A novel duplex real-time PCR permits simultaneous detection and differentiation of Borrelia miyamotoi and Borrelia burgdorferi sensu lato

Development and validation of a multi-target TaqMan qPCR method for detection of Borrelia burgdorferi sensu lato

Reliable detection of bacteria belonging to the Borrelia burgdorferi sensu lato species complex in vertebrate reservoirs, tick vectors, and patients is key to answer questions regarding Lyme borreliosis epidemiology. Nevertheless, the description of characteristics of qPCRs for the detection of B. burgdorferi s. l. are often limited. This study covers the development and validation of two duplex taqman qPCR assays used to target four markers on the chromosome of genospecies of B. burgdorferi s. l. Analytical specificity was determined with a panel of spirochete strains. qPCR characteristics were specified using water or tick DNA spiked with controlled quantities of the targeted DNA sequences of B. afzelii, B. burgdorferi sensu stricto or B. bavariensis. The effectiveness of detection results was finally evaluated using DNA extracted from ticks and biopsies from mammals whose infectious status had been determined by other detection assays. The developed qPCR assays allow exclusive detection of B. burgdorferi s. l. with the exception of the M16 marker which also detect relapsing fever Borreliae. The limit of detection is between 10 and 40 copies per qPCR reaction depending on the sample type, the B. burgdorferi genospecies and the targeted marker. Detection tests performed on various kind of samples illustrated the accuracy and robustness of our qPCR assays. Within the defined limits, this multi-target qPCR method allows a versatile detection of B. burgdorferi s. l., regardless of the genospecies and the sample material analyzed, with a sensitivity that would be compatible with most applications and a reproducibility of 100% under measurement conditions of limits of detection, thereby limiting result ambiguities.

Lyme Borreliosis in Dogs: Background, Epidemiology, Diagnostics, Treatment and Prevention

Lyme borreliosis (LB) is a multisystemic tick-borne disease that can affect many organs and have various clinical manifestations in dogs. We attempted to summarise various aspects of Lyme disease: i. e., pathogenesis, epidemiology, benefits and risks of diagnostic approaches, treatment options, and prevention in dogs. Several diagnostic bottlenecks for LB in dogs and humans are compared. Because the occurrence of LB in both humans and dogs is closely related, monitoring its prevalence in dogs as sentinel animals is an excellent aid in assessing the risk of Lyme disease in a given geographic area. Although clinical symptoms in humans help clinicians diagnose LB, they are ineffective in dogs because canines rarely exhibit LB symptoms. Despite significant differences in sensitivity and specificity, sero-logical two-step detection of antibodies against Borrelia spp. (ELISA and Western blot) is the most commonly used method in humans and dogs. The limitations of the assay highlight the need for further research to develop new clinical markers and more accurate diagnostic tests. Due to the lack of a specific all-encompassing LB test, a definitive diagnosis of LB remains a difficult and time-consuming process in human and veterinary medicine. Understanding the disease prevalence and diagnostics, as well as preventing its spread with effective and timely treatment, are fundamental principles of good disease management.

Regional seropositivity for Borrelia burgdorferi and associated risk factors: findings from the Rhineland Study, Germany

Background

Lyme borreliosis is the most prevalent vector-borne disease in Europe, and numbers might increase due to climate change. However, borreliosis is not notifiable in North Rhine-Westphalia (NRW), Germany. Hence, little is known about the current human seroprevalence in NRW. However, the proportion of Borrelia burgdorferi sensu lato-infected ticks has increased in a NRW nature reserve. The literature suggests increasing age and male sex as risk factors for seropositivity, whereas the influence of socioeconomic status is controversial. Thus, we aimed to determine regional seropositivity for Borrelia burgdorferi sensu lato (B. burgdorferi s.l.) and its risk factors in the Rhineland Study population in Bonn, NRW, and to compare it with previous surveys to evaluate potential effects of climate change.

Methods

We assessed seropositivity in 2865 Rhineland Study participants by determining immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies for B. burgdorferi s.l. using a two-step algorithm combining enzyme-linked immunosorbent assay tests and line immunoblots. We calculated the odds of being classified as IgG or IgM positive as a function of age, sex, and educational level using binomial logistic regression models. We applied varying seropositivity classifications and weights considering age, sex and education to compensate for differences between the sample and regional population characteristics.

Results

IgG antibodies for B. burgdorferi s.l. were present in 2.4% and IgM antibodies in 0.6% of the participants (weighted: 2.2% [IgG], 0.6% [IgM]). The likelihood of IgG seropositivity increased by 3.0% (95% confidence interval [CI] 1.5–5.2%) per 1 year increase in age. Men had 1.65 times the odds for IgG seropositivity as women (95% CI 1.01–2.73), and highly educated participants had 1.83 times the odds (95% CI 1.10–3.14) as participants with an intermediate level of education. We found no statistically significant link between age, sex, or education and IgM seropositivity. Our weighted and age-standardized IgG seroprevalence was comparable to the preceding serosurvey German Health Interview and Examination Survey for Adults (DEGS) for NRW.

Conclusions

We confirmed that increasing age and male sex are associated with increased odds for IgG seropositivity and provide evidence for increased seropositivity in the highly educated group. B. burgdorferi s.l. seropositivity remained constant over the past decade in this regional German population.

Graphical abstract

LoopTag FRET Probe System for Multiplex qPCR Detection of Borrelia Species

Background: Laboratory diagnosis of Lyme borreliosis refers to some methods with known limitations. Molecular diagnostics using specific nucleic acid probes may overcome some of these limitations. Methods: We describe the novel reporter fluorescence real-time polymerase chain reaction (PCR) probe system LoopTag for detection of Borrelia species. Advantages of the LoopTag system include having cheap conventional fluorescence dyes, easy primer design, no restrictions for PCR product lengths, robustness, high sequence specificity, applicability for multiplex real-time PCRs, melting curve analysis (single nucleotide polymorphism analysis) over a large temperature range, high sensitivity, and easy adaptation of conventional PCRs. Results: Using the LoopTag probe system we were able to detect all nine tested European species belonging to the Borrelia burgdorferi (sensu lato) complex and differentiated them from relapsing fever Borrelia species. As few as 10 copies of Borrelia in one PCR reaction were detectable. Conclusion: We established a novel multiplex probe real-time PCR system, designated LoopTag, that is simple, robust, and incorporates melting curve analysis for the detection and in the differentiation of European species belonging to the Borrelia burgdorferi s.l. complex.

Ticks and their epidemiological role in Slovakia: from the past till present

In Slovakia, 22 tick species have been found to occur to date. Among them, Ixodes ricinus, Dermacentor reticulatus, D. marginatus and marginally Haemaphysalis concinna, H. inermis and H. punctata have been identified as the species of public health relevance. Ticks in Slovakia were found to harbour and transmit zoonotic and/or potentially zoonotic agents such as tick-borne encephalitis virus (TBEV), spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex, the relapsing fever sprirochaete Borrelia miyamotoi, bacteria belonging to the orders Rickettsiales (Rickettsia spp., Anaplasma phagocytophilum, Neoehrlichia mikurensis), Legionellales (Coxiella burnetii), and Thiotrichales (Francisella tularensis), and Babesia spp. parasites (order Piroplasmida). Ixodes ricinus is the principal vector of the largest variety of microorganisms including viruses, bacteria and piroplasms. TBEV, B. burgdorferi s.l., rickettsiae of the spotted fever group, C. burnetii and F. tularensis have been found to cause serious diseases in humans, whereas B. miyamotoi, A. phagocytophilum, N. mikurensis, Babesia microti, and B. venatorum pose lower or potential risk to humans. Distribution of TBEV has a focal character. During the last few decades, new tick-borne encephalitis (TBE) foci and their spread to new areas have been registered and TBE incidence rates have increased. Moreover, Slovakia reports the highest rates of alimentary TBE infections among the European countries. Lyme borreliosis (LB) spirochaetes are spread throughout the distribution range of I. ricinus. Incidence rates of LB have shown a slightly increasing trend since 2010. Only a few sporadic cases of human rickettsiosis, anaplasmosis and babesiosis have been confirmed thus far in Slovakia. The latest large outbreaks of Q fever and tularaemia were recorded in 1993 and 1967, respectively. Since then, a few human cases of Q fever have been reported almost each year. Changes in the epidemiological characteristics and clinical forms of tularaemia have been observed during the last few decades. Global changes and development of modern molecular tools led to the discovery and identification of emerging or new tick-borne microorganisms and symbionts with unknown zoonotic potential. In this review, we provide a historical overview of research on ticks and tick-borne pathogens in Slovakia with the most important milestones and recent findings, and outline future directions in the investigation of ticks as ectoparasites and vectors of zoonotic agents and in the study of tick-borne diseases.

A nationwide study on Borrelia burgdorferi s.l. infection rates in questing Ixodes ricinus: a six-year snapshot study in protected recreational areas in England and Wales

Understanding the variation in Borrelia burgdorferi s.l. infection rates in Ixodes ricinus ticks is important for assessing the potential for Lyme borreliosis transmission. This study aimed to investigate infection rates of B. burgdorferi s.l. bacteria in I. ricinus across 24 field sites in England and Wales, focussing on protected recreational areas in National Parks (NPs) and Areas of Outstanding Natural Beauty (AONBs), to provide comparable data across multiple years to assess spatio-temporal changes in B. burgdorferi s.l. infection. Working with park rangers, questing ticks were collected each spring from 2014 to 2019. A subset of ticks, 4104 nymphs, were analysed using a pan-Borrelia qPCR assay, as well as a Borrelia miyamotoi-specific qPCR, and sequenced to determine Borrelia burgdorferi s.l. genospecies. Site-specific B. burgdorferi s.l. infection rates in I. ricinus nymphs varied from 0% to 24%, with overall infection rates ranging from 2.5% to 5.1% across the years. Genospecies composition of sequenced samples was 62.5% B. garinii, 20.3% B. valaisiana and 17.2% B. afzelii. Borrelia miyamotoi was detected in 0.2% of ticks. This study increases our knowledge on B. burgdorferi s.l.. infection in areas used by the public for outdoor activity across England and Wales, highlighting the spatial and temporal variability which can impact the changing risk to humans from infected tick bites.

Presence of Human Pathogens of the Borrelia burgdorferi sensu lato Complex Shifts the Sequence Read Abundances of Tick Microbiomes in Two German Locations

The distribution of human Lyme borreliosis (LB) is assumed random in Germany, indicating that the human pathogenic species of the Borrelia burgdorferi sensu lato complex (Bb) are similarly distributed as part of the tick microbiome. The aim of this study was to differentiate if the presence of Bb occurs with a defined tick microbiome composition. Furthermore, the effect of location on tick microbiome composition was addressed for two German locations. Therefore, nucleic acid extracts from 82 Borrelia-positive and 118 Borrelia-negative Ixodes ricinus ticks sampled from human hosts in both districts were selected. Nucleic acid extracts were used for human pathogenic Bb species diagnostics based on qPCR and multilocus sequence typing (MLST) and bacterial 16S rRNA gene amplicon sequencing followed by network analyses. As a result, the presence of Bb shifted the sequence read abundances of Candidatus Midichloria, Rickettsia, Pseudomonas, Staphylococcus, and Candidatus Neoehrlichia and their topological roles in the tick microbiome. Moreover, the location was less important in the tick microbiome composition but shifted significantly sequence read abundances of Pseudomonas and Wolbachia as well as the topological role of microbial members. Since the presence of human pathogenic Bb species with other tick-associated pathogens varies regionally, we suggest that a bacterial 16S rRNA gene-based microbiome survey should be implemented in the routine diagnostics for both tick and host if human pathogenic species of Bb were detected. This diagnostic extension will help to optimize therapeutic approaches against Bb infection and co-occurring pathogens.

Borrelia burgdorferi Sensu Lato in Questing and Engorged Ticks from Different Habitat Types in Southern Germany

Borrelia burgdorferi sensu lato (s.l.) causes the most common tick-borne infection in Europe, with Germany being amongst the countries with the highest incidences in humans. This study aimed at (1) comparing infection rates of B. burgdorferi s.l. in questing Ixodes ricinus ticks from different habitat types in Southern Germany, (2) analysing genospecies distribution by habitat type, and (3) testing tissue and ticks from hosts for B. burgdorferi s.l. Questing ticks from urban, pasture, and natural habitats together with feeding ticks from cattle (pasture) and ticks and tissue samples from wild boars and roe deer (natural site) were tested by PCR and RFLP for species differentiation. B. burgdorferi s.l. was found in 29.8% questing adults and 15% nymphs. Prevalence was lower at the urban sites with occurrence of roe deer than where these were absent. Borrelia burgdorferi s.l. DNA was found in 4.8% ticks from roe deer, 6.3% from wild boar, and 7.8% from cattle. Six genospecies were identified in unfed ticks: Borrelia afzelii (48.6%), Borrelia burgdorferi sensu stricto (16%), Borrelia garinii (13.2%), Borrelia valaisiana (7.5%), Borrelia spielmanii (6.2%), and Borrelia bavariensis (0.9%). This study shows high infection levels and a great diversity of Borrelia in questing ticks. The presence of roe deer seems to reduce B. burgdorferi s.l. infection rates in tick populations.

The Prevalence of Different Human Pathogenic Microorganisms Transmitted by Ixodes Tick Vectors in Belarus

Pathogens transmitted by ticks cause several important diseases in humans, including Lyme disease, the incidence of which has been increasing in Belarus. Between April and October 2017, a total of 504 questing Ixodid ticks (77% Ixodes ricinus and 23% Dermacentor reticulatus) were collected from six regions and city of Minsk, in Belarus. All ticks were analyzed by RT-PCR amplification for the presence of Borrelia burgdorferi sensu lato, tick-borne encephalitis virus (TBEV), Anaplasma phagocytophillum, Ehrlihia muris, and Borrelia miyamotoi. B. burgdorferi s.l. and Rickettsia spp. were the most commonly detected tick-borne pathogens, with prevalence rates of 31.08% and 33.7%, respectively. A. phagocytophillum was found in 104 (20.63%), and 107 (21.2%) ticks were positive for E. muris. TBEV was detected in 83 (16.47%). Circulation of Borrelia miyamotoi spirochete in I. ricinus ticks in Brest, Gomel, and Minsk region was detected for the first time. Our data provide a basis for further studies to determine the distribution and abundance of different tick species in Belarus and therefore a capacity to predict where cases of important tick-borne diseases may occur.

Ticks, fleas and rodent-hosts analyzed for the presence of Borrelia miyamotoi in Slovakia: the first record of Borrelia miyamotoi in a Haemaphysalis inermis tick

In Slovakia, little knowledge is available on the occurrence, hosts and vectors of Borrelia miyamotoi of the relapsing fever group. In the current study, 2160 questing and rodent-attached ticks of six species (Ixodes ricinus, Ixodes trianguliceps, Dermacentor marginatus, Dermacentor reticulatus, Haemaphysalis concinna and Haemaphysalis inermis), 279 fleas belonging to 9 species (Ctenophthalmus agyrtes, Ctenophthalmus solutus, Ctenophthalmus assimilis, Megabothris turbidus, Amalareus penicilliger, Hystrichopsylla orientalis, Ctenophthalmus uncinatus, Doratopsylla dasycnema and Nosopsyllus fasciatus) and skin biopsies from 245 small mammals belonging to eight species (Apodemus agrarius, Apodemus flavicollis, Apodemus uralensis, Myodes glareolus, Crocidura leucodon, Micromys minutus, Microtus arvalis, Microtus subterraneus) were screened for the presence of B. miyamotoi DNA. The overall prevalence of B. miyamotoi found in questing and rodent-attached ticks was 1.8% (23 positive/1260 examined) and 3.4% (31 positive/900 examined), respectively. Borrelia miyamotoi was detected in questing I. ricinus, rodent-attached I. ricinus and H. inermis ticks, and in one male of the common vole (M. arvalis) in different habitats (mainly rural) in eastern Slovakia. However, B. miyamotoi was not found in any of the tested fleas. Our findings indicate that rural habitats with different species of tick vectors and hosts are appropriate for the occurrence of B. miyamotoi.

Longitudinal study of prevalence and spatio-temporal distribution of Borrelia burgdorferi sensu lato in ticks from three defined habitats in Latvia, 1999-2010

Members of the Borrelia burgdorferi sensu lato (s.l.) species complex are known to cause human Lyme borreliosis. Because of longevity of some reservoir hosts and the Ixodes tick vectors' life cycle, long-term studies are required to better understand species and population dynamics of these bacteria in their natural habitats. Ticks were collected between 1999 and 2010 in three ecologically different habitats in Latvia. We used multilocus sequence typing utilizing eight chromosomally located housekeeping genes to obtain information about species and population fluctuations and/or stability of B. burgdorferi s.l. in these habitats. The average prevalence over all years was 18.9%. From initial high-infection prevalences of 25.5%, 33.1% and 31.8%, from 2002 onwards the infection rates steadily decreased to 7.3%. Borrelia afzelii and Borrelia garinii were the most commonly found genospecies but striking local differences were obvious. In one habitat, a significant shift from rodent-associated to bird-associated Borrelia species was noted whilst in the other habitats, Borrelia species composition was relatively stable over time. Sequence types (STs) showed a random spatial and temporal distribution. These results demonstrated that there are temporal regional changes and extrapolations from one habitat to the next are not possible.

A new Borrelia on the block: Borrelia miyamotoi - a human health risk?

Background

Borrelia miyamotoi clusters phylogenetically among relapsing fever borreliae, but is transmitted by hard ticks. Recent recognition as a human pathogen has intensified research into its ecology and pathogenic potential.

Aims

We aimed to provide a timely critical integrative evaluation of our knowledge on B. miyamotoi, to assess its public health relevance and guide future research.

Methods

This narrative review used peer-reviewed literature in English from January 1994 to December 2018.

Results

Borrelia miyamotoi occurs in the world’s northern hemisphere where it co-circulates with B. burgdorferi sensu lato, which causes Lyme disease. The two borreliae have overlapping vertebrate and tick hosts. While ticks serve as vectors for both species, they are also reservoirs for B. miyamotoi. Three B. miyamotoi genotypes are described, but further diversity is being recognised. The lack of sufficient cultivable isolates and vertebrate models compromise investigation of human infection and its consequences. Our understanding mainly originates from limited case series. In these, human infections mostly present as influenza-like illness, with relapsing fever in sporadic cases and neurological disease reported in immunocompromised patients. Unspecific clinical presentation, also occasionally resulting from Lyme- or other co-infections, complicates diagnosis, likely contributing to under-reporting. Diagnostics mainly employ PCR and serology. Borrelia miyamotoi infections are treated with antimicrobials according to regimes used for Lyme disease.

Conclusions

With co-infection of tick-borne pathogens being commonplace, diagnostic improvements remain important. Developing in vivo models might allow more insight into human pathogenesis. Continued ecological and human case studies are key to better epidemiological understanding, guiding intervention strategies.

Getting under the birds' skin: tissue tropism of Borrelia burgdorferi s.l. in naturally and experimentally infected avian hosts

Wild birds are frequently exposed to the zoonotic tick-borne bacteria Borrelia burgdorferi sensu lato (s.l.), and some bird species act as reservoirs for some Borrelia genospecies. Studying the tropism of Borrelia in the host, how it is sequestered in different organs, and whether it is maintained in circulation and/or in the host's skin is important to understand pathogenicity, infectivity to vector ticks and reservoir competency.We evaluated tissue dissemination of Borrelia in blackbirds (Turdus merula) and great tits (Parus major), naturally and experimentally infected with Borrelia genospecies from enzootic foci. We collected both minimally invasive biological samples (feathers, skin biopsies and blood) and skin, joint, brain and visceral tissues from necropsied birds. Infectiousness of the host was evaluated through xenodiagnoses and infection rates in fed and moulted ticks. Skin biopsies were the most reliable method for assessing avian hosts' Borrelia infectiousness, which was supported by the agreement of infection status results obtained from the analysis of chin and lore skin samples from necropsied birds and of their xenodiagnostic ticks, including a significant correlation between the estimated concentration of Borrelia genome copies in the skin and the Borrelia infection rate in the xenodiagnostic ticks. This confirms a dermatropism of Borrelia garinii, B. valaisiana and B. turdi in its avian hosts. However, time elapsed from exposure to Borrelia and interaction between host species and Borrelia genospecies may affect the reliability of skin biopsies. The blood was not useful to assess infectiousness of birds, even during the period of expected maximum spirochetaemia. From the tissues sampled (foot joint, liver, spleen, heart, kidney, gut and brain), Borrelia was detected only in the gut, which could be related with infection mode, genospecies competition, genospecies-specific seasonality and/or excretion processes.

Borrelia miyamotoi and Borrelia burgdorferi (sensu lato) identification and survey of tick-borne encephalitis virus in ticks from north-eastern Germany

Background

Ixodes ricinus is the most common tick species in Europe and the main vector for Borrelia burgdorferi (sensu lato) and tick-borne encephalitis virus (TBEV). It is involved also in the transmission of Borrelia miyamotoi, a relapsing fever spirochete that causes health disorders in humans. Little is known regarding the circulation of Borrelia species and the natural foci of TBEV in north-eastern Germany. The goal of this study was to investigate the infection rates of Borrelia spp. and of TBEV in I. ricinus ticks from north-eastern Germany.

Methods

Ticks were collected by flagging from 14 forest sites in Mecklenburg-Western Pomerania between April and October 2018. RNA and DNA extraction was performed from individual adult ticks and from pools of 2–10 nymphs. Real time reverse transcription PCR (RT-qPCR) targeted the 3′ non-coding region of TBEV, while DNA of Borrelia spp. was tested by nested PCR for the amplification of 16S-23S intergenic spacer. Multilocus sequence typing (MLST) was performed on B. miyamotoi isolates.

Results

In total, 2407 ticks were collected (239 females, 232 males and 1936 nymphs). Female and male I. ricinus ticks had identical infection rates (both 12.1%) for Borrelia spp., while nymphal pools showed a minimum infection rate (MIR) of 3.3%. Sequencing revealed four Borrelia species: B. afzelii, B. garinii, B. valaisiana and B. miyamotoi. Borrelia afzelii had the highest prevalence in adult ticks (5.5%) and nymphs (MIR of 1.8%). Borrelia miyamotoi was identified in 3.0% of adults and registered the MIR of 0.8% in nymphs. Borrelia valaisiana was confirmed in 2.5% adult ticks and nymphs had the MIR of 0.7%, while B. garinii was present in 1.1% of adults and showed a MIR of 0.1% in nymphs. The MLST of B. miyamotoi isolates showed that they belong to sequence type 635. No tick sample was positive after RT-qPCR for TBEV RNA.

Conclusions

The prevalence of B. miyamotoi in I. ricinus ticks registered similar levels to other reports from Europe suggesting that this agent might be well established in the local tick population. The detection of B. burgdorferi (s.l.) indicates a constant circulation in tick populations from this region.

Whole genome sequencing of Borrelia miyamotoi isolate Izh-4: reference for a complex bacterial genome

BACKGROUND

The genus Borrelia comprises spirochaetal bacteria maintained in natural transmission cycles by tick vectors and vertebrate reservoir hosts. The main groups are represented by a species complex including the causative agents of Lyme borreliosis and relapsing fever group Borrelia. Borrelia miyamotoi belongs to the relapsing fever group of spirochetes and forms distinct populations in North America, Asia, and Europe. As all Borrelia species B. miyamotoi possess an unusual and complex genome consisting of a linear chromosome and a number of linear and circular plasmids. The species is considered an emerging human pathogen and an increasing number of human cases are being described in the Northern hemisphere. The aim of this study was to produce a high quality reference genome that will facilitate future studies into genetic differences between different populations and the genome plasticity of B. miyamotoi.

RESULTS

We used multiple available sequencing methods, including Pacific Bioscience single-molecule real-time technology (SMRT) and Oxford Nanopore technology (ONT) supplemented with highly accurate Illumina sequences, to explore the suitability for whole genome assembly of the Russian B. miyamotoi isolate, Izh-4. Plasmids were typed according to their potential plasmid partitioning genes (PF32, 49, 50, 57/62). Comparing and combining results of both long-read (SMRT and ONT) and short-read methods (Illumina), we determined that the genome of the isolate Izh-4 consisted of one linear chromosome, 12 linear and two circular plasmids. Whilst the majority of plasmids had corresponding contigs in the Asian B. miyamotoi isolate FR64b, there were only four that matched plasmids of the North American isolate CT13-2396, indicating differences between B. miyamotoi populations. Several plasmids, e.g. lp41, lp29, lp23, and lp24, were found to carry variable major proteins. Amongst those were variable large proteins (Vlp) subtype Vlp-α, Vlp-γ, Vlp-δ and also Vlp-β. Phylogenetic analysis of common plasmids types showed the uniqueness in Russian/Asian isolates of B. miyamotoi compared to other isolates.

CONCLUSIONS

We here describe the genome of a Russian B. miyamotoi clinical isolate, providing a solid basis for future comparative genomics of B. miyamotoi isolates. This will be a great impetus for further basic, molecular and epidemiological research on this emerging tick-borne pathogen.

Prevention of transmission of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum by Ixodes spp. ticks to dogs treated with the Seresto® collar (imidacloprid 10% + flumethrin 4.5%)

The capability of imidacloprid 10% + flumethrin 4.5% (Seresto®) collars to prevent transmission of Borrelia burgdorferi sensu lato (Bbsl) and Anaplasma phagocytophilum (Ap) by naturally infected ticks was evaluated in two studies with 44 dogs. In each study, one group served as non-treated control, whereas the other groups were treated with the Seresto® collar. All dogs were exposed to naturally Bbsl- and Ap-infected hard ticks (Ixodes ricinus, Ixodes scapularis). In study 1, tick infestation was performed on study day (SD) 63 (2 months post-treatment [p.t.]); in study 2, it was performed on SD 32 (one month p.t.) respectively SD 219 (seven months p.t.). In situ tick counts were performed 2 days after infestation. Tick counts and removals followed 6 (study 1) or 5 days (study 2) later. Blood sampling was performed for the detection of specific Bbsl and Ap antibodies and, in study 1, for the documentation of Ap DNA by PCR. Skin biopsies were examined for Bbsl by PCR and culture (only study 1). The efficacy against Ixodes spp. was 100% at all time points. In study 1, two of six non-treated dogs became infected with Bbsl, and four of six tested positive for Ap; none of the treated dogs tested positive for Bbsl or Ap. In study 2, ten of ten non-treated dogs became infected with Bbsl and Ap; none of the treated dogs tested positive for Bbsl or Ap; 100% acaricidal efficacy was shown in both studies. Transmission of Bbsl and Ap was successfully blocked for up to 7 months.

Ixodes inopinatus in northern Germany: occurrence and potential vector role for Borrelia spp., Rickettsia spp., and Anaplasma phagocytophilum in comparison with Ixodes ricinus

In 2014, a new tick species, Ixodes inopinatus, was described, which is closely related to Ixodes ricinus. So far, I. inopinatus has been found in Tunisia, Morocco, Spain, Portugal, Romania, Austria, and southern Germany. No data is yet available regarding occurrence of I. inopinatus in northern Germany and the potential role of I. inopinatus as a vector for tick-borne pathogens. Therefore, 3845 DNA samples from Ixodes ticks collected for prevalence studies on Borrelia spp., Rickettsia spp., and Anaplasma phagocytophilum during the years 2010-2015 in the northern German cities of Hamburg and Hanover were differentiated into I. ricinus or I. inopinatus by sequencing a part of the 16S rRNA gene. In total, 4% (137/3845) of the sequenced ticks were assigned to the species I. inopinatus and 96% (3708/3845) to I. ricinus. The prevalence of Borrelia spp., Rickettsia spp., and A. phagocytophilum DNA in I. inopinatus was 34% (46/137), 46% (63/137), and 3% (4/137), respectively, whereas the prevalence of these bacteria in I. ricinus was 25% (919/3708), 47% (1729/3708), and 4% (135/3708), respectively. Compared with I. ricinus, significantly more I. inopinatus ticks tested positive for Borrelia. To the best of our knowledge, this is the first report of I. inopinatus in northern Germany. Detection of the DNA of Borrelia spp., Rickettsia spp., and A. phagocytophilum in questing I. inopinatus indicates a potential role of this tick species as a vector of these pathogens, which needs to be confirmed by transmission experiments.

Screening for infectious diseases among newly arrived asylum seekers, Bavaria, Germany, 2015

Background and aimAs a consequence of socioeconomic and political crises in many parts of the world, many European Union/European Economic Area (EU/EEA) countries have faced an increasing number of migrants. In the German federal state of Bavaria, a mandatory health screening approach is implemented, where individuals applying for asylum have to undergo a medical examination that includes serological testing for HIV and hepatitis B, screening for tuberculosis, and until September 2015, stool examination for Salmonella spp. and Shigella spp.. Methods: Data from mandatory screening of all first-time asylum seekers in Bavaria in 2015 was extracted from the mandatory notification and laboratory information system and evaluated. Results: The HIV positivity and hepatitis B surface antigen (HBsAg) positivity rate of tested samples from asylum seekers were 0.3% and 3.3%, respectively, while detection rate of active tuberculosis was between 0.22% and 0.38%. The rates for HIV, hepatitis B, and tuberculosis among asylum seekers were similar to the corresponding prevalence rates in most of their respective countries of birth. Only 47 Salmonella spp. (0.1%) were isolated from stool samples: 45 enteric and two typhoid serovars. Beyond mandatory screening, louse-borne relapsing fever was found in 40 individuals. Conclusions: These results show that mandatory screening during 2015 in Bavaria yielded overall low positivity rates for all tested infectious diseases in asylum seekers. A focus of mandatory screening on specific diseases in asylum seekers originating from countries with higher prevalence of those diseases could facilitate early diagnosis and provision of treatment to affected individuals while saving resources.

Case Report and Genetic Sequence Analysis of Candidatus Borrelia kalaharica, Southern Africa

Tickborne relapsing fever caused by Borrelia species is rarely reported in travelers returning from Africa. We report a case of a 71-year-old woman who sought treatment at University Medical Center in Freiburg, Germany, in 2015 with recurrent fever after traveling to southern Africa. We detected spirochetes in Giemsa-stained blood smears. Treatment with doxycycline for suspected tickborne relapsing fever was successful. Sequence analyses of several loci (16S rRNA, flagellin, uvrA) showed high similarity to the recently described Candidatus Borrelia kalaharica, which was found in a traveler returning from the same region earlier that year. We provide additional information regarding the genetic relationship of Candidatus B. kalaharica. Sequence information for an additional 6 housekeeping genes enables improved comparability to other borrelial species that cause relapsing fever. Our report underlines the importance and possible emergence of the only recently delineated pathogen in southern Africa.

Simultaneous Occurrence of Borrelia miyamotoi, Borrelia burgdorferi Sensu Lato, Anaplasma phagocytophilum and Rickettsia helvetica in Ixodes ricinus Ticks in Urban Foci in Bratislava, Slovakia

BACKGROUND

Questing Ixodes ricinus ticks were collected in two urban parks (Železná studienka and Horský park) of the capital city of Slovakia, Bratislava, during two consecutive years in 2011 and 2012. A total of 932 ticks were analyzed for the presence of tick-borne agents: B. miyamotoi, B. burgdorferi s.l., A. phagocytophilum and R. helvetica.

RESULTS

PCR analysis confirmed the presence of all pathogens at both localities. The overall infection prevalence of B. miyamotoi, B. burgdorferi s.l., A. phagocytophilum and R. helvetica was 0.75, 13.2, 5.6 and 8.9%, respectively. B. burgdorferi s.l. positive samples were represented by six genospecies. The most frequent one was B. afzelii followed by B. garinii and B. valaisiana.

CONCLUSION

Our study confirms the presence of I. ricinus ticks and at least nine tick-borne bacterial agents in city forest parks, which are used for recreational purposes. Ordination analysis revealed significant differences in the composition of pathogens with respect to study site location, time of season and ambient temperature, despite the fact that both sites are located relatively close to one another within the city.

Shifts in Borrelia burgdorferi (s.l.) geno-species infections in Ixodes ricinus over a 10-year surveillance period in the city of Hanover (Germany) and Borrelia miyamotoi-specific Reverse Line Blot detection

BACKGROUND

Lyme borreliosis caused by spirochetes of the Borrelia burgdorferi (sensu lato) complex is still the most common tick-borne disease in Europe, posing a considerable threat to public health. The predominant vector in Europe is the widespread hard tick Ixodes ricinus, which also transmits the relapsing fever spirochete B. miyamotoi as well as pathogenic Rickettsiales (Anaplasma phagocytophilum, Rickettsia spp.). To assess the public health risk, a long-term monitoring of tick infection rates with the named pathogens is indispensable.

METHODS

The present study is the first German 10-year follow-up monitoring of tick infections with Borrelia spp. and co-infections with Rickettsiales. Furthermore, a specific Reverse Line Blot (RLB) protocol for detection of B. miyamotoi and simultaneous differentiation of B. burgdorferi (s.l.) geno-species was established.

RESULTS

Overall, 24.0% (505/2100) of ticks collected in the city of Hanover were infected with Borrelia. In detail, 35.4% (203/573) of adult ticks [38.5% females (111/288) and 32.3% males (92/285)] and 19.8% nymphs (302/1527) were infected, representing consistent infection rates over the 10-year monitoring period. Geno-species differentiation using RLB determined B. miyamotoi in 8.9% (45/505) of positive ticks. Furthermore, a significant decrease in B. afzelii and B. spielmanii infection rates from 2010 to 2015 was observed. Co-infections with Rickettsia spp. and A. phagocytophilum increased between 2010 and 2015 (7.3 vs 10.9% and 0.3 vs 1.1%, respectively).

CONCLUSIONS

Long-term monitoring is an essential part of public health risk assessment to capture data on pathogen occurrence over time. Such data will reveal shifts in pathogen geno-species distribution and help to answer the question whether or not climate change influences tick-borne pathogens.

First report of Borrelia miyamotoi in an Ixodes ricinus tick in Augsburg, Germany

Borrelia miyamotoi, a spirochete found in the hard tick Ixodes ricinus, is thought to cause relapsing fever. The disease caused by this bacterium can manifest with high fever, fatigue and other symptoms. It may also lead to central nervous system involvement with symptoms similar to meningoencephalitis. DNA from ticks from the greater Augsburg region in Germany was subjected to qPCR for Borrelia spp., followed by nested PCR and subsequent sequencing for species identification of the qPCR positive samples. From 112 ticks, 20 were found to be positive for Borrelia. The DNA sequenced showed 50% Borrelia afzelli, 15% Borrelia garinii, 5% Borrelia valaisiana and one sequence was identified as Borrelia miyamotoi. The positive identification of Borrelia miyamotoi is unlikely to be due to contamination. In conclusion, Borrelia miyamotoi has been found in a tick in the Augsburg region for the first time. This follows on from previous reports of a low incidence of this bacterium in southern Germany around Lake Constance and in the Munich region. This infectious agent should be taken into account when patients present with recurring fever or neurological symptoms which cannot be otherwise explained. Tick-borne relapsing fever should now be considered as a cause of such symptoms and medical professionals should contemplate differential Borrelia testing when presented with corresponding symptoms.

Presence of Borrelia spp. DNA in ticks, but absence of Borrelia spp. and of Leptospira spp. DNA in blood of fever patients in Madagascar

The occurrence of tick-borne relapsing fever and leptospirosis in humans in Madagascar remains unclear despite the presence of their potential vectors and reservoir hosts. We screened 255 Amblyomma variegatum ticks and 148 Rhipicephalus microplus ticks from Zebu cattle in Madagascar for Borrelia-specific DNA. Borrelia spp. DNA was detected in 21 Amblyomma variegatum ticks and 2 Rhipicephalus microplus ticks. One Borrelia found in one Rhipicephalus microplus showed close relationship to Borrelia theileri based on genetic distance and phylogenetic analyses on 16S rRNA and flaB sequences. The borreliae from Amblyomma variegatum could not be identified due to very low quantities of present DNA reflected by high cycle threshold values in real-time-PCR. It is uncertain whether these low numbers of Borrelia spp. are sufficient for transmission of infection from ticks to humans. In order to determine whether spirochaete infections are relevant in humans, blood samples of 1009 patients from the highlands of Madagascar with fever of unknown origin were screened for Borrelia spp. - and in addition for Leptospira spp. - by real-time PCR. No target DNA was detected, indicating a limited relevance of these pathogens for humans in the highlands of Madagascar.

Species Identification and Phylogenetic Analysis of Borrelia burgdorferi Sensu Lato Using Molecular Biological Methods

Bacterial species identification is required in different disciplines and-depending on the purpose-levels of specificity or resolution of typing may vary. Nowadays, molecular methods are the mainstay for bacterial identification and sequence-based analyses are of ever-growing importance. For diagnostics, immediate results are needed and often real-time PCR of one or two loci is the method of choice while for epidemiological or evolutionary studies sequence data of several loci improve phylogenetic resolution to required levels. Multilocus sequence typing (MLST) and multilocus sequence analyses (MLSA) utilize sequences information of several housekeeping loci (eight for Borrelia) to distinguish between species. This method has been widely used for bacterial species and strain identification and will be described in this chapter.As more and more diversity is being detected in the Borrelia burgdorferi sensu lato species complex, the importance of accurate species and strain typing has come to the fore. This is particularly significant with a view of differentiating human pathogenic and non-pathogenic strains or species and understanding the epidemiology, ecology, population structure, and evolution of species.

Diagnosing Borreliosis

Borrelia species fall into two groups, the Borrelia burgdorferi sensu lato (Bbsl) complex, the cause of Lyme borreliosis (also known as Lyme disease), and the relapsing fever group. Both groups exhibit inter- and intraspecies diversity and thus have variations in both clinical presentation and diagnostic approaches. A further layer of complexity is derived from the fact that ticks may carry multiple infectious agents and are able to transmit them to the host during blood feeding, with potential overlapping clinical manifestations. Besides this, pathogens like Borrelia have developed strategies to evade the host immune system, which allows them to persist within the host, including humans. Diagnostics can be applied at different times during the clinical course and utilize sample types, each with their own advantages and limitations. These differing methods should always be considered in conjunction with potential exposure and compatible clinical features. Throughout this review, we aim to explore different approaches providing the reader with an overview of methods appropriate for various situations. This review will cover human pathogenic members of Bbsl and relapsing fever borreliae, including newly recognized Borrelia miyamotoi spirochetes.

Lyme borreliae prevalence and genospecies distribution in ticks removed from humans

Lyme borreliosis (LB) is the most important human tick-borne disease, but Borrelia genospecies cause different clinical manifestations. Ticks of the genus Ixodes removed from humans between 2006 and 2012 were analysed for Borrelia burgdorferi sensu lato (sl) infections. The majority of ticks originated from the Greater Hanover region in Northern Germany. The engorgement status varied over the entire spectrum from unengorged (no evidence of started blood feeding) to fully engorged. In the present study, prevalence data for B. burgdorferi sl 2011 and 2012 were obtained by quantitative real-time PCR and compared to those from a former study including years 2006-2010 (Strube et al., 2011) to evaluate B. burgdorferi sl infections in ticks affecting humans over a 7-year period. In 2011, 34.2% (70/205) of adult ticks, 22.2% (94/423) of nymphs, 8.3% of larvae (1/12) as well 3 of 6 not differentiated ticks were Borrelia positive. In 2012, 31.8% (41/129) of adult ticks, 20.4% of nymphs (69/337) as well as 1 of 4 of the not differentiated ticks were determined positive. Total Borrelia infection rates decreased significantly from 23.1% in 2006 to 17.1% in 2010, followed by a significant increase to 26.0% in 2011 and 23.4% in 2012. Furthermore, B. burgdorferi sl genospecies distribution in 2006-2012 was determined in the present study by applying Reverse Line Blot technique. Borrelia genospecies differentiation was successful in 641 (67.3%) out of 953 positive tick samples. The most frequently occurring genospecies was B. afzelii (40.5% of infected ticks), followed by B. garinii/B. bavariensis (12.4%). Amongst the 641 ticks analysed for their genospecies, 74 (11.5%) carried more than one genospecies, of which 69 (10.7%) were double-infected and five (0.8%) were triple-infected. Comparison of genospecies distribution in ticks removed from humans with those from questing ticks flagged in the same geographical area revealed that ticks removed from humans were significantly more frequently infected with B. afzelii (p=0.0004), but significantly less infected with B. burgdorferi sensu stricto (p=0.0001).

Borrelia miyamotoi and Co-Infection with Borrelia afzelii in Ixodes ricinus Ticks and Rodents from Slovakia

Borrelia miyamotoi causes relapsing fever in humans. The occurrence of this spirochete has been reported in Ixodes ricinus and wildlife, but there are still gaps in the knowledge of its eco-epidemiology and public health impact. In the current study, questing I. ricinus (nymphs and adults) and skin biopsies from rodents captured in Slovakia were screened for the presence of B. miyamotoi and Borrelia burgdorferi s.l. DNA. The prevalence of B. miyamotoi and B. burgdorferi s.l. in questing ticks was 1.7 and 16.9%, respectively. B. miyamotoi was detected in Apodemus flavicollis (9.3%) and Myodes glareolus (4.4%). In contrast, B. burgdorferi s.l. was identified in 11.9% of rodents, with the highest prevalence in Microtus arvalis (68.4%) and a lower prevalence in Apodemus spp. (8.4%) and M. glareolus (12.4%). Borrelia afzelii was the prevailing genospecies infecting questing I. ricinus (37.9%) and rodents (72.2%). Co-infections of B. miyamotoi and B. burgdorferi s.l. were found in 24.1 and 9.3% of the questing ticks and rodents, respectively, whereas the proportion of ticks and rodents co-infected with B. miyamotoi and B. afzelii was 6.9 and 7.0%, respectively. The results suggest that B. miyamotoi and B. afzelii share amplifying hosts. The sequences of the B. miyamotoi glpQ gene fragment from our study showed a high degree of identity with sequences of the gene amplified from ticks and human patients in Europe. The results seem to suggest that humans in Slovakia are at risk of contracting tick-borne relapsing fever, and in some cases together with Lyme borreliosis.

Paired real-time PCR assays for detection of Borrelia miyamotoi in North American Ixodes scapularis and Ixodes pacificus (Acari: Ixodidae)

Borrelia miyamotoi is an emerging, tick-borne human pathogen. In North America, it is primarily associated with Ixodes scapularis and Ixodes pacificus, two species known to bite humans. Here we describe the development and evaluation of a pair of real-time TaqMan PCR assays designed to detect B. miyamotoi in North American ticks. We sought to achieve sensitivity to B. miyamotoi strains associated with ticks throughout North America, the full genetic diversity of which is unknown, by targeting sequences that are largely conserved between B. miyamotoi strains from the eastern United States and genetically distinct B. miyamotoi strains from Japan. The two assays target different loci on the B. miyamotoi chromosome and can be run side by side under identical cycling conditions. One of the assays also includes a tick DNA target that can be used to verify the integrity of tick-derived samples. Using both recombinant plasmid controls and genomic DNA from North American and Japanese strains, we determined that both assays reliably detect as few as 5 copies of the B. miyamotoi genome. We verified that neither detects B. burgdorferi, B. lonestari or B. turicatae. This sensitive and specific pair of assays successfully detected B. miyamotoi in naturally-infected, colony-reared nymphs and in field-collected I. scapularis and I. pacificus from the Northeast and the Pacific Northwest respectively. These assays will be useful in screening field-collected Ixodes spp. from varied regions of North America to assess the risk of human exposure to this emerging pathogen.

"Candidatus Borrelia kalaharica" Detected from a Febrile Traveller Returning to Germany from Vacation in Southern Africa

A 26 year-old female patient presented to the Tropical Medicine outpatient unit of the Ludwig Maximilians-University in Munich with febrile illness after returning from Southern Africa, where she contracted a bite by a large mite-like arthropod, most likely a soft-tick. Spirochetes were detected in Giemsa stained blood smears and treatment was started with doxycycline for suspected tick-borne relapsing fever. The patient eventually recovered after developing a slight Jarisch-Herxheimer reaction during therapy. PCR reactions performed from EDTA-blood revealed a 16S rRNA sequence with 99.4% similarity to both, Borrelia duttonii, and B. parkeri. Further sequences obtained from the flagellin gene (flaB) demonstrated genetic distances of 0.066 and 0.097 to B. parkeri and B. duttonii, respectively. Fragments of the uvrA gene revealed genetic distance of 0.086 to B. hermsii in genetic analysis and only distant relations with classic Old World relapsing fever species. This revealed the presence of a novel species of tick-borne relapsing fever spirochetes that we propose to name “Candidatus Borrelia kalaharica”, as it was contracted from an arthropod bite in the Kalahari Desert belonging to both, Botswana and Namibia, a region where to our knowledge no relapsing fever has been described so far. Interestingly, the novel species shows more homology to New World relapsing fever Borrelia such as B. parkeri or B. hermsii than to known Old World species such as B. duttonii or B. crocidurae.

A patient reported an arthropod bite on her dorsal metatarsal region 2/3 of her anterior foot during a trip to the Kalahari Desert in Southern Africa. Eventually, a rash developed at the site of the bite and high-grade fever started 8 days later. Spirochetes were detected in the blood smear and the patient was treated with the suspected diagnosis of tick-borne relapsing fever. The presence of Borrelia spp. in fresh patient blood could be confirmed using DNA amplification and sequencing techniques. Homology searches of the obtained sequences from 16S rRNA, flaB, and uvrA revealed surprisingly distant relationships to known Borrelia species. It is concluded that the infection was caused by a new species of tick-borne relapsing fever Borrelia capable of infecting humans that we propose to name “Candidatus Borrelia kalaharica”, which is described within this manuscript. The blood sample was discarded after initial analysis; therefore, no successful culture could be obtained.

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.