Prevalence of Borrelia burgdorferi in Ixodes ricinus ticks in urban recreational areas of Helsinki

Prevalence of Borrelia burgdorferi Sensu Lato in Ixodes ricinus Ticks Collected from Kaylaka Park in Pleven, Bulgaria

We aimed to determine the presence and distribution of Borrelia burgdorferi sensu lato (s.l.) in Ixodes ricinus ticks collected from urbanized and wild areas in Kaylaka Park (Bulgaria). A total of 546 ticks were collected over three years (2017–2019). The presence of Borrelia in 334 of the collected I. ricinus was detected by dark-field microscopy (DFM) and two nested PCRs (nPCR) targeting the borrelial 5S-23S rRNA intergenic spacer and Flagellin B (FlaB) gene. DFM was performed on a total of 215 ticks, of which 86 (40%) were positive. PCR was performed on 153 of the ticks. In total, 42.5% of the 5S-23S rRNA intergenic spacer and 49% of FlaB were positive. Considering as positive any single tick in which Borrelia sp. was detected regardless of the used method, the infection rate reached 37% (10/27) in the nymphs and 48.5% (149/307) in the adults (48.7% (77/158) females, 48.3% (72/149) males). The incidence of B. burgdorferi infection in I. ricinus did not differ statistically significantly between female, male, and nymph. This study provides evidence that Lyme disease spirochetes are present in various regions of Kaylaka Park with extremely high prevalence in their vectors.

Questing Ixodes ricinus ticks and Borrelia spp. in urban green space across Europe: A review

For more than three decades, it has been recognized that Ixodes ricinus ticks occur in urban green space in Europe and that they harbour multiple pathogens linked to both human and animal diseases. Urban green space use for health and well‐being, climate mitigation or biodiversity goals is promoted, often without consideration for the potential impact on tick encounters or tick‐borne disease outcomes. This review synthesizes the results of over 100 publications on questing I. ricinus and Borrelia spp. infections in ticks in urban green space in 24 European countries. It presents data on several risk indicators for Lyme borreliosis and highlights key research gaps and recommendations for future studies. Across Europe, mean density of I. ricinus in urban green space was 6.9 (range; 0.1–28.8) per 100 m² and mean Borrelia prevalence was 17.3% (range; 3.1%–38.1%). Similar density estimates were obtained for nymphs, which had a Borrelia prevalence of 14.2% (range; 0.5%–86.7%). Few studies provided data on both questing nymph density and Borrelia prevalence, but those that did found an average of 1.7 (range; 0–5.6) Borrelia‐infected nymphs per 100 m² of urban green space. Although a wide range of genospecies were reported, Borrelia afzelii was the most common in most parts of Europe, except for England where B. garinii was more common. The emerging pathogen Borrelia miyamotoi was also found in several countries, but with a much lower prevalence (1.5%). Our review highlights that I. ricinus and tick‐borne Borrelia pathogens are found in a wide range of urban green space habitats and across several seasons. The impact of human exposure to I. ricinus and subsequent Lyme borreliosis incidence in urban green space has not been quantified. There is also a need to standardize sampling protocols to generate better baseline data for the density of ticks and Borrelia prevalence in urban areas.

Urban woodland habitat is important for tick presence and density in a city in England

Urban green spaces provide an opportunity for contact between members of the public and ticks infected with pathogens. Understanding tick distribution within these areas and the drivers for increased tick density or Borrelia infection are important from a risk management perspective. This study aimed to generate data on tick presence, nymph density and Borrelia infection across a range of urban green space habitats, in order to identify those that may potentially present a higher risk of Lyme borreliosis to members of the public. Several sites were visited across the English city of Bath during 2015 and 2016. Tick presence was confirmed in all habitats surveyed, with increased likelihood in woodland and woodland edge. Highest nymph densities were also reported in these habitats, along with grassland during one of the sampling years. Adult ticks were more likely to be infected compared to nymphs, and the highest densities of infected nymphs were associated with woodland edge habitat. In addition to Lyme borreliosis causing Borrelia genospecies, Borrelia miyamotoi was also detected at several sites. This study adds to the growing evidence that urban green space habitats present a public health risk from tick bites, and this has implications for many policy areas including health and wellbeing, climate adaptation and urban green space planning.

Enhanced threat of tick-borne infections within cities? Assessing public health risks due to ticks in urban green spaces in Helsinki, Finland

Most tick‐related studies in Europe have been conducted in nonurban areas, but ticks and tick‐borne pathogens also occur in urban green spaces. From a public health perspective, risks regarding tick‐borne infections should be studied in these urban areas, where contacts between infected ticks and humans may be more frequent than elsewhere, due to high human activity. We examined the risk of encountering an infected tick in urban green spaces in Helsinki, Finland. We collected ticks at nine sites throughout Helsinki, recorded the prevalence of several pathogens and identified areas with a high potential for contacts between infected ticks and humans. Moreover, we explored the relationship between the density of Borrelia burgdorferi sensu lato‐infected ticks and locally diagnosed cases of borreliosis and compared the potential for human‐tick encounters in Helsinki to those in nonurban areas in south‐western Finland. During 34.8 km of cloth dragging, 2,417 Ixodes ricinus were caught (402 adults, 1,399 nymphs and 616 larvae). From analysed nymphs, we found 11 distinct tick‐borne pathogens, with 31.5% of nymphs carrying at least one pathogen. Tick activity was highest in August and September, leading to the density of nymphs infected with B. burgdorferi s.l., and concurrently infection risk, to also be highest during this time. Nymph densities varied between the sampling sites, with obvious implications to spatial variation in infection risk. While ticks and tick‐borne pathogens were found in both Helsinki and nonurban areas in south‐western Finland, the estimates of human activity were generally higher in urban green spaces, leading to a higher potential for human‐tick contacts therein. The presence of ticks and tick‐borne pathogens and high local human activity in urban green spaces suggest that they form potential foci regarding the acquisition of tick‐borne infections. Risk areas within cities should be identified and knowledge regarding urban ticks increased.

Comparison of tick-borne pathogen prevalence in Ixodes ricinus ticks collected in urban areas of Europe

Tick-borne diseases are a major threat to human and animal health. An increasing number of natural habitats have been transformed into urban areas by human activity; hence, the number of reported tick bites in urban and suburban areas has risen. This retrospective analysis evaluated 53 scientific reports concerning infections of Ixodes ricinus ticks collected from urban and suburban areas of Europe between 1991 and 2017. The results indicate significant differences in many variables, including a higher number of Anaplasma phagocytophilum infections in Eastern Europe than in Western Europe. The opposite result was observed for Candidatus Neoehrlichia mikurensis infections. A comparison of climate zones revealed that Borrelia burgdorferi s.l. infections have the greatest median incidence rate in subtropical climate zones. No statistical significance was found when comparing other tick-borne pathogens (TBPs), such as Borrelia miyamotoi, Rickettsia spp., Babesia spp., Bartonella spp., Ehrlichia spp., Coxiella burnetii and Francisella tularensis. The analysis also showed significant differences in the overall prevalence of TBPs according to average temperatures and rainfall across Europe. This retrospective study contributes to the knowledge on the occurrence and prevalence of TBPs in urbanized areas of Europe and their dependence on the habitats and geographical distributions of ticks. Due to the increased risk of tick bites, it is of great importance to investigate infections in ticks from urban and suburban areas.

Prevalence of <i>Borrelia burgdorferi sensu</i> lato genetic markers in blood-sucking ticks in suburban park zones in Saint Petersburg

Tick-borne bacterial and viral infections are widespread in middle latitudes of the Northern hemisphere. Natural foci of such infections coincide with geographic areas inhabited by ixodid ticks. Ixodid tick-borne borreliosis is a pressing issue for some territories of Russia, especially for the North-Western Federal District and St. Petersburg megalopolis as well as adjacent areas of the Leningrad District, where people may become infected after tick bite in recreational zones in suburban park areas. Currently, very few publications regarding prevalence of tick-borne pathogens in St. Petersburg area are available. In our study, questing ticks flagged in park zone (northern coast of Finnish Gulf, Kurortny District) were examined with PCR for carriage of pathogenic B. burgdorferi sensu lato complex. In addition, samples positive for Borrelia DNA signal were further genotyped with species-specific primers against rpoBgene fragment. It was found that Ixodes persulcatus dominated in this area. Prevalence of Borrelia burgdorferi s.l. complex comprised 9.33%. Genospecies B. afzelii and less frequently B. garinii were detected. A mixt-infection with two Borel-lia species was detected in one sample. Interestingly, all Borrelia-infected ticks belonged to I. persulcatus suggesting a closer association for certain species in «pathogen-vector» system. Our findings are essential in investigating distribution of ixodid borreliosis foci in St. Petersburg and suburbs, obtaining new data regarding epidemiology, diagnostics, treatment and prevention of this infection. It is noteworthy than prevalence of pathogenic Borrelia spp. vs. tick-borne encephalitis virus in vectors was higher thereby accounting for its higher morbidity. Comparing our data with those published elsewhere by European researchers allows to note that prevalence of pathogenic Borrelia spp. in ticks varies broadly in diverse geographic regions. It is necessary to take into consideration that prevalence of Borrelia markers achieves ~10% in ticks given frequent attendance of park areas near St. Petersburg that point at risk of developing bor-reliosis in recreational zones.

Ticks and tick-borne diseases in the city: Role of landscape connectivity and green space characteristics in a metropolitan area

Green spaces in the city are important for human wellbeing, but are also zones in which humans can become infected with zoonotic diseases. Therefore, there is a need to understand how infection risk is related to green space characteristics, wildlife communities and connectivity with rural areas hosting reservoir populations of hosts. Our hypothesis is that wildlife hosts in urban green spaces, and thereby the prevalence of questing ticks and their Lyme disease causing pathogens (Borrelia burgdorferi s.l.), can be partly predicted based on green space characteristics as well as measures of connectivity to known source areas. We sampled ticks in twenty-two green spaces during Spring (2014 and 2016) and Autumn 2016, located along an urbanization gradient in Antwerp (Belgium). More than 18,000 m² was sampled, with tick densities ranging from 0 to 386 individuals/100 m². We estimated connectivity using the least-cost algorithm as either the cost distance to the nearest green space, or to a known population of roe deer (Capreolus capreolus), known to be an important tick propagation host. Both connectivity measures turned out to be correlated, reflecting a gradient in green space isolation from the periphery to the urban center. In 87% of plots where ticks were trapped, at least one Borrelia-infected tick was found. The overall Borrelia-prevalence in nymphs was 17.8%, in adults 32.6%. Density of infected ticks decreased with urbanization and increased with connectivity. Nymphs in larger green spaces were more likely to be infected. While density and infection prevalence for adults increased with the amount of neighboring agricultural land, the larval density and nymphal infection prevalence decreased. Interestingly, the proportion of Borrelia genospecies associated with birds or mammals was comparable in rural and (sub)urban areas (bird/mammal: 0.38), suggesting that even in small green spaces Borrelia infections can persist in local host populations.

Lyme Borreliosis in Finland, 1995-2014

We investigated the epidemiology of Lyme borreliosis (LB) in Finland for the period 1995–2014 by using data from 3 different healthcare registers. We reviewed data on disseminated LB cases from the National Infectious Diseases Register (21,051 cases) and the National Hospital Discharge Register (10,402 cases) and data on primary LB (erythema migrans) cases from the Register for Primary Health Care Visits (11,793 cases). Incidence of microbiologically confirmed disseminated LB cases increased from 7/100,000 population in 1995 to 31/100,000 in 2014. Incidence of primary LB cases increased from 44/100,000 in 2011 to 61/100,000 in 2014. Overall, cases occurred predominantly in women, and we observed a bimodal age distribution in all 3 registers. Our results clearly demonstrate that the geographic distribution of LB has expanded in Finland and underscore the importance of LB as an increasing public health concern in Finland and in northern Europe in general.

Effects of conservation management of landscapes and vertebrate communities on Lyme borreliosis risk in the United Kingdom

Landscape change and altered host abundance are major drivers of zoonotic pathogen emergence. Conservation and biodiversity management of landscapes and vertebrate communities can have secondary effects on vector-borne pathogen transmission that are important to assess. Here we review the potential implications of these activities on the risk of Lyme borreliosis in the United Kingdom. Conservation management activities include woodland expansion, management and restoration, deer management, urban greening and the release and culling of non-native species. Available evidence suggests that increasing woodland extent, implementing biodiversity policies that encourage ecotonal habitat and urban greening can increase the risk of Lyme borreliosis by increasing suitable habitat for hosts and the tick vectors. However, this can depend on whether deer population management is carried out as part of these conservation activities. Exclusion fencing or culling deer to low densities can decrease tick abundance and Lyme borreliosis risk. As management actions often constitute large-scale perturbation experiments, these hold great potential to understand underlying drivers of tick and pathogen dynamics. We recommend integrating monitoring of ticks and the risk of tick-borne pathogens with conservation management activities. This would help fill knowledge gaps and the production of best practice guidelines to reduce risks.

This article is part of the themed issue ‘Conservation, biodiversity and infectious disease: scientific evidence and policy implications’.

Lyme disease ecology in a changing world: consensus, uncertainty and critical gaps for improving control

Lyme disease is the most common tick-borne disease in temperate regions of North America, Europe and Asia, and the number of reported cases has increased in many regions as landscapes have been altered. Although there has been extensive work on the ecology and epidemiology of this disease in both Europe and North America, substantial uncertainty exists about fundamental aspects that determine spatial and temporal variation in both disease risk and human incidence, which hamper effective and efficient prevention and control. Here we describe areas of consensus that can be built on, identify areas of uncertainty and outline research needed to fill these gaps to facilitate predictive models of disease risk and the development of novel disease control strategies. Key areas of uncertainty include: (i) the precise influence of deer abundance on tick abundance, (ii) how tick populations are regulated, (iii) assembly of host communities and tick-feeding patterns across different habitats, (iv) reservoir competence of host species, and (v) pathogenicity for humans of different genotypes of Borrelia burgdorferi Filling these knowledge gaps will improve Lyme disease prevention and control and provide general insights into the drivers and dynamics of this emblematic multi-host-vector-borne zoonotic disease.This article is part of the themed issue 'Conservation, biodiversity and infectious disease: scientific evidence and policy implications'.

Crowdsourcing-based nationwide tick collection reveals the distribution of Ixodes ricinus and I. persulcatus and associated pathogens in Finland

A national crowdsourcing-based tick collection campaign was organized in 2015 with the objective of producing novel data on tick distribution and tick-borne pathogens in Finland. Nearly 20 000 Ixodes ticks were collected. The collected material revealed the nationwide distribution of I. persulcatus for the first time and a shift northwards in the distribution of I. ricinus in Finland. A subset of 2038 tick samples containing both species was screened for Borrelia burgdorferi sensu lato (the prevalence was 14.2% for I. ricinus and 19.8% for I. persulcatus), B. miyamotoi (0.2% and 0.4%, respectively) and tick-borne encephalitis virus (TBEV; 0.2% and 3.0%, respectively). We also report new risk areas for TBEV in Finland and, for the first time, the presence of B. miyamotoi in ticks from mainland Finland. Most importantly, our study demonstrates the overwhelming power of citizen science in accomplishing a collection effort that would have been impossible with the scientific community alone.

Immunogenetic Markers Definition in Latvian Patients with Lyme Borreliosis and Lyme Neuroborreliosis

The aim of this study was to determine the human leukocyte antigen (HLA)-DRB1 alleles in two groups of patients in Latvia: patients with Lyme borreliosis and patients with Lyme neuroborreliosis. The study included 216 patients with Lyme borreliosis, 29 patients with Lyme neuroborreliosis and 282 control persons. All surveyed persons were residents of Latvia. The HLA-DR genotyping was performed by polymerase chain reaction- sequence specific primer (PCR-SSP). The predisposition to the Lyme borreliosis is associated with the HLA-DRB1*07, -DRB1*17(03), -DRB1*04, -DRB1*15(02) alleles. The allele -DRB1*11(05), -DRB1*14(06) and -DRB1*13(06) were significantly more frequent in controls. In-group with Lyme neuroborreliosis differences were found for the -DRB1*07 and -DRB1*04 alleles, but only HLA-DRB1*07 allele was statistically significant after Bonferroni correction and associated with Lyme neuroborreliosis in Latvian patients.

Tick-borne bacterial pathogens in southwestern Finland

Background

Ixodes ricinus and Ixodes persulcatus are the main vectors of Lyme borreliosis spirochetes and several other zoonotic bacteria in northern Europe and Russia. However, few studies screening bacterial pathogens in Finnish ticks have been conducted. Therefore, reports on the occurrence and prevalence of several bacterial pathogens detected from ticks elsewhere in Europe and Russia are altogether missing from Finland. The main aim of the current study was to produce novel data on the occurrence and prevalence of several tick-borne bacterial pathogens in ticks collected from southwestern Finland.

Methods

Ticks were collected in 2013–2014 by blanket dragging from 25 localities around southwestern Finland, and additionally from a dog in Lempäälä. Collected ticks were molecularly identified and screened for Borrelia burgdorferi s.l., Borrelia miyamotoi, Rickettsia, Bartonella and Candidatus Neoehrlichia mikurensis using quantitative PCR. Furthermore, detected Rickettsia spp. were sequenced using conventional PCR to determine species.

Results

A total of 3169 ticks in 1174 DNA samples were screened for the listed pathogens. The most common bacteria detected was B. burgdorferi (s.l.) (18.5 % nymphal and 23.5 % adult ticks), followed by Rickettsia spp. (1.1 %; 5.1 %) and B. miyamotoi (0.51 %; 1.02 %). B. miyamotoi and Rickettsia spp. were also detected in larval samples (minimum infection rates 0.31 % and 0.21 %, respectively). Detected Rickettsia spp. were identified by sequencing as R. helvetica and R. monacensis. All screened samples were negative for Bartonella spp. and Ca. N. mikurensis.

Conclusions

In the current study we report for the first time the presence of Rickettsia in Finnish ticks. Furthermore, Rickettsia spp. and B. miyamotoi were found from larval tick samples, emphasizing the importance they may have as vectors of these pathogens. Comparisons of tick density estimates and B. burgdorferi (s.l.) prevalence made between the current study and a previous study conducted in 2000 in ten out of the 25 study localities suggest that an increase in tick abundance and B. burgdorferi (s.l.) prevalence has occurred in at least some of the study localities.

Making green infrastructure healthier infrastructure

Increasing urban green and blue structure is often pointed out to be critical for sustainable development and climate change adaptation, which has led to the rapid expansion of greening activities in cities throughout the world. This process is likely to have a direct impact on the citizens' quality of life and public health. However, alongside numerous benefits, green and blue infrastructure also has the potential to create unexpected, undesirable, side-effects for health. This paper considers several potential harmful public health effects that might result from increased urban biodiversity, urban bodies of water, and urban tree cover projects. It does so with the intent of improving awareness and motivating preventive measures when designing and initiating such projects. Although biodiversity has been found to be associated with physiological benefits for humans in several studies, efforts to increase the biodiversity of urban environments may also promote the introduction and survival of vector or host organisms for infectious pathogens with resulting spread of a variety of diseases. In addition, more green connectivity in urban areas may potentiate the role of rats and ticks in the spread of infectious diseases. Bodies of water and wetlands play a crucial role in the urban climate adaptation and mitigation process. However, they also provide habitats for mosquitoes and toxic algal blooms. Finally, increasing urban green space may also adversely affect citizens allergic to pollen. Increased awareness of the potential hazards of urban green and blue infrastructure should not be a reason to stop or scale back projects. Instead, incorporating public health awareness and interventions into urban planning at the earliest stages can help insure that green and blue infrastructure achieves full potential for health promotion.

Assessing the abundance, seasonal questing activity, and Borrelia and tick-borne encephalitis virus (TBEV) prevalence of Ixodes ricinus ticks in a Lyme borreliosis endemic area in Southwest Finland

Studies have revealed that Ixodes ricinus (Acari: Ixodidae) have become more abundant and their geographical distribution extended northwards in some Nordic countries during the past few decades. However, ecological data of tick populations in Finland are sparse. In the current study, I. ricinus abundance, seasonal questing activity, and their Borrelia spp. and tick-borne encephalitis virus (TBEV) prevalence were evaluated in a Lyme borreliosis endemic area in Southwest Finland, Seili Island, where a previous study mapping tick densities was conducted 12 years earlier. A total of 1940 ticks were collected from five different biotopes by cloth dragging during May-September 2012. The overall tick density observed was 5.2 ticks/100m(2) for nymphs and adults. Seasonal questing activity of ticks differed between biotopes and life stages: bimodal occurrences were observed especially for nymphal and adult ticks in forested biotopes, while larvae in pastures exhibited mostly unimodal occurrence. Prevalence of Borrelia and TBEV in ticks was evaluated using conventional and real-time PCR. All samples were negative for TBEV. Borrelia prevalence was 25.0% for adults (n=44) and the minimum infection rate (MIR) 5.6% for pooled nymph samples (191 samples, 1-14 individuals per sample; 30/191 positive). No Borrelia were detected in pooled larval samples (63 samples, 1-139 individuals per sample). Five species of Borrelia were identified from the samples: B. afzelii, B. burgdorferi s.s., B. garinii, B. valaisiana and B. miyamotoi. In Finland, B. valaisiana and B. miyamotoi have previously been reported from the Åland Islands but not from the mainland or inner archipelago. The results of the present study suggest an increase in I. ricinus abundance on the island.

Seroprevalence of Borrelia burgdorferi in occupationally exposed persons in the Belgrade area, Serbia

Lyme disease (LD) is a natural focal zoonotic disease caused by Borrelia burgdorferi, which is mainly transmitted through infected Ixodes ricinus tick bites. The presence and abundance of ticks in various habitats, the infectivity rate, as well as prolonged human exposure to ticks are factors that may affect the infection risk as well as the incidence of LD. In recent years, 20% to 25% of ticks infected with different borrelial species, as well as about 5,300 citizens with LD, have been registered in the Belgrade area. Many of the patients reported tick bites in city’s grassy areas. The aim of this study was to assess the seroprevalence of B. burgdorferi in high-risk groups (forestry workers and soldiers) in the Belgrade area, and to compare the results with healthy blood donors. A two-step algorithm consisting of ELISA and Western blot tests was used in the study. Immunoreactivity profiles were also compared between the groups. The results obtained showed the seroprevalence to be 11.76% in the group of forestry workers, 17.14% in the group of soldiers infected by tick bites and 8.57% in the population of healthy blood donors. The highest IgM reactivity was detected against the OspC protein, while IgG antibodies showed high reactivity against VlsE, p19, p41, OspC, OspA and p17. Further investigations in this field are necessary in humans and animals in order to improve protective and preventive measures against LD.

Threat of attacks of Ixodes ricinus ticks (Ixodida: Ixodidae) and Lyme borreliosis within urban heat islands in south-western Poland

Background

The increased incidence of Lyme disease in Europe necessitates permanent monitoring of the occurrence and activity of its vector. Therefore, in this study, we have investigated the presence and seasonal activity of Ixodes ricinus ticks in various habitats of a large industrial region in south-western Poland in correlation with environmental factors present in urban heat islands. Additionally, the risk of borreliosis in this part of Poland has been assessed.

Methods

The investigations were carried out at two-week intervals between April and October 2001 and 2002. Ticks were collected from four localities in Upper Silesia, i.e. in a city park (CH), on the outskirts of two large cities (KO, MI), and in a forest (KL). We analysed the impact of temperature and humidity measured during the collection period in the I. ricinus habitats, the climatic conditions prevailing in the study area, and the degree of environmental contamination on the abundance and activity of these ticks in the respective sites. The degree of borreliosis risk in the region was determined on the basis of the results of research on the prevalence of Borrelia burgdorferi s.l. in ticks and reports from sanitary-epidemiological stations.

Results

In total, 2061 I. ricinus ticks, including 606 nymphs and 1455 adults, were collected in the study area. The number and activity of the ticks varied during the collection in the different sites. In the urban locality CH, tick abundance was the lowest (455 throughout the investigation period), and the seasonal activity of females was unimodal and persisted for as long as 4 months. In the suburban localities KO and MI, tick abundance was higher (485 and 481 specimens, respectively) and the activity of females was unimodal. The highest abundance (640 ticks) and a bimodal pattern of female activity were reported from the forest locality KL. In all the localities, the activity of nymphs was unimodal. Humidity was found to be a factor influencing I. ricinus abundance and activity, whereas temperature did not affect their number and behaviour significantly. The climate parameters within the urban heat islands noted during the investigations contributed to dispersal of dust and gas pollutants. The analysis of the data reveals that there is a risk of borreliosis in the entire study area; however, it is higher in the urban localities than in the suburban sites.

Conclusions

Environmental conditions (habitat, climate, and dust and gas pollution) prevailing within urban heat islands may exert an impact on tick abundance and activity and the prevalence of Lyme disease in the study area. The greatest effect of the environmental factors on ticks was found in the city park, where the risk of human infection with B. burgdorferi s.l. spirochetes is the highest as well.

Ixodes ricinus and Its Transmitted Pathogens in Urban and Peri-Urban Areas in Europe: New Hazards and Relevance for Public Health

Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis," Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.

Borrelia miyamotoi in host-seeking Ixodes ricinus ticks in England

This paper reports the first detection of Borrelia miyamotoi in UK Ixodes ricinus ticks. It also reports on the presence and infection rates of I. ricinus for a number of other tick-borne pathogens of public health importance. Ticks from seven regions in southern England were screened for B. miyamotoi, Borrelia burgdorferi sensu lato (s.l.), Anaplasma phagocytophilum and Neoehrlichia mikurensis using qPCR. A total of 954 I. ricinus ticks were tested, 40 were positive for B. burgdorferi s.l., 22 positive for A. phagocytophilum and three positive for B. miyamotoi, with no N. mikurensis detected. The three positive B. miyamotoi ticks came from three geographically distinct areas, suggesting a widespread distribution, and from two separate years, suggesting some degree of endemicity. Understanding the prevalence of Borrelia and other tick-borne pathogens in ticks is crucial for locating high-risk areas of disease transmission.

Ixodes ricinus and Its Transmitted Pathogens in Urban and Peri-Urban Areas in Europe: New Hazards and Relevance for Public Health

Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis," Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.

Tick infestation risk for dogs in a peri-urban park

BACKGROUND

Increases in the abundance and distribution of ticks and tick borne disease (TBD) within Europe have been reported extensively over the last 10-20 years. Changes in climate, habitat management, economic patterns and changes in the abundance of hosts, particularly deer, may all have influenced this change to varying extents. Increasing abundances of tick populations in urban and peri-urban environments, such as parks, are of particular concern. In these sites, suitable habitat, wildlife hosts, tick populations, people and their pets may be brought into close proximity and hence may provide foci for tick infestation and, ultimately, disease transmission.

METHODS

The distribution and abundance of ticks were examined in an intensively used, peri-urban park. First the seasonal and spatial distribution and abundance of ticks in various habitat types were quantified by blanket dragging. Then the pattern of pet dog movement in the park was mapped by attaching GPS recorders to the collars of dogs brought to the park for exercise, allowing their walking routes to be tracked. Information about the dog, its park use and its history of tick attachment were obtained from the dog-owners.

RESULTS

Ticks were found predominantly in woodland, woodland edge and deer park areas and were least abundant in mown grassland. Tick infestation of dogs was a relatively frequent occurrence with, on average, one case of tick attachment reported per year for a dog walked once per week, but for some dogs walked daily, infestation 4-5 times per week was reported. All dogs appeared to be at equal risk, regardless of walk route or duration and infestation was primarily influenced by the frequency of exposure.

CONCLUSIONS

In peri-urban green spaces, tick-biting risk for dogs may be high and here was shown to be related primarily to exposure frequency. While tick-biting is of direct veterinary importance for dogs, dogs also represent useful sentinels for human tick-exposure.

Seasonal dynamics of tick species in an urban park of Rome

Regular collections were obtained in the Natural Reserve of the Insugherata of Rome during 2011 in order to obtain the tick species composition and the respective seasonal dynamics of the area. A total of 325 ticks was collected in selected sites by means of drag sampling. Among the identified species, Rhipicephalus turanicus was the most abundant (72.3%), followed by Ixodes ricinus (19.7%), Dermacentor marginatus (6.5%), Haemaphysalis punctata (1.2%), and Rhipicephalus bursa (0.3%). R. turanicus occurred mainly in pastures, showing a mono-modal seasonal activity pattern from spring to early summer. Questing I. ricinus were prevalent in woodland from October to May, and the seasonal trend of specimens showed a weak peak in winter. Although adult D. marginatus exhibited seasonal dynamics similar to I. ricinus, with an activity period from October to April, this species occurred in a different environment (pasture) and with considerably lower densities. Haemaphysalis punctata and R. bursa were rare, with an apparent autumn and autumn-winter seasonal activity, respectively. While the species diversity recorded appears as an unequivocal consequence of the natural state of the park, the remarkable R. turanicus density could be a direct effect of the recent introduction of wild boar, as carriers, from the close Veio Park. The presence of the species, a proven vector of various diseases in humans and domestic animals, is discussed in the light of the possible risk of tick-bite exposure of park workers and visitors.

Borrelia burgdorferi sensu lato prevalence in tick populations in Estonia

Background

Estonia is located in a unique area of co-distribution of Ixodes ricinus and I. persulcatus, which are the main tick vectors of Borrelia burgdorferi sensu lato. In the last decade, the incidence rate of Lyme borreliosis in Estonia has increased dramatically up to 115.4 per 100,000 in 2012. Here we present the first survey of the presence, the prevalence and genetic characteristics of B. burgdorferi s.l. complex spirochetes in the tick population in Estonia.

Methods

During the years 2006–2009, 2833 unfed Ixodes ricinus and I. persulcatus were collected from 43 sites in 7 counties in mainland Estonia as well as in 10 sites on the Saaremaa Island. DNA samples from ticks were analyzed individually using nested PCR of the ribosomal 5S-23S spacer region followed by bidirectional sequencing.

Results

The overall estimated prevalence of B. burgdorferi s.l was 9.7% and varied from 4.9% to 24.2% on the mainland and to 10.7% in Saaremaa Island. Ixodes persulcatus ticks showed significantly higher prevalence rates compared to that in I. ricinus-16.3% and 8.2%, respectively. The most prevalent genospecies was B. afzelii which was detected in 53.5% of Borrelia-positive ticks, followed by B. garinii and B. valaisiana with 26.2% and 5.5%, respectively. Also, B. bavariensis and B. burgdorferi s.s. DNA in single I. ricinus ticks were detected. Borrelia afzelii, B. garinii and B. valaisiana were detected in both tick species. Two genetic subgroups of B. garinii (NT29 and 20047) and two genetic subgroups of B. afzelii (NT28 and VS461) were found to be circulating in all studied regions as well as in both tick species, except B. garinii subgroup NT29, which was found only in I. persulcatus ticks.

Conclusions

In the current study we detected the circulation of five B. burgdorferi s.l. genospecies and estimated the prevalence in ticks in different regions of Estonia. Detection and genetic characterization of Borrelia genospecies, especially those of public health importance, in the natural foci may help assessing high risk areas of human exposure to B. burgdorferi s.l.

Seropositivity of Lyme borreliosis and associated risk factors: a population-based study in Children and Adolescents in Germany (KiGGS)

Background

Lyme borreliosis (LB) caused by spirochetes of the Borrelia burgdorferi sensu lato complex is the most common tick-borne disease in the northern hemisphere. Data on the distribution and on risk factors in Germany are sketchy.

Methodology/Principal Findings

Blood samples of a nationwide population-based cross-sectional study from 2003–2006 in children and adolescents aged 1 to 17 years in Germany (KiGGS) were analysed (n = 12,614) to assess the seroprevalence of anti-Borrelia antibodies. Data from standardized interviews were used to assess potential risk factors. First, sera were screened for anti-Borrelia antibodies by ELISA. The overall prevalence was 4.8% (95% confidence interval (CI) 4.3–5.4%). Positive and borderline ELISA test results were confirmed by a line blot revealing a combined prevalence of 4.0% (95% CI 3.6–4.5%). Seroprevalence of ELISA was significantly higher in males (odds ratio (OR) = 1.37; CI 1.15–1.63) and in the southern part of Germany (OR = 1.41; CI 1.09–1.83), but significantly lower in children and adolescents with migration background (OR = 0.33; CI 0.24–0.44). Study participants from households with cats had a higher chance of seropositivity (OR = 6.7; CI 5.6–8.0). In a multivariable model the odds of seropositivity increases by 11% for every year of age for boys and 6% for girls.

Conclusions/Significance

This survey is the first nationwide, representative seroprevalence survey of LB in children and young adolescents. The study shows that infections with Borrelia burgdorferi are endemic in all parts of Germany despite regional differences. Even at a young age children are exposed to tick bites including seropositivity. Encouraging a thorough check for ticks and promptly removal of ticks are the key public health strategies to reduce the risk of LB and other tick-borne diseases in children and adolescents. Further epidemiological studies are warranted to better understand the burden of disease related to LB.

Study on ticks and tick-borne zoonoses in public parks in Italy

A survey on tick density and on tick-borne zoonoses was carried out in four public parks in the outskirts of Imola (northern Italy) from June to October 2006. All stages of Ixodes ricinus and only larvae of Riphicephalus sanguineus were recovered by dragging, performed on 100-m transects. Almost all ticks (99%) were harvested in one park. I. ricinus density (nymphs/100 m(2) ) ranged from 0 in park L to 6.3 in park F. Nymphs and adults of I. ricinus were subjected to PCR for Anaplasma phagocytophilum, Bartonella spp., Borrelia burgdorferi s. l. and Rickettsia spp. The observed prevalences were 38.3% for Bartonella henselae, 5.2% for Bartonella clarridgeiae, 10.4% for B. burgdorferi s. l., 2.6% for Rickettsia helvetica and 13% for Rickettsia monacensis, respectively. No DNA of A. phagocytophilum was found. Acarological risks (AR) were calculated as probabilities of collecting at least one infected nymph per transect. The AR values calculated for the various zoonotic agents were 11.4% for R. helvetica, 27.7% for B. clarridgeiae, 49.7% for B. burgdorferi s. l., 57.2% for R. monacensis and 90.4% for B. henselae, respectively. In this study, B. clarridgeiae was for the first time identified in I. ricinus ticks.

Prevalence of Anaplasma phagocytophilum in Ixodes ricinus in Bavarian public parks, Germany

Previous studies have shown that public parks provide extraordinary habitats for ticks and tick-borne pathogens. Therefore, the aim of this study was to investigate the tick abundance (ticks/100 m(2)) in urban areas and the prevalence of Anaplasma phagocytophilum. Collection of ticks was performed by the flagging method in selected Bavarian public parks in a 2-year survey. DNA from 30 ticks of each developmental stage, sampling site and month was extracted and screened by specific real-time PCR for A. phagocytophilum. Selected positive samples were further genetically differentiated by nested PCR, targeting the 16S rRNA gene. A total of 13,403 Ixodes ricinus were collected with an average tick abundance of 15-53 ticks/100 m(2) in 2009 and 15-35 ticks/100 m(2) in 2010, depending on the sampling site. DNA of A. phagocytophilum was detected in 11.6% (n=146) and 8.5% (n=50) of adult females, 13.3% (n=164) and 9.2% (n=51) of adult males as well as 5% (n=60) and 3.9% (n=29) of nymphs for 2009 (n=3685) and 2010 (n=1884), respectively. 16S rRNA gene analysis revealed 6 different genetic variants, 2 of which were 100% identical to known sequences in humans. The results give strong evidence that the occurrence of A. phagocytophilum in I. ricinus is highly variable in different habitat types due to geographical, climatic, and biological factors as well as different genetic variants of A. phagocytophilum circulated in ticks with a noticeable habitat and host tropism.

Expression and sequence diversity of the complement regulating outer surface protein E in Borrelia afzelii vs. Borrelia garinii in patients with erythema migrans or neuroborreliosis

Outer surface protein E (OspE) is a complement factor H-binding virulence factor of borrelial subspecies. It is usually absent from in vitro grown Borrelia garinii, although in vivo B. garinii causes neuroborreliosis (NB). We analyzed the presence and sequence spectrum of the ospE genes in vivo in Borrelia spirochetes. DNA samples from the skin, serum and cerebrospinal fluid (CSF) of patients with infections caused by Borrelia afzelii or B. garinii were studied, and anti-OspE antibodies in the corresponding patient sera were detected by IgG ELISA using recombinant OspE as an antigen. ospE genes were found in 20 of 23 erythema migrans (EM) skin biopsies with B. afzelii, in 2 EM skin biopsies with unknown underlying subspecies, in 5 of 9 EM biopsies with B. garinii, and in 1 of 4 CSF samples of NB patients with B. garinii infection. All OspE sequences from B. garinii samples were identical. In contrast, OspE of B. afzelii origin showed more variation. Anti-OspE antibodies were found in 8/21 (38.0%) sera from patients with B. afzelii-associated EM. In conclusion, our results indicate that all borrelial subspecies, but not necessarily all strains, causing human infections can carry ospE genes to protect themselves against complement attack in vivo.

Improved laboratory diagnostics of Lyme neuroborreliosis in children by detection of antibodies to new antigens in cerebrospinal fluid

BACKGROUND

Laboratory diagnostics in Lyme neuroborreliosis need improvement. We hereby investigate 4 new recombinant or peptide Borrelia antigens in cerebrospinal fluid in children with neuroborreliosis to evaluate their performance as diagnostic antigens.

METHODS

An enzyme-linked immunosorbent assay was used to detect IgG antibodies to recombinant decorin binding protein A (DbpA), BBK32, outer surface protein C (OspC), and the invariable region 6 peptide (IR6). The recombinant antigens originated from 3 pathogenic subspecies; Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi sensu stricto. Cerebrospinal fluid and serum from children with clinical features indicative for neuroborreliosis (n = 57) were analyzed. Classification of patients was based on clinical symptoms and laboratory findings. Controls were children with other neurologic diseases (n = 20) and adult patients with no proven infection (n = 16).

RESULTS

Sensitivity for DbpA was 82%, for BBK32 70%, for OspC 58% and for IR6 70%. Specificities were 94%, 100%, 97%, and 97%, respectively. No single antigen was superior. When new antigens were combined in a panel, sensitivity was 80% and specificity 100%. The reference flagella antigen showed a sensitivity of 60% and a specificity of 100%. Over all, the B. garinii related antigens dominated.

CONCLUSIONS

Recombinant DbpA and BBK32 as well as the peptide antigen IR6 perform well in laboratory diagnostics of neuroborreliosis in children. New antigens seem to improve diagnostic performance when compared with the routine flagella antigen. If different antigens are combined in a panel to cover the antigenic diversity, sensitivity improves further and a specificity of 100% can be achieve.

Detection and identification of Borrelia burgdorferi sensu lato genospecies in ticks from three different regions in Slovakia

Lyme borreliosis is one of the most common tick-borne diseases that occur in Slovakia. In this study, Borrelia burgdorferi sensu lato was detected and cultivated from questing ticks collected in three areas of Slovakia. Two methods, restriction fragment length polymorphism and reverse line blot, were used for identification of isolates and determination of the prevalence of B. burgdorferi s.l. in the ticks. The prevalence of B. burgdorferi s.l. in I. ricinus detected by reverse line blot was 31.9%. Four genospecies, namely B. garinii, B. valaisiana, B. afzelii and B. burgdorferi sensu stricto were found. B. garinii was the most prevalent genospecies.

Antibodies to recombinant decorin-binding proteins A and B in the cerebrospinal fluid of patients with Lyme neuroborreliosis

Cerebrospinal fluid (CSF) and serum samples from 34 patients with proven neuroborreliosis (NB) and 22 patients with suspected neuroborreliosis (SNB) from Finland were analysed for antibodies to decorin-binding proteins A (DbpA) and B (DbpB). Antibodies to recombinant protein antigens originating from Borrelia burgdorferi sensu stricto, B. afzelii, or B. garinii species were studied by enzyme-linked immunosorbent assay (ELISA). Of the 34 patients with NB, 100% of the CSF and 88% of the serum samples had IgG antibodies to 1 to 3 variants of DbpA and 79% of the CSF and 70% of the serum samples were positive for 1 to 3 DbpB variants. Antibodies to DbpB seemed to be associated with lymphocytic pleocytosis in the CSF and short duration of the disease, whereas antibodies to DbpA in the CSF were observed irrespective of the duration of the disease and lymphocytic pleocytosis. Among the variant antigens, CSF reactivity was mainly with the DbpB from B. garinii, whereas positivity with the DbpA from B. afzelii or B. garinii predominated. The results suggest that CSF antibodies to DbpB might be useful as a marker of active infection whereas antibodies to DbpA seem to persist a long time after acute phases of NB.

A study of the presence of B. burgdorferi, Anaplasma (previously Ehrlichia) phagocytophilum, Rickettsia, and Babesia in Ixodes ricinus collected within the territory of Belluno, Italy

In the years 2000 and 2001, we sampled ticks in order to establish the distribution of Ixodes ricinus in the province of Belluno; 5987 tick samples from 244 sites throughout the province were gathered, by dragging for a 5-min period. In 40 sites, seasonal variations and cycle stages of the parasites were studied at monthly intervals from March to September. A polymerase chain reaction (PCR) technique was used to identify the tick-infected sites. Of 1931 individual ticks, 8.23% were positive for Borrelia burgdorferi, 4.4% were positive for Ehrlichia, 1.6% were positive for Rickettsia, and 1.6% were positive for Babesia. The co-presence of Borrelia and Ehrlichia (1.2%) and Babesia (0.5%), Borrelia, Ehrlichia and Rickettsia (0.1%) was also found.

Antigenicity of borrelial protein BBK32 fragments in early Lyme borreliosis

Recombinantly produced borrelial BBK32 protein fragments originating from Borrelia burgdorferi sensu stricto, Borrelia garinii and Borrelia afzelii were evaluated as antigens in the serology of Lyme borreliosis (LB). In ELISA, a mid-portion hydrophilic fragment reacted with LB patient sera. Of the 23 patients with culture- or PCR-positive erythema migrans (EM), 43 % at diagnosis and 52 % at convalescence were positive for at least one Borrelia species-specific variant BBK32 fragment antigen. In parallel ELISAs with BBK32 whole proteins from the three borrelial subspecies as antigens, 17 % at diagnosis and 26 % at convalescence were positive. These results suggest that BBK32 protein fragments may improve the early IgG serology of LB compared to the BBK32 whole protein.

Prevalence of Borrelia burgdorferi sensu lato and Anaplasmataceae members in Ixodes ricinus ticks in Alsace, a focus of Lyme borreliosis endemicity in France

Due to the high Lyme borreliosis incidence in Alsace, in northeastern France, we investigated in 2003-2004 three cantons in this region in order to determine the density of Ixodes ricinus ticks infected by Borrelia burgdorferi sensu lato and Anaplasmataceae. The peak density of nymphs infected by B. burgdorferi sensu lato at Munster and Guebwiller, where the disease incidence was high, was among the highest reported in Europe (105 and 114 per 100 m(2), respectively). In contrast, the peak density of infected nymphs was low in the canton of Dannemarie (5/100 m(2)), where the disease incidence was low. The two main species detected in ticks were Borrelia afzelii, more frequent in nymphs, and Borrelia garinii, more frequent in adult ticks. The rates of tick infection by Anaplasma phagocytophilum were 0.4% and 1.2% in nymphs and adults, respectively.

Prevalence of Borrelia burgdorferi sensu lato genospecies in Ixodes ricinus ticks in Europe: a metaanalysis

In Europe, Borrelia burgdorferi genospecies causing Lyme borreliosis are mainly transmitted by the tick Ixodes ricinus. Since its discovery, B. burgdorferi has been the subject of many epidemiological studies to determine its prevalence and the distribution of the different genospecies in ticks. In the current study we systematically reviewed the literature on epidemiological studies of I. ricinus ticks infected with B. burgdorferi sensu lato. A total of 1,186 abstracts in English published from 1984 to 2003 were identified by a PubMed keyword search and from the compiled article references. A multistep filter process was used to select relevant articles; 110 articles from 24 countries contained data on the rates of infection of I. ricinus with Borrelia in Europe (112,579 ticks), and 44 articles from 21 countries included species-specific analyses (3,273 positive ticks). These data were used to evaluate the overall rate of infection of I. ricinus with Borrelia genospecies, regional distributions within Europe, and changes over time, as well as the influence of different detection methods on the infection rate. While the infection rate was significantly higher in adults (18.6%) than in nymphs (10.1%), no effect of detection method, tick gender, or collection period (1986 to 1993 versus 1994 to 2002) was found. The highest rates of infection of I. ricinus were found in countries in central Europe. B. afzelii and B. garinii are the most common Borrelia species, but the distribution of genospecies seems to vary in different regions in Europe. The most frequent coinfection by Borrelia species was found for B. garinii and B. valaisiana.

Lyme borreliosis in Europe and North America

Since the discovery of the Lyme disease spirochete in North America in 1982 and in Europe in 1983, a plethora of studies on this unique group of spirochetes that compriseBorrelia burgdorferisensu lato has been accumulated. In an attempt to compare and contrast Lyme borreliosis in Europe and North America we have reviewed the biology of the aetiologic agents, as well as the clinical aspects, diagnosis and treatment of this disease on both continents. Moreover, we have detailed the ecology of theIxodesticks that transmit this infection and the reservoir hosts that maintain the spirochete cycle in nature. Finally, we have examined the transmission dynamics of the spirochete on both continents, as well as the available prevention strategies. Although it has been over two decades since the discovery of the Lyme disease spirochete, Lyme borreliosis is an expanding public health problem that has defied our attempts to control it. By comparing the accumulated experience of investigators in North America and Europe, where the disease is most frequently reported, we hope to advance the cause of developing novel approaches to combat Lyme borreliosis.

Borrelia burgdorferi infection prevalences in questing Ixodes ricinus ticks (Acari: Ixodidae) in urban and suburban Bonn, western Germany

From March to October 2003, a total of 2,518 host-seeking Ixodes ricinus ticks (1,944 nymphs, 264 females, 310 males) were collected by blanket dragging at 45 sites all over the city area of Bonn, western Germany, to be checked for Borrelia burgdorferi infection. The collection sites included 20 private gardens, nine public recreational parks, the boundaries of 14 sylvatic suburban areas and two footpaths between suburban farmed fields. Generally, numbers of specimens collected along sylvatic suburban areas and at urban sites with dense tree populations were significantly higher than at the other collection sites. Out of 1,394 specimens (865 nymphs, 241 females, 288 males) that were randomly chosen for Borrelia analysis by a simple PCR, 250 (17.9 %) were found to be infected with B. burgdorferi sensu lato. While the infection prevalences varied significantly between females (26.6%), males (12.5%) and nymphs (17.3%), there were no striking differences between sylvatic and unwooded sites. A total of 92.8% of the ticks Borrelia-positive by the simple PCR were also positive in a diagnostic nested PCR. Using genospecies-specific oligonucleotide probes, single Borrelia genospecies infections (91.4%) could be assigned to B. afzelii (39.5%), B. garinii (27.9%), B. burgdorferi sensu stricto (15.6%) and B. valaisiana (8.6%) by DNA hybridization. Various combinations of double infections were observed in 4.3% of the infected ticks. Another 4.3% of the Borrelia infections were untypeable. The B. burgdorferi genospecies distribution in the city area was shown to be variable from site to site and, even more, it was distinct from rural collection sites near Bonn. This is ascribed to a different spectrum of reservoir hosts. Taking into account the infection prevalences of host-seeking ticks in the forested surroundings of Bonn, our study demonstrates that the risk of acquiring Lyme disease after a tick bite in urban/suburban areas is comparably as high as in woodlands outside of the city.

Substantial rise in the prevalence of Lyme borreliosis spirochetes in a region of western Germany over a 10-year period

More than a decade after a study on the transmission cycle of Borrelia burgdorferi sensu lato in the Siebengebirge, a nature reserve near Bonn, Germany, questing nymphal and adult Ixodes ricinus ticks were collected again in three selected areas of the same low mountain range and examined for infection with B. burgdorferi sensu lato. Between May and October 2001, a total of 1,754 ticks were collected by blanket dragging; 374 ticks were analyzed for B. burgdorferi sensu lato by both an immunofluorescence assay (IFA) and at least two different PCR tests, whereas 171 ticks were analyzed by PCR only. By combining all assays, an average of 14% of the ticks tested positive for B. burgdorferi sensu lato, 5.5, 15.8, and 21.8% in the three collection areas. Of the nymphs and adults examined, 12.9 and 21.1%, respectively, were found to be spirochete infected. A lower total infection prevalence was obtained by IFA (14.4%) than by a nested PCR approach (16.5%), but both were higher than that obtained by a simple PCR approach (11.9%). Compared with data collected over a decade ago, the mean infection prevalence of B. burgdorferi sensu lato in the ticks was significantly higher for all three biotopes, whereas a similar pattern of habitat-specific infection prevalence was observed. Genotyping of B. burgdorferi sensu lato revealed high relative prevalences of B. valaisiana (identified in 43.1% of infected ticks) and B. garinii (32.3%), whereas B. afzelii (12.3%) and B. burgdorferi sensu stricto (1.5%) were relatively rare. We conclude that B. burgdorferi sensu lato infection has increased in this region over the last 15 years due to presently unknown changes in ecological conditions, perhaps related to climate change or wildlife management.

Identification of Borrelia burgdorferi sensu lato, Anaplasma and Ehrlichia species, and spotted fever group Rickettsiae in ticks from Southeastern Europe

Prevalence data for tick-borne pathogens are used to assess the risk for human health. In this study the presence and identity of Borrelia burgdorferi sensu lato, Ehrlichia, Anaplasma, and Rickettsia species in Bulgarian Ixodes ricinus ticks and in non- Ixodes ticks from Turkey and Albania was determined by polymerase chain reaction (PCR) and reverse line blot hybridization. In the adult Bulgarian ticks, the prevalence of Borrelia burgdorferi sensu lato infection was approximately 40%, while Borrelia afzelii was the predominant species, representing more than half of all Borrelia-positive ticks. Ehrlichia and Anaplasma species were detected in 35% of the adult Ixodes ricinus ticks and in 10% of the nymphs. Sequence analysis of PCR products reacting with the Anaplasma phagocytophila probe revealed a 16S rRNA gene identical to that of the Anaplasma phagocytophila prototype strain. Ehrlichia and Anaplasma species were found in approximately 7% of the non- Ixodes ticks. Sequence analysis of some of these samples revealed the presence of Anaplasma ovis, Ehrlichia canis, and a species closely resembling Ehrlichia chaffeensis. About half of all adult ticks examined and approximately 20% of all nymphs were infected with Rickettsia species. In Ixodes ricinus ticks, Rickettsia helvetica and a Rickettsia species designated as IRS3 were found in high prevalence. Rickettsia conorii was found in virtually all non- Ixodes tick species from Albania and Turkey. The results of this study show that many tick-borne diseases are most probably endemic in the Balkan area. Furthermore, the results suggest that there is a considerable chance for simultaneous transmission of tick-borne pathogens to human beings.

Borrelia burgdorferi s.l. in Ixodes ricinus (Acari: Ixodidae) ticks collected from vegetation and small rodents in recreational areas of the city of Poznań

During 1998-1999, Ixodes ricinus (L.) populations were investigated in three different biotopes (deciduous, mixed, coniferous forest) situated in popular recreational areas in Poznań, Poland. In total, 1,123 questing ticks (1,002 nymphs, 69 males, 52 females) were collected by flagging vegetation. Additionally, in 1998 between May and September small rodents were trapped and inspected for feeding ticks. Altogether, 213 rodents of three species: Apodemus agrarius Pall., A. flavicollis Melchior, Clethrionomys glareolus Schreber were captured. Of 323 engorged ticks, 304 were larvae and 19 nymphs. All ticks collected from vegetation, as well as from rodents were examined for the presence of Borrelia burgdorferi Johnson, Schmid, Hyde, Steigenwalt & Brenner s.l. spirochetes by indirect immunofluorescence assay (IFA) using PAB 1B29. The seasonal pattern of activity of questing I. ricinus was always bimodal (May/June and August/September). The most abundant tick population occurred in the deciduous forest. The total infection rate in questing ticks was 16.2%. Differences in mean infection prevalence of host-seeking ticks between three biotopes each year were not significant. On average more larvae parasitized on the genus of Apodemus than on C. glareolus. 17.8% of larvae and 31.6% of nymphs fed on rodents harbored spirochetes. The three rodent species contributed to a different degree in to transmission of the pathogen to subadult stages. Approximately 27% of larvae infested on A. agrarius, 22% on C. glareolus, and only 4.2% on A. flavicollis contained spirochetes. The results suggest that the prevalence of A. agrarius and C. glareolus in disturbed urban forests used for leisure activities seems to be crucial for the maintenance of B. burgdorferi s.l. in I. ricinus populations.

Interaction between Borrelia burgdorferi and immature human dendritic cells

Antigen uptake and the following maturation of dendritic cells (DCs) are pivotal to the initiation of specific antimicrobial immune responses. DCs also play an important role in the recruitment and activation of the cells of the innate immune system. We have examined the interactions of DCs with Borrelia burgdorferi to find explanations for the difficulties the human immune system has in dealing with the bacterium. Phagocytosis of B. burgdorferi by immature DCs and the effect of the bacterium on the maturation and interleukin-8 (IL-8) secretion of DCs were studied. Borreliae were phagocytized and processed into fragments by DCs; narrow tube-like pseudopods and broad pseudopods were used for the engulfment. The immature DC population gained a heterogeneous appearance within 2 h of incubation with the borreliae. A 24 h coculture with borreliae induced maturation and IL-8 secretion in the DCs in a manner comparable with the effect of lipopolysaccharides. All strains studied, including a mutant strain lacking outer surface proteins A and B, were capable of inducing these responses. Thus, our results did not show any clear inadequacy concerning the way DCs are dealing with B. burgdorferi. However, further studies on the subject are required.

Prevalence of Borrelia burgdorferi species and identification of Borrelia valaisiana in questing Ixodes ricinus in the Lyon region of France as determined by polymerase chain reaction-restriction fragment length polymorphism

Many cases of Lyme borreliosis have been reported over the years in the region of Lyon, France. The identification and prevalence of Borrelia burgdorferi sensu lato in Ixodes ricinus were investigated by polymerase chain reaction (PCR) of the flagellin gene and restriction fragment length polymorphism (RFLP) analysis. Questing Ixodes ricinus larvae, nymphs and adults were collected by the flagging method from deciduous forests in four areas in the Lyon region of France between October 1994 and September 1995 and in June 1998. The overall prevalence of Borrelia burgdorferi sensu lato was 13.2% (91/688). No significant differences in prevalence were observed between the different stages and sex of the ixodids or between collection areas. The majority of infections were simple infections (82.4%; 75/91), most of which were due to Borrelia afzelii (41.4%), while coinfections (12.1%) were predominantly (54.5%) a combination of Borrelia valaisiana and Borrelia garinii. No tick was infected with more than two borrelial species, nor was Borrelia lusitaniae identified. The Borrelia valaisiana species was detected for the first time in France, confirming its widespread presence in Europe. This study confirms that the surroundings of Lyon are risk areas for contracting Lyme disease and that no particular clinical manifestations predominate due to the heterogeneous distribution of Borrelia genospecies. Moreover, the polymerase chain reaction restriction fragment length polymorphism analysis is a rapid and easy method for genotyping of Borrelia species.

Prevalence of granulocytic Ehrlichia and Borrelia burgdorferi sensu lato in Ixodes ricinus ticks collected from Southwestern Finland and from Vormsi Island in Estonia

Altogether, 343 adult and 111 nymphal Ixodes ricinus ticks collected from parks in Turku and suburban and rural islands of the Turku archipelago, Finland, and 100 adult I. ricinus ticks collected from Vormsi Island, Estonia, were included in this study. Using the polymerase chain reaction the ticks were examined for 16S rDNA of the Ehrlichia phagocytophila genogroup and for Borrelia burgdorferi sensu lato recA and flagellin genes. None of the Finnish ticks was found to be infected with E. phagocytophila, whereas 3% of the Estonian ticks were positive for this organism. The rate of Finnish ticks infected with B. burgdorferi sensu lato varied from 0% to 11.6% (mean 5%; 9% for adult and 4% for nymphal ticks). The corresponding rate for Estonian ticks was 15%. Borrelia afzelii was the most common genospecies in both Finnish (2.6%) and Estonian (12%) ticks. B. burgdorferi sensu stricto was detected in 2.0% of the Finnish ticks, but in none of the Estonian ticks. These results suggest that the E. phagocytophila genogroup is very rare in Finnish ticks, although the ticks were collected from an area endemic for Lyme borreliosis. In Estonia, E. phagocytophila is found in ticks and may cause disease.

Morphoea and Borrelia burgdorferi: results from the Scottish Highlands in the context of the world literature

AIMS

Previous studies investigating the link between infection with Borrelia burgdorferi and morphoea have produced conflicting results. Often, these studies have been undertaken in patients from different regions or countries, and using methods of varying sensitivity for detecting Borrelia burgdorferi infection. This study aimed to establish whether a relation could be demonstrated in the Highlands of Scotland, an area with endemic Lyme disease, with the use of a sensitive method for detecting the organism.

METHODS

The study was performed on biopsies of lesional skin taken from 16 patients from the Highlands of Scotland with typical clinical features of morphoea. After histological confirmation of the diagnosis, a nested polymerase chain reaction (PCR) using primers to a unique conserved region of the Borrelia burgdorferi flagellin gene was performed on DNA extracts from each biopsy. A literature search was also performed for comparable studies.

RESULTS

None of the 16 patients had documented clinical evidence of previous infection with B burgdorferi. DNA was successfully extracted from 14 of the 16 cases but all of these were negative using PCR for B burgdorferi specific DNA, despite successful amplification of appropriate positive controls in every test. The results were compared with those of other documented studies.

CONCLUSIONS

Examination of the literature suggests that there is a strong geographical relation between B burgdorferi and morphoea. These results, in which no such association was found, indicate that morphoea may not be associated with the subspecies of B burgdorferi found in the Highlands of Scotland.

Sublethal concentrations of complement can effectively opsonize Borrelia burgdorferi

The fate of borreliae invading a human may depend on the early innate response they induce. The interactions of human complement system and neutrophils with two strains of the Lyme borreliosis spirochete Borrelia burgdorferi were studied. Borrelia burgdorferi sensu stricto B31 (resistant to a 28% concentration of normal human serum (NHS)) and Borrelia garinii Bg A218/98 (sensitive to 7% NHS) were examined. Both strains induced neutrophil oxidative burst in a complement-dependent manner. B31 required the presence of 7% NHS, but Bg A218/98 required the presence of only 0.7% NHS for optimal induction of the burst. At all concentrations of NHS, the proportion of the spirochetes with C3bi on their surfaces and the relative amount of C3bi bound per spirochete were larger with Bg A218/98 than with B31. Bg A218/98 was able to induce an oxidative burst, when provided with serum with blocked classical pathway of complement, whereas B31 required the presence of the classical pathway. We suggest a role for the opsonizing effect of complement in controlling borreliae that are either resistant to direct killing by complement or located in the compartments of the human body at sublethal concentrations of the same.