targets. An additional 97 A. maculatum collected in 2013 were tested by amplification of 16S rRNA gene target. Two ticks, one collected in 2009 and the other in 2010, were positive by PCR of the flaB and 16S rRNA gene targets; both were collected from the same location in central Mississippi. Interestingly, 16S rRNA gene amplicons from these two tick extracts were 98% identical to twelve Borrelia spp. including the reptile-associated spirochete B. turcica and Borrelia sp. "tAG158M"; flaB amplicons from these two ticks shared closest identity (89%) to the reptile-associated spirochete, B. turcica. These results demonstrate a Borrelia sp. in unfed A. maculatum ticks that is unique from other species in the NCBI database and in a clade with reptile-associated Borrelia species. Detection of a previously unrecognized Borrelia in a hard tick species generates additional questions regarding the bacterial fauna in these arthropods and warrants further studies to better understand this fauna.

Zoonotic pathogens associated with Hyalomma aegyptium in endangered tortoises: evidence for host-switching behaviour in ticks?

BACKGROUND

Hyalomma aegyptium is a hard-tick with a typical three-host life cycle. The main hosts are Palearctic tortoises of genus Testudo. However, other hosts can be used by immature ticks for feeding in natural conditions. Given this complex ecology and multiple host use, the circulation of pathogens by H. aegyptium between various hosts can be important from epidemiological point of view. The aim of this study was to evaluate the role of H. aegyptium as natural carrier of four important zoonotic pathogens.

METHODS

From 2008 to 2011, 448 H. aegyptium ticks were collected from 45 Spur-thighed tortoises, Testudo graeca in Romania. DNA was extracted individually from each tick using a commercial kit. DNA was examined for the presence of specific sequences of Borrelia burgdorferi s.l., Anaplasma phagocytophilum, Ehrlichia canis and Coxiella burnetii by PCR, according to previously described protocols.

RESULTS

PCR analysis of H. aegyptium revealed the presence of A. phagocytophilum (18.8%), E. canis (14.1%) and C. burnetii (10%). 32.4% of the ticks were infected with at least one pathogen and 9.8% had co-infections. The stages most frequently infected were nymphs (50%) followed by males (33.9%) and females (27%). The number of tortoises which harboured infected ticks was 27/45 examined (60%). From all tested T. graeca, 40% harboured ticks infected with A. phagocytophilum, 46.7% had ticks infected with E. canis and 33.3% had ticks with C. burnetii. This study reports for the first time the presence of A. phagocytophilum and E. canis in H. aegyptium.

CONCLUSIONS

The presence and relatively high prevalence of three important zoonotic pathogens in H. aegyptium raises the question of their epidemiologic importance in disease ecology. As tortoises are unlikely to be reservoir hosts for A. phagocytophilum and E. canis and both these pathogens are common in H. aegyptium, this is an important indication for (1) a possible increased host-switching behaviour of these ticks to competent reservoir hosts (i.e. hedgehogs) and (2) transstadial transmission. Furthermore, if we consider also the presence of C. burnetii, we conclude that T. graeca and its ticks should be evaluated more seriously when assessing the eco-epidemiology of zoonotic diseases.

Exploring gaps in our knowledge on Lyme borreliosis spirochaetes--updates on complex heterogeneity, ecology, and pathogenicity

The Lyme borreliosis complex is a heterogeneous group of tick-borne spirochaetes of the genus Borrelia (Spirochaetales: Spirochaetaceae) that are distributed all over the temperate zone of the northern hemisphere. Due to the usage of new methods for phylogenetic analysis, this group has expanded rapidly during the past 5 years. Along with this development, the number of Borrelia spp. regarded as pathogenic to humans also increased. Distribution areas as well as host and vector ranges of Lyme borreliosis agents turned out to be much wider than previously thought. Furthermore, there is evidence that ticks, reservoir hosts, and patients can be coinfected with multiple Borrelia spp. or other tick-borne pathogens, which indicates a need to establish new and well-defined diagnostic and therapeutic standards for Lyme borreliosis. This review gives a broad overview on the occurrence of Lyme borreliosis spirochaetes worldwide with particular emphasis on their vectors and vertebrate hosts as well as their pathogenic potential and resultant problems in diagnosis and treatment. Against the background that many issues regarding distribution, species identity, ecology, pathogenicity, and coinfections are still unsolved, the purpose of this article is to reveal directions for future research on the Lyme borreliosis complex.

Risk for the introduction of exotic ticks and pathogens into Italy through the illegal importation of tortoises, Testudo graeca

In April 2008, 585 tortoises illegally imported into Italy from North Africa were examined for the presence of ticks. Of these, 221 tortoises (37.8%) were infested with a mean intensity of 3.9 +/- 3.1 ticks (range 1-17 ticks). A total of 798 ticks (672 males, 125 females and one nymph) were collected and identified as Hyalomma aegyptium (L.) (Acari: Ixodidae). The overall male : female ratio observed was 5 : 1. The prevalence and mean intensity [+/-standard deviation (SD)] of ticks were higher among male (67.4%, 4.0 +/- 3.2) than female (55.6%, 3.8 +/- 3.1) tortoises, although this difference was not significant. By contrast, the prevalence and mean intensity of ticks were significantly higher on tortoises weighing >100 g (61.5%, 4.0 +/- 3.2) compared with tortoises weighing <100 g (12.1%, 2.1 +/- 1.1). Of the infested tortoises, 89.8% had ticks on their hind limbs, 21.0% on forelimbs, 18.6% on the tail and pre-anal area, and 4.8% on the head; thus the hind limbs were evidently the preferred attachment site. The present report highlights the need to develop surveillance systems to prevent the introduction and spreading of exotic ticks and tick-borne pathogens in Italy and other European countries.