Spatial disaggregation of tick occurrence and ecology at a local scale as a preliminary step for spatial surveillance of tick-borne diseases: general framework and health implications in Belgium

The prevalence of pathogens in ticks collected from humans in Belgium, 2021, versus 2017

BACKGROUND

Ticks carry a variety of microorganisms, some of which are pathogenic to humans. The human risk of tick-borne diseases depends on, among others, the prevalence of pathogens in ticks biting humans. To follow-up on this prevalence over time, a Belgian study from 2017 was repeated in 2021.

METHODS

During the tick season 2021, citizens were invited to have ticks removed from their skin, send them and fill in a short questionnaire on an existing citizen science platform for the notification of tick bites (TekenNet). Ticks were morphologically identified to species and life stage level and screened using multiplex qPCR targeting, among others, Borrelia burgdorferi (sensu lato), Anaplasma phagocytophilum, Borrelia miyamotoi, Neoehrlichia mikurensis, Babesia spp., Rickettsia helvetica and tick-borne encephalitis virus (TBEV). The same methodology as in 2017 was used.

RESULTS

In 2021, the same tick species as in 2017 were identified in similar proportions; of 1094 ticks, 98.7% were Ixodes ricinus, 0.8% Ixodes hexagonus and 0.5% Dermacentor reticulatus. A total of 928 nymphs and adults could be screened for the presence of pathogens. Borrelia burgdorferi (s.l.) was detected in 9.9% (95% CI 8.2-12.0%), which is significantly lower than the prevalence of 13.9% (95% CI 12.2-15.7%) in 2017 (P = 0.004). The prevalences of A. phagocytophilum (4.7%; 95% CI 3.5-6.3%) and R. helvetica (13.3%; 95% CI 11.2-15.6%) in 2021 were significantly higher compared to 2017 (1.8%; 95% CI 1.3-2.7% and 6.8%; 95% CI 5.6-8.2% respectively) (P < 0.001 for both). For the other pathogens tested, no statistical differences compared to 2017 were found, with prevalences ranging between 1.5 and 2.9% in 2021. Rickettsia raoultii was again found in D. reticulatus ticks (n = 3/5 in 2021). Similar to 2017, no TBEV was detected in the ticks. Co-infections were found in 5.1% of ticks. When combining co-infection occurrence in 2017 and 2021, a positive correlation was observed between B. burgdorferi (s.l.) and N. mikurensis and B. burgdorferi (s.l.) and B. miyamotoi (P < 0.001 for both).

CONCLUSIONS

Although the 2021 prevalences fell within expectations, differences were found compared to 2017. Further research to understand the explanations behind these differences is needed.

East-to-west dispersal of bird-associated ixodid ticks in the northern Palaearctic: Review of already reported tick species according to longitudinal migratory avian hosts and first evidence on the genetic connectedness of Ixodes apronophorus between Siberia and Europe

Birds are long-known as important disseminators of ixodid ticks, in which context mostly their latitudinal, south-to-north migration is considered. However, several bird species that occur in the eastern part of the northern Palaearctic are known to migrate westward. In this study, a female tick collected from the sedge warbler, Acrocephalus schoenobaenus, in Lithuania was identified morphologically and analyzed with molecular-phylogenetic methods. In addition, literature data were reviewed on ixodid tick species known to be associated with birds that have recorded east-to-west migratory route in the Palaearctic. The tick collected from A. schoenobaenus was morphologically identified as Ixodes apronophorus. Two mitochondrial genetic markers for this specimen showed 100% identity with a conspecific tick reported previously in Western Siberia, Russia. Based on literature data, as many as 82 bird species from 11 orders were found to have records of ringing in the easternmost part of the northern Palaearctic and recaptures in Europe. Of these bird species, 31 ixodid tick species were reported in the Euro-Siberian region. Nearly all passeriform bird species with east-to-west migration were reported to carry ticks, whereas no reports of tick infestation were documented from the majority of wetland-associated bird species, mostly from the orders Anseriformes and Charadriiformes. The first European sequences of bona fide I. apronophorus revealed genetic connectedness with conspecific ticks reported from Siberia. Since the principal hosts of this tick species are rodents which do not migrate large distances, the most likely explanation for genetic similarity in this direction is dispersal of this tick species via migratory birds. Given the high number of tick species that are known to associate with bird species migrating in westward direction, this appears to be an important means of the gene flow between geographically distant tick populations in the northern Palaearctic.

Ectoparasitic mites, ticks (Acari: Trombidiformes, Mesostigmata, Ixodida) and insects (Insecta: Psocodea, Siphonaptera) of ground-dwelling small mammals in the Baltic States. An annotated checklist

This paper presents an annotated checklist of 77 species of ectoparasitic mites, ticks (Acari: Trombidiformes, Mesostigmata, Ixodida) and insects (Insecta: Psocodea, Siphonaptera) found on ground-dwelling small mammals in the Baltic States (Estonia, Latvia, Lithuania). Eight species of five genera of chigger mites (Trombidiformes: Trombiculidae), 26 species of eight genera of laelapid mites (Mesostigmata: Laelapidae), six species of two genera of ixodid ticks (Ixodida: Ixodidae), 11 species of three genera of blood-sucking lice (Psocodea: Hoplopleuridae, Pediculidae, Polyplacidae) and 26 species of 15 genera of fleas (Siphonaptera: Ceratophyllidae, Ctenophthalmidae, Hystrichopsyllidae, Pulicidae) were recorded on ground-dwelling small mammals in the Baltic States. Neotrombicula japonica (Tanaka, Kaiwa, Teramura & Kagaya), Neotrombicula vulgaris (Schluger), Miyatrombicula muris (Oudemans), Hoplopleura edentula Fahrenholz and Polyplax hannswrangeli Eichler are recorded for the first time in the Baltic States.

First molecular detection of Babesia vulpes and Babesia capreoli in wild boars from southern Italy

Introduction

Following the increase of wild boar (Sus scrofa) populations in Europe, a potential risk of emerging infections by vector-borne pathogens may occur. Despite this, the circulation of piroplasmid species in these ungulates is still a neglected topic, particularly in the Mediterranean basin. Therefore, this study aimed to investigate the presence of Babesia/Theileria spp. in wild boars from southern Italy to assess the epidemiological role of these ungulates in the circulation of piroplasmids.

Methods

By using a citizen science approach among hunters and veterinarians, wild boar spleen samples were collected in the Campania region (southern Italy) between 2016 and 2022. A combined semi-nested PCR/sequencing analysis targeting the V4 hyper-variable region of 18S rRNA was run to detect Babesia/Theileria spp. DNA.

Results

Out of 243 boars, 15 (i.e., 6.2, 95% CI: 3.4-9.9) tested positive to Babesia/Theileria spp., Babesia vulpes (n = 13, 5.3, 95% CI: 3.1-8.9) the most prevalent, followed by Babesia capreoli (n = 2, 0.8, 95% CI: 0.2-2.9). Three different B. vulpes sequence types were identified (i.e., ST1, ST2, ST3), with the most representative as ST1 (60%), and a single B. capreoli sequence type. No statistically significant difference (p > 0.05) were found between the presence of the pathogens and boar age, sex, province and sample collection year.

Discussion

Data demonstrate for the first time the occurrence of B. vulpes and B. capreoli in wild boars, which may play a role in the biological cycle of piroplasmids. We emphasize the importance of monitoring these ungulates to prevent potential foci of infection. The engagement of hunters in epidemiological scientifically based surveys can constitute a technically sound control strategy of piroplasmids in a One Health perspective.

The Eurasian shrew and vole tick Ixodes trianguliceps: geographical distribution, climate preference, and pathogens detected

The Eurasian shrew and vole tick Ixodes trianguliceps Birula lives in the nests and burrows of its small mammalian hosts and is-along with larvae and nymphs of Ixodes ricinus or Ixodes persulcatus-one of the most commonly collected tick species from these hosts in its Eurasian range. Ixodes trianguliceps is a proven vector of Babesia microti. In this study, up-to-date maps depicting the geographical distribution and the climate preference of I. trianguliceps are presented. A dataset was compiled, resulting in 1161 georeferenced locations in Eurasia. This data set covers the entire range of I. trianguliceps for the first time. The distribution area between 8[Formula: see text] W-105[Formula: see text] E and 40-69[Formula: see text] N extends from Northern Spain to Western Siberia. To investigate the climate adaptation of I. trianguliceps, the georeferenced locations were superimposed on a high-resolution map of the Köppen-Geiger climate classification. The Köppen profile for I. trianguliceps, i.e., a frequency distribution of the tick occurrence under different climates, shows two peaks related to the following climates: warm temperate with precipitation all year round (Cfb), and boreal with warm or cold summers and precipitation all year round (Dfb, Dfc). Almost 97% of all known I. trianguliceps locations are related to these climates. Thus, I. trianguliceps prefers climates with warm or cold summers without dry periods. Cold winters do not limit the distribution of this nidicolous tick species, which has been recorded in the European Alps and the Caucasus Mountains up to altitudes of 2400 m. Conversely, I. trianguliceps does not occur in the Mediterranean area with its hot and dry summers.

Substantial viral and bacterial diversity at the bat-tick interface

Ticks harbour a high diversity of viruses, bacteria and protozoa. The soft tick Carios vespertilionis (Argasidae) is a common ectoparasite of bats in the Palearctic region and is suspected to be vector and reservoir of viruses and other microbial species in bat populations, some of which may act as zoonotic agents for human disease. The Soprano pipistrelle (Pipistrellus pygmaeus, Vespertilionidae) is widely distributed in Europe, where it can be found inside or close to human habitation. We used meta-transcriptomic sequencing to determine the RNA virome and common microbiota in blood-fed C. vespertilionis ticks collected from a Soprano pipistrelle bat roosting site in south-central Sweden. Our analyses identified 16 viruses from 11 virus families, of which 15 viruses were novel. For the first time in Sweden we identified Issuk-Kul virus, a zoonotic arthropod-borne virus previously associated with outbreaks of acute febrile illness in humans. Probable bat-associated and tick-borne viruses were classified within the families Nairoviridae, Caliciviridae and Hepeviridae, while other invertebrate-associated viruses included members of the Dicistroviridae, Iflaviridae, Nodaviridae, Partitiviridae, Permutotetraviridae, Polycipiviridae and Solemoviridae. Similarly, we found abundant bacteria in C. vespertilionis, including genera with known tick-borne bacteria, such as Coxiella spp. and Rickettsia spp. These findings demonstrate the remarkable diversity of RNA viruses and bacteria present in C. vespertilionis and highlight the importance of bat-associated ectoparasite surveillance as an effective and non-invasive means to track viruses and bacteria circulating in bats and ticks.

Tick maps on the virtual globe: First results using the example of Dermacentor reticulatus

Digital maps, particularly displayed on virtual globes, will represent the most important source of geographical knowledge in the future. The best known of these virtual globes is Google Earth, whose use in teaching at schools and universities is now common practice. As the first result of a series of forthcoming digital tick maps, the worldwide distribution of the marsh tick Dermacentor reticulatus is shown on Google Earth. For this purpose, various distribution maps of D. reticulatus were compiled, including digitized expert maps and a map of suitable habitats compiled with a species distribution model (SDM). A random forest model that estimates suitable habitats by combining information from tick observations, bioclimatic variables, altitude, and land cover was chosen for the latter. In the Google Earth application, the following maps can be selected: a historical expert map, a current expert map, a SDM predicted habitat suitability map, a combined expert-habitat suitability map (considered to be the best representation of the current distribution of D. reticulatus), and a map of rasterized tick locations. Users can overlay these maps according to their own requirements or combine it with other Google Earth content. For example, a comparison of the historical with the current expert map shows the spread of D. reticulatus over the past few decades. Additionally, high-resolution city maps of Bilbao (Spain), Grenoble (France), Berlin (Germany), Wrocław (Poland), Budapest (Hungary), Bucharest (Romania), and Tomsk (Russia) demonstrate the urban distribution of D. reticulatus in public parks, fallow land, and recreational areas. The Google Earth application, developed using the Keyhole Markup Language (KML), also contains fact sheets on biology, ecology, seasonal activity, and vector competence of D. reticulatus. This information has been prepared in a compact and easily understandable way for the target group, i.e. scientists from various disciplines, students, and lay people interested in the geographical distribution of ticks.

Atlas of ticks (Acari: Argasidae, Ixodidae) in Germany: 1st data update

The first data update of the atlas of ticks in Germany published in 2021 is presented here. This atlas provides maps based on georeferenced tick locations of 21 species endemic in Germany as well as three tick species that are regularly imported to Germany. The data update includes the following numbers of newly georeferenced tick locations: 17 Argas reflexus, 79 Carios vespertilionis, 2 Dermacentor marginatus, 43 Dermacentor reticulatus, 4 Haemaphysalis concinna, 3 Haemaphysalis punctata, 3 Hyalomma rufipes, 3 Ixodes apronophorus, 9 Ixodes arboricola, 1 Ixodes ariadnae, 30 Ixodes canisuga, 3 Ixodes frontalis, 80 Ixodes hexagonus, 3 Ixodes lividus, 497 Ixodes ricinus/inopinatus, 1 Ixodes rugicollis, 17 Ixodes trianguliceps, 14 Ixodes vespertilionis, and 45 Rhipicephalus sanguineus sensu lato. Old and new tick findings were mapped, such as the northernmost occurrence of D. marginatus in Germany observed in 2021, but also the historical records from the first descriptions of I. apronophorus and I. arboricola, which were georeferenced here for the first time. The digital dataset of tick locations available for Germany is supplemented by 854 new tick locations. These records increase the number of tick species mapped in the federal states Bavaria, Brandenburg and Mecklenburg Western Pomerania by five each, those in Berlin and Schleswig-Holstein by four each, those in Hamburg by three, those in Baden-Wuerttemberg, Bremen, Lower Saxony, Northrhine-Westphalia, Rhineland Palatinate and Thuringia by two each, and those in Hesse, Saxony and Saxony-Anhalt by one each. Thus, the first data update of the tick atlas in Germany and the underlying digital dataset significantly improve our knowledge of the distribution of these tick species and helps to investigate the effects of climate change and habitat changes on them.

Hard ticks (Acari: Ixodidae) associated with birds in Europe: Review of literature data

Hard ticks (Acari: Ixodidae) are considered the most important transmitters of pathogens in the temperate zone that covers most of Europe. In the era of climate change tick-borne diseases are predicted to undergo geographical range expansion toward the north through regions that are connected to southern areas of the continent by bird migration. This alone would justify the importance of synthesized knowledge on the association of tick species with avian hosts, yet birds also represent the most taxonomically and ecologically diverse part of urban vertebrate fauna. Birds frequently occur in gardens and near animal keeping facilities, thus playing a significant role in the dispersal of ticks and tick-borne pathogens in synanthropic environments. The primary aim of this review is to provide a comprehensive reference source (baseline data) for future studies, particularly in the context of discovering new tick-host associations after comparison with already published data. The records on the ixodid tick infestations of birds were assessed from nearly 200 papers published since 1952. In this period, 37 hard tick species were reported from 16 orders of avian hosts in Europe. Here we compile a list of these tick species, followed by the English and Latin name of all reported infested bird species, as well as the tick developmental stage and country of origin whenever this information was available. These data allowed a first-hand analysis of general trends regarding how and at which developmental stage of ticks tend to infest avian hosts. Five tick species that were frequently reported from birds and show a broad geographical distribution in the Western Palearctic (Ixodes arboricola, I. frontalis, I. ricinus, Haemaphysalis concinna and Hyalomma marginatum) were also selected for statistical comparisons. Differences were demonstrated between these tick species regarding their association with bird species that typically feed from the ground and those that rarely occur at the soil level. The ecology of these five bird-infesting tick species is also illustrated here according to avian orders, taking into account the ecology (habitat type) and activity (circadian rhythm and feeding level) of most bird species that represent a certain order.

Maps of ticks (Acari: Argasidae, Ixodidae) for Austria and South Tyrol, Italy

A first compilation of georeferenced tick locations in Austria and South Tyrol, Italy, is presented here. This allows the tick fauna to be examined in the various climatic regions of the European Alps. The dataset comprises 424 tick locations of Austria and 48 tick locations of South Tyrol, which were digitized from literature and visualized in the form of geographical maps. The tick fauna of Austria includes two species of Argasidae in the genera Argas and Carios and 15 species of Ixodidae in the genera Dermacentor, Haemaphysalis, and Ixodes, altogether 17 tick species. In addition, two species of Ixodidae in the genera Hyalomma (each spring imported by migratory birds) and Rhipicephalus (occasionally imported by dogs returning from abroad with their owners) are included in the tick atlas. Of these, the georeferenced locations of 18 tick species are depicted in maps. The occurrence of the one remaining tick species, Ixodes inopinatus, is given at the level of the federal states. The first Austrian distribution map of the long-legged bat tick Ixodes vespertilionis, which was reported from 21 caves, deserves special mention. The most common and widespread tick species is Ixodes ricinus, with records in all nine federal states of Austria, followed by Ixodes canisuga, Ixodes hexagonus, and I. vespertilionis in six federal states each. Haemaphysalis concinna and Dermacentor reticulatus are only endemic in the eastern plains, while Dermacentor marginatus only occurs in the west, in the Tyrolean Alpine valleys. Eight tick species were reported from South Tyrol, Italy. There, the most frequently flagged tick from the vegetation is also I. ricinus, while D. marginatus and Haemaphysalis punctata are often collected from sheep. The locations are shown together with those from North and East Tyrol on a separate Tyrol map. The tick atlas in Austria and South Tyrol as well as the underlying digital dataset in the supplement contribute to the closing of data gaps in global distribution maps of ticks and improve the data basis for new species distribution models.

Soft ticks (Acari: Argasidae) in the island nations of Southeast Asia: A review on their distribution, associated hosts and potential pathogens

Soft ticks (Acari: Argasidae) are the second major family of the blood feeding metastriates and vectors of a number of viral and bacterial pathogens for both humans and animals. Despite the growing effort on tick surveillance and studies worldwide, there is still limited information on the soft tick distribution in the island nations of Southeast Asia, especially species that are medically and veterinarily important. With the aim to provide an overview of the current status of knowledge on soft tick distribution in the island nations of Southeast Asia (Malaysia, Singapore, Brunei, Indonesia, the Philippines and Timor-Leste), this article reviews the species of soft ticks (Acari: Argasidae) and their associated hosts and pathogens, with the addition of a pictorial summary and list of tick species discovered in this region. The most prevalent soft tick genus is Carios, and the host species most associated with findings of soft ticks in this region are bats, particularly of the Pteropodidae and Vespertilionidae families. Furthermore, the only known pathogen originating from soft ticks in the island nations of Southeast Asia was the Keterah virus, which was isolated from Argas pusillus tick in Malaysia.

Environmental determinants of Anaplasma phagocytophilum infection in cattle using a kernel density function

The study of vector-borne zoonotic diseases often relies on partial data, because of the constraints associated with observing various elements of the transmission cycle: the pathogen, the vector, the host - wild or domestic. Each angle comes with its own practical challenges, leading to data reflecting poorly either on spatial or temporal dynamics, or both. In this study, we investigated the effect of landscape on the presence of bovine ehrlichiosis infection in Walloon cattle. This disease is transmitted to cattle through the bite of a tick infected by the bacterium Anaplasma phagocytophilum. The first case of bovine ehrlichiosis in the southern region of Belgium (Wallonia) was detected in 2005 and the high seroprevalence found in herds suggests that the disease is endemic. The presence of antibodies of A. phagocytophilum in one cow selected in each of 1445 herds in 2010 and 2011 was detected using indirect immunofluorescence. Samples were geolocated at the farm. However, the precise location of infection remains uncertain. To account for the data sparsity, we elaborated a spatial index for the intensity of the presence of seropositive animals, based on a non-parametric kernel density estimation. We examined this index with the landscape surrounding the pastures, using multiple regressions. Landscape factors were selected using a conceptual framework based on the ecological resources needed for the transmission cycle of A. phagocytophilum. Results suggest that our spatial index adequately reflected infection presence in cattle in Wallonia, which was highest in central regions, corresponding to more forested and fragmented landscapes. We noticed that the presence of large hosts, wild or domestic, as well as the composition and configuration of the landscape of the pasture, influenced the capacity of the pasture to support the presence of bovine ehrlichiosis in Walloon herds. This is consistent with the ecology of A. phagocytophilum and current knowledge about risk factors of tick-borne diseases in cattle at the regional scale. The nature of the kernel density index, based on uncertainties over the location of cases positive to A. phagocytophilum, reflected the infectiousness profile at the landscape and not at the pasture level. Results also highlighted that the effects of some environmental variables remain, even when considering the different agro-geographic regions of Wallonia, which present contrasted landscapes and different levels of intensity of A. phagocytophilum infection. The kernel density index is a useful tool to help veterinary practitioner to quickly target areas where A. phagocytophilum infection is likely.

Exploration of the Ixodes ricinus virosphere unveils an extensive virus diversity including novel coltiviruses and other reoviruses

Recent metagenomics studies have revealed several tick species to host a variety of previously undiscovered RNA viruses. Ixodes ricinus, which is known to be a vector for many viral, bacterial, and protozoan pathogens, is the most prevalent tick species in Europe. For this study, we decided to investigate the virosphere of Belgian I. ricinus ticks. High-throughput sequencing of tick pools collected from six different sampling sites revealed the presence of viruses belonging to many different viral orders and families, including Mononegavirales, Bunyavirales, Partitiviridae, and Reoviridae. Of particular interest was the detection of several new reoviruses, two of which cluster together with members of the genus Coltivirus. This includes a new strain of Eyach virus, a known causative agent of tick-borne encephalitis. All genome segments of this new strain are highly similar to those of previously published Eyach virus genomes, except for the fourth segment, encoding VP4, which is markedly more dissimilar, potentially indicating the occurrence of a genetic reassortment. Further polymerase chain reaction-based screening of over 230 tick pools for 14 selected viruses showed that most viruses could be found in all six sampling sites, indicating the wide spread of these viruses throughout the Belgian tick population. Taken together, these results illustrate the role of ticks as important virus reservoirs, highlighting the need for adequate tick control measures.

Atlas of ticks (Acari: Argasidae, Ixodidae) in Germany

An updated and increased compilation of georeferenced tick locations in Germany is presented here. This data collection extends the dataset published some years ago by another 1448 new tick locations, 900 locations of which were digitized from literature and 548 locations are published here for the first time. This means that a total of 3492 georeferenced tick locations is now available for Germany. The tick fauna of Germany includes two species of Argasidae in the genera Argas and Carios and 19 species of Ixodidae in the genera Dermacentor, Haemaphysalis, and Ixodes, altogether 21 tick species. In addition, three species of Ixodidae in the genera Hyalomma (each spring imported by migratory birds) and Rhipicephalus (occasionally imported by dogs returning from abroad with their owners) are included in the tick atlas. Of these, the georeferenced locations of 23 tick species are depicted in maps. The occurrence of the one remaining tick species, the recently described Ixodes inopinatus, is given at the level of the federal states. The most common and widespread tick species is Ixodes ricinus, with records in all 16 federal states. With the exception of Hamburg, Dermacentor reticulatus was also found in all federal states. The occurrence of the ixodid ticks Ixodes canisuga, Ixodes frontalis, Ixodes hexagonus and I. inopinatus were documented in at least 11 federal states each. The two mentioned argasid tick species were also documented in numerous federal states, the pigeon tick Argas reflexus in 11 and the bat tick Carios vespertilionis in seven federal states. The atlas of ticks in Germany and the underlying digital dataset in the supplement can be used to improve global tick maps or to study the effects of climate change and habitat alteration on the distribution of tick species.

Assessment of tick-borne pathogens presence in Dermacentor reticulatus ticks in north-eastern Poland

PURPOSE

Dermacentor reticulatus is the second most common tick species in Poland after Ixodes ricinus. The aim of the study was to analyze the presence of pathogen DNA in D. reticulatus.

MATERIALS AND METHODS

Ticks were collected in The Protected Landscape Area of the Bug and Nurzec Valley (52°40' N and 22°28' E) between 2016 and 2017. End-point PCR for Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Babesia spp., Rickettsia spp., Bartonella spp. and Coxiella burnetii detection was performed.

RESULTS

Tick-borne pathogens' DNA was detected in 11.3% of 301 ticks: B. burgdorferi s.l. in 3.6%, Babesia spp. in 6.3%, A. phagocytophilum in 0.7% and B. burgdorferi s.l.-Babesia spp. co-infection in 0.7%. In all 21 Babesia spp. positive samples, sequence analysis confirmed the presence of Babesia canis with an 80.3%-98.3% homology with the B. canis sequences in GenBank. C. burnetii, Bartonella spp., and Rickettsia spp. DNA were not detected.

CONCLUSIONS

Dermacentor reticulatus from north-eastern Poland were found to carry three of the most common tick-borne pathogens (B. burgdorferi s.l., Babesia canis, A. phagocytophilum) which lead to single and mixed infections. Babesia canis was the most prevalent pathogen identified in D. reticulatus.

Molecular survey on tick-borne pathogens and Leishmania infantum in red foxes (Vulpes vulpes) from southern Italy

Red foxes (Vulpes vulpes) have been recognised to harbour and transmit a wide range of tick-borne pathogens (TBPs) including those of zoonotic concern. To investigate the prevalence and the distribution of TBPs and of Leishmania infantum in foxes (n = 244), spleen samples were collected within the frame of a multi-regional wildlife health surveillance program in Italy. A combined PCR/sequencing approach was performed for the detection of Anaplasma spp., Babesia spp., Borrelia spp., Ehrlichia spp., Hepatozoon spp. and L. infantum DNA. Overall, 146 foxes (59.8 %, 95 % CI: 53.6-65.8) tested positive for at least one pathogen with Hepatozoon canis being the most prevalent (i.e., n = 124; 50.8 %, 95 % CI: 44.6-57.0), followed by Babesia vulpes (n = 20; 8.2 %, 95 % CI: 5.4-12.3), different spirochete species from Borrelia burgdorferi sensu lato complex (n = 9; 3.7 %, 95 % CI: 1.9-6.9), Ehrlichia canis and L. infantum (n = 7; 2.9 % each, 95 % CI: 1.4-5.8), Anaplasma platys (n = 4; 1.6 %, 95 % CI: 0.6-4.1), Anaplasma phagocytophilum ecotype I and Candidatus Neoehrlichia sp. (n = 3; 1.2 % each, 95 % CI: 0.4-3.5). All samples scored negative for Babesia canis and Borrelia miyamotoi. This study revealed the presence of spirochetes from B. burgdorferi s.l. complex, Ca. Neoehrlichia sp., A. platys and A. phagocytophilum ecotype I in red fox population from Italy, underling the necessity to monitoring these carnivores, mainly because they live in contact with dogs and humans. Data on the tick fauna circulating on wildlife species will complement information herein obtained, instrumentally to establish preventive strategies for minimizing the risk of infection for animals and humans.

Mitochondrial sequences of Rhipicephalus and Coxiella endosymbiont reveal evidence of lineages co-cladogenesis

Rhipicephalus ticks are competent vectors of several pathogens, such as Spotted Fever Group Rickettsiae (SFGR) and many Babesia species. Within this genus, different R. sanguineus s.l. lineages show an unequal vector competence and resistance regarding some pathogenic strains. Current literature supports that tick endosymbionts may play an essential role in the transmission ability of a vector. Indeed, the microbial community of Rhipicephalus seems to be dominated by Coxiella-like endosymbionts (CLE). Still, their co-evolutionary associations with the complicated phylogeny of Rhipicephalus lineages and their transmissible pathogens remain unclear. We performed a phylogenetic congruence analysis to address whether divergent R. sanguineus s.l. lineages had a different symbiont composition. For that, we applied a PCR based approach to screen part of the microbial community present in 279 Rhipicephalus ticks from the Iberian Peninsula and Africa. Our analyses detected several qPCR-positive signals for both SFGR and Babesia species, of which we suggest R. sanguineus-tropical lineage as a natural vector of Babesia vogeli and R. sanguineus-temperate lineage of SFGR. The acquisition of 190 CLE sequences allowed to evaluate co-phylogenetic associations between the tick and the symbiont. With this data, we observed a strong but incomplete co-cladogenesis between CLE strains and their Rhipicephalus tick lineages hosts.

Dermacentor reticulatus and Babesia canis in Bavaria (Germany)-A Georeferenced Field Study with Digital Habitat Characterization

The hard tick Dermacentor reticulatus transmits Babesia canis, the causative agent of canine babesiosis. Both the occurrence and local distribution of D. reticulatus as well as infection rates of questing ticks with B. canis are thus far poorly known in Bavaria, Germany. The objectives of this study were to conduct (1) a georeferenced field study on the occurrence of D. reticulatus with digital habitat characterization and (2) a PCR analysis of D. reticulatus collected in Bavaria for infection with B. canis. Dermacentor reticulatus were collected by flagging at 60 sites specifically selected according to habitat conditions and screened individually for Babesia DNA. A digital habitat characterization for D. reticulatus was performed according to results of the field analysis including the parameters land use, proximity to water, “potential natural vegetation”, red deer corridors and climate data. Altogether, 339 D. reticulatus ticks (214 females and 125 males) were collected between 2010 and 2013 at 12 out of 60 sampling sites. All 12 sites were characterized by high humidity with marshy areas. Babesia canis DNA was detected in 1 out of 301 (0.3%) questing D. reticulatus in Bavaria. The digital habitat characterization revealed 15 forest areas in Bavaria with similar ecological characteristics as the sites positive for D. reticulatus.

Prevalence of pathogens in ticks collected from humans through citizen science in Belgium

BACKGROUND

In order to evaluate the risk of human exposure to tick-borne pathogens in Belgium, a study on the prevalence of several pathogens was conducted on feeding ticks removed from humans in 2017.

METHODS

Using a citizen science approach based on an existing notification tool for tick bites, a sample of ticks was collected across the country. Collected ticks were screened by PCR for the presence of the following pathogens: Anaplasma phagocytophilum, Babesia spp., Borrelia burgdorferi (sensu lato), Borrelia miyamotoi, Neoehrlichia mikurensis, Rickettsia helvetica and tick-borne encephalitis virus (TBEV).

RESULTS

In total, 1599 ticks were included in the sample. The great majority of ticks belonged to Ixodes ricinus (99%); other tick species were identified as Ixodes hexagonus (0.7%) and Dermacentor reticulatus (0.3%). Borrelia burgdorferi (s.l.) was detected in 14% of nymphs and adult ticks. Adult ticks (20%) were more likely to be infected than nymphs (12%). The most common genospecies were B. afzelii (52%) and B. garinii (21%). Except for TBEV, the other tick-borne pathogens studied were all detected in the tick sample, although at a lower prevalence: 1.5% for Babesia spp.; 1.8% for A. phagocytophilum; 2.4% for B. miyamotoi; 2.8% for N. mikurensis; and 6.8% for R. helvetica. Rickettsia raoultii, the causative agent of tick-borne lymphadenopathy, was identified for the first time in Belgium, in two out of five D. reticulatus ticks. Co-infections were found in 3.9% of the examined ticks. The most common co-infection was B. burgdorferi (s.l.) + N. mikurensis.

CONCLUSIONS

Although for most of the tick-borne diseases in Belgium, other than Lyme borreliosis, no or few cases of human infection are reported, the pathogens causing these diseases were all (except for TBEV) detected in the tick study sample. Their confirmed presence can help raise awareness among citizens and health professionals in Belgium on possible diseases other than Lyme borreliosis in patients presenting fever or other non-characteristic symptoms after a tick bite.

Active neuroborreliosis or inflammation: are the diagnostic guidelines at stake?

Neuroborreliosis can induce a variety of neurological syndromes: e.g., cranial neuritis, plexitis, radiculitis, meningitis, cerebellitis, … We report on five cases of patients with a diagnosis of neuroborreliosis based on clinical symptoms, serologic tests and MR imaging results. However, neither of them fulfils the diagnostic criteria for definite neuroborreliosis. Are the diagnostic criteria still valid or is there a need to revise them? Is our diagnosis correct? Are these cases post-Lyme auto-immune neuronal inflammation, and not due to still active spirochetal infection? Do we need to consider immunosuppressive therapy instead of third-generation cephalosporins?

A framework for adaptive surveillance of emerging tick-borne zoonoses

Significant global ecological changes continue to drive emergence of tick-borne zoonoses around the world. This poses an important threat to both human and animal health, and highlights the need for surveillance systems that are capable of monitoring these complex diseases effectively across different stages of the emergence process. Our objective was to develop an evidence-based framework for surveillance of emerging tick-borne zoonoses. We conducted a realist review to understand the available approaches and major challenges associated with surveillance of emerging tick-borne zoonoses. Lyme disease, with a specific focus on emergence in Canada, was used as a case study to provide real-world context, since the process of disease emergence is ongoing in this country. We synthesize the results to propose a novel framework for adaptive surveillance of emerging tick-borne zoonoses. Goals for each phase of disease emergence are highlighted and approaches are suggested. The framework emphasizes the needs for surveillance systems to be inclusive, standardized, comprehensive and sustainable. We build upon a growing body of infectious disease literature that is advocating for reform to surveillance systems. Although our framework has been developed for tick-borne zoonoses, it is flexible and has the potential to be applied to a variety of other vector-borne and zoonotic diseases.

Ixodes frontalis: a neglected but ubiquitous tick species in Germany

The ornithophilic tick species Ixodes frontalis (Panzer) is spatially distributed in Europe, Asia and northern Africa. It can serve as a carrier of different bacteria and viruses, but little is known of its actual vector competence. In addition, adult females of this species are associated with the avian "tick-related syndrome" (TRS). Like most ornithophilic tick species, I. frontalis is usually collected from bird nests or directly from their hosts. Reports of I. frontalis being collected with the flagging method are scarce. In Germany, the species is considered as very rare. In the few reports that are available, the majority of ticks has been discovered on migrating birds. Therefore, knowledge of the actual distribution of this species in Germany was strictly limited. In this study, we report the finding of 1084 individuals of I. frontalis collected with the flagging method in urban areas and gardens in several regions of Germany. Furthermore, the species was discovered on 35 dead Eurasian blackbirds (Turdus merula) from all over Germany. Finally, we report of five new possible cases of TRS, three in free-ranging birds and two in captive birds, including a Harris's hawk (Parabuteo unicinctus) kept for falconry.

Factors affecting abundance of different stages of the endophilic tick Ixodes anatis in brown kiwi (Apteryx mantelli) shelters

Ixodes anatis is a species of endophilic (nidicolous) tick species parasitizing brown kiwi (Apteryx mantelli). Even though they are endemic to New Zealand like their host, very little is known about these ticks or their population dynamics and relationships with their hosts. We conducted a study from May 2013 to June 2014 to evaluate the effect of shelter location (one of three gullies), habitat (forest, scrub and pasture) and type (tree, soil and surface) on the abundance of the different life stages of I. anatis. In total, 12,172 ticks were collected from 63 shelters, which were sampled monthly for 11 months over the 14 month period. Un-engorged larvae predominated over other stages accounting for 87.2% of the samples collected. We found that location, habitat in which the shelters were located, and the type of shelter were significant predictors of I. anatis abundance. Tree shelters in forests had significantly higher tick abundance than those in scrub and pasture. Tree and soil shelters in general had significantly more ticks than surface shelters. Shelters located in Kauri Bush a drier site, had higher abundances than those in wetter sites. While some of these changes can be explained with the movement of the host, we believe more research needs to be done on the effect of shelters' microclimate on I. anatis' life cycle.

Annotated List of the Hard Ticks (Acari: Ixodida: Ixodidae) of New Jersey

Standardized tick surveillance requires an understanding of which species may be present. After a thorough review of the scientific literature, as well as government documents, and careful evaluation of existing accessioned tick collections (vouchers) in museums and other repositories, we have determined that the verifiable hard tick fauna of New Jersey (NJ) currently comprises 11 species. Nine are indigenous to North America and two are invasive, including the recently identified Asian longhorned tick, Haemaphysalis longicornis (Neumann, 1901). For each of the 11 species, we summarize NJ collection details and review their known public health and veterinary importance and available information on seasonality. Separately considered are seven additional species that may be present in the state or become established in the future but whose presence is not currently confirmed with NJ vouchers. We compare our list of hard ticks in NJ with those from neighboring states (Connecticut, New York, Pennsylvania, Delaware, and Maryland), discuss the importance of vouchers in tick research and surveillance, and examine the likelihood and public health consequences of additional hard tick species becoming established in NJ.

Repeated isolation of tick-borne encephalitis virus from adult Dermacentor reticulatus ticks in an endemic area in Germany

Background

Tick-borne encephalitis (TBE) virus is transmitted to humans and animals through tick bites and is thought to circulate in very strictly defined natural environments called natural foci. The most common tick serving as a vector for the TBE virus in central Europe is Ixodes ricinus; it is rarely found in other tick species and in Dermacentor reticulatus it has, so far, only been reported in Poland.

Methods

Between autumn 2016 and spring 2018 ticks were collected by the flagging method in a new TBE focus in the district of northern Saxony, Germany, outside the known risk areas as defined by the national Robert Koch Institute. Ticks were morphologically identified and tested in pools for the presence of TBE virus using a real-time RT-PCR. TBE virus from positive pools was isolated in A549 cells, and the E gene sequences were determined after conventional RT-PCR, followed by a phylogenetic comparison.

Results

TBE virus was detected in 11 pools, 9 times in flagged adults D. reticulatus (n = 1534; MIR: 0.59%, CI: 0.29–11.3%) and only twice in I. ricinus nymphs (n = 349; MIR: 0.57%, CI: 0.02–2.2%). All other ticks, I. ricinus males (n = 33), females (n = 30) and larvae (n = 58), as well as 5 I. inopinatus (2 females, 3 males) and 14 Haemaphysalis concinna (3 females, 11 nymphs), tested negative for TBE virus. TBE virus was not detected in I. ricinus during the summer, when D. reticulatus is not active. Sequence comparison of the entire E gene of the isolated virus strains resembled each other with only 3 nucleotide differences. The most closely related viral sequences belong to TBE virus strains from Poland and Neustadt an der Waldnaab (county of Neustadt an der Waldnaab, Bavaria), approximately 200 km east and 200 km south-west of the new focus, respectively.

Conclusions

TBE virus was found in northern Saxony, Germany, with similar MIRs in D. reticulatus and I. ricinus, indicating that D. reticulatus plays an equal role to I. ricinus in virus circulation when both tick species are sympatric.

Seroprevalence of Borrelia burgdorferi in Belgian forestry workers and associated risk factors

Background

As forest is the preferred environment for ticks, forestry workers are exposed to tick bites and tick-borne diseases. We assessed the seroprevalence of anti-Borrelia burgdorferi (Bb) antibodies and investigated, using an integrated landscape approach, the individual and environmental factors associated with the seroprevalence of Bb in Belgian forestry workers, a high-risk group in Belgium.

Methods

A group of 310 Belgian forest workers was examined to assess the seroprevalence of anti-Borrelia IgG antibodies. Using principal component analysis and binary logistic regression, the joint effects of individual characteristics and environmental characteristics were examined.

Results

Sixty-seven of the 310 workers were seropositive for Lyme disease (LD), leading to a seroprevalence of 21.6%. The seroprevalence was higher among forest workers visiting forests more frequently (P = 0.003) or who reported over 100 tick bites (P-value < 0.001). The intensity of tick bites and the use of protection measures against tick bites have a positive impact on LD seroprevalence while the quantity of shadow from trees at ground level had a negative one.

Conclusions

This study showed that forest workers are a population at risk for LD and, by extension, at risk for various tick-borne diseases. In addition to the role of the environment, our results also showed the importance of considering exposure when predicting the risk of infection by Bb.

Individual and environmental factors associated with the seroprevalence of Borrelia burgdorferi in Belgian farmers and veterinarians

BACKGROUND

Lyme disease (LD) is a common tick-borne disease in Europe. Diverse factors at various scales determine the spatial distribution of Borrelia burgdorferi infection risk and a better understanding of those factors in a spatially explicit framework is needed for disease management and prevention. While the ecology of ticks and the landscape favoring their abundance have been extensively studied, the environmental conditions favoring an intense contact with susceptible humans, including groups at risk, are sparse. The aim of this study is to assess which individual and environmental factors can favor B. burgdorferi infection in a Belgian group professionally at risk.

METHODS

Serological results of 127 veterinarians and farmers enrolled in this study were analyzed, taking into account their municipality of residence. Using binary logistic regression and considering interaction terms, the joint effects of landscape composition and configuration, and forest and wildlife management were examined.

RESULTS

Seven of the 127 workers were seropositive for LD, leading to a seroprevalence of 5.51%. Seropositivity was higher in older persons. The proportion of forest and semi-natural habitats and wetland had a positive impact on LD seroprevalence while arable land-grassland ecotones had a negative one. Our results confirmed the need to consider complex interactions between landscape variables in order to model risk.

CONCLUSIONS

Our data show that LD has to be considered as a risk for farmers and veterinarians. Rather than focusing either on ecological aspects of tick and pathogen distribution or on purely epidemiological aspects such as individual risk factors, our model highlights the role of human-environment interactions in LD risk assessment.

Novel Rickettsia and emergent tick-borne pathogens: A molecular survey of ticks and tick-borne pathogens in Shimba Hills National Reserve, Kenya

Ticks are important vectors of emerging and re-emerging zoonoses, the majority of which originate from wildlife. In recent times, this has become a global public health concern that necessitates surveillance of both known and unknown tick-borne pathogens likely to be future disease threats, as well as their tick vectors. We carried out a survey of the diversity of ticks and tick-borne pathogens in Kenya's Shimba Hills National Reserve (SHNR), an area with intensified human-livestock-wildlife interactions, where we collected 4297 questing ticks (209 adult ticks, 586 nymphs and 3502 larvae). We identified four tick species of two genera (Amblyomma eburneum, Amblyomma tholloni, Rhipicephalus maculatus and a novel Rhipicephalus sp.) based on both morphological characteristics and molecular analysis of 16S rRNA, internal transcribed spacer 2 (ITS 2) and cytochrome oxidase subunit 1 (CO1) genes. We pooled the ticks (3-8 adults, 8-15 nymphs or 30 larvae) depending on species and life-cycle stages, and screened for bacterial, arboviral and protozoal pathogens using PCR with high-resolution melting analysis and sequencing of unique melt profiles. We report the first molecular detection of Anaplasma phagocytophilum, a novel Rickettsia-like and Ehrlichia-like species, in Rh. maculatus ticks. We also detected Ehrlichia chaffeensis, Coxiella sp., Rickettsia africae and Theileria velifera in Am. eburneum ticks for the first time. Our findings demonstrate previously unidentified tick-pathogen relationships and a unique tick diversity in the SHNR that may contribute to livestock, and possibly human, morbidity in the region. This study highlights the importance of routine surveillance in similar areas to elucidate disease transmission dynamics, as a critical component to inform the development of better tick-borne disease diagnosis, prevention and control measures.

Relative density of host-seeking ticks in different habitat types of south-western Slovakia

Ixodes ricinus is a vector of microbial pathogens of medical and veterinary importance in Europe. Recently, increasing abundance of ticks has been observed in urban and suburban areas. The aim of this study was to investigate the tick species composition and examine correlations between local environmental variables and the relative density of host-seeking I. ricinus in two habitat types. Questing ticks were collected along six 100 m(2) transects in urban/suburban locations of Bratislava town, and in a non-fragmented deciduous forest in the Small Carpathians Mountains (south-western Slovakia) during 2011-2013. In total, 6015 I. ricinus were collected (3435 and 2580 in the urban/suburban and natural habitat, respectively), out of which over 80 % were nymphs. Haemaphysalis concinna comprised 1.3 % of the tick collections. Peak I. ricinus nymph and adult host-seeking activities were registered in April-June. Spatial and temporal variation in tick relative density and differences in the subadult/adult ratio were observed between habitats and between locations within the same habitat type. The relative density of questing I. ricinus nymphs correlated negatively with altitude, geographical aspect and saturation deficit in a 64-day period comprising the 8-day period including the date of tick sampling and previous 56 days. No significant correlation was found between roe deer density and questing nymph density. The study revealed the presence of abundant I. ricinus populations in green areas of Bratislava, suggesting a risk of exposure of town dwellers and domestic and companion animals to potentially infected ticks.

Dermacentor reticulatus: a vector on the rise

Dermacentor reticulatus is a hard tick species with extraordinary biological features. It has a high reproduction rate, a rapid developmental cycle, and is also able to overcome years of unfavourable conditions. Dermacentor reticulatus can survive under water for several months and is cold-hardy even compared to other tick species. It has a wide host range: over 60 different wild and domesticated hosts are known for the three active developmental stages. Its high adaptiveness gives an edge to this tick species as shown by new data on the emergence and establishment of D. reticulatus populations throughout Europe. The tick has been the research focus of a growing number of scientists, physicians and veterinarians. Within the Web of Science database, more than a fifth of the over 700 items published on this species between 1897 and 2015 appeared in the last three years (2013–2015). Here we attempt to synthesize current knowledge on the systematics, ecology, geographical distribution and recent spread of the species and to highlight the great spectrum of possible veterinary and public health threats it poses. Canine babesiosis caused by Babesia canis is a severe leading canine vector-borne disease in many endemic areas. Although less frequently than Ixodes ricinus, D. reticulatus adults bite humans and transmit several Rickettsia spp., Omsk haemorrhagic fever virus or Tick-borne encephalitis virus. We have not solely collected and reviewed the latest and fundamental scientific papers available in primary databases but also widened our scope to books, theses, conference papers and specialists colleagues’ experience where needed. Besides the dominant literature available in English, we also tried to access scientific literature in German, Russian and eastern European languages as well. We hope to inspire future research projects that are necessary to understand the basic life-cycle and ecology of this vector in order to understand and prevent disease threats. We conclude that although great strides have been made in our knowledge of the eco-epidemiology of this species, several gaps still need to be filled with basic research, targeting possible reservoir and vector roles and the key factors resulting in the observed geographical spread of D. reticulatus.

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

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

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

Detection of Bartonella tamiae, Coxiella burnetii and rickettsiae in arthropods and tissues from wild and domestic animals in northeastern Algeria

Background

In recent years, the scope and importance of emergent vector-borne diseases has increased dramatically. In Algeria, only limited information is currently available concerning the presence and prevalence of these zoonotic diseases. For this reason, we conducted a survey of hematophagous ectoparasites of domestic mammals and/or spleens of wild animals in El Tarf and Souk Ahras, Algeria.

Methods

Using real-time PCR, standard PCR and sequencing, the presence of Bartonella spp., Rickettsia spp., Borrelia spp. and Coxiella burnetii was evaluated in 268/1626 ticks, 136 fleas, 11 Nycteribiidae flies and 16 spleens of domestic and/or wild animals from the El Tarf and Souk Ahras areas.

Results

For the first time in Algeria, Bartonella tamiae was detected in 12/19 (63.2 %) Ixodes vespertilionis ticks, 8/11 (72.7 %) Nycteribiidae spp. flies and in 6/10 (60 %) bat spleens (Chiroptera spp.). DNA from Coxiella burnetii, the agent of Q fever, was also identified in 3/19 (15.8 %) I. vespertilionis from bats. Rickettsia slovaca, the agent of tick-borne lymphadenopathy, was detected in 1/1 (100 %) Haemaphysalis punctata and 2/3 (66.7 %) Dermacentor marginatus ticks collected from two boars (Sus scrofa algira) respectively. Ri. massiliae, an agent of spotted fever, was detected in 38/94 (40.4 %) Rhipicephalus sanguineus sensu lato collected from cattle, sheep, dogs, boars and jackals. DNA of Ri. aeschlimannii was detected in 6/20 (30 %) Hyalomma anatolicum excavatum and 6/20 (30 %) Hy. scupense from cattle. Finally, Ri. felis, an emerging rickettsial pathogen, was detected in 80/110 (72.7 %) Archaeopsylla erinacei and 2/2 (100 %) Ctenocephalides felis of hedgehogs (Atelerix algirus).

Conclusion

In this study, we expanded knowledge about the repertoire of ticks and flea-borne bacteria present in ectoparasites and/or tissues of domestic and wild animals in Algeria.

Geographical distribution of Dermacentor marginatus and Dermacentor reticulatus in Europe

The goal of this paper is to present up-to-date maps depicting the geographical distribution of Dermacentor species in Europe based on georeferenced sampling sites. Therefore, a dataset was compiled, resulting in 1286 D. marginatus (Sulzer, 1776) and 1209 D. reticulatus (Fabricius, 1794) locations. Special emphasis is given to the region of the European Alps depicting a presumable climate barrier of the mountains and to overlaps in the distribution of both species as well as on the situation in eastern European countries. For the latter newly described Dermacentor findings comprise 59 locations in Romania and 62 locations in Ukraine. The geographical distributions of both species in Europe range from Portugal to Ukraine (and continue to the east of Kazakhstan). Although it is well known that D. marginatus is adapted to a warmer and drier climate at more southern latitudes and D. reticulatus to a moderately moist climate at more northern latitudes, the distribution limits of both species were not well known. Here, the northern and southern distribution limits for both species in Europe, as determined from the georeferenced database, were specified for D. marginatus by the belt of 33-51° N latitude and for D. reticulatus by the belt of 41-57° N latitude. Thus, overlapping species distributions were found between 41° N and 51° N.

The Assessment of African Swine Fever Virus Risk to Belgium Early 2014, using the Quick and Semiquantitative Pandora Screening Protocol

A risk assessment was organized during the early EU ASF outbreaks of early 2014 (February-April) and performed in cooperation with 15 Belgian and European experts on ASFV and its epidemiology in pigs/wild boar. African swine fever (ASF) is considered as one of the most dangerous infectious pig diseases, causing many outbreaks. Since the end of 2013 - early 2014, several outbreaks within the European Union (Lithuania, Poland, Estonia and Latvia) were reported to OIE, which prompted several risk assessments by (inter)national bodies and scientists. In this study, the open source, semiquantitative Pandora risk assessment tool was used for a quick overall screening of the risk posed by ASF to Belgium early 2014. A set of integrated risk scores was calculated within the Pandora framework. Experts scored the questions and uncertainty levels in the Pandora modules individually, after which the calculations were performed and averaged scores were used within pre-defined risk scales to define and visualize the ASF risk to Belgium. Emergence risk was considered low (Pandora score 0.29), while disease consequences were deemed high (0.93); the resulting multiplicative overall risk of ASFV for Belgium was low (0.27). The Belgian experts tended to give lower risk scores than the European experts, especially for entry risk and trade/public opinion consequences. These risk scores are further interpreted with a due consideration of the qualitative data in the expert remarks and of other ASF risk assessments. The results are similar to more extensive and elaborate risk assessment models/procedures which may require more time and resources. The Pandora tool allows sequential updates to monitor (rates of) increasing risk and provides information for risk managers to organize targeted control.

Challenges posed by tick-borne rickettsiae: eco-epidemiology and public health implications

Rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variety of arthropod vectors, primarily by fleas and ticks. Once transmitted or experimentally inoculated into susceptible mammals, some rickettsiae may cause febrile illness of different morbidity and mortality, and which can manifest with different types of exhanthems in humans. However, most rickettsiae circulate in diverse sylvatic or peridomestic reservoirs without having obvious impacts on their vertebrate hosts or affecting humans. We have analyzed the key features of tick-borne maintenance of rickettsiae, which may provide a deeper basis for understanding those complex invertebrate interactions and strategies that have permitted survival and circulation of divergent rickettsiae in nature. Rickettsiae are found in association with a wide range of hard and soft ticks, which feed on very different species of large and small animals. Maintenance of rickettsiae in these vector systems is driven by both vertical and horizontal transmission strategies, but some species of Rickettsia are also known to cause detrimental effects on their arthropod vectors. Contrary to common belief, the role of vertebrate animal hosts in maintenance of rickettsiae is very incompletely understood. Some clearly play only the essential role of providing a blood meal to the tick while other hosts may supply crucial supplemental functions for effective agent transmission by the vectors. This review summarizes the importance of some recent findings with known and new vectors that afford an improved understanding of the eco-epidemiology of rickettsiae; the public health implications of that information for rickettsial diseases are also described. Special attention is paid to the co-circulation of different species and genotypes of rickettsiae within the same endemic areas and how these observations may influence, correctly or incorrectly, trends, and conclusions drawn from the surveillance of rickettsial diseases in humans.

The first German map of georeferenced ixodid tick locations

BACKGROUND

Georeferenced locations of ixodid ticks are required to depict the observed distribution of species. Further, they are used as input data for species distribution models also known as niche models. The latter were applied to describe current and future (projected) tick distributions. Beside model assumptions and selected climate parameters, the number of georeferenced tick locations available as a digital dataset is of fundamental importance for the reliability of such models. For Germany, however, no comprehensive dataset of ixodid tick species exists. The goal of this study was to put together all the available information on ixodid tick locations in Germany to produce such a digital dataset and to visualize it in a map.

FINDINGS

A total of 2,044 georeferenced locations of ixodid ticks in Germany were compiled from two existing datasets (altogether 993 locations) and an extensive literature study (1,051 locations). The resulting digital dataset comprises the following tick species: Ixodes ricinus (1,855 locations), Ixodes apronophorus (1), Ixodes frontalis (1), Ixodes hexagonus (1), Ixodes trianguliceps (4), Dermacentor marginatus (77), Dermacentor reticulatus (96), Haemaphysalis concinna (8) and Hyalomma marginatum (1). The data were used to draw a tick map for Germany, showing I. ricinus occurring in the whole federal territory, while D. marginatus has been restricted to the climatically favoured region of the Rhine valley. Clustered locations of D. reticulatus were also documented in the Rhine valley as well as in Berlin and its vicinity.

CONCLUSIONS

The introduced map depicts for the first time the available geographical coordinates of ixodid tick locations in Germany. The digital dataset used to draw the map is provided to the scientific community as a basis for further investigations such as species distribution modelling.

Immediate efficacy and persistent speed of kill of a novel oral formulation of afoxolaner (NexGardTM) against induced infestations with Ixodes ricinus ticks

Background

Ticks are hematophageous arthropods that transmit a wide spectrum of pathogens to human and animals. The ability of an acaricidal product to kill ticks quickly provides an important added benefit, especially as protecting dogs from tick bites remains the best preventive measure against tick-borne diseases. The speed of kill of afoxolaner in a novel soft chewable formulation (NexGard^TM) against induced infestations with Ixodes ricinus adult ticks was evaluated during a full-month negative controlled and blinded study following a single oral administration.

Methods

12 healthy beagle dogs were included and randomly allocated to 2 groups of six dogs each. One Group was a negative control while the other group was treated with an oral formulation of afoxolaner on Day 0. Tick infestations with 40 (±5) female and 10 male adult unfed I. ricinus were performed on Days -1, 7, 14, 21 and 28. To evaluate immediate efficacy, the number of live ticks were thumb counted at 12 and 24 hours post treatment. To evaluate the persistent speed of kill following further infestations, ticks were thumb counted 12 and 24 hours post infestations. Ticks were removed 24 hours post treatment or infestation.

Results

Afoxolaner starts to kill the pre-existing tick infestations rapidly with an immediate efficacy of 93.4% and 100% respectively at 12 h and 24 h post treatment. The persistent speed of kill of afoxolaner was significant (p < 0,05), as compared with untreated controls, at 12 hours after infestations at D7 and D21. Efficacy at 12 h was 76.6%, 41.9%, 36.9% and 38.5% at D7, D14, D21 and D28 respectively. Efficacy at 24 h ranged from 91% to 100% for the entire month.

Conclusions

This study demonstrated that besides the excellent acaricidal efficacy of afoxolaner after single oral administration, the product has a rapid speed of kill against one of the most important European tick species and controlled the weekly re-infestations for 28 days post treatment.

Human tick infestation pattern, tick-bite rate, and associated Borrelia burgdorferi s.l. infection risk during occupational tick exposure at the Seedorf military training area, northwestern Germany

The human tick infestation pattern, tick bite rate, and associated Borrelia burgdorferi s.l.-infection risk were investigated during occupational tick exposure of military personnel at the Seedorf military training area, northwestern Germany, from January to December 2009. Borrelia burgdorferi s.l. seroconversion rates were monitored from April to September 2009. Continuous occupational health surveillance and education were established. Feeding ticks were mostly removed by medical personnel, transferred to 70% ethanol, identified, and tested for B. burgdorferi s.l. Pre- and post-exposure sera were screened for B. burgdorferi s.l. antibodies. A total of 710 feeding ticks was removed, 704 (99.2%) of which were I. ricinus, 5 were I. hexagonus (0.7%), and one was H. concinna (0.1%). Of the I. ricinus specimens, 63.9% were nymphs, 24.7% larvae, 10.9% adult females, and 0.5% adult males. The tick bite rate among occupationally exposed personnel was 42.2% from April to September 2009. Up to 18 simultaneously feeding ticks per person per exposure incident were detected. The mean number of attached ticks was 2.0±2.2 per person per exposure incident. Overall, 86.4% of all feeding ticks were removed from patients within less than 24h after attachment. Borrelia burgdorferi s.l. DNA could be detected in 3.5% of larval, 4.4% of nymphal, 13% of adult female, and 33.3% of adult male ticks, indicating a mean prevalence of 5.3%. Among the genospecies detected, B. afzelii accounted for 84%, B. burgdorferi s.s. for 11%, B. garinii for 3%, and B. spielmanii for 3%. The overall seroconversion rate in 566 personnel exposed from April to September was 1.7%, and 0.7% acquired clinical Lyme borreliosis. Experiences reported herein indicate the need to further improve personal protection measures, health education, and medical staff training in order to minimize exposure to ticks and optimize diagnosis of tick-borne diseases.