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

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

Introduction

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

Methods

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

Results

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

Discussion

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

Italian peninsula as a hybridization zone of Ixodes inopinatus and I. ricinus and the prevalence of tick-borne pathogens in I. inopinatus, I. ricinus, and their hybrids

BACKGROUND

Ixodes inopinatus was described from Spain on the basis of morphology and partial sequencing of 16S ribosomal DNA. However, several studies suggested that morphological differences between I. inopinatus and Ixodes ricinus are minimal and that 16S rDNA lacks the power to distinguish the two species. Furthermore, nuclear and mitochondrial markers indicated evidence of hybridization between I. inopinatus and I. ricinus. In this study, we tested our hypothesis on tick dispersal from North Africa to Southern Europe and determined the prevalence of selected tick-borne pathogens (TBPs) in I. inopinatus, I. ricinus, and their hybrids.

METHODS

Ticks were collected in Italy and Algeria by flagging, identified by sequencing of partial TROSPA and COI genes, and screened for Borrelia burgdorferi s.l., B. miyamotoi, Rickettsia spp., and Anaplasma phagocytophilum by polymerase chain reaction and sequencing of specific markers.

RESULTS

Out of the 380 ticks, in Italy, 92 were I. ricinus, 3 were I. inopinatus, and 136 were hybrids of the two species. All 149 ticks from Algeria were I. inopinatus. Overall, 60% of ticks were positive for at least one TBP. Borrelia burgdorferi s.l. was detected in 19.5% of ticks, and it was significantly more prevalent in Ixodes ticks from Algeria than in ticks from Italy. Prevalence of Rickettsia spotted fever group (SFG) was 51.1%, with significantly greater prevalence in ticks from Algeria than in ticks from Italy. Borrelia miyamotoi and A. phagocytophilum were detected in low prevalence (0.9% and 5.2%, respectively) and only in ticks from Italy.

CONCLUSIONS

This study indicates that I. inopinatus is a dominant species in Algeria, while I. ricinus and hybrids were common in Italy. The higher prevalence of B. burgdorferi s.l. and Rickettsia SFG in I. inopinatus compared with that in I. ricinus might be due to geographical and ecological differences between these two tick species. The role of I. inopinatus in the epidemiology of TBPs needs further investigation in the Mediterranean Basin.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Spotted Fever Group Rickettsiae in Ticks and Small Mammals from Grassland and Forest Habitats in Central Germany

Rickettsiae of the spotted fever group (SFG) are zoonotic tick-borne pathogens. Small mammals are important hosts for the immature life stages of two of the most common tick species in Europe, Ixodes ricinus and Dermacentor reticulatus. These hosts and vectors can be found in diverse habitats with different vegetation types like grasslands and forests. To investigate the influence of environmental and individual factors on Rickettsia prevalence, this study aimed to analyse the prevalence of SFG rickettsiae in ticks and small mammals in different small-scale habitats in central Germany for the first time. Small mammals of ten species and ticks of two species were collected from grasslands and forests in the Hainich-Dün region, central Germany. After species identification, DNA samples from 1098 ticks and ear snips of 1167 small mammals were screened for Rickettsia DNA by qPCR targeting the gltA gene. Positive samples were retested by conventional PCR targeting the ompB gene and sequencing. Rickettsia DNA was detected in eight out of ten small mammal species. Small mammal hosts from forests (14.0%) were significantly more often infected than those from grasslands (4.4%) (p < 0.001). The highest prevalence was found in the mostly forest-inhabiting genus Apodemus (14.8%) and the lowest in Microtus (6.6%), which inhabits grasslands. The prevalence was higher in D. reticulatus (46.3%) than in the I. ricinus complex (8.6%). Adult ticks were more often infected than nymphs (p = 0.0199). All sequenced rickettsiae in I. ricinus complex ticks were R. helvetica, and the ones in D. reticulatus were R. raoultii. Unlike adults, questing nymphs have had only one blood meal, which explains the higher prevalence in I. ricinus adults. Interestingly, habitat type did influence infection probability in small mammals, but did not in ticks. A possible explanation may be the high prevalence in Apodemus flavicollis and A. sylvaticus which were more abundant in the forest.

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.

Co-Infection of Potential Tick-Borne Pathogens of the Order Rickettsiales and Borrelia burgdorferi s. l. and Their Link to Season and Area in Germany

The prevalence of potential human pathogenic members of the order Rickettsiales differs between Borrelia burgdorferi sensu lato-positive and -negative tick microbiomes. Here, co-infection of members of the order Rickettsiales, such as Rickettsia spp., Anaplasma phagocytophilum, Wolbachia pipientis, and Neoehrlichia mikurensis as well as B. burgdorferi s.l. in the tick microbiome was addressed. This study used conventional PCRs to investigate the diversity and prevalence of the before-mentioned bacteria in 760 nucleic acid extracts of I. ricinus ticks detached from humans, which were previously tested for B. burgdorferi s.l.. A gltA gene-based amplicon sequencing approach was performed to identify Rickettsia species. The prevalence of Rickettsia spp. (16.7%, n = 127) and W. pipientis (15.9%, n = 121) were similar, while A. phagocytophilum was found in 2.8% (n = 21) and N. mikurensis in 0.1% (n = 1) of all ticks. Co-infection of B. burgdorferi s. l. with Rickettsia spp. was most frequent. The gltA gene sequencing indicated that Rickettsia helvetica was the dominant Rickettsia species in tick microbiomes. Moreover, R, monacensis and R. raoultii were correlated with autumn and area south, respectively, and a negative B. burgdorferi s. l. finding. Almost every fifth tick carried DNA of at least two of the human pathogenic bacteria studied here.

Revealing the Tick Microbiome: Insights into Midgut and Salivary Gland Microbiota of Female Ixodes ricinus Ticks

The ectoparasite Ixodes ricinus is an important vector for many tick-borne diseases (TBD) in the northern hemisphere, such as Lyme borreliosis, rickettsiosis, human granulocytic anaplasmosis, or tick-borne encephalitis virus. As climate change will lead to rising temperatures in the next years, we expect an increase in tick activity, tick population, and thus in the spread of TBD. Consequently, it has never been more critical to understand relationships within the microbial communities in ticks that might contribute to the tick's fitness and the occurrence of TBD. Therefore, we analyzed the microbiota in different tick tissues such as midgut, salivary glands, and residual tick material, as well as the microbiota in complete Ixodes ricinus ticks using 16S rRNA gene amplicon sequencing. By using a newly developed DNA extraction protocol for tick tissue samples and a self-designed mock community, we were able to detect endosymbionts and pathogens that have been described in the literature previously. Further, this study displayed the usefulness of including a mock community during bioinformatic analysis to identify essential bacteria within the tick.

Prevalence of Tick-Borne Pathogens in Questing Ixodes ricinus and Dermacentor reticulatus Ticks Collected from Recreational Areas in Northeastern Poland with Analysis of Environmental Factors

Ticks, such as Ixodes ricinus and Dermacentor reticulatus, act as vectors for multiple pathogens posing a threat to both human and animal health. As the process of urbanization is progressing, those arachnids are being more commonly encountered in urban surroundings. In total, 1112 I. ricinus (n = 842) and D. reticulatus (n = 270) ticks were collected from several sites, including recreational urban parks, located in Augustów and Białystok, Poland. Afterwards, the specimens were examined for the presence of Borrelia spp., Babesia spp., Anaplasma phagocytophilum, Rickettsia spp., Bartonella spp., and Coxiella burnetii using the PCR method. Overall obtained infection rate reached 22.4% (249/1112). In total, 26.7% (225/842) of I. ricinus was infected, namely with Borrelia spp. (25.2%; 212/842), Babesia spp. (2.0%; 17/842), and A. phagocytophilum (1.2%; 10/842). Among D. reticulatus ticks, 8.9% (24/270) were infected, specifically with Babesia spp. (7.0%; 19/270), A. phagocytophilum (1.1%; 3/270), and Borrelia burgdorferi s.l. (0.7%; 2/270). No specimen tested positively for Rickettsia spp., Bartonella spp., or Coxiella burnetii. Co-infections were detected in 14 specimens. Results obtained in this study confirm that I. ricinus and D. reticulatus ticks found within the study sites of northeastern Poland are infected with at least three pathogens. Evaluation of the prevalence of pathogens in ticks collected from urban environments provides valuable information, especially in light of the growing number of tick-borne infections in humans and domesticated animals.

Sympatric occurrence of Ixodes ricinus with Dermacentor reticulatus and Haemaphysalis concinna and the associated tick-borne pathogens near the German Baltic coast

Background

Ixodid ticks from the Northern Hemisphere have registered a northward expansion in recent years, and Dermacentor reticulatus is such an example in Europe, its expansion being considered a result of climate change alongside other factors. The aim of this study was to identify the composition of questing tick species and the associated pathogens at different sites near the German Baltic coast.

Methods

Questing ticks were collected monthly at four sites (May–November, 2020), mainly grasslands, and in October and November 2020 at a fifth site. Molecular screening of ticks for pathogens included RT-qPCR for the tick-borne encephalitis virus (TBEV), qPCR for Anaplasma phagocytophilum, PCR for Babesia species and Rickettsia species, and nested PCR for Borrelia species.

Results

Altogether 1174 questing ticks were collected: 760 Ixodes ricinus, 326 D. reticulatus and 88 Haemaphysalis concinna. The highest activity peak of I. ricinus and D. reticulatus was in May, in June for H. concinna while a second peak was observed only for I. ricinus and D. reticulatus in September and October, respectively. All samples tested negative for TBEV. For A. phagocytophilum, 1.5% of I. ricinus adults tested positive while the minimum infection rate (MIR) in nymphs was 1.3%. This pathogen was found in 0.6% of D. reticulatus. Babesia spp. were detected in I. ricinus (18.2% adults, 2.1% MIR in nymphs) and H. concinna (13.3% adults, 9.7% MIR in nymphs). Borrelia spp. were present only in I. ricinus (49.1% adults, 11.9% MIR in nymphs), while Rickettsia spp. were detected in I. ricinus (14% adults, 8.9% MIR in nymphs) and D. reticulatus (82%). Co-detection of pathogens was observed in 26.6% and 54.8% of positive I. ricinus adults and nymph pools, respectively, while one D. reticulatus tested positive for A. phagocytophilum and Rickettsia spp. The most common co-infection in I. ricinus adults was Babesia microti and Borrelia afzelii (12.3% of positive ticks).

Conclusions

The results of this study confirm the northern expansion of D. reticulatus and H. concinna in Germany. The detailed data of the infection levels at each location could be useful in assessing the risk of pathogen acquisition following a tick bite.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05173-2.

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

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

Seroprevalence and Risk Factors of Anaplasma spp. in German Small Ruminant Flocks

Knowledge about the distribution of Anaplasma spp. in small ruminants from Germany is limited. Therefore, serum samples were examined from 71 small ruminant flocks (2731 sheep, 447 goats) located in the five German federal states: Schleswig-Holstein (SH), Lower Saxony (LS), North Rhine-Westphalia (NRW), Baden-Wuerttemberg (BW) and Bavaria (BAV). Antibodies to Anaplasma spp. were determined by a cELISA based on the MSP5 antigen. A risk factor analysis at animal and flock level was also performed. Antibodies to Anaplasma spp. were detected in 70/71 flocks without significant difference in the intra-flock prevalence (IFP) between the federal states. The mean antibody levels from sheep were significantly lower in northern Germany (LS, SH) compared to west (NRW) and south Germany (BW, BAV). Sheep had a 2.5-fold higher risk of being seropositive than goats. Females and older animals (>2 years) were more likely to have antibodies to Anaplasma spp. in one third and one quarter of cases, respectively. Flocks used for landscape conservation had a five times higher risk of acquiring an IFP greater than 20%. Cats and dogs on the farms increased the probability for small ruminant flocks to have an IFP of above 20% 10-fold and 166-fold, respectively. Further studies are necessary to assess the impact of Anaplasma species on the health of small ruminants in Germany.

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

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

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

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

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.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

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

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

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

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

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

Prevalence and molecular characterization of Rickettsia spp. in questing ticks from north-western Spain

Tick-borne rickettsioses, most of them belonging to the spotted fever group (SFG), have been recognized as important emerging vector-borne zoonotic diseases. In order to determine the presence of Rickettsia spp. in questing ticks from north-western Spain, 1056 Ixodes ricinus, 19 Dermacentor marginatus, 17 Dermacentor reticulatus and one Ixodes acuminatus were processed. Rickettsia DNA was detected by PCR targeting rOmpA and rOmpB genes. A total of 219 (20.7%) I. ricinus, 19 (100%) D. marginatus and four D. reticulatus (23.5%) were positive. The prevalence was significantly higher in I. ricinus from coastal areas and in winter. Five species were identified: Rickettsia felis, Rickettsia monacensis, Rickettsia raoultii, Rickettsia slovaca and "Candidatus Rickettsia rioja". Our results reveal a significant presence of some pathogenic Rickettsia species in questing tick populations from this area which involves a noticeable risk of rickettsiosis. As R. raoultii, R. slovaca and "Ca. R. rioja" DNA were identified in I. ricinus, considered an unusual vector for these Rickettsia species, further studies are needed to unravel the role of that tick species in the maintenance and transmission of these three Rickettsia species in north-western Spain.

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

BACKGROUND

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

RESULTS

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

CONCLUSION

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

Prevalence of different Rickettsia spp. in Ixodes ricinus and Dermacentor reticulatus ticks (Acari: Ixodidae) in north-eastern Poland

In two surveys conducted in April and May 2013, a total of 1148 unfed ticks belonging to two species, Ixodes ricinus and Dermacentor reticulatus, were collected by flagging lower vegetation in 15 different localities throughout the Białowieża Primeval Forest (Podlaskie voivodship; north-eastern Poland) and in its buffer zone. In order to establish their infection rate with Rickettsia spp. individual adult ticks and pooled nymphs were tested by real-time PCR targeting the gltA gene. For the further identification of rickettsial species, positive samples were subjected for nested and semi-nested PCR targeting ompA and 16S rRNA genes, respectively, followed by sequencing analysis. Rickettsial DNA was detected in at least 279 ticks (minimum infection rate [MIR], 23.9%), including 52 nymphal and adult I. ricinus (MIR 8.6%) and 222 adult D. reticulatus (41%). Three species of SFG rickettsiae were identified: Rickettsia helvetica and 'Candidatus R. mendelii' in I. ricinus and R. raoultii in D. reticulatus and I. ricinus. Moreover, unidentified Rickettsia spp. which showed 99.4% identity, among others, with the uncultured Rickettsia sp. isolated from Cicadella viridis leafhopper, Rickettsia endosymbiont of Lasioglossum semilucens bee and R. bellii, were detected in I. ricinus, while Rickettsia sp. 98.3-98.4% homologous to Rickettsia secondary endosymbionts of Curculio spp. weevils was found in D. reticulatus. These results confirm the diversity of rickettsiae occurring in Poland. Further studies are needed to expand the knowledge on the species spectrum, prevalence and epidemiology of SFG rickettsiae in the country.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Rapid identification of nine species of diphyllobothriidean tapeworms by pyrosequencing

The identification of diphyllobothriidean tapeworms (Cestoda: Diphyllobothriidea) that infect humans and intermediate/paratenic hosts is extremely difficult due to their morphological similarities, particularly in the case of Diphyllobothrium and Spirometra species. A pyrosequencing method for the molecular identification of pathogenic agents has recently been developed, but as of yet there have been no reports of pyrosequencing approaches that are able to discriminate among diphyllobothriidean species. This study, therefore, set out to establish a pyrosequencing method for differentiating among nine diphyllobothriidean species, Diphyllobothrium dendriticum, Diphyllobothrium ditremum, Diphyllobothrium latum, Diphyllobothrium nihonkaiense, Diphyllobothrium stemmacephalum, Diplogonoporus balaenopterae, Adenocephalus pacificus, Spirometra decipiens and Sparganum proliferum, based on the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene as a molecular marker. A region of 41 nucleotides in the cox1 gene served as a target, and variations in this region were used for identification using PCR plus pyrosequencing. This region contains nucleotide variations at 12 positions, which is enough for the identification of the selected nine species of diphyllobothriidean tapeworms. This method was found to be a reliable tool not only for species identification of diphyllobothriids, but also for epidemiological studies of cestodiasis caused by diphyllobothriidean tapeworms at public health units in endemic areas.

Prevalence of Rickettsia spp. in Ticks and Serological and Clinical Outcomes in Tick-Bitten Individuals in Sweden and on the Åland Islands

Tick-transmitted diseases are an emerging health problem, and the hard tick Ixodes ricinus is the main vector for Borrelia spp., tick-borne encephalitis virus and most of the spotted fever Rickettsiae in Europe. The aim of the present study was to examine the incidence of rickettsial infection in the southernmost and south central parts of Sweden and the Åland Islands in Finland, the risk of infection in humans and its correlation with a bite of a Rickettsia-infected tick, the self-reported symptoms of rickettsial disease, and the prevalence of co-infection between Rickettsia spp. and Borrelia spp. Persons with a recent tick bite were enrolled through public media and asked to answer a questionnaire, provide a blood sample and bring detached ticks at enlistment and at follow-up three months later. Blood samples were previously analysed for Borrelia spp. antibodies and, for this report, analysed for antibodies to Rickettsia spp. by immunofluorescence and in 16 cases also using Western Blot. Ninety-six (44.0%) of the 218 participants were seropositive for IgG antibodies to Rickettsia spp. Forty (18.3%) of the seropositive participants had increased titres at the follow-up, indicating recent/current infection, while four (1.8%) had titres indicating probable recent/current infection (≥1:256). Of 472 ticks, 39 (8.3%) were Rickettsia sp. positive. Five (31.3%) of 16 participants bitten by a Rickettsia-infected tick seroconverted. Experience of the self-reported symptoms nausea (p = 0.006) and radiating pain (p = 0.041) was more common among those with recent, current or probable infection compared to those who did not seroconvert. Participants who showed seroreactivity or seroconversion to Rickettsia spp. had more symptoms than those who were seronegative. Seven (3.2%) participants showed seroconversion to Borrelia spp., and three (1.4%) of these showed seroconversion to both Rickettsia spp. and Borrelia spp., in accordance with previous studies in Sweden. Symptoms of rickettsial disease were in most of the cases vague and general that were difficult to differentiate from other tick-borne diseases.

Kampinos National Park: a risk area for spotted fever group rickettsioses, central Poland?

Ixodid ticks are important vectors of a variety of bacterial and protozoan pathogens which cause infections in humans. In this study, altogether 1041 questing Ixodes ricinus (n = 305) and Dermacentor reticulatus ticks (n = 736), sympatrically occurring in Kampinos National Park (KPN), central-east Poland, were analyzed by PCR for Rickettsia species. Overall, the pathogen prevalence in ticks was 27.5 % for I. ricinus and 42.8 % for D. reticulatus. Sequencing analysis showed that the first tick species was exclusively infected with R. helvetica, whereas the latter was infected with R. raoultii. These organism may pose a threat for populations exposed to ticks. Preliminary results of a serosurvey of 74 KPN employees, inhabitants and visitors from the same area showed a 31.1 % total seroprevalence against SFG rickettsiae compared to 13.3 % seropositive blood donors of the control group. Risk factors significantly associated with IgG seropositivity were: occupational exposure to ticks (p = 0.002), frequency of tick bites (p = 0.02) and male gender (p = 0.005). Seropositive and seronegative individuals occupationally exposed to ticks did not differ significantly with respect to age and years of employment.

Detection of Rickettsia helvetica in Ixodes ricinus infesting wild and domestic animals and in a botfly larva (Cephenemyia stimulator) infesting roe deer in Germany

Ixodes ricinus is a well-known vector of different human pathogens including Rickettsia helvetica. The role of wild mammals in the distribution and probable maintenance of Rickettsia in nature is still to be determined. We therefore investigated various parasites from different wild mammals as well as companion animals for the presence of Rickettsia. A total of 606 I. ricinus, 38 Cephenemyia stimulator (botfly larvae), one Dermacentor reticulatus, 24 Haematopinus suis (hog lice) and 30 Lipoptena cervi (deer flies) were collected from free-ranging animals during seasonal hunting, and from companion animals. Sample sites included hunting leases at three main sampling areas and five additional areas in West and Central Germany. All collected parasites were screened for Rickettsia spp. and I. ricinus were investigated for tick-borne encephalitis virus (TBEV) in addition. While no TBEV was detected, the minimum infection rate (MIR) of I. ricinus with Rickettsia was 4.1% referring to all sampling sites and up to 6.9% at the main sampling site in Koblenz area. Sequencing of a fragment of the ompB gene identified R. helvetica. Approximately one third (29.5%) of the animals carried Rickettsia-positive ticks and the MIR in ticks infesting wild mammals ranged from 4.1% (roe deer) to 9.5%. These data affirm the widespread distribution of R. helvetica in Germany. One botfly larva from roe deer also harboured R. helvetica. Botfly larvae are obligate parasites of the nasal cavity, pharynx and throat of cervids and feed on cell fragments and blood. Based on this one might hypothesise that R. helvetica likely induces rickettsemia in cervids thus possibly contributing to maintenance and distribution of this rickettsia in the field.

Rickettsia helvetica and R. monacensis infections in immature Ixodes ricinus ticks derived from sylvatic passerine birds in west-central Poland

The aim of this study was to assess the importance of forest passerine birds in spreading ixodid ticks infected with rickettsiae of spotted fever group (SFG) in sylvatic habitats in western Poland. In total, 834 immature Ixodes ricinus ticks were found on 64 birds of 11 species which were captured during the tick-questing season between May and September of 2006. Ground-foraging passerines hosted most of the ticks compared with arboreal species, and therefore, only the former group was included into a detailed analysis. Significant predominance of larvae over nymphs was observed (581 vs. 253, respectively). Blackbirds and song thrushes hosted 82 % (n = 681) of the ticks collected from all infested passerines. The overall prevalence range of SF rickettsiae (including Rickettsia helvetica and Rickettsia monacensis) in bird-derived ticks was 10.5–26.9 %, exceeding that in questing ticks, and in ticks feeding on rodents and deer reported earlier from the same study area. This high prevalence of infection in immature I. ricinus ticks feeding on passerine birds strongly implies that they are involved in the enzootic maintenance of spotted fever group rickettsiae in the tick vector populations occurring in sylvatic habitats.

Prevalence of pathogenic bacteria in Ixodes ricinus ticks in Central Bohemia

Bacteria associated with the tick Ixodes ricinus were assessed in specimens unattached or attached to the skin of cats, dogs and humans, collected in the Czech Republic. The bacteria were detected by PCR in 97 of 142 pooled samples including 204 ticks, i.e. 1-7 ticks per sample, collected at the same time from one host. A fragment of the bacterial 16S rRNA gene was amplified, cloned and sequenced from 32 randomly selected samples. The most frequent sequences were those related to Candidatus Midichloria midichlori (71% of cloned sequences), followed by Diplorickettsia (13%), Spiroplasma (3%), Rickettsia (3%), Pasteurella (3%), Morganella (3%), Pseudomonas (2%), Bacillus (1%), Methylobacterium (1%) and Phyllobacterium (1%). The phylogenetic analysis of Spiroplasma 16S rRNA gene sequences showed two groups related to Spiroplasma eriocheiris and Spiroplasma melliferum, respectively. Using group-specific primers, the following potentially pathogenic bacteria were detected: Borellia (in 20% of the 142 samples), Rickettsia (12%), Spiroplasma (5%), Diplorickettsia (5%) and Anaplasma (2%). In total, 68% of I. ricinus samples (97/142) contained detectable bacteria and 13% contained two or more putative pathogenic groups. The prevalence of tick-borne bacteria was similar to the observations in other European countries.

Tick survey for prevalent pathogens in peri-urban recreation sites in Saarland and Rhineland-Palatinate (Germany)

Ixodid ticks are important vectors of human pathogens in Central Europe. Despite this fact, prevalence studies are scarce, especially with regard to much-frequented peri-urban recreation sites. In this pilot study, 4.014 larvae, nymphs and adult ticks sampled monthly during the active seasons in 2011 and 2012 from 14 distinct collection sites in two German states (Saarland and Rhineland-Palatinate) were screened for Borrelia spp., Anaplasma spp. and tick-borne encephalitis virus. Mean prevalence rates were 19.8 % for Borrelia spp., 1.9 % for Anaplasma spp. and 0.1 % for tick-borne encephalitis virus (TBEV), which are in accordance with those reported from other regions in Germany and neighbouring countries. Nevertheless, the detection of TBEV-infected ticks is the first positive result after several unsuccessful efforts over the previous years in official "TBE-risk" zones of Saarland and Rhineland-Palatinate which supports the presumption of the origin of observed local infection. Besides ixodid ticks a non-engorged adult female tick of the invading species Dermacentor reticulatus has been found reflecting the appearance of another vector eventually jeopardising the health of host animals as well as humans.

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

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

Anaplasma marginale and Anaplasma phagocytophilum: Rickettsiales pathogens of veterinary and public health significance

Anaplasma marginale and Anaplasma phagocytophilum are the most important tick-borne bacteria of veterinary and public health significance in the family Anaplasmataceae. The objective of current review is to provide knowledge on ecology and epidemiology of A. phagocytophilum and compare major similarities and differences of A. marginale and A. phagocytophilum. Bovine anaplasmosis is globally distributed tick-borne disease of livestock with great economic importance in cattle industry. A. phagocytophilum, a cosmopolitan zoonotic tick transmitted pathogen of wide mammalian hosts. The infection in domestic animals is generally referred as tick-borne fever. Concurrent infections exist in ticks, domestic and wild animals in same geographic area. All age groups are susceptible, but the prevalence increases with age. Movement of susceptible domestic animals from tick free non-endemic regions to disease endemic regions is the major risk factor of bovine anaplasmosis and tick-borne fever. Recreational activities or any other high-risk tick exposure habits as well as blood transfusion are important risk factors of human granulocytic anaplasmosis. After infection, individuals remain life-long carriers. Clinical anaplasmosis is usually diagnosed upon examination of stained blood smears. Generally, detection of serum antibodies followed by molecular diagnosis is usually recommended. There are problems of sensitivity and cross-reactivity with both the Anaplasma species during serological tests. Tetracyclines are the drugs of choice for treatment and elimination of anaplasmosis in animals and humans. Universal vaccine is not available for either A. marginale or A. phagocytophilum, effective against geographically diverse strains. Major control measures for bovine anaplasmosis and tick-borne fever include rearing of tick-resistant breeds, endemic stability, breeding Anaplasma-free herds, identification of regional vectors, domestic/wild reservoirs and control, habitat modification, biological control, chemotherapy, and vaccinations (anaplasmosis and/or tick vaccination). Minimizing the tick exposure activities, identification and control of reservoirs are important control measures for human granulocytic anaplasmosis.

Serological differentiation of antibodies against Rickettsia helvetica, R. raoultii, R. slovaca, R. monacensis and R. felis in dogs from Germany by a micro-immunofluorescent antibody test

Background

Spotted Fever Group (SFG) Rickettsiae can cause febrile diseases with or without rash in humans worldwide. In Germany only limited data are available about their medical significance. Serological screening tests for antibodies against rickettsiae usually only distinguish between SFG and Typhus Group (TG) Rickettsiae due to the strong cross reactivities within the groups. Seroprevalence rates in dogs, as possible sentinels for tick-borne diseases, could serve as an indicator for the distribution of different Rickettsia species.

Methods

In this study, a micro-immunofluorescence assay (micro-IFA) was established for detection and differentiation of antibodies against five Rickettsia species in dogs (R. helvetica, R. raoultii, R. slovaca, R. monacensis and R. felis). Dogs that never left Germany (n = 605) previously investigated with an SFG-ELISA were included in this study and screened at a 1:128 dilution. Endpoint titres of fifty randomly selected seropositive samples of each of the five investigated regions in Germany were determined in order to allow a differentiation of the causative Rickettsia species. Sensitivity and specificity of the micro-IFA were compared with ELISA results of the previous study.

Results

A total of 93.9% of the dogs were positive for antibodies of the SFG Rickettsiae at the screening titer of 1:128. Differentiation of SFG Rickettsiae with the micro-IFA was possible in 70.4%, but in 29.6% of the cases the detected antibodies were not differentiable. Considering a clear differentiation by a twofold titre difference between observed reactions, the seroprevalence rates were 66.0% for R. helvetica, 2.8% for R. raoultii, 1.6% for R. slovaca, but no serological reaction could be clearly attributed to R. monacensis or R. felis. No statistically significant regional differences were found for R. helvetica, R. slovaca and R. raoultii comparing the five regions of Germany. Comparison of micro-IFA with ELISA revealed a sensitivity of 82.0% and a specificity of 83.8% for the Rickettsia SFG ELISA.

Conclusions

The micro-IFA is a useful serological tool to differentiate antibodies against different Rickettsia species in dogs. Seroprevalence rates in dogs correspond to the prevalence rates and distribution of Rickettsia-carrying tick species.

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.

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.