Human seroprevalence of antibodies to tick-borne microbes in southern Norway

The tick Ixodes ricinus is widespread along the coastline of southern Norway, but data on human exposure to tick-borne microbes are scarce. We aimed to assess the seroprevalence of IgG antibodies to various tick-borne microbes in the general adult population living in a Norwegian municipality where ticks are abundant. Søgne is a coastline municipality in the southernmost part of Norway, and has a high density of ticks. All individuals aged 18-69 years with residential address in Søgne municipality (n = 7424) were invited to give a blood sample and answer a questionnaire. Blood samples from 3568 individuals were available for analysis. All samples were analyzed for IgG antibodies to Borrelia burgdorferi sensu lato (Bbsl), and around 1500 samples for IgG antibodies to other tick-borne microbes. Serum IgG antibodies to Bbsl were present in 22.0% (785/3568) of the tested samples, tick-borne encephalitis virus (TBEV) in 3.1% (45/1453), Anaplasma phagocytophilum in 11.0% (159/1452), Babesia microti in 2.1% (33/1537), Bartonella henselae/B. quintana in 0.1% (2/1451) and Rickettsia helvetica/R. conorii in 4.2% (60/1445). Serum IgG antibodies to A. phagocytophilum and R. helvetica/R. conorii were significantly more prevalent (p = 0.010 and p = 0.016, respectively) among individuals with serum IgG antibodies to Bbsl than among individuals without. In conclusion, our study showed a high exposure to Bbsl in the general adult population living in a coastline municipality in the southernmost part of Norway. The population is also exposed to A. phagocytophilum, R. helvetica/R. conorii, B. microti and TBEV, but very rarely B. henselae/B. quintana.     

Delineating Anaplasma phagocytophilum Ecotypes in Coexisting, Discrete Enzootic Cycles

The emerging tick-borne pathogen Anaplasma phagocytophilum is under increasing scrutiny for the existence of subpopulations that are adapted to different natural cycles. Here, we characterized the diversity of A. phagocytophilum genotypes circulating in a natural system that includes multiple hosts and at least 2 tick species, Ixodes ricinus and the small mammal specialist I. trianguliceps. We encountered numerous genotypes, but only 1 in rodents, with the remainder limited to deer and host-seeking I. ricinus ticks. The absence of the rodent-associated genotype from host-seeking I. ricinus ticks was notable because we demonstrated that rodents fed a large proportion of the I. ricinus larval population and that these larvae were abundant when infections caused by the rodent-associated genotype were prevalent. These observations are consistent with the conclusion that genotypically distinct subpopulations of A. phagocytophilum are restricted to coexisting but separate enzootic cycles and suggest that this restriction may result from specific vector compatibility.     

Tick-borne zoonotic pathogens in ticks feeding on the common nightingale including a novel strain of Rickettsia sp.

We examined 77 Ixodes ricinus ticks found on 33 out of 120 common nightingales (Luscinia megarhynchos) sampled in the Czech Republic in 2008 for the presence of Borrelia spirochetes, Anaplasma phagocytophilum, Rickettsia spp., and Babesia spp. We detected Borrelia garinii (in 4% of ticks), A. phagocytophilum (1%), Rickettsia helvetica (3%), a novel strain of Rickettsia sp. (sister taxon of R. bellii; 1%), and Babesia sp. EU1 (1%). Thus, we conclude that nightingales are unlikely to be important reservoir hosts for tick-borne pathogens.     

The potential role of migratory birds in transmission cycles of Babesia spp., Anaplasma phagocytophilum,and Rickettsia spp.

Babesia spp., Anaplasma phagocytophilum, and Rickettsia spp. are potentially emerging tick-borne pathogens, whereas many issues about their ecology, e.g. reservoir host specificity, are still unclear. In spring 2007, we collected 191 feeding Ixodes ricinus ticks from 99 birds of 11 different species on a German bird conservation island in the Baltic Sea. Babesia spp. were detected in 4.7% (9/191), A. phagocytophilum was present in 2.6% (5/191), and Rickettsia spp. were identified in 7.3% (14/191) of the investigated ticks. Further characterization of Babesia spp. infections resulted in B. divergens and B. microti. Among the Rickettsia spp. infections, we identified at least 2 different species: R. monacensis and R. helvetica. Furthermore, 2 ticks harboured mixed infections. Our study provides first interesting insights into the role of migratory birds in the distribution of several emerging tick-borne pathogens.     

Anaplasma infections in ticks and reservoir host from Slovakia

Anaplasma phagocytophilum is a worldwide distributed bacterium with a significant medical and veterinary importance. It grows within the phagosome of infected neutrophils and is responsible for human granulocytic anaplasmosis (HGA), tick-borne fever (TBF) of small ruminants and cattle, canine and equine granulocytic anaplasmosis, but infects also a great variety of wildlife species. Wild ungulates and rodents are considered reservoirs of infection in natural foci. The objective of this study was to determine the spectrum of animal species involved in the circulation of A. phagocytophilum in Slovakia and to analyze the variability of obtained nucleotide sequences, in order to determine whether genotypes from Slovakia cluster according to host-species or geographical location.Several animal species and vector ticks were screened for the presence of members of the family Anaplasmataceae using PCR based methods. Additional data on the molecular evidence of Anaplasma ovis and Candidatus Neoehrlichia mikurensis are presented. These pathogens were detected in tested sheep flocks and rodents with the mean infection rates of 8.16% and 10.75%, respectively. A. phagocytophilum was genotyped by 16S rRNA and groEL gene sequencing. Bacterial DNA was confirmed in questing ixodid ticks, in domesticated canine, wild rodents and several species of wild ungulates.In European isolates, 16S rRNA gene does not seem to be an appropriate locus for the analyses of heterogeneity as it is too conservative. Similarly, 16S rRNA isolates from our study did not reveal any polymorphisms. All isolates were identical in overlapped region and showed identity with sequences from ticks, horses or ruminants previously isolated elsewhere in the world. On the other hand, the groESL heat shock operon is widely used for determination of diversity and the analyses have already revealed considerable degree of heterogeneity.Tested ungulates were infected with A. phagocytophilum to a considerable extent. High proportions of red and roe deer tested positive and the rates of infection reached over 60.0%. GroEL sequences from canine, wild ungulates and ticks from Slovakia clustered within a clade together with isolates from horses, humans, wild ungulates and ticks from Slovakia or elsewhere in the world. Sequences from rodents clustered apart from those obtained from wild ungulates, ticks and humans. These results suggest that European rodents do not harbour A. phagocytophilum strains with strong zoonotic potential such as those from United States.     

Tick-borne diseases under the radar in the North Sea Region

The impact of tick-borne diseases caused by pathogens such as Anaplasma phagocytophilum, Neoehrlichia mikurensis, Borrelia miyamotoi, Rickettsia helvetica and Babesia species on public health is largely unknown.Data on the prevalence of these pathogens in Ixodes ricinus ticks from seven countries within the North Sea Region in Europe as well as the types and availability of diagnostic tests and the main clinical features of their corresponding diseases is reported and discussed. Raised awareness is needed to discover cases of these under-recognized types of tick-borne disease, which should provide valuable insights into these diseases and their clinical significance.     

Two Anaplasma phagocytophilum Strains in Ixodes scapularis Ticks,Canada

We developed PCR-based assays to distinguish a human pathogenic strain of Anaplasma phagocytophilum, Ap-ha, from Ap-variant 1, a strain not associated with human infection. The assays were validated on A. phagocytophilum-infected blacklegged ticks (Ixodes scapularis) collected in Canada. The relative prevalence of these 2 strains in I. scapularis ticks differed among geographic regions.     

Detection of Rickettsia spp. and Anaplasma phagocytophilum in Ixodes ricinus ticks in a region of Middle Germany (Thuringia)

Rickettsia spp. and Anaplasma spp. are regarded as potentially emerging tick-borne pathogens, but so far data on prevalence rates in questing ticks and reports on human diseases in several parts of Europe are rarely available.In this study, 430 nymphs and 570 adult Ixodes (I.) ricinus ticks were collected from a frequently visited forest region of Thuringia (Zeitzgrund, near Stadtroda) in 2006 (n=506) and 2007 (n=494). Individual ticks were investigated for a part of the citrate synthase gene (gltA) of Rickettsia spp. and the 16S rRNA gene of Anaplasma phagocytophilum. Positive amplicons were identified with restriction fragment length polymorphism (RFLP) and/or sequencing. Overall, 14.7% (147/1000) of investigated ticks were infected with Rickettsia spp. After sequencing of 64/147 positive amplicons R. helvetica (29/64) was detected predominantly. Prevalence varied in different developmental stages between 9.3% (40/430) in nymphs and 18.8% (107/570) in adults. A. phagocytophilum-specific DNA was detected in 5.4% (54/1000) of ticks with an infection rate of 4.7% (20/430) in nymphs and 6.0% (34/570) in adults. In 1% (10/1000) of ticks coinfections with Rickettsia spp. and A. phagocytophilum were found. Our study provides interesting insights into the circulation and cocirculation of different rickettsial species and A. phagocytophilum in the same biotope.     

Long-term persistence of Anaplasma phagocytophilum and Ehrlichia muris in wild rodents

Wild animals are reservoir hosts for a number of tick-transmitted agents, and long-term persistence of the agents is a key factor for their effective transmission from animal hosts to ticks. To study the persistence of Anaplasmataceae in rodents, 59 adult Myodes spp. voles (M. rutilus, M. rufocanus, and M. glareolus) were captured in Omsk Province, Asian Russia, freed from all ectoparasites, and kept in individual cages. Their blood samples were regularly analyzed for the presence of DNA of Anaplasma phagocytophilum, Ehrlichia muris, and “Candidatus Neoehrlichia mikurensis”. Anaplasma phagocytophilum, E. muris, and mixed infections were found in 29 (49 %), 17 (29 %), and 14 (24 %) voles, respectively. DNA of “Candidatus N. mikurensis” was not identified. Long-term persistence of A. phagocytophilum and E. muris in naturally infected Myodes spp. was shown for the first time. Thus, 12 animals with A. phagocytophilum were found infected for more than three months and four of them carried the bacterium throughout 22–55 weeks of observation. Four voles were infected with E. muris for 26–40 weeks. Fragments of groESL operon were sequenced for genotyping A. phagocytophilum and E. muris. In voles with A. phagocytophilum, the determined sequences belonged to two phylogenetic clusters. Most sequences were identical or closely related to those found in small mammals and Ixodes trianguliceps ticks from Western Siberia and European countries; one sequence was previously identified in rodents and Ixodes persulcatus and Ixodes pavlovskyi ticks from Asian Russia. Sequences of groESL fragments from E. muris were close to those determined previously in small mammals and I. persulcatus ticks from Siberia. In addition, a new groESL sequence of E. muris was identified in one vole and the sequence substantially differed from all known corresponding E. muris sequences (≥ 14 mismatches).     

Infections with Candidatus Neoehrlichia mikurensis and Cytokine Responses in 2 Persons Bitten by Ticks,Sweden

The prevalence of Candidatus Neoehrlichia mikurensis infection was determined in 102 persons bitten by ticks in Sweden. Two infected women had erythematous rashes; 1 was co-infected with a Borrelia sp., and the other showed seroconversion for Anaplasma phagocytophilum. Both patients had increased levels of Neoehrlichia DNA and serum cytokines for several months.     

Seasonal activity and tick-borne pathogen infection rates of Ixodes ricinus ticks in Hungary

Ixodes ricinus is the most important tick species in Europe as it is most widely distributed and transmits the majority of tick-borne zoonotic pathogens. As limited data are available for Hungary, the aim of the present study was to investigate the seasonal timing of questing by I. ricinus and the infection rate of this tick species with all major tick-borne zoonotic pathogens. Monthly collections of I. ricinus were carried out over 3 consecutive years by dragging a blanket in 6 biotopes representing different areas of Hungary. Altogether, 1800 nymphs (300 per collection point) were screened as pooled samples (each of 5 specimens) by PCR-based methods for tick-borne pathogens. I. ricinus larvae, nymphs, and adults had bimodal activity patterns with a major peak in the spring. As newly moulted ticks of all stages are thought to emerge in the autumn of each year, it appears that most newly emerged ticks delayed their questing until the following spring. The minimum prevalence of Borrelia burgdorferi sensu lato was 2.5%. Borr. afzelii, Borr. burgdorferi sensu stricto, Borr. garinii, Borr. lusitaniae, and Borr. valaisiana were identified by hybridization. The minimum infection rate with spotted fever group rickettsiae was 1.9%. Rickettsia helvetica was identified in all biotopes. The minimum prevalence of Anaplasma phagocytophilum, Babesia divergens and Bab. microti was low (0.3–0.5%). Bartonella spp.-, Francisella tularensis-, and TBE virus-specific amplification products were not detected. Relative to the results of comparable studies carried out in the Carpathian Basin, the prevalence of tick-borne pathogens was low in Hungary. This might be attributed to the climatic difference between the lowland areas of Hungary and submountain areas of the surrounding countries involved in the studies.     

Turkey tick news: A molecular investigation into the presence of tick-borne pathogens in host-seeking ticks in Anatolia; Initial evidence of putative vectors and pathogens,and footsteps of a secretly rising vector tick,Haemaphysalis parva

This Turkey-based study investigated the presence of various tick-borne microorganisms in a broad-range of host-seeking ticks (n = 1019) that exhibit both hunter and ambusher characteristics. All collected ticks were analyzed individually via PCR-sequencing, resulting in the identification of 18 different microorganisms: six Babesia spp., including one putative novel species (Ba. occultans, Ba. crassa, Ba. rossi, Babesia sp. tavsan1, Babesia sp. tavsan2, and Babesia sp. nov.); six SFG rickettsiae (Ri. aeschlimannii, Ri. s. mongolitimonae, Ri. slovaca, Ri. raoultii, Ri. monacensis, and Ri. hoogstraalii); two Borrelia burgdorferi sensu lato spp. (Bo. afzelii and Bo. lusitaniae); two unnamed Hepatozoon spp.; Theileria annulata; and Hemolivia mauritanica. This provided evidence for the natural transstadial survival of these tick-borne microorganisms in adult ticks (in addition a nymph) of Turkey. Surprisingly, this study determined the presence of five different microorganisms (Ba. crassa, Ba. rossi, Babesia sp. Ucbas, Hepatozoon sp., and Ri. hoogstraalii) in host-seeking Haemaphysalis parva adults, for which poor data exist on its vectorial competence. Therefore, this study provides important data indicating the potential vectorial capacity of Ha. parva. This study also revealed the presence of the close ecological and evolutionary relationships between two important vector ticks, Hyalomma marginatum and Hy. aegyptium and determined genetic variations (distinct phylogenetic divergences inside the main clades) in some pathogenic SFG rickettsiae that are found in these ticks. Additionally, the presence of two Babesia species described very recently in hares with unknown vectors, namely Babesia sp. tavsan1 and Babesia sp. tavsan2, were detected for the first time in ticks. Finally, two unnamed Hepatozoon spp. were detected in Haemaphysalis ticks and their phylogenetic positions were demonstrated. Consequently, this study provides important data on the diversity of tick-borne microorganisms in host-seeking ticks and on potentially novel microorganisms (Babesia and Hepatozoon species) and their possible vectors (Ha. parva, Ha. sulcata, Hy. aegyptium, Hy. marginatum, and Rh. turanicus).     

Molecular identification of tick-borne pathogens (Rickettsia spp., Anaplasma phagocytophilum,Borrelia burgdorferi sensu lato,Coxiella burnetii and piroplasms) in questing and feeding hard ticks from North-Western Spain

The occurrence of tick-borne pathogens (TBPs) of human and veterinary interest was studied in questing and feeding ticks collected from wild animals in a region in North-Western Spain. A total of 529 ticks (489 questing, 40 feeding) of seven different species (386 Ixodes ricinus, 53 Haemaphysalis concinna, 27 Haemaphysalis punctata, 25 Dermacentor marginatus, 21 Haemaphysalis inermis, 15 Dermacentor reticulatus, and two Rhipicephalus bursa) were analyzed. Molecular analysis of the 16S rRNA gene in I. ricinus ticks, revealed the presence of two phylogenetic groups in the region. Most of the sequenced ticks (96%) were assigned to I. ricinus haplogroup and 4% of the ticks were phylogenetically related to I. inopinatus haplogroup. Feeding ticks were removed from 17 animals from seven wild species (seven roe deer -Capreolus capreolus-, three wolves -Canis lupus-, two Iberian red deer -Cervus elaphus hispanicus-, two European wild boar -Sus scrofa-, one Cantabrian brown bear -Ursus arctos-, one Eurasian badger -Meles meles-, and one red fox -Vulpes vulpes-). Presence of Rickettsia spp., Anaplasma phagocytophilum, piroplasms, Borrelia burgdorferi sensu lato (s.l.) and Coxiella burnetii were tested in ticks by specific PCR. A total of 92 (17.4%) of the 529 ticks analyzed were positive for at least one of the TBPs tested. Sequencing revealed the presence of the genospecies “Candidatus Rickettsia rioja”, Rickettsia raoultii, and Anaplasma phagocytophilum in both questing and feeding ticks. Rickettsia slovaca, Borrelia lusitaniae, Borrelia afzelii, Borrelia garinii, Borrelia burgdorferi sensu stricto and Babesia bigemina were only detected in questing ticks, while Babesia sp. badger type A, Theileria OT3 and Hepatozoon canis occurred only in engorged ticks. None of the ticks were positive for C. burnetii. The analysis of the 16S rRNA gene sequences of A. phagocytophilum revealed the presence of three variants (I, X and W) circulating in the region. New host-tick-pathogen interactions have been revealed, finding for the first time the human pathogen R. raoultii in D. reticulatus removed from a Cantabrian brown bear. Co-occurrence between different TBPs were detected in 4.3% of the ticks. The association B. burgdorferi s.l./Rickettsia spp. was detected in questing ticks; and Rickettsia spp./piroplasms and A. phagocytophilum/Theileria OT3 in feeding ticks. The presence of pathogenic agents constitutes a threat to human and animal health, and should be considered in the diagnosis and treatment after a tick bite. This study increases the knowledge on TBPs diversity of medical and veterinary interest circulating between ticks and their hosts in North-Western Spain.     

A 15-year monitoring of Rickettsiales (Anaplasma phagocytophilum and Rickettsia spp.) in questing ticks in the city of Hanover,Germany

Rickettsiales (Anaplasma phagocytophilum and Rickettsia spp.) are regarded as potentially emerging tick-borne pathogens and may change in abundance in response to global climate change. However, continuous monitoring on their prevalence in questing ticks is only available for the northern German city of Hanover. In the presented follow-up of this long-term study, 2100 questing ticks of the Ixodes ricinus/Ixodes inopinatus-complex collected from April to October 2020 at ten different recreation sites in Hanover were individually analysed for Rickettsia and A. phagocytophilum infection by quantitative real-time PCR. Together with previous results from years 2005, 2010 and 2015, the current study allows to assess potential changes in tick infection rates with Rickettsiales over a 15-year monitoring period. In 2020, 3.0% (63/2100) of ticks were infected with A. phagocytophilum, 36.0% (756/2100) with Rickettsia spp. and 1.2% (26/2100) with both pathogens. Regarding the different developmental tick stages, nymphs showed a significantly lower A. phagocytophilum prevalence of 0.5% (5/1050) than adult ticks (5.5% [58/1050]) as well as compared to females (5.4% [38/700]) and males (5.7% [20/350]). For Rickettsia spp., nymphs also showed a lower prevalence of 33.2% (349/1050) with a significant difference to adult ticks (38.8% [407/1050]) and female ticks (40.7% [285/700]), while males had a Rickettsia infection rate of 34.9% (122/350). Comparison with previous years indicated a stable A. phagocytophilum prevalence over the 15-year monitoring period. In contrast, fluctuating Rickettsia prevalences were observed, with a peak in 2015 in all developmental stages, but similar infection rates in 2005 and 2020. Therefore, epidemiological changes in response to climate change are not (yet) evident. Nevertheless, the long-term monitoring study will be continued in the future, as climatic impacts on tick and reservoir host populations may have a delayed effect on pathogen prevalence and, consequently, transmission to humans and domestic animals.     

Seroprevalence of tick-borne encephalitis (TBE) in naturally exposed monkeys (Macaca sylvanus) and sheep and prevalence of TBE virus in ticks in a TBE endemic area in Germany

In a recently published study, a clinical case of severe tick-borne encephalitis (TBE) in a monkey (Macaca sylvanus) was described after natural exposure (tick bite) in a TBE endemic area in Germany, and from the tissue of this monkey the strain ‘Salem’, closely related to the strain ‘Neudoerfl’, was isolated and characterized.In this study, it was our aim to test all the available data for characterizing a TBE endemic area like TBE cases in humans and animals, TBE virus (TBEV) in ticks, and TBE-positive sera from animals. Sera from 283 monkeys and 100 sheep as well as 294 unfed ticks were collected at the monkey mountain Salem and its surroundings. A seroprevalence of 2.6% in monkeys and 9% in sheep were found. Furthermore, a new real-time RT-PCR method was established and used, in combination with an already published RT-qPCR, for TBEV genome detection in field-collected ticks, but no TBEV could be detected in the ticks tested.     

Inter-annual variation in prevalence of Borrelia burgdorferi sensu stricto and Anaplasma phagocytophilum in host-seeking Ixodes scapularis (Acari: Ixodidae) at long-term surveillance sites in the upper midwestern United States: Implications for public health practice

The geographic range of the blacklegged tick, Ixodes scapularis, and its associated human pathogens have expanded substantially over the past 20 years putting an increasing number of persons at risk for tick-borne diseases, particularly in the upper midwestern and northeastern United States. Prevention and diagnosis of tick-borne diseases rely on an accurate understanding by the public and health care providers of when and where persons may be exposed to infected ticks. While tracking changes in the distribution of ticks and tick-borne pathogens provides fundamental information on risk for tick-borne diseases, metrics that incorporate prevalence of infection in ticks better characterize acarological risk. However, assessments of infection prevalence are more labor intensive and costly than simple measurements of tick or pathogen presence. Our objective was to examine whether data derived from repeated sampling at longitudinal sites substantially influences public health recommendations for Lyme disease and anaplasmosis prevention, or if more constrained sampling is sufficient. Here, we summarize inter-annual variability in prevalence of the agents of Lyme disease (Borrelia burgdorferi s.s.) and anaplasmosis (Anaplasma phagocytophilum) in host-seeking I. scapularis nymphs and adults at 28 longitudinal sampling sites in the Upper Midwestern US (Michigan, Minnesota, and Wisconsin). Infection prevalence was highly variable among sites and among years within sites. We conclude that monitoring infection prevalence in ticks aids in describing coarse acarological risk trends, but setting a fixed prevalence threshold for prevention or diagnostic decisions is not feasible given the observed variability and lack of temporal trends. Reducing repeated sampling of the same sites had minimal impact on regional (Upper Midwest) estimates of average infection prevalence; this information should be useful in allocating scarce public health resources for tick and tick-borne pathogen surveillance, prevention, and control activities.     

Immature hard ticks infected with Rickettsia amblyommatis on breeding birds from Pantanal

Immature hard ticks from the genus Amblyomma feed on blood from a wide range of Neotropical avian hosts. They serve as vectors for pathogens of medical and veterinary importance, such as Rickettsia agents of the spotted fever group (SFG). Hence, determining ecological factors that increase encounter rates between immature ticks and their avian hosts may contribute to the understanding of tick-borne diseases transmission. Here, we used 720 individual birds from 96 species surveyed in the Brazilian Pantanal to test whether host breeding season influenced tick infestation probabilities. Additionally, collected ticks were screened for Rickettsia agents to describe new avian-tick-bacteria associations. Our models revealed that the probability of an individual bird being infested with immature ticks was similar during the breeding and pre-breeding season, but higher loads of immature tick stages were found during the breeding season. Host sex did not predict infestation probability, but Rickettsia agents recovered from ticks were more prevalent during the pre-breeding season. The new records of host usage by larvae and nymphs of Amblyomma in Pantanal and the growing body of tick surveys in Neotropical avian communities, suggest that immature ticks may benefit from avian blood sources during their annual cycle. The low number of infected ticks with Rickettsia agents on Pantanal birds suggest that this vertebrate group are likely not acting as reservoirs for these microorganisms. However, long-term surveys at the same site are imperative to determine which tick species are acting as reservoirs for Rickettsia agents in Pantanal and determine whether birds are playing a role in dispersing ticks and tick-borne pathogens.     

Infections with Tickborne Pathogens after Tick Bite,Austria, 2015–2018

The aim of this prospective study was to assess the risk for tickborne infections after a tick bite. A total of 489 persons bitten by 1,295 ticks were assessed for occurrence of infections with Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia spp., Babesia spp., Candidatus Neoehrlichia mikurensis, and relapsing fever borreliae. B. burgdorferi s.l. infection was found in 25 (5.1%) participants, of whom 15 had erythema migrans. Eleven (2.3%) participants were positive by PCR for Candidatus N. mikurensis. One asymptomatic participant infected with B. miyamotoi was identified. Full engorgement of the tick (odds ratio 9.52) and confirmation of B. burgdorferi s.l. in the tick by PCR (odds ratio 4.39) increased the risk for infection. Rickettsia helvetica was highly abundant in ticks but not pathogenic to humans. Knowledge about the outcome of tick bites is crucial because infections with emerging pathogens might be underestimated because of limited laboratory facilities.     

Reservoir Competence of Vertebrate Hosts for Anaplasma phagocytophilum

Fourteen vertebrate species (10 mammals and 4 birds) were assessed for their ability to transmit Anaplasma phagocytophilum, the bacterium that causes human granulocytic anaplasmosis, to uninfected feeding ixodid ticks. Small mammals were most likely to infect ticks but all species assessed were capable of transmitting the bacterium, in contrast to previous findings.