Establishment of a minor groove binder-probe based quantitative real time PCR to detect Borrelia burgdorferi sensu lato and differentiation of Borrelia spielmanii by ospA-specific conventional PCR

Prevalence of tick-borne bacterial pathogens in Germany-has the situation changed after a decade?

Introduction

Tick-borne pathogens, such as Borreliella spp., Rickettsia spp., and Anaplasma spp., are frequently detected in Germany. They circulate between animals and tick vectors and can cause mild to severe diseases in humans. Knowledge about distribution and prevalence of these pathogens over time is important for risk assessment of human and animal health.

Methods

Ixodes ricinus nymphs were collected at different locations in 2009/2010 and 2019 in Germany and analyzed for tick-borne pathogens by real-time PCR and sequencing.

Results

Borreliella spp. were detected with a prevalence of 11.96% in 2009/2010 and 13.10% in 2019 with B. afzelii and B. garinii as dominant species. Borrelia miyamotoi was detected in seven ticks and in coinfection with B. afzelii or B. garinii. Rickettsia spp. showed a prevalence of 8.82% in 2009/2010 and 1.68% in 2019 with the exclusive detection of R. helvetica. The prevalence of Anaplasma spp. was 1.00% in 2009/2010 and 7.01% in 2019. A. phagocytophilum was detected in seven tick samples. None of the nymphs were positive for C. burnetii.

Discussion

Here, observed changes in prevalence were not significant after a decade but require longitudinal observations including parameters like host species and density, climatic factors to improve our understanding of tick-borne diseases.

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.

Potential drivers of vector-borne pathogens in urban environments: European hedgehogs (Erinaceus europaeus) in the spotlight

Vector-borne diseases (VBDs) are considered as (re-)emerging, but information on the transmission cycles and wildlife reservoirs is often incomplete, particularly with regard to urban areas. The present study investigated blood samples from European hedgehogs (Erinaceus europaeus) presented at wildlife rehabilitation centres in the region of Hanover. Past exposure to B. burgdorferi sensu lato (s.l.) and tick-borne encephalitis virus (TBEV) was assessed by serological detection of antibodies, while current infections with Borrelia spp., Anaplasma phagocytophilum, Rickettsia spp., Neoehrlichia mikurensis, Bartonella spp., Babesia spp. and Spiroplasma ixodetis were investigated by (q)PCR. Of 539 hedgehogs tested for anti-Borrelia antibodies, 84.8% (457/539) were seropositive, with a higher seropositivity rate in adult than subadult animals, while anti-TBEV antibodies were detected in one animal only (0.2%; 1/526). By qPCR, 31.2% (168/539) of hedgehog blood samples were positive for Borrelia spp., 49.7% (261/525) for A. phagocytophilum, 13.0% (68/525) for Bartonella spp., 8.2% for S. ixodetis (43/525), 8.0% (42/525) for Rickettsia spp. and 1.3% (7/525) for Babesia spp., while N. mikurensis was not detected. While further differentiation of Borrelia spp. infections was not successful, 63.2% of the A. phagocytophilum infections were assigned to the zoonotic ecotype I and among Rickettsia spp. infections, 50.0% to R. helvetica by ecotype- or species-specific qPCR, respectively. Sequencing revealed the presence of a Rickettsia sp. closely related to Rickettsia felis in addition to a Bartonella sp. previously described from hedgehogs, as well as Babesia microti and Babesia venatorum. These findings show that hedgehogs from rehabilitation centres are valuable sources to identify One Health pathogens in urban areas. The hedgehogs are not only exposed to pathogens from fleas and ticks in urban areas, but they also act as potent amplifiers for these vectors and their pathogens, relevant for citizens and their pets.

Frequency of Anaplasma phagocytophilum, Borrelia spp., and coinfections in Ixodes ricinus ticks collected from dogs and cats in Germany

BACKGROUND

Changing geographical and seasonal activity patterns of ticks may increase the risk of tick infestation and tick-borne pathogen (TBP) transmission for both humans and animals.

METHODS

To estimate TBP exposure of dogs and cats, 3000 female I. ricinus from these hosts were investigated for Anaplasma phagocytophilum and Borrelia species.

RESULTS

qPCR inhibition, which was observed for ticks of all engorgement stages but not questing ticks, was eliminated at a template volume of 2 µl. In ticks from dogs, A. phagocytophilum and Borrelia spp. prevalence amounted to 19.0% (285/1500) and 28.5% (427/1500), respectively, while ticks from cats showed significantly higher values of 30.9% (464/1500) and 55.1% (827/1500). Accordingly, the coinfection rate with both A. phagocytophilum and Borrelia spp. was significantly higher in ticks from cats (17.5%, 262/1500) than dogs (6.9%, 104/1500). Borrelia prevalence significantly decreased with increasing engorgement duration in ticks from both host species, whereas A. phagocytophilum prevalence decreased only in ticks from dogs. While A. phagocytophilum copy numbers in positive ticks did not change significantly over the time of engorgement, those of Borrelia decreased initially in dog ticks. In ticks from cats, copy numbers of neither A. phagocytophilum nor Borrelia spp. were affected by engorgement. Borrelia species differentiation was successful in 29.1% (365/1254) of qPCR-positive ticks. The most frequently detected species in ticks from dogs were B. afzelii (39.3% of successfully differentiated infections; 70/178), B. miyamotoi (16.3%; 29/178), and B. valaisiana (15.7%; 28/178), while B. afzelii (40.1%; 91/227), B. spielmanii (21.6%; 49/227), and B. miyamotoi (14.1%; 32/227) occurred most frequently in ticks from cats.

CONCLUSIONS

The differences in pathogen prevalence and Borrelia species distribution between ticks collected from dogs and cats may result from differences in habitat overlap with TBP reservoir hosts. The declining prevalence of A. phagocytophilum with increasing engorgement duration, without a decrease in copy numbers, could indicate transmission to dogs over the time of attachment. The fact that this was not observed in ticks from cats may indicate less efficient transmission. In conclusion, the high prevalence of A. phagocytophilum and Borrelia spp. in ticks collected from dogs and cats underlines the need for effective acaricide tick control to protect both animals and humans from associated health risks.

Genome diversity of Borrelia garinii in marine transmission cycles does not match host associations but reflects the strains evolutionary history

Borrelia burgdorferi sensu lato is a species complex of spirochetal bacteria that occupy different ecological niches which is reflected in their reservoir host- and vector-associations. Borrelia genomes possess numerous linear and circular plasmids. Proteins encoded by plasmid genes play a major role in host- and vector-interaction and are important for Borrelia niche adaptation. However, the plasmid composition and therewith the gene repertoire may vary even in strains of a single species. Borrelia garinii, one of the six human pathogenic species, is common in Europe (vector Ixodes ricinus), Asia (vector Ixodes persulcatus) and in marine birds (vector Ixodes uriae). For the latter, only a single culture isolate (Far04) and its genome were previously available. The genome was rather small containing only one circular and six linear plasmids with a notable absence of cp32 plasmids. To further investigate B. garinii from marine transmission cycles and to explore i) whether the small number of plasmids found in isolate Far04 is a common feature in B. garinii from marine birds and presents an adaptation to this particular niche and ii) whether there may be a correlation between genome type and host species, we initiated in vitro cultures from live I. uriae collected in 2017 and 2018 from marine avian hosts and their nests. Hosts included common guillemots, Atlantic Puffin, razorbill, and kittiwake. We obtained 17 novel isolates of which 10 were sequenced using Illumina technology, one also with Pacific Bioscience technology. The 10 genomes segregated into five different genome types defined by plasmid types (based on PFam32 loci). We show that the genomes of seabird associated B. garinii contain fewer plasmids (6-9) than B. garinii from terrestrial avian species (generally ≥10), potentially suggesting niche adaptation. However, genome type did not match an association with the diverse avian seabird hosts investigated but matched the clonal complex they originated from, perhaps reflecting the isolates evolutionary history. Questions that should be addressed in future studies are (i) how is plasmid diversity related to host- and/or vector adaptation; (ii) do the different seabird species differ in reservoir host competence, and (iii) can the genome types found in seabirds use terrestrial birds as reservoir hosts.

Microorganisms associated with hedgehog arthropods

Hedgehogs are small synanthropic mammals that live in rural areas as well as in urban and suburban areas. They can be reservoirs of several microorganisms, including certain pathogenic agents that cause human and animal public health issues. Hedgehogs are often parasitized by blood-sucking arthropods, mainly hard ticks and fleas, which in turn can also carry various vector-born microorganisms of zoonotic importance. Many biotic factors, such as urbanization and agricultural mechanization, have resulted in the destruction of the hedgehog's natural habitats, leading these animals to take refuge near human dwellings, seeking food and shelter in parks and gardens and exposing humans to zoonotic agents that can be transmitted either directly by them or indirectly by their ectoparasites. In this review, we focus on the microorganisms detected in arthropods sampled from hedgehogs worldwide. Several microorganisms have been reported in ticks collected from these animals, including various Borrelia spp., Anaplasma spp., Ehrlichia spp., and Rickettsia spp. species as well as Coxiella burnetii and Leptospira spp. As for fleas, C. burnetii, Rickettsia spp., Wolbachia spp., Mycobacterium spp. and various Bartonella species have been reported. The detection of these microorganisms in arthropods does not necessarily mean that they can be transmitted to humans and animals. While the vector capacity and competence of fleas and ticks for some of these microorganisms has been proven, in other cases the microorganisms may have simply been ingested with blood taken from an infected host. Further investigations are needed to clarify this issue. As hedgehogs are protected animals, handling them is highly regulated, making it difficult to conduct epidemiological studies on them. Their ectoparasites represent a very interesting source of information on microorganisms circulating in populations of these animals, especially vector-born ones.

15-year Borrelia prevalence and species distribution monitoring in Ixodes ricinus/inopinatus populations in the city of Hanover, Germany

Lyme borreliosis, caused by Borrelia burgdorferi sensu lato (s.l.) spirochaetes, is the most common tick-borne disease (TBD) in the Northern Hemisphere. Rising incidences indicate that its epidemiology may be affected by global changes. Therefore, the current study aimed to assess changes in tick infection rates with Borrelia spp. over a 15-year monitoring period in the city of Hanover, Germany, as a follow-up to previous prevalence studies (years 2005, 2010 and 2015). To assess the epidemiological risk, ticks of the Ixodes ricinus/inopinatus-complex were sampled from April to October 2020 by the flagging method at 10 frequently visited recreation areas in Hanover. Analysis by quantitative real-time PCR of 2100 individual ticks revealed an overall Borrelia prevalence of 25.5% (535/2100). Regarding different tick developmental stages, nymphs showed a significantly lower Borrelia prevalence (18.4% [193/1050]) than adult ticks (32.6% [342/1050]). Comparison with previous years revealed a stable total Borrelia prevalence along with consistent infection rates in the different developmental stages over the 15-year monitoring period. Borrelia species differentiation by Reverse Line Blot was successful in 67.3% of positive ticks collected in 2020, with B. afzelii being the dominating species (59.2% of the differentiated infections), besides B. burgdorferi sensu stricto (s.s.), B. garinii, B. valaisiana, B. spielmanii, B. bavariensis and B. bissettiae and the relapsing fever spirochaete B. miyamotoi. Additionally, the proportion of infections attributed to B. afzelii showed a significant increase in 2020 compared to 2005 and 2015 (59.2% vs. 37.6% and 32.0% of successfully differentiated infections, respectively). Coinfections with Anaplasma phagocytophilum and Rickettsia spp. stayed stable comparing 2020 with previous years. Therefore, although changes in the Borrelia prevalence in questing ticks were not observed throughout the 15-year monitoring period, shifts in Borrelia species distribution may alter the epidemiological risk.

Diagnosis of Lyme Borreliosis With a Novel, Seminested Real-Time Polymerase Chain Reaction Targeting the 5S-23S Intergenic Spacer Region: Clinical Features, Histopathology, and Immunophenotype in 44 Patients

ABSTRACT

Lyme borreliosis (LB) is the most common tick-borne infection in Europe and North America. Polymerase chain reaction (PCR) is an important tool to confirm the diagnosis, but not always successful, especially when organisms are sparse. We developed a novel, seminested real-time PCR assay [target: 5S-23S intergenic spacer region (IGS)] and compared it with 3 well-established conventional PCR assays (IGS/OspA/real-time IGS) on 596 formalin-fixed, paraffin-embedded routine skin biopsies. The seminested real-time assay identified 46 cases of borreliosis while 25, 27, and 38 were identified by the 3 other assays, respectively (P 0.01, P 0.02, and P 0.42; significance P < 0.05). Clinicopathologic and immunophenotypic analysis of PCR-positive cases revealed 38 erythema migrans (EM), 6 Borrelia lymphocytomas, and 2 acrodermatitis chronica atrophicans (ACA). In the 44 PCR-confirmed cases, plasma cells were present in only a third of EM cases. By contrast, CD123-positive plasmacytoid dendritic cells were common (74%) and therefore are unlikely to be helpful in the differential diagnosis between EM and tumid lupus erythematosus. A loss of CD34 in a third of all LB specimens limits its diagnostic value in the differential diagnosis with morphea. Interstitial macrophages were common in cutaneous LB (42/43) forming interstitial granulomas in a third of all cases, and 3/38 EM, 3/6 Borrelia lymphocytomas, and 1/2 ACA were only identified by the new seminested real-time assay, suggesting that it is especially helpful in confirming the diagnosis of Borrelia lymphocytoma.

No evidence of Borrelia in Cutaneous Infiltrates of B-cell lymphomas with a highly sensitive, semi-nested real time Polymerase chain reaction (PCR) targeting the 5S-23S intergenic spacer region (IGS)

BACKROUND

The role of Borrelia in the development of skin lymphomas has been under discussion for decades. A similar association has been shown for Helicobacter pylori and gastric lymphomas (MALT type). Nevertheless, few molecular studies investigated Borrelia in skin lymphomas and the results are controversial.

METHODS

We analysed 46 formalin-fixed, paraffin-embedded skin specimens of clincopathologically confirmed B-cell lymphomas (15 marginal zone lymphomas; 20 follicular lymphomas; 3 diffuse large B-cell lymphomas; 8 secondary cutaneous infiltrates) taken from 36 patients from Northern Germany, an endemic area for Borrelia. Fifteen pseudolymphomatous lesions of cutaneous Borreliosis served as control. Both groups were examined with a real time (rt) PCR and a semi-nested PCR targeting the 5S-23S intergenic spacer region (IGS). A multiplex PCR was used to investigate B-cell clonality in all lymphomatous infiltrates (Biomed Primers).

RESULTS

With both assays no B. burgdorferi-specific DNA was identified in any of the B-cell lymphomas, while all 15 Borreliosis specimens gave a positive PCR result in the semi-nested PCR protocol, 12 were also positive in the rt PCR (p<.01). All B-cell lymphomas showed monoclonal IgH-Rearrangement. Analysis of cutaneous B-cell lymphomas from available studies including ours (n=334) reveals an Odds ratio < 1.

CONCLUSION

While some previous studies suggested an association between B. burgdorferi and the development of cutaneous B-cell lymphomas in endemic areas, we were unable to confirm this in our patients, despite a highly sensitive Borrelia PCR assay. Our results including meta-analysis of previous studies question the need for antibiotic therapy in patients with cutaneous B-cell lymphomas.

Borrelia Infections in Ageing Ticks: Relationship with Morphometric Age Ratio in Field-Collected Ixodes ricinus Nymphs

In Europe, Ixodes ricinus plays a major role as a vector of Borrelia burgdorferi sensu lato (s.l.) spirochaetes, the causative agents of Lyme borreliosis, among other pathogens. In unfed ticks, Borrelia spirochaetes experience prolonged nutrient restriction. However, only few studies exist with regard to Borrelia infections in unfed ticks of different physiological ages. Changing body dimensions of unfed ticks, due to the consumption of energy reserves, allow physiological age estimation. The present study investigated the relationship of morphometric age with Borrelia prevalence and spirochaete load in 1882 questing I. ricinus nymphs, collected at two different locations in northern Germany in 2020. In addition, Borrelia species composition was investigated by employing a reverse line blot (RLB) probe panel suitable for the detection of ten different B. burgdorferi s.l. species, as well as the relapsing-fever spirochaete B. miyamotoi. Overall, Borrelia prevalence was 25.8% (485/1882). Whilst there was no statistically significant difference in Borrelia prevalence between the different morphometric age groups, Borrelia infection intensity as determined by probe-based quantitative real-time PCR significantly declined with increasing morphometric age. Borrelia species differentiation by RLB was successful in 29.5% of positive ticks, and revealed B. afzelii as the dominating species (65.0% of the differentiated infections). Additionally, B. garinii, B. valaisiana, B. burgdorferi sensu stricto, B. spielmanii, and B. miyamotoi were detected.

Distribution of Borrelia burgdorferi s.l. and Borrelia miyamotoi in Ixodes tick populations in Northern Germany, co-infections with Rickettsiales and assessment of potential influencing factors

To determine Borrelia spp. (Spirochaetales: Spirochaetaceae) prevalence and species distribution in Northern Germany, Ixodes ticks were sampled from April to October in 2018 and 2019 by the flagging method at three locations each in five regions. Analysis by quantitative real-time PCR of 3150 individual ticks revealed an overall prevalence of 30.6%, without significant differences between tick stages (31.7% positive adults, 28.6% positive nymphs). Significant differences were observed in seasonal infection rates, but not between regions, landscape types or sampling years. Analysis of co-infections with Rickettsiales indicated a negative association between Borrelia and Anaplasma phagocytophilum infection. The most frequent Borrelia species differentiated by Reverse Line Blot were B. afzelii and B. garinii/B. bavariensis, followed by B. valaisiana, B. burgdorferi sensu stricto, B. spielmanii and B. lusitaniae. Furthermore, B. miyamotoi was identified in 12.9% of differentiable samples. No effect of region nor landscape type on species composition was found, but significant variations in the distribution at the different sampling sites within a region were observed. The detected monthly fluctuations in prevalence and the differences in intra-regional Borrelia species distribution underline the importance of long-term and multi-location monitoring of Borrelia spp. in ticks as an essential part of public health assessment.

Immunoreactivity of Polish Lyme Disease Patient Sera to Specific Borrelia Antigens-Part 1

The diverse clinical picture and the non-specificity of symptoms in Lyme disease (LD) require the implementation of effective diagnostics, which should take into account the heterogeneity of Borrelia antigens. According to available guidelines, laboratories should use a two-tier serological diagnosis based on the enzyme-linked immunosorbent (ELISA) screening test and confirmation of the immunoblot (IB). The aim of the study was to investigate the immunoreactivity of LD patient sera to Borrelia antigens and to attempt to identify the genospecies responsible for LD using an ELISA–IB assay combination. Eighty patients with suspected LD and 22 healthy people participated in the study. All samples were tested with ELISA and IB assays in both IgM and IgG antibodies. In the case of the ELISA assay, more positive results were obtained in the IgM class than in the IgG class. In the case of the IB assay, positive results dominated in the IgG class. Positive results obtained in the IB assay most often showed IgM antibodies against the OspC and flagellin antigens, whereas the IgG antibodies were against VlsE, BmpA, OspC, p41, and p83 antigens. The IB assay is an important part of LD serodiagnosis and should be mandatory in diagnostic laboratories.

Regional, seasonal, biennial and landscape-associated distribution of Anaplasma phagocytophilum and Rickettsia spp. infections in Ixodes ticks in northern Germany and implications for risk assessment at larger spatial scales

Tick-associated Rickettsiales are important pathogens with relevance for public and animal health; therefore, knowledge regarding their distribution is essential for risk assessment and disease prevention. To investigate the prevalence of Anaplasma phagocytophilum and Rickettsia spp. in northern Germany, Ixodes ticks were flagged monthly from April to October in 2018 and 2019 at three collection sites each in the regions of Bremen, Emsland, Hanover, Kassel and Uelzen. A total of 3150 ticks (1052 females, 1048 males and 1050 nymphs) were individually examined for rickettsial infections using probe-based quantitative real-time PCR. Overall prevalence of A. phagocytophilum was 6.4 % (202/3150; 6.7 % [71/1052] in females, 7.5 % [79/1048] in males and 5.0 % [52/1050] in nymphs). For Rickettsia spp., the overall prevalence was 29.6 % (931/3150; 33.4 % [351/1052] in females, 28.3 % [297/1048] in males and 27.0 % [283/1050] in nymphs). Rickettsia species identification by real-time pyrosequencing on a subset of 409 positive samples was successful in 407 cases (99.5 %). Rickettsia helvetica was the predominant species with a detection rate of 99.8 % (406/407). Additionally, Rickettsia monacensis was detected in one tick (0.2 %). Generalized linear mixed models showed significant regional as well as monthly differences regarding the prevalence of both pathogens. In addition, the prevalence of both pathogens was significantly higher in 2018 (A. phagocytophilum: 8.0 % [126/1575], Rickettsia spp.: 35.4 % [558/1575]) than in 2019 (A. phagocytophilum: 4.8 % [76/1575], Rickettsia spp.: 23.9 % [373/1575]). In contrast, no effect of landscape type on pathogen prevalence was found. As Rickettsia spp.-detection was based on the single-copy gene gltA, it was possible to calculate the individual pathogen load per tick, which was significantly higher in female ticks than in nymphs (mean values: 8.19 × 10⁴ vs. 9.58 × 10³). Regional, seasonal and biennial prevalence differences of tick-transmitted Rickettsiales show the necessity to investigate ticks from multiple locations, over several months and in more than one year to reliably assess the infection risk on a larger geographical scale.

Spatial variability in prevalence and genospecies distributions of Borrelia burgdorferi sensu lato from ixodid ticks collected in southern Germany

Lyme borreliosis (LB) is the most common arthropod-borne disease in Europe and North America and is caused by members of the Borrelia burgdorferi sensu lato (Bbsl) species complex. These bacteria are transmitted by ixodid tick vectors and therefore human LB risk is influenced by the prevalence and distribution of Bbsl genospecies within tick vectors throughout the wild. These distributions can easily change over spatiotemporal scales and, to understand LB risk fully, up to date information on prevalence and distribution of Bbsl is required. The last survey of Bbsl in southern Germany, including parts of the Munich metropolitan area, was completed in 2006 and new data is needed. Ixodid ticks were collected in seven plots located in and around Munich, Germany, from March to July 2019 and were screened for Bbsl. Borrelia burgdorferi s. l. positive ticks (52 adults, 158 nymphs) were found in all plots and adults (0-61.5 % Bbsl positive/plot) and nymphs (17.4-59.5 % Bbsl positive/plot) did not differ significantly in their overall Bbsl prevalence. The number of Bbsl positive nymphs did vary significantly between plots but the number of positive adults did not. In total, six Bbsl genospecies were located with B. afzelii and B. garinii dominating. Additionally, the relapsing-fever species B. miyamotoi was found in two sampling plots. Our results highlight the variability in Bbsl prevalence and genospecies distribution over short geographic distances and aid in understanding LB risk in and around the Munich metropolitan area.

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.

Tick populations from endemic and non-endemic areas in Germany show differential susceptibility to TBEV

Tick-borne encephalitis virus (TBEV) is endemic in twenty-seven European countries, transmitted via the bite of an infected tick. TBEV is the causative agent of one of the most important viral diseases of the central nervous system (CNS). In Germany, 890 human cases were registered between the years 2018–2019. The castor bean tick, Ixodes ricinus, is the TBEV vector with the highest importance in Central Europe, including Germany. Despite the nationwide distribution of this tick species, risk areas of TBEV are largely located in Southern Germany. To increase our understanding of TBEV-tick interactions, we collected ticks from different areas within Germany (Haselmühl/Bavaria, Hanover/Lower Saxony) and infected them via an in vitro feeding system. A TBEV isolate was obtained from an endemic focus in Haselmühl. In two experimental series conducted in 2018 and 2019, ticks sampled in Haselmühl (TBEV focus) showed higher artificial feeding rates, as well as higher TBEV infections rates than ticks from the non-endemic area (Hanover). Other than the tick origin, year and month of the infection experiment as well as co-infection with Borrelia spp., had a significant impact on TBEV Haselmühl infection rates. Taken together, these findings suggest that a specific adaptation of the tick populations to their respective TBEV virus isolates or vice versa, leads to higher TBEV infection rates in those ticks. Furthermore, co-infection with other tick-borne pathogens such as Borrelia spp. can lower TBEV infection rates in specific populations.

Interrupted Blood Feeding in Ticks: Causes and Consequences

Ticks are obligate hematophagous arthropods and act as vectors for a great variety of pathogens, including viruses, bacteria, protozoa, and helminths. Some tick-borne viruses, such as Powassan virus and tick-borne encephalitis virus, are transmissible within 15–60 min after tick attachment. However, a minimum of 3–24 h of tick attachment is necessary to effectively transmit bacterial agents such as Ehrlichia spp., Anaplasma spp., and Rickettsia spp. to a new host. Longer transmission periods were reported for Borrelia spp. and protozoans such as Babesia spp., which require a minimum duration of 24–48 h of tick attachment for maturation and migration of the pathogen. Laboratory observations indicate that the probability of transmission of tick-borne pathogens increases with the duration an infected tick is allowed to remain attached to the host. However, the transmission time may be shortened when partially fed infected ticks detach from their initial host and reattach to a new host, on which they complete their engorgement. For example, early transmission of tick-borne pathogens (e.g., Rickettsia rickettsii, Borrelia burgdorferi, and Babesia canis) and a significantly shorter transmission time were demonstrated in laboratory experiments by interrupted blood feeding. The relevance of such situations under field conditions remains poorly documented. In this review, we explore parameters of, and causes leading to, spontaneous interrupted feeding in nature, as well as the effects of this behavior on the minimum time required for transmission of tick-borne pathogens.

Two-year monitoring of tick abundance and influencing factors in an urban area (city of Hanover, Germany)

Ticks may transmit a variety of human and animal pathogens. Prevalence of Borrelia spp., Rickettsia spp. and Anaplasma phagocytophilum in ticks has been monitored in the city of Hanover, Germany, since 2005. However, to determine the infection risk for humans and animals, not only pathogen prevalence, but also tick abundance and seasonality need to be taken into account. Therefore, the aim of this study was to investigate tick abundance at ten different collection sites in the city of Hanover, Germany. Collection of questing ticks was performed by the flagging method in the first and second half of each month during the tick season (April-October) in 2017 and 2018. At each 200 m² collection site, one of four 50 m² fields was sampled per visit on a rotational basis, resulting in 100 m² sampled per month. In addition, data on weather conditions, near-ground temperature, relative humidity and vegetation composition were noted at each collection event. In 2017, a total of 1770 ticks were collected, while 1866 ticks were collected in 2018. Ixodes ricinus was the most prevalent species (97.0 % of all ticks, 98.0 % of nymphs, 91.6 % of adults) followed by I. inopinatus (2.3 % of all ticks, 1.1 % of nymphs, 8.0 % of adults), I. frontalis (0.6 % of all ticks, 0.6 % of nymphs, 0.3 % of adults) and I. hexagonus (0.03 % of all ticks, 0.03 % of nymphs, 0.0 % of adults). Using generalized linear mixed modeling, density of I. ricinus and I. inopinatus in 2017 was significantly higher than in 2018. Regarding different landscape types, ticks were significantly more abundant in mixed forests than in parks, with more than 50 ticks/100 m² on average in both years. In urban parks, average tick density amounted to 15 ticks/100 m² in 2017 and 11 ticks/100 m² in 2018 and in broad-leaved forests average tick density was 13 and 18 ticks/100 m² in 2017 and 2018, respectively. Tick density showed a marked peak in June 2017 and in May 2018 at most sites, whereas a less pronounced peak was recognizable in September. Tick density varied considerably between collection sites. However, no statistically significant effect of (micro-)climatic variables, including near-ground temperature, relative humidity and saturation deficit, was found. Thus, further factors, such as the abundance of wildlife hosts, need to be considered in future studies to explain the differences between collection sites.

Transovarial transmission of Borrelia spp., Rickettsia spp. and Anaplasma phagocytophilum in Ixodes ricinus under field conditions extrapolated from DNA detection in questing larvae

Background

Ixodes ricinus constitutes the main European vector tick for the Lyme borreliosis pathogen Borrelia burgdorferi (sensu lato), the relapsing fever borrelia Borrelia miyamotoi, as well as Anaplasma phagocytophilum and several Rickettsia species. Under laboratory conditions, a transovarial transmission to the next tick generation is described for Rickettsia spp. and Borrelia spp., especially regarding B. miyamotoi, whereas the efficiency of transovarial transfer under field conditions is largely unstudied.

Methods

In order to better estimate the potential infection risk by tick larvae for humans and animals, 1500 I. ricinus larvae from 50 collected “nests” (larvae adhering to the flag in a clumped manner) were individually examined for Borrelia, Rickettsia and A. phagocytophilum DNA using quantitative real-time PCR (qPCR).

Results

Thirty-nine of 50 nests each (78.0%, 95% CI: 64.0–88.5%) were positive for Borrelia spp. and Rickettsia spp. DNA, and in three nests (6.0%, 95% CI: 1.3–16.5%) A. phagocytophilum DNA was detected. Overall, DNA from at least one pathogen could be detected in 90.0% (45/50, 95% CI: 78.2–96.7%) of the nests. Of the 1500 larvae, 137 were positive for Borrelia spp. DNA (9.1%, 95% CI: 7.7–10.7%), 341 for Rickettsia spp. DNA (22.7%, 95% CI: 20.6–24.9%) and three for A. phagocytophilum DNA (0.2%, 95% CI: 0–0.6%). Quantity of Borrelia spp. and Anaplasma spp. DNA in positive larvae was low, with 2.7 × 10⁰Borrelia 5S-23S gene copies and 2.4 × 10¹A. phagocytophilum msp2/p44 gene copies detected on average, while Rickettsia-positive samples contained on average 5.4 × 10²gltA gene copies. Coinfections were found in 66.0% (33/50, 95% CI: 51.2–78.8%) of the nests and 8.6% (38/443, 95% CI: 6.1–11.6%) of positive larvae. In fact, larvae had a significantly higher probability of being infected with Borrelia spp. or Rickettsia spp. when both pathogens were present in the nest.

Conclusions

This study provides evidence for transovarial transmission of Rickettsia spp. and Borrelia spp. in I. ricinus under field conditions, possibly facilitating pathogen persistence in the ecosystem and reducing the dependence on the presence of suitable reservoir hosts. Further studies are needed to prove transovarial transmission and to explain the surprisingly high proportion of nests containing Rickettsia and/or Borrelia DNA-positive larvae compared to infection rates in adult ticks commonly reported in other studies.

Borrelia prevalence and species distribution in ticks removed from humans in Germany, 2013-2017

Lyme borreliosis caused by spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex is the most common tick-borne disease in Europe. In addition, the relapsing-fever spirochaete Borrelia miyamotoi, which has been associated with febrile illness and meningoencephalitis in immunocompromised persons, is present in Europe. This study investigated Borrelia prevalence and species distribution in ticks removed from humans and sent as diagnostic material to the Institute for Parasitology, University of Veterinary Medicine Hannover, in 2013-2017. A probe-based real-time PCR was carried out and Borrelia-positive samples were subjected to species determination by reverse line blot (RLB), including a B. miyamotoi-specific probe. The overall Borrelia-infection rate as determined by real-time PCR was 20.02 % (510/2547, 95 % CI: 18.48-21.63 %), with annual prevalences ranging from 17.17 % (90/524, 95 % CI: 14.04-20.68 %) in 2014 to 24.12 % (96/398, 95 % CI: 19.99-28.63 %) in 2015. In total, 271/475 (57.1 %) positive samples available for RLB were successfully differentiated. Borrelia afzelii was detected in 30.53 % of cases (145/475, 95 % CI: 26.41-34.89), followed by B. garinii/B. bavariensis (13.26 % [63/475], 95 % CI: 10.34-16.65). Borrelia valaisiana occurred in 5.89 % (28/475, 95 % CI: 3.95-8.41), B. spielmanii in 4.63 % (22/475, 95 % CI: 2.93-6.93), B. burgdorferi sensu stricto (s.s.)/B. carolinensis in 2.32 % (11/475, 95 % CI: 1.16-4.11), B. lusitaniae in 0.63 % (3/475, 95 % CI: 0.13-1.83) and B. bisettiae in 0.42 % (2/475, 95 % CI: 0.05-1.51) of positive ticks. Borrelia kurtenbachii was not detected, while B. miyamotoi was identified in 7.37 % (35/475, 95 % CI: 5.19-10.10) of real-time PCR-positive samples. Sanger sequencing of B. garinii/B. bavariensis-positive ticks revealed that the majority were B. garinii-infections (50/52 successfully amplified samples), while only 2 ticks were infected with B. bavariensis. Furthermore, 6/12 B. burgdorferi s.s./B. carolinensis-positive samples could be differentiated; all of them were identified as B. burgdorferi sensu stricto. Thirty-nine ticks (8.21 %, 95 % CI: 5.90-11.05) were coinfected with two different species. Comparison of the species distribution between ticks removed from humans in 2015 and questing ticks collected in the same year and the same area revealed a significantly higher B. afzelii-prevalence in diagnostic tick samples than in questing ticks, confirming previous observations. The obtained data indicate that Borrelia prevalence fluctuated in the same range as observed in a previous study, analysing the period from 2006 to 2012. Detection of B. miyamotoi in 7.37 % of Borrelia-positive samples points to the fact that clinicians should be aware of this pathogen as a differential diagnosis in cases of febrile illness.

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.

A 4-Yr Survey of the Range of Ticks and Tick-Borne Pathogens in the Lehigh Valley Region of Eastern Pennsylvania

Questing ticks were surveyed by dragging in forested habitats within the Lehigh Valley region of eastern Pennsylvania for four consecutive summers (2015-2018). A high level of inter-annual variation was found in the density of blacklegged tick nymphs, Ixodes scapularis Say, with a high density of host-seeking nymphs (DON) in summer 2015 and 2017 and a relatively low DON in summer 2016 and 2018. Very few American dog ticks (Dermacentor variabilis Say) and Ixodes cookei Packard were collected. Lone star ticks (Amblyomma americanum L.) and longhorned ticks (Haemaphysalis longicornis Neumann) were not represented among the 6,398 ticks collected. For tick-borne pathogen surveillance, DNA samples from 1,721 I. scapularis nymphs were prepared from specimens collected in summers 2015-2017 and screened using qPCR, high resolution melting analysis, and DNA sequencing when necessary. The overall 3-yr nymphal infection prevalence of Borrelia burgdorferi was 24.8%, Borrelia miyamotoi was 0.3%, Anaplasma phagocytophilum variant-ha was 0.8%, and Babesia microti was 2.8%. Prevalence of coinfection with B. burgdorferi and B. microti as well as B. burgdorferi and A. phagocytophilum variant-ha were significantly higher than would be expected by independent infection. B. burgdorferi nymphal infection prevalence is similar to what other studies have found in the Hudson Valley region of New York, but levels of B. microti and A. phagocytophilum variant-ha nymphal infection prevalence are relatively lower. This study reinforces the urgent need for continued tick and pathogen surveillance in the Lehigh Valley region.

Multiple infections in questing nymphs and adult female Ixodes ricinus ticks collected in a recreational forest in Denmark

During its lifecycle, the generalist Ixodes ricinus takes up three blood meals from a wide selection of vertebrate hosts, some of which are reservoirs for multiple vector-associated pathogens. Since I. ricinus also readily bites humans, pets, and livestock, these hosts are at risk of becoming infected with more than one tick-borne pathogen. Multiple tick-borne infections are a public health concern, since they may increase diversity and duration of symptoms and complicate differential diagnosis and therapy. We used an existing Fluidigm real-time PCR chip to identify the minimum risk of exposure to infected/co-infected ticks in Denmark. We screened 509 nymphs and 504 adult female I. ricinus ticks for 17 different vector-associated pathogenic agents. The questing ticks were collected by flagging during the same season in two consecutive years in Grib forest in the capital region of Copenhagen. Overall, 19.1% of the nymphs and 52.2% of the adult female ticks harbored at least one zoonotic pathogen. The main agents were Borrelia spp., Anaplasma phagocytophilum and Rickettsia helvetica, while Candidatus Neoehrlichia mikurensis and Babesia venatorum both were present in less than 1% of the ticks. In 3.5% of the nymphs and 12.3% of adults we found more than one tick-borne pathogen. Of these, 15% were potentially triple or quadruple infections. Whereas mixed infections with Borrelia were equally distributed among both life stages, the adult ticks hosted 84.5% of the co-infections with different species of tick-borne pathogens, chiefly involving Borrelia species in combination with either R. helvetica or A. phagocytophilum. Statistical analyses indicated non-random co-occurrence of Borrelia spielmanii/Borrelia garinii in both life stages and B. garinii/Borrelia afzelii and B. garinii/Borrelia valaisiana in the nymphs. Although the overall prevalence of ticks hosting more than one infection only constituted 7.9% at the particular site investigated in this study, our results still underline that co-infections should be considered in diagnosis and treatment of tick-borne diseases in northern Europe.

Dermacentor reticulatus in Berlin/Brandenburg (Germany): Activity patterns and associated pathogens

Dermacentor reticulatus is one of the most important European tick species. However, its spatial distribution, seasonality and regional vector role are not well known. This study aimed to gather information about abundance patterns of questing ticks and associated pathogens in unfed female adult D. reticulatus in the Berlin/Brandenburg area. Using the flagging method, questing ticks were collected at four sites in 2010-2012 and 2000 D. reticulatus were analysed regarding infection with Rickettsia, Babesia, Borrelia and Anaplasmataceae by conventional or real-time PCR. Dermacentor reticulatus showed a bimodal activity pattern: highest numbers of adult ticks were recorded between March and end of May (mean 50 ticks/h) and from mid-August until end of November (mean 102 ticks/h). During summer, almost complete inactivity was observed (mean 0.4 ticks/h). Sporadic samplings from December to February revealed tick activity also during winter (mean 47 ticks/h), which was characterised by large fluctuations. Using negative binomial regression analysis, significant influences of the variables sampling site, season and temperature on the abundance of questing D. reticulatus were determined. The parameters relative humidity and year were not of significant importance. PCR analyses showed an average prevalence of 64% for Rickettsia sp. Large differences in pathogen frequencies were observed between sampling sites (31.4-78.3%). Regression analysis demonstrated a significant influence of the sampling site but not of season and year. Examinations regarding other pathogen groups indicated prevalences of 0.25% (Borrelia sp.) and 0.05% (Anaplasmataceae) but absence of Babesia sp. Sequencing of positive samples revealed infections with Rickettsia raoultii, Borrelia miyamotoi, Borrelia afzelii and Anaplasma phagocytophilum. The study shows stable populations of D. reticulatus in Berlin/Brandenburg. People should be aware of ticks throughout the year since Ixodes ricinus is co-endemic and active in spring, summer and autumn while adult D. reticulatus are active throughout the year and even in winter during periods of frost as long as it is warming up during the day. Prevalence of R. raoultii in the present study is among the highest described for D. reticulatus. Borrelia miyamotoi was detected for the first time in D. reticulatus, illustrating the importance of screening studies to evaluate the pathogen structure in D. reticulatus populations.

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.

A 10-year surveillance of Rickettsiales (Rickettsia spp. and Anaplasma phagocytophilum) in the city of Hanover, Germany, reveals Rickettsia spp. as emerging pathogens in ticks

BACKGROUND

Rickettsiales (Rickettsia spp. and Anaplasma phagocytophilum) transmitted by ticks are considered (re-)emerging pathogens posing a risk to public health. Nevertheless, year-long monitoring studies on prevalences of these pathogens in questing ticks to contribute to public health risk assessment are rare.

METHODS

The current study extends previous prevalence surveillances (2005 and 2010) by 2015 to a 10-year monitoring. Therefore, 2100 questing Ixodes ricinus were collected from April to October 2015 at ten different recreation sites in the city of Hanover, Germany, to determine potential changes in tick infection rates with Rickettsiales.

RESULTS

Of the collected ticks, 288 were adult females, 285 adult males and 1527 nymphs. Overall, 3.8% (79/2100) of ticks were infected with A. phagocytophilum, 50.8% (1066/2100) with Rickettsia spp. and 2.2% (46/2100) with both pathogens. Statistical analyses revealed stagnating A. phagocytophilum infection rates over the 10-year monitoring period, whereas Rickettsia infections increased significantly (33.3% in 2005 and 26.2% in 2010 vs 50.8% in 2015). This increase was also characterized by prominent seasonality with higher prevalences from July to October.

CONCLUSIONS

As increased tick infection rates result in an increased risk for public health, the long-term data reported here provide significant implications for the understanding of progressing Rickettsiales distribution in ticks and essentially contribute to reliable public health risk assessments.

Association of Borrelia and Rickettsia spp. and bacterial loads in Ixodes ricinus ticks

In recent years, awareness of coinfections has increased as synergistic or antagonistic effects on interacting bacteria have been observed. To date, several reports on coinfections of ticks with Rickettsia and Borrelia spp. are available. However, associations are rarely described and studies are based on rather low sample sizes. In the present study, coinfections of Ixodes ricinus with these pathogens were investigated by determining their association in a meta-analysis. A total of 5079 tick samples examined for Rickettsia and Borrelia spp. via probe-based quantitative real-time PCR in previous prevalence studies or as submitted diagnostic material were included. In Borrelia-positive ticks, genospecies were determined by Reverse Line Blot. Determination of bacterial loads resulted in an increase between developmental tick stages with highest mean bacterial loads in female ticks (7.96×10⁴ in Borrelia single-infected, 4.87×10⁵ in Rickettsia single-infected and 3.22×10⁵ in Borrelia-Rickettsia coinfected females). The determined Borrelia-Rickettsia tick coinfection rate was 12.3% (626/5079) with a significant difference to the expected coinfection rate of 9.0% (457/5079). A significant slight association as well as correlation between Borrelia and Rickettsia were determined. In addition, a significant interrelation of the bacterial load in coinfected ticks was shown. At the level of Borrelia genospecies, significant weak associations with Rickettsia spp. were detected for B. afzelii, B. garinii/bavariensis, B. valaisiana and B. lusitaniae. The positive association provides evidence for interactions between Borrelia and Rickettsia spp. in the tick vector, presumably resulting in higher bacterial replication rates in the tick vector and possibly the reservoir host. However, coinfection may impact the vector negatively as indicated by an absent increase in coinfection rates from nymphs to adults. Future studies are needed to investigate the underlying mechanisms of the positive association in ticks and possible associations in the vertebrate host as well as the potential influence of environmental factors.

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).

Did Garin and Bujadoux Actually Report a Case of Lyme Radiculoneuritis?

Although a 1922 report by Garin and Bujadoux is widely regarded as describing the first case of neurologic Lyme borreliosis, the many highly atypical features raises the question of whether the paper deserves the historic recognition that it has received.

A 1922 report by Garin and Bujadoux is widely regarded as describing the first case of neurologic Lyme borreliosis. Although the patient reported had a tick bite followed by the development of a rash and radiculoneuritis, there were a number of highly atypical features, raising the question of whether the patient, in fact, had neurologic Lyme borreliosis. The paper may not deserve the historic recognition that it has received.

Tick infestation in birds and prevalence of pathogens in ticks collected from different places in Germany

The importance of ticks and tick-borne pathogens for human and animal health has been increasing over the past decades. For their transportation and dissemination, birds may play a more important role than wingless hosts. In this study, tick infestation of birds in Germany was examined. Eight hundred ninety-two captured birds were infested with ticks and belonged to 48 different species, of which blackbirds (Turdus merula) and song thrushes (Turdus philomelos) were most strongly infested. Ground feeders were more strongly infested than non-ground feeders, sedentary birds more strongly than migratory birds, and short-distance migratory birds more strongly than long-distance migratory birds. Mean tick infestation per bird ranged between 2 (long-distance migratory bird) and 4.7 (sedentary bird), in some single cases up to 55 ticks per bird were found. With the exception of three nymphs of Haemaphysalis spp., all ticks belonged to Ixodes spp., the most frequently detected tick species was Ixodes ricinus. Birds were mostly infested by nymphs (65.1 %), followed by larvae (32.96 %). Additionally, ticks collected from birds were examined for several pathogens: Tick-borne encephalitis virus (TBEV) and Sindbisvirus with real-time RT-PCR, Flaviviruses, Simbuviruses and Lyssaviruses with broad-range standard RT-PCR-assays, and Borrelia spp. with a Pan-Borrelia real-time PCR. Interestingly, no viral pathogens could be detected, but Borrelia spp. positive ticks were collected from 76 birds. Borrelia (B.) garinii, B. valaisiaina, B. burgdorferi s.s. and B. afzelii were determined. The screening of ticks and birds for viral pathogens with broad range PCR-assays was tested and the use as an “early warning system” is discussed.

Larvae of Ixodes ricinus transmit Borrelia afzelii and B. miyamotoi to vertebrate hosts

Background

Lyme borreliosis is the most common tick-borne human disease and is caused by Borrelia burgdorferi sensu lato (s.l.). Borrelia miyamotoi, a relapsing fever spirochaete, is transmitted transovarially, whereas this has not been shown for B. burgdorferi (s.l). Therefore, B. burgdorferi (s.l) is considered to cycle from nymphs to larvae through vertebrates. Larvae of Ixodes ricinus are occasionally B. burgdorferi (s.l) infected, but their vector competence has never been studied.

Methods

We challenged 20 laboratory mice with field-collected larvae of I. ricinus. A subset of these larvae was analysed for infections with B. burgdorferi (s.l) and B. miyamotoi. After three to four challenges, mice were sacrificed and skin and spleen samples were analysed for infection by PCR and culture.

Results

Field-collected larvae were naturally infected with B. burgdorferi (s.l) (0.62 %) and B. miyamotoi (2.0 %). Two mice acquired a B. afzelii infection and four mice acquired a B. miyamotoi infection during the larval challenges.

Conclusion

We showed that larvae of I. ricinus transmit B. afzelii and B. miyamotoi to rodents and calculated that rodents have a considerable chance of acquiring infections from larvae compared to nymphs. As a result, B. afzelii can cycle between larvae through rodents. Our findings further imply that larval bites on humans, which easily go unnoticed, can cause Lyme borreliosis and Borrelia miyamotoi disease.

Borrelia burgdorferi sensu lato and co-infections with Anaplasma phagocytophilum and Rickettsia spp. in Ixodes ricinus in Hamburg, Germany

To obtain initial data on Borrelia burgdorferi sensu lato (Spirochaetales: Spirochaetaceae) in Ixodes ricinus (Ixodida: Ixodidae) ticks in Hamburg, Germany, 1400 questing ticks were collected by flagging at 10 different public recreation areas in 2011 and analysed using probe-based quantitative real-time polymerase chain reaction. The overall rate of infection with B. burgdorferi s.l. was 34.1%; 30.0% of adults were infected (36.7% of females and 26.0% of males), as were 34.5% of nymphs. Significant differences in tick infection rates were observed between the spring and summer/autumn months, as well as among sampling locations. Borrelia genospecies identification by reverse line blotting was successful in 43.6% of positive tick samples. The most frequent genospecies was Borrelia garinii/Borrelia bavariensis, followed by Borrelia afzelii, Borrelia valaisiana, B. burgdorferi sensu stricto, Borrelia spielmanii, Borrelia bissettii and Borrelia lusitaniae. Based on previously published data, co-infection of Borrelia and Rickettsiales spp. was determined in 25.8% of ticks. Overall, 22.9% of ticks were co-infected with Rickettsia spp. (Rickettsiales: Rickettsiaceae), 1.7% with Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae), and 1.2% with both pathogens. Study results show a high prevalence of Borrelia-positive ticks in recreation areas in the northern German city of Hamburg and the potential health risk to humans in these areas should not be underestimated.

Relatively low prevalence of Babesia microti and Anaplasma phagocytophilum in Ixodes scapularis ticks collected in the Lehigh Valley region of eastern Pennsylvania

Several human pathogens are transmitted by the blacklegged tick, Ixodes scapularis. These include the spirochetes that cause Lyme disease (Borrelia burgdorferi) which is endemic to the Lehigh Valley region of eastern Pennsylvania. Emerging and currently rare tick-borne diseases have been of increasing concern in this region, including tick-borne relapsing fever (caused by Borrelia miyamotoi), human granulocytic anaplasmosis (caused by Anaplasma phagocytophilum), and human babesiosis (caused by Babesia microti). Real-time PCR assays and in some instances, conventional PCR followed by DNA sequencing, were used to screen 423 DNA samples that were prepared from questing adult and nymph stage I. scapularis ticks for infection with four tick-borne human pathogens. B. burgdorferi was detected in 23.2% of the sampled ticks, while B. miyamotoi, B. microti and a human variant of A. phagocytophilum were detected in less than 0.5% of the ticks. Our results are consistent with those expected in a region where Lyme disease is prevalent and human cases of tick-borne relapsing fever, babesiosis and human granulocytic anaplasmosis are not currently widespread. It is expected that this study will serve as a baseline for future studies of tick-borne pathogens in an area that is in close proximity to regions of high endemicity for Lyme disease, human granulocytic anaplasmosis and human babesiosis.

Revisited: Borrelia burgdorferi sensu lato infections in hard ticks (Ixodes ricinus) in the city of Hanover (Germany)

Background

The present study investigated the prevalence of Borrelia burgdorferi sensu lato (s.l.) genospecies in Ixodes ricinus ticks collected in Hanover, Northern Germany, in 2010. At the same time the study served as fifth-year-follow-up study for data comparison with 2005.

Methods

A total of 2100 questing ticks were collected and analysed by quantitative real-time PCR (qPCR) with subsequent species differentiation via Reverse Line Blot and Sanger sequencing. Simultaneously, results obtained in 2010 were compared to infection rates from 2005 to evaluate the development of B. burgdorferi s.l. infection rates in Hanoverian ticks.

Results

Overall, 22.7% (476/2,100) of collected ticks were tested positive for B. burgdorferi s.l. infections. Adult ticks showed an infection rate of 33.3% (124/372), subdivided into 29.6% (58/196) positive males and 37.5% (66/176) positive females. Nymph and larvae infection rates were found to be 20.3% (344/1,697) and 25.8% (8/31), respectively. Species identification was successful for 59.2% (282/476) of positive ticks with B. afzelii as the most frequently detected genospecies, followed by B. garinii (including B. bavariensis) and B. spielmanii. B. burgdorferi sensu stricto (s.s.), B. bissettii, B. valaisiana and B. lusitaniae were also identified. Significant differences concerning seasonal fluctuations as well as local differences were observed. Comparing infection rates of Hanoverian ticks between years, a significant increase (P = 0.002) could be observed for larvae with 1.7% positives (2/60) in 2005 and 25.8% positives (8/31) in 2010. In the latter year, coinfections with Borrelia and Rickettsiales were detected in a total of 7.8% (163/2,100) of collected ticks. Of these, 7.3% (153/2,100) were coinfected with Rickettsia spp., 0.3% (7/2,100) with A. phagocytophilum and 0.1% (3/2,100) were coinfected with all three pathogens. Between years 2005 and 2010, no statistically significant differences in coinfection rates were found.

Conclusions

Comparing B. burgdorferi s.l. infections in Hanoverian I. ricinus ticks in 2010 with data from 2005, a statistically significant increase of infected larvae was noted, whereas the other stages revealed no statistically significant differences. Whether the increased larvae infection rate is an isolated event or results from factual circumstances, e.g. increasing effectiveness of transovarial transmission due to unknown factors, has to be evaluated in further studies.

Evaluation of Borrelia real time PCR DNA targeting OspA, FlaB and 5S-23S IGS and Borrelia 16S rRNA RT-qPCR

Borrelia burgdorferi non-sensu lato (s.l.) strains occurred in the Netherlands. A multiplex OspA, FlaB, IGS real time PCR was compared to 16S rRNA/rDNA RT-qPCR with lower average Cycle threshold (Ct) and LOD on strain dilutions. Multiplexing increased sensitivity on CSF samples (n=74), distinguishing B. burgdorferi s.l. from non-s.l. strains.

Genotyping of Borrelia from formalin-fixed paraffin-embedded skin biopsies of cutaneous borreliosis and tick bite reactions by assays targeting the intergenic spacer region, ospA and ospC genes

BACKGROUND

Lyme borreliosis has a broad spectrum of clinical presentations involving the skin, joints and nervous system. The variable manifestations have been attributed to different Borrelia genospecies but genotyping required culture or fresh tissue. However, in dermatology practice, formalin-fixed paraffin-embedded biopsies are used for dermatopathological examination. Polymerase chain reaction (PCR) for Borrelia burgdorferi sensu latu has been established on such specimens, but studies attempting genotyping of subspecies or strains are lacking.

OBJECTIVES

To adapt PCR assays for genotyping of Borrelia using paraffin-embedded biopsies, to identify Borrelia genospecies and to compare clinicopathological features of different genospecies.

METHODS

Eighty-two paraffin-embedded biopsies from 68 patients, with erythema migrans, acrodermatitis chronica atrophicans, lymphocytoma cutis or tick bite reactions, were studied with assays targeting the intergenic spacer (IGS), ospA and ospC, followed by sequencing and phylogenetic analysis. Clinicopathological data were analysed comparing different Borrelia genospecies.

RESULTS

Genotyping by IGS, ospA and ospC was successful in 85% of patients (91% B. afzelii, 7% B. garinii, 2% B. bavariensis). ospA serotyping identified type 2 (90%), type 3 (8%) and type 4 (2%). ospC-PCR was positive in 40% of the patients revealing 12 different groups, noninvasive forms being seen only in tick bite reactions and erythema migrans. No major clinicopathological differences could be identified between the genospecies, but neural inflammation and arthralgia were seen more often in lesions caused by invasive ospC strains.

CONCLUSIONS

Genotyping of Borrelia can be easily implemented in a routine dermatopathology setting, especially as a fast method to confirm early cutaneous borreliosis. Genotyping could also enable earlier treatment of patients infected with invasive strains.

Prevalence of Rickettsiales (Anaplasma phagocytophilum and Rickettsia spp.) in hard ticks (Ixodes ricinus) in the city of Hamburg, Germany

To narrow the gap of missing knowledge on Rickettsia spp. and Anaplasma phagocytophilum infections in ticks in northwestern Germany and, at the same time, to provide first prevalence data on these pathogens in the city of Hamburg, a total of 1,400 questing Ixodes ricinus ticks were collected at ten different public green areas from April until October 2011. Ticks were examined using probe-based quantitative real-time PCR. A percentage of 3.6% (51/1,400) ticks were tested positive for A. phagocytophilum infections divided into 2.1% (3/141) adults [1.7% (1/60) females and 2.5% (2/81) males] and 3.8% (48/1,259) nymphs. The percentage of infected ticks per sampling site varied statistically significantly from 0.7% (1/140) to 12.1% (17/140), whereas between sampling months, no statistically significant differences were observed (2.0-6.5%, 4-13/140). The overall Rickettsia spp. infection rate was 52.5% (735/1,400). In adult ticks, Rickettsia spp. infection rate was 56% (79/141) divided into 61.7% (37/60) infected females and 51.9% (42/81) infected males. Nymphs showed an infection rate of 52.1% (656/1,259). In contrast to A. phagocytophilum infections, no statistically significant differences in Rickettsia spp. infection rates among sampling sites (44.3-63.6%, 62-89/140) were observed, whereas seasonal variations were obvious: the percentage of Rickettsia-positive ticks was significantly lower in April (36.5%, 73/200) and May (29.5%, 59/200) compared to the summer and fall months (55.0-64.5%, 110-129/200). Rickettsia species differentiation via real-time pyrosequencing revealed Rickettsia helvetica as the only occurring species. Co-infections with both Rickettsia spp. and A. phagocytophilum were detected in 2.0% (28/1,400) of the ticks. The present study revealed that in the city of Hamburg, the tick infection rate with A. phagocytophilum is comparable with other German data, whereas the Rickettsia spp. infection rate of 52.5% is by far the highest prevalence detected in Germany so far. As the city of Hamburg has 1.8 million inhabitants and attracts millions of tourists every year, the potential health risk should not be underestimated.

Anaplasma phagocytophilum and Rickettsia spp. infections in hard ticks (Ixodes ricinus) in the city of Hanover (Germany): revisited

The present study aimed to determine the prevalence of Rickettsiales (A. phagocytophilum and Rickettsia spp.) in 2100 I. ricinus ticks collected at 10 different sampling sites every month during the tick season 2010 in the city of Hanover, northern Germany. At the same time, the results served as a fifth-year-follow-up study to monitor whether changes or stagnation of tick infection rates - possibly due to climate change--were obvious or not. To detect infections with A. phagocytophilum and/or Rickettsia spp., tick samples were analysed by quantitative real-time PCR. Differentiation of Rickettsia species was accomplished using real-time pyrosequencing technology. Overall, 4.5% (94/2100) of the collected ticks were tested positive for A. phagocytophilum and 26.2% (551/2100) were positive for Rickettsia spp. infections. Species differentiation of Rickettsia-positive ticks via real-time pyrosequencing was possible in 48.6% (268/551) of samples, which were all identified as R. helvetica. Coinfections with both pathogens were found in 1.0% (20/2100) of ticks. Statistically significant seasonal fluctuations between sampling months as well as local differences between sampling sites were detected for Rickettsia spp. infection rates. For A. phagocytophilum infections, only significant seasonal variations were found. When comparing infection rates of Hanoverian ticks in 2010 to those in 2005, infection rates of A. phagocytophilum-infected nymphs increased statistically significant (P=0.008, power: 0.762) from 2.3% in 2005 (Schicht et al., 2011) to 4.5% in 2010. Rickettsia spp. infections in female ticks decreased significantly (P=0.049, power: 0.491) from 41.8% in 2005 (Schicht et al., 2012) to 32.4% in 2010. Comparison of the remaining tick stages showed no statistically significant differences.

Associations of passerine birds, rabbits, and ticks with Borrelia miyamotoi and Borrelia andersonii in Michigan, U.S.A

Background

Wild birds contribute to maintenance and dissemination of vectors and microbes, including those that impact human, domestic animal, and wildlife health. Here we elucidate roles of wild passerine birds, eastern cottontail rabbits (Sylvilagus floridanus), and Ixodes dentatus ticks in enzootic cycles of two spirochetes, Borrelia miyamotoi and B. andersonii in a region of Michigan where the zoonotic pathogen B. burgdorferi co-circulates.

Methods

Over a four-year period, wild birds (n = 19,631) and rabbits (n = 20) were inspected for tick presence and ear tissue was obtained from rabbits. Samples were tested for Borrelia spirochetes using nested PCR of the 16S-23S rRNA intergenic spacer region (IGS) and bidirectional DNA sequencing. Natural xenodiagnosis was used to implicate wildlife reservoirs.

Results

Ixodes dentatus, a tick that specializes on birds and rabbits and rarely bites humans, was the most common tick found, comprising 86.5% of the 12,432 ticks collected in the study. The relapsing fever group spirochete B. miyamotoi was documented for the first time in ticks removed from wild birds (0.7% minimum infection prevalence; MIP, in I. dentatus), and included two IGS strains. The majority of B. miyamotoi-positive ticks were removed from Northern Cardinals (Cardinalis cardinalis). Borrelia andersonii infected ticks removed from birds (1.6% MIP), ticks removed from rabbits (5.3% MIP), and rabbit ear biopsies (5%) comprised twelve novel IGS strains. Six species of wild birds were implicated as reservoirs for B. andersonii. Frequency of I. dentatus larval and nymphal co-feeding on birds was ten times greater than expected by chance. The relatively well-studied ecology of I. scapularis and the Lyme disease pathogen provides a context for understanding how the phenology of bird ticks may impact B. miyamotoi and B. andersonii prevalence and host associations.

Conclusions

Given the current invasion of I. scapularis, a human biting species that serves as a bridge vector for Borrelia spirochetes, human exposure to B. miyamotoi and B. andersonii in this region may increase. The presence of these spirochetes underscores the ecological complexity within which Borrelia organisms are maintained and the need for diagnostic tests to differentiate among these organisms.

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.

Development and application of a loop-mediated isothermal amplification assay for rapid detection of Borrelia burgdorferi s. l. in ticks

A loop-mediated isothermal amplification (LAMP) assay was developed to detect Borrelia burgdorferi s. l. in ticks, which is a pathogen that causes Lyme disease. Cross-reactions with Chlamydia psittaci, Mycoplasma mycoides subsp. capri and some tick-borne pathogens were excluded. Analytical sensitivity of LAMP showed its detection limit was from 0.02 to 0.2 pg of DNA in detection of the reference samples at 65°C for 40 min. The performance of LAMP was assessed by testing 110 samples from susceptible tick species and comparing the results with conventional and nested PCR tests previously described. The results demonstrated that LAMP was significantly more sensitive than the conventional PCR (32.7% versus 15.5%, P < 0.05) and slightly more sensitive, although not significantly so, than nested PCR (32.7% versus 26.4%, P > 0.05). The assay was used to analyse a total of 1052 ticks collected from eight provinces in China. The results showed that the infection rates of B. burgdorferi s. l. varied from 12.5% to 88.9% across the different geographical sites. Selected positive samples were subjected to sequencing and sequence analysis for conformation of the accuracy of the assay. Here we report a highly sensitive, specific and easy diagnostic assay based on LAMP technology. These data indicate that LAMP is a useful approach for detecting B. burgdorferi s. l. in field-collected ticks and has the potential as an alternative tool for the ecological and epidemiological surveillance of Lyme disease.

Rickettsia spp. and coinfections with other pathogenic microorganisms in hard ticks from northern Germany

Rickettsia species are the causative agent of different forms of spotted fever and thus, monitored in a number of prevalence studies. The current study examined the status of ticks from the city of Hanover, Northern Germany, regarding the presence of Rickettsia spp. and coinfections with Borrelia burgdorferi sensu lato (sl) and Anaplasma phagocytophilum. In total, 1,089 questing Ixodes ricinus L. ticks were analyzed using quantitative real time polymerase chain reaction. A duplex quantitative real time polymerase chain reaction for simultaneous detection of Rickettsia spp. and Ixodes spp.-DNA as positive control for successful DNA-isolation was established. Rickettsia spp. were detected in 363 (33.3%) of the 1,089 investigated ticks. Quantification of Rickettsia showed that larvae contained up to 50,000 bacteria, nymphs up to 85 million and adults up to 200 million per tick. Species differentiation was possible in 178 out of 363 Rickettsia positive samples and resulted in a predominant occurrence of R. helvetica (98.9%, 176/178), whereas R. monacensis was rarely found (1.1%, 2/178). Besides detection of Rickettsia, positive ticks were compared with results from previous studies to examine coinfections with B. burgdorferi sl and A. phagocytophilum. The resulting coinfection rates were 9.1% (99/1,089) for B. burgdorferi sl and 2.8% (11/391) for A. phagocytophilum. Triple-infection with Rickettsia spp., B. burgdorferi sl, and A. phagocytophilum occurred in 5 (1.3%) out of 391 ticks. The current study is the first presenting quantitative data concerning the load of Ixodes ticks with Rickettsia individuals.

Absence of Lyme disease spirochetes in larval Ixodes ricinus ticks

To determine which kind of spirochete infects larval Ixodes ricinus, we examined questing larvae and larvae derived from engorged females for the presence of particular spirochetal DNA that permitted species differentiation. Borrelia miyamotoi was the sole spirochete detected in larval ticks sampled while questing on vegetation. Questing nymphal and adult ticks were infected mainly by Borrelia afzelii, whereas larval ticks resulting from engorged females of the same population were solely infected by B. miyamotoi. Since larvae acquire Lyme disease spirochetes within a few hours of attachment to an infected rodent, questing larvae in nature may have acquired Lyme disease spirochetes from an interrupted host contact. Even if transovarial transmission of Lyme disease spirochetes may occasionally occur, it seems to be an exceedingly rare event. No undisputable proof exists for vertical transmission of Lyme disease spirochetes, whereas B. miyamotoi appears to be readily passed between generations of vector ticks.

Prevalence of Anaplasma phagocytophilum and coinfection with Borrelia burgdorferi sensu lato in the hard tick Ixodes ricinus in the city of Hanover (Germany)

The castor bean tick Ixodes ricinus has been found to be the main vector for Lyme borreliosis spirochetes and Anaplasma phagocytophilum in Central Europe. 1646 I. ricinus ticks from Hanover, a city located in Northern Germany, were examined for infection with A. phagocytophilum and coinfection with Borrelia burgdorferi sensu lato (sl) to obtain so far missing prevalence data for this region. The total A. phagocytophilum infection rate was 3.2% (52/1646 ticks), divided into 4.1% (32/777) adults and 2.3% (20/869) nymphs. Coinfections with B. burgdorferi sl were found in 0.9% of all tick stages. The detected genospecies were B. afzelii, B. garinii, B. burgdorferi sensu stricto (ss), and B. garinii, which was the most frequent species in coinfected ticks.

Population genetics, taxonomy, phylogeny and evolution of Borrelia burgdorferi sensu lato

In order to understand the population structure and dynamics of bacterial microorganisms, typing systems that accurately reflect the phylogenetic and evolutionary relationship of the agents are required. Over the past 15 years multilocus sequence typing schemes have replaced single locus approaches, giving novel insights into phylogenetic and evolutionary relationships of many bacterial species and facilitating taxonomy. Since 2004, several schemes using multiple loci have been developed to better understand the taxonomy, phylogeny and evolution of Lyme borreliosis spirochetes and in this paper we have reviewed and summarized the progress that has been made for this important group of vector-borne zoonotic bacteria.

Reservoir competence of various rodents for the lyme disease Spirochete Borrelia spielmanii

To determine whether the pathogenic Lyme disease spirochete Borrelia spielmanii is adapted exclusively to garden dormice, we compared the reservoir competence of various rodent species for this spirochete, including sympatric and peridomestic rodents. The different kinds of rodents varied in their attractiveness to nymphal ticks and their level of susceptibility to tick-borne B. spielmanii infection, but only the edible dormouse appeared to be refractory. Although hazel dormice and Norway rats became infectious to ticks somewhat later than did garden dormice, they remained infectious for a longer period of time. During the course of a tick season, garden and hazel dormice contributed theoretically more than twice as many B. spielmanii-infected ticks than the somewhat less susceptible Norway rats and wood or yellow-necked mice. Hazel dormice appeared to be extraordinarily competent as reservoir hosts for B. spielmanii. Because peridomestic rodents proved to be reservoir competent, urban foci of transmission of B. spielmanii may affect the health of townspeople.