The role of the sand lizard (Lacerta agilis) in the transmission cycle of Borrelia burgdorferi sensu lato

Bacterial pathogens in Ixodes ricinus collected from lizards Lacerta agilis and Zootoca vivipara in urban areas of Wrocław, SW Poland- preliminary study

The aim of this study was to determine the level of infection of Ixodes ricinus ticks with pathogens (Borrelia spp., Rickettsia spp., and Anaplasma spp.) collected from Lacerta agilis and Zootoca vivipara lizards in the urban areas of Wrocław (SW Poland). The study was carried out in July-August 2020. Lizards were caught by a noose attached to a pole or by bare hands, identified by species, and examined for the presence of ticks. Each lizard was then released at the site of capture. Ticks were removed with tweezers, identified by species using keys, and molecular tests were performed for the presence of pathogens. From 28 lizards (17 specimens of Z. vivipara and 11 specimens of L. agilis) a total of 445 ticks, including 321 larvae and 124 nymphs, identified as I. ricinus were collected. A larger number of ticks were obtained from L. agilis compared to Z. vivipara. Molecular tests for the presence of pathogens were performed on 445 specimens of I. ricinus. The nested PCR method for the fla gene allowed the detection of Borrelia spp. in 9.4% of ticks, and it was higher in ticks from L. agilis (12.0%) than from Z. vivipara (1.0%). The RFLP method showed the presence of three species, including two belonging to the B. burgdorferi s.l. complex (B. lusitaniae and B. afzelii), and B. miyamotoi. The overall level of infection of Rickettsia spp. was 19.3%, including 27.2% in ticks collected from Z. vivipara and 17.0% from L. agilis. Sequencing of randomly selected samples confirmed the presence of R. helvetica. DNA of Anaplasma spp. was detected only in one pool of larvae collected from L. agilis, and sample sequencing confirmed the presence of (A) phagocytophilum. The research results indicate the important role of lizards as hosts of ticks and their role in maintaining pathogens in the environment including urban agglomeration as evidenced by the first recorded presence of (B) miyamotoi and (A) phagocytophilum in I. ricinus ticks collected from L. agilis. However, confirmation of the role of sand lizards in maintaining (B) miyamotoi and A. phagocytophilum requires more studies and sampling of lizard tissue.

The role of wildlife in the epidemiology of tick-borne diseases in Slovakia

Tick-borne diseases (TBD) represent an important challenge for human and veterinary medicine. In Slovakia, studies on the epidemiology of tick-borne pathogens (TBP) regarding reservoir hosts have focused on small mammals and to a lesser extent on birds or lizards, while knowledge of the role of the remaining vertebrate groups is limited. Generally, wild ungulates, hedgehogs, small- and medium-sized carnivores, or squirrels are important feeding hosts for ticks and serve as reservoirs for TBP. Importantly, because they carry infected ticks and/or are serologically positive, they can be used as sentinels to monitor the presence of ticks and TBP in the environment. With their increasing occurrence in urban and suburban habitats, wild ungulates, hedgehogs or foxes are becoming an important component in the developmental cycle of Ixodes ricinus and of TBP such as Anaplasma phagocytophilum or Babesia spp. On the other hand, it has been postulated that cervids may act as dilution hosts for Borrelia burgdorferi (sensu lato) and tick-borne encephalitis virus. In southwestern Slovakia, a high prevalence of infection with Theileria spp. (100%) was observed in some cervid populations, while A. phagocytophilum (prevalence of c.50%) was detected in cervids and wild boars. The following pathogens were detected in ticks feeding on free-ranging ungulates, birds, and hedgehogs: A. phagocytophilum, Rickettsia spp., Coxiella burnetii, Neoehrlichia mikurensis, B. burgdorferi (s.l.), and Babesia spp. The growing understanding of the role of wildlife as pathogen reservoirs and carriers of pathogen-infected ticks offers valuable insights into the epidemiology of TBP, providing a foundation for reducing the risk of TBD.

First isolation of Borrelia lusitaniae DNA from green lizards (Lacerta viridis) and Ixodes ricinus ticks in the Czech Republic

This study aimed to reveal whether green lizards (Lacerta viridis), common hosts of tick larvae and nymphs, might be involved in the transmission cycle of Borrelia burgdorferi sensu lato in the Czech Republic. Green lizards were sampled in two areas at the Tiché Údolí Nature Reserve (site A: 50.1482 N, 14.3669E; site B: 50.1476 N, 14.3745 E), Central Bohemian Region, Czech Republic. The skin biopsy specimens and attached ticks (if any) were collected from 52 captured lizards. Also, questing ticks from both areas were collected by flagging. The touchdown polymerase chain reaction and gel electrophoresis revealed Borrelia lusitaniae in three lizard tissue samples. Most lizards (19/30, 63%) had at least one Borrelia positive tick. Borrelia lusitaniae formed 92% (34/37) and 59% (17/29) of all borreliae detected in larvae and nymphs, respectively. Borrelia lusitaniae (6/10, 60%) was also the major pathogen in questing nymphs from site B. At site A, 13% (2/16) of questing nymphs were positive for B. lusitaniae. Based on our data, it can be assumed that B. lusitaniae is a common pathogen at lizard sites in the Czech Republic, and further research to prove this hypothesis is therefore highly recommended. As lizards often inhabit urban areas, the data presented may also contribute to raising awareness of the possible spread and risk of Borrelia infection.

Reptile vector-borne diseases of zoonotic concern

Reptile vector-borne diseases (RVBDs) of zoonotic concern are caused by bacteria, protozoa and viruses transmitted by arthropod vectors, which belong to the subclass Acarina (mites and ticks) and the order Diptera (mosquitoes, sand flies and tsetse flies). The phyletic age of reptiles since their origin in the late Carboniferous, has favored vectors and pathogens to co-evolve through millions of years, bridging to the present host-vector-pathogen interactions. The origin of vector-borne diseases is dated to the early cretaceous with Trypanosomatidae species in extinct sand flies, ancestral of modern protozoan hemoparasites of zoonotic concern (e.g., Leishmania and Trypanosoma) associated to reptiles. Bacterial RVBDs are represented by microorganisms also affecting mammals of the genera Aeromonas, Anaplasma, Borrelia, Coxiella, Ehrlichia and Rickettsia, most of them having reptilian clades. Finally, reptiles may play an important role as reservoirs of arborivuses, given the low host specificity of anthropophilic mosquitoes and sand flies. In this review, vector-borne pathogens of zoonotic concern from reptiles are discussed, as well as the interactions between reptiles, arthropod vectors and the zoonotic pathogens they may transmit.

Investigation of Tick-Borne Pathogens in Ixodes ricinus in a Peri-Urban Park in Lombardy (Italy) Reveals the Presence of Emerging Pathogens

Ticks are important vectors of a great range of pathogens of medical and veterinary importance. Lately, the spread of known tick-borne pathogens has been expanding, and novel ones have been identified as (re)emerging health threats. Updating the current knowledge on tick-borne pathogens in areas where humans and animals can be easily exposed to ticks represents a starting point for epidemiological studies and public awareness. A PCR screening for tick-borne pathogens was carried out in Ixodes ricinus ticks collected in a peri-urban recreational park in Ticino Valley, Italy. The presence of Rickettsia spp., Borrelia burgdorferi senso latu complex, Anaplasma spp. and Babesia spp. was evaluated in a total of 415 I. ricinus specimens. Rickettsia spp. (R monacensis and R. helvetica) were detected in 22.96% of the samples, while B. burgdorferi s.l. complex (B. afzelii and B. lusitaniae) were present in 10.94%. Neoehrlichia mikurensis (1.99%) and Babesia venatorum (0.73%) were reported in the area of study for the first time. This study confirmed the presence of endemic tick-borne pathogens and highlighted the presence of emerging pathogens that should be monitored especially in relation to fragile patients, the difficult diagnosis of tick-borne associated diseases and possible interactions with other tick-borne pathogens.

General Microbiota of the Soft Tick Ornithodoros turicata Parasitizing the Bolson Tortoise (Gopherus flavomarginatus) in the Mapimi Biosphere Reserve, Mexico

The general bacterial microbiota of the soft tick Ornithodoros turicata found on Bolson tortoises (Gopherus flavomarginatus) were analyzed using next generation sequencing. The main aims of the study were to establish the relative abundance of bacterial taxa in the tick, and to document the presence of potentially pathogenic species for this tortoise, other animals, and humans. The study was carried-out in the Mapimi Biosphere Reserve in the northern-arid part of Mexico. Bolson tortoises (n = 45) were inspected for the presence of soft ticks, from which 11 tortoises (24.4%) had ticks in low loads (1–3 ticks per individual). Tick pools (five adult ticks each) were analyzed through 16S rRNA V3–V4 region amplification in a MiSeq Illumina, using EzBioCloud as a taxonomical reference. The operational taxonomic units (OTUs) revealed 28 phyla, 84 classes, 165 orders, 342 families, 1013 genera, and 1326 species. The high number of taxa registered for O. turicata may be the result of the variety of hosts that this tick parasitizes as they live inside G. flavomarginatus burrows. While the most abundant phyla were Proteobacteria, Actinobacteria, and Firmicutes, the most abundant species were two endosymbionts of ticks (Midichloria-like and Coxiella-like). Two bacteria documented as pathogenic to Gopherus spp. were registered (Mycoplasma spp. and Pasteurella testudinis). The bovine and ovine tick-borne pathogens A. marginale and A. ovis, respectively, were recorded, as well as the zoonotic bacteria A. phagocytophilum,Coxiella burnetii, and Neoehrlichia sp. Tortoises parasitized with O. turicata did not show evident signs of disease, which could indicate a possible ecological role as a reservoir that has yet to be demonstrated. In fact, the defense mechanisms of this tortoise against the microorganisms transmitted by ticks during their feeding process are still unknown. Future studies on soft ticks should expand our knowledge about what components of the microbiota are notable across multiple host–microbe dynamics. Likewise, studies are required to better understand the host competence of this tortoise, considered the largest terrestrial reptile in North America distributed throughout the Chihuahuan Desert since the late Pleistocene.

To cool or not to cool? Intestinal coccidians disrupt the behavioral hypothermia of lizards in response to tick infestation

It is generally accepted that parasites exert negative effects on their hosts and that natural selection favors specific host responses that mitigate this impact. It is also known that some components of the host immune system often co-evolve with parasite antigens resulting in a host-parasite arms race. In addition to immunological components of the anti-parasitic response, host behavioral responses are also important in this arms race and natural selection may favor avoidance strategies that preclude contact with parasites, or shifts in the host's thermoregulatory strategy to combat active infections (e.g., behavioral fever). Ticks are widespread parasites with direct and indirect costs on their vertebrate hosts. Their saliva provokes hemolysis in the blood of their hosts and can transmit a plethora of tick-borne pathogens. We enquired whether tick infestation by Ixodes pacificus can provoke a thermoregulatory response in Sceloporus occidentalis. For this, we compared the thermoregulatory behavior of tick-infested lizards against tick-infested lizards co-infected with two different species of coccidians (Lankesterella occidentalis and Acroeimeria sceloporis). After this, lizards were kept in individual terraria with a basking spot and fed ad libitum. We found that tick-infested lizards sought cooler temperatures in proportion to their tick load, and this response was independent of the co-infection status by L. occidentalis. This was consistent in April and June (when tick loads were significantly lower) and suggests a conservative strategy to save energy which might have been selected to overcome tick infestations during phenological peaks of this parasite. However, this behavior was not observed in lizards co-infected with A. sceloporis, suggesting that co-infection with this intestinal parasite prompt lizards to be active. Cost of tick infestation was confirmed because housed lizards lost weight at a constant ratio to initial tick load, independently of other infections. The broader implications of these findings are discussed in the context of climate change.

Borrelia burgdorferi (sensu lato) in ectoparasites and reptiles in southern Italy

BACKGROUND

Borrelia burgdorferi (sensu lato) is a complex containing pathogenic bacteria of which some species, such as Borrelia lusitaniae, use birds, small mammals and reptiles as reservoirs. In Italy, the bacteria have been detected in reptilian and avian reservoirs in the northern and central regions.

RESULTS

Here, 211 reptiles from three orders [Squamata (Sauria with seven species in five families and Ophidia with 11 species in three families), Crocodylia (one family and two species), and Testudines (two families and two species)] were examined for ectoparasites and molecular detection of B. burgdorferi (s.l.) in three different sites of southern Italy, an area for which no information was previously available on the occurrence of borreliosis in animals and humans. Borrelia lusitaniae was molecularly detected in larvae and nymphs (11.6%) of Ixodes ricinus infesting lizards (i.e. Podarcis muralis, Podarcis siculus and Lacerta bilineata) and in 12.3% blood samples of P. siculus. Finally, B. lusitaniae and Borrelia garinii were detected in 5.1% (32/630) of questing I. ricinus.

CONCLUSIONS

These results show the circulation of B. lusitaniae in southern Italy and suggest that P. siculus could play a role as a reservoir, representing a potential medical threat to humans living in or visiting these localities.

Importance of Common Wall Lizards in the Transmission Dynamics of Tick-Borne Pathogens in the Northern Apennine Mountains, Italy

During the investigations on ticks and tick-borne pathogens (TBP) range expansion in the Northern Apennines, we captured 107 Podarcis muralis lizards. Sixty-eight animals were infested by immature Ixodes ricinus, Haemaphysalis sulcata and H. punctata. Borrelia burgdorferi s.l. was detected in 3.7% of I. ricinus larvae and 8.0% of nymphs. Together with the species-specific B. lusitaniae, we identified B. garinii, B. afzelii and B. valaisiana. Rickettsia spp. (18.1% larvae, 12.0% nymphs), namely R. monacensis, R. helvetica and R. hoogstraalii, were also found in I. ricinus. R. hoogstraalii was detected in H. sulcata nymphs as well, while the two H. punctata did not harbour any bacteria. One out of 16 lizard tail tissues was positive to R. helvetica. Our results support the hypothesis that lizards are involved in the epidemiological cycles of TBP. The heterogeneity of B. burgdorferi genospecies mirrors previous findings in questing ticks in the area, and their finding in attached I. ricinus larvae suggests that lizards may contribute to the maintenance of different genospecies. The rickettsiae are new findings in the study area, and R. helvetica infection in a tail tissue indicates a systemic infection. R. hoogstraalii is reported for the first time in I. ricinus ticks. Lizards seem to favour the bacterial exchange among different tick species, with possible public health consequences.

Borrelia Diversity and Co-infection with Other Tick Borne Pathogens in Ticks

Identifying Borrelia burgdorferi as the causative agent of Lyme disease in 1981 was a watershed moment in understanding the major impact that tick-borne zoonoses can have on public health worldwide, particularly in Europe and the USA. The medical importance of tick-borne diseases has long since been acknowledged, yet little is known regarding the occurrence of emerging tick-borne pathogens such as Borrelia spp., Anaplasma phagocytophilum, Rickettsia spp., Bartonella spp., “Candidatus Neoehrlichia mikurensis”, and tick-borne encephalitis virus in questing ticks in Romania, a gateway into Europe. The objective of our study was to identify the infection and co-infection rates of different Borrelia genospecies along with other tick-borne pathogens in questing ticks collected from three geographically distinct areas in eastern Romania. We collected 557 questing adult and nymph ticks of three different species (534 Ixodes ricinus, 19 Haemaphysalis punctata, and 4 Dermacentor reticulatus) from three areas in Romania. We analyzed ticks individually for the presence of eight different Borrelia genospecies with high-throughput real-time PCR. Ticks with Borrelia were then tested for possible co-infections with A. phagocytophilum, Rickettsia spp., Bartonella spp., “Candidatus Neoehrlichia mikurensis”, and tick-borne encephalitis virus. Borrelia spp. was detected in I. ricinus ticks from all sampling areas, with global prevalence rates of 25.8%. All eight Borrelia genospecies were detected in I. ricinus ticks: Borrelia garinii (14.8%), B. afzelii (8.8%), B. valaisiana (5.1%), B. lusitaniae (4.9%), B. miyamotoi (0.9%), B. burgdorferi s.s (0.4%), and B. bissettii (0.2%). Regarding pathogen co-infection 64.5% of infected I. ricinus were positive for more than one pathogen. Associations between different Borrelia genospecies were detected in 9.7% of ticks, and 6.9% of I. ricinus ticks tested positive for co-infection of Borrelia spp. with other tick-borne pathogens. The most common association was between B. garinii and B. afzelii (4.3%), followed by B. garinii and B. lusitaniae (3.0%). The most frequent dual co-infections were between Borrelia spp. and Rickettsia spp., (1.3%), and between Borrelia spp. and “Candidatus Neoehrlichia mikurensis” (1.3%). The diversity of tick-borne pathogens detected in this study and the frequency of co-infections should influence all infection risk evaluations following a tick bite.

Natural foci of Borrelia lusitaniae in a mountain region of Central Europe

Lyme borreliosis is the most prevalent tick-borne disease in Europe. It is caused by spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex and transmitted to humans by ticks of the genus Ixodes. Borrelia afzelii, Borrelia garinii, and Borrelia valaisiana are the most common genospecies in Central Europe. In contrast, Borrelia lusitaniae predominates in Mediterranean countries such as Portugal, Morocco, and Tunisia. In Slovakia, its prevalence is low and restricted to only a few sites. The aim of our research was to study the expansion of ticks into higher altitudes in the ecosystem of the Malá Fatra mountains (north Slovakia) and their infection with B. burgdorferi s.l. pathogens. Questing ticks were collected by flagging in seven years (2004, 2006-2011) at three different altitudes: low (630-660 m above sea level (ASL)), intermediate (720-750 m ASL), and high (1040-1070 m ASL). Tick abundance was highest at the lowest altitude and lowest at the highest altitude. The average infection prevalence of B. burgdorferi s.l. in nymphs and adults was 16.8% and 36.2%, respectively. The number of infected ticks decreased from 38.5% at the lowest altitude to 4.4% at the highest altitude. B. lusitaniae was the most frequently found genospecies (>60% of the ticks found positive for B. burgdorferi s.l.) in all sites in all the studied years with the exception of 2008 when B. afzelii predominated (62%). Our study confirms the spread of Ixodes ricinus ticks to higher altitudes in Slovakia. The discovery that our mountain study sites were a natural foci of B. lusitaniae was unexpected because this genospecies is usually associated with lizards and xerothermic habitats.

Effects of temperature on feeding duration, success, and efficiency of larval western black-legged ticks (Acari: Ixodidae) on western fence lizards

The western black-legged tick (Ixodes pacificus) is a common tick species throughout the western USA and is the major vector for Borrelia burgdorferi, the Lyme disease causing bacterium. Western fence lizards (Sceloporus occidentalis) are a major host for juvenile I. pacificus, but are incompetent hosts for B. burgdorferi, which makes this host-parasite relationship of particular interest. In order to shed further light on this complex host-parasite relationship, we investigated the effects of temperature on feeding duration (number of days to repletion), success (number feeding to repletion), and efficiency (replete tick mass) of larval I. pacificus. Western fence lizards were experimentally infested with larval ticks and exposed to three constant temperatures (21, 27, 33 °C). Larvae feeding at 21 °C took approximately twice as long as larvae at 27 and 33 °C. Effects of temperature on feeding duration are likely mediated through effects on host blood circulation and functionality of tick salivary proteins. Our results here suggest temperature is another important factor influencing the feeding dynamics of I. pacificus, and likely other tick species. Future research is needed to clarify the exact mechanisms behind temperature effects on tick feeding.

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.

Real-time PCR-based identification of Borrelia burgdorferi sensu lato species in ticks collected from humans in Romania

The aims of our study were to determine (i) which tick species bite humans in Romania and (ii) the prevalence of Borrelia (B.) burgdorferi genospecies in these ticks. All ticks collected from patients who presented to the Clinic of Infectious Diseases Cluj Napoca in spring/summer 2010 were morphologically identified by an entomologist and tested for B. burgdorferi genospecies prevalence by a real-time PCR assay targeting the hbb gene and melting curve analysis. Out of 532 ticks, 518 were Ixodes ricinus, 10 Dermacentor marginatus, and 3 Haemaphysalis spp. ticks, and one unidentified tick due to destruction. Since evaluation of the hbb PCR revealed that it was not possible to differentiate between B. spielmanii/B. valaisiana and B. garinii/B. bavariensis, sequencing of an 800-bp fragment of the ospA gene was performed in these cases. Out of 389 investigated ticks, 43 were positive by hbb PCR for B. burgdorferi sensu lato. The positive samples were 42 Ixodes ricinus (11.1% B. burgdorferi sensu lato prevalence) and the one unidentified tick. Species identification revealed the presence of mainly B. afzelii, but also of B. garinii, B. burgdorferi sensu stricto, B. valaisiana, and B. lusitaniae. In 4 samples, differentiation between B. spielmanii/B. valaisiana was impossible. Our study shows that the most relevant human pathogenic B. burgdorferi genospecies - predominantly B. afzelii - are present in ticks collected from Romanian patients.

Do the ticks of birds at an important migratory hotspot reflect the seasonal dynamics of Ixodes ricinus at the migration initiation site? A case study in the Danube Delta

Migratory birds play important roles as distributors of ticks within and between continents. In the Old World, the most important migratory route of birds links Asia, Europe and Africa. During their migration, birds use various stopover sites, where they feed and rest and where ticks may attach or detach, creating new natural foci for vector-borne diseases. Danube Delta is one of the most important migration hotspots and so far no studies were focused on ticks of migratory birds herein. The aim of the present study was to assess the species diversity and seasonal dynamics of ticks parasitizing migratory birds in Danube Delta Biosphere Reserve. Migratory birds were trapped on Grindul Lupilor (44°41′N; 28°56′E) using mist nets during 4 migratory seasons (2 spring and 2 autumn) in 2011 and 2012. From each bird, all the ticks were collected and identified based on morphological features. Epidemiological parameters (prevalence, mean abundance, mean intensity) were calculated and all data were analysed statistically based on the season (spring and autumn), regional status of birds (migrants and breeding) and foraging behaviour (ground feeders, reed-bed feeders, foliage feeders). A total of 1434 birds (46 species) were captured. Ticks were found on 94 birds (10 species). Significantly more migratory birds hosted ticks, compared to resident birds. The 400 collected ticks belonged to four species: Ixodes ricinus (92.25%), I. arboricola (6.25%), I. redikorzevi (1.00%) and Haemaphysalis punctata (0.50%). A higher prevalence was found for I. ricinus in spring, with higher prevalence of nymphs in this season, while larvae occurred with the same prevalence in both seasons. Larval intensity was higher during spring and nymphs were more abundant during autumn. The seasonal differences in our study may be related not to the local seasonal dynamics of ticks, but on the seasonal dynamics at the site of migration initiation.

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.

Geographical distribution and prevalence of Borrelia burgdorferi genospecies in questing Ixodes ricinus from Romania: a countrywide study

The paper reports the prevalence and geographical distribution of Borrelia burgdorferi sensu lato (s.l.) and its genospecies in 12,221 questing Ixodes ricinus ticks collected at 183 locations from all the 41 counties of Romania. The unfed ticks were examined for the presence of B. burgdorferi s.l. by PCR targeting the intergenic spacer 5S-23S. Reverse line blot hybridization (RLB) and restriction fragment length polymorphism (RFLP) analysis were performed for identification of B. burgdorferi genospecies. The overall prevalence of infection was 1.4%, with an average local prevalence between 0.75% and 18.8%. B. burgdorferi s.l. was found in ticks of 55 of the 183 localities. The overall prevalence B. burgdorferi s.l. in ticks in the infected localities was 3.8%. The total infection prevalence was higher in female ticks than in other developmental stages. Three Borrelia genospecies were detected. The most widely distributed genospecies was B. afzelii, followed by B. garinii and B. burgdorferi sensu stricto (s.s.). The study is the first countrywide study and the first report of B. burgdorferi s.s. in Romania. The distribution maps show that higher prevalences were recorded in hilly areas, but Lyme borreliosis spirochetes were also present in forested lowlands, albeit with a lower prevalence.

Zoonotic pathogens associated with Hyalomma aegyptium in endangered tortoises: evidence for host-switching behaviour in ticks?

BACKGROUND

Hyalomma aegyptium is a hard-tick with a typical three-host life cycle. The main hosts are Palearctic tortoises of genus Testudo. However, other hosts can be used by immature ticks for feeding in natural conditions. Given this complex ecology and multiple host use, the circulation of pathogens by H. aegyptium between various hosts can be important from epidemiological point of view. The aim of this study was to evaluate the role of H. aegyptium as natural carrier of four important zoonotic pathogens.

METHODS

From 2008 to 2011, 448 H. aegyptium ticks were collected from 45 Spur-thighed tortoises, Testudo graeca in Romania. DNA was extracted individually from each tick using a commercial kit. DNA was examined for the presence of specific sequences of Borrelia burgdorferi s.l., Anaplasma phagocytophilum, Ehrlichia canis and Coxiella burnetii by PCR, according to previously described protocols.

RESULTS

PCR analysis of H. aegyptium revealed the presence of A. phagocytophilum (18.8%), E. canis (14.1%) and C. burnetii (10%). 32.4% of the ticks were infected with at least one pathogen and 9.8% had co-infections. The stages most frequently infected were nymphs (50%) followed by males (33.9%) and females (27%). The number of tortoises which harboured infected ticks was 27/45 examined (60%). From all tested T. graeca, 40% harboured ticks infected with A. phagocytophilum, 46.7% had ticks infected with E. canis and 33.3% had ticks with C. burnetii. This study reports for the first time the presence of A. phagocytophilum and E. canis in H. aegyptium.

CONCLUSIONS

The presence and relatively high prevalence of three important zoonotic pathogens in H. aegyptium raises the question of their epidemiologic importance in disease ecology. As tortoises are unlikely to be reservoir hosts for A. phagocytophilum and E. canis and both these pathogens are common in H. aegyptium, this is an important indication for (1) a possible increased host-switching behaviour of these ticks to competent reservoir hosts (i.e. hedgehogs) and (2) transstadial transmission. Furthermore, if we consider also the presence of C. burnetii, we conclude that T. graeca and its ticks should be evaluated more seriously when assessing the eco-epidemiology of zoonotic diseases.

Ixodes ricinus is the dominant questing tick in forest habitats in Romania: the results from a countrywide dragging campaign

In 2010 and 2011, questing ticks were collected from 188 forested locations in all the 41 counties of Romania using the dragging method. The total of 13,771 ticks collected belonged to eleven species: Ixodes ricinus (86.9 %), Dermacentor marginatus (9.5 %), Haemaphysalis punctata (2.6 %), H. concinna (0.6 %), H. sulcata (0.3 %), H. parva (0.1 %), Hyalomma marginatum (0.02 %), D. reticulatus (0.02 %), I. crenulatus (0.007 %), I. hexagonus (0.007 %) and I. laguri (0.007 %). Ixodes ricinus was present in 97.7 % (n = 180) of locations, occurring exclusively in 41.7 % of the locations, whereas it was the dominant species in 38.8 % of the other locations, accounting for over 70 % of the total tick community. The following most common questing ticks were D. marginatus, H. punctata and H. concinna. Ixodes ricinus co-occurred with one, two or three sympatric species. The occurrence of D. reticulatus in forested habitats from Romania was found to be accidental.

Synopsis of the hard ticks (Acari: Ixodidae) of Romania with update on host associations and geographical distribution

The current paper is a synoptic review of the distribution and host associations of the 25 species of hard tick fauna (family Ixodidae) in Romania. In addition to a full literature survey, original data is presented, based on eight years of occasional or targeted sample collection. The literature data on geographical distribution was transposed digitally to the decimal degree coordinate system. For each species, an updated distribution map is given together with all historical data and new host associations. Overall, our paper records 58 new tick-host associations for Romania: 20 for Ixodes ricinus, 1 for I. apronophorus, 6 for I. arboricola, 2 for I. hexagonus, 9 for I. redikorzevi, 1 for I. trianguliceps, 2 for I. vespertilionis, 2 for Haemaphysalis punctata, 1 for H. sulcata, 2 for H. concinna, 1 for D. marginatus, 4 for Rhipicephalus sanguineus sensu lato, 1 for R. bursa and 6 for Hyalomma marginatum.

Anaplasmataceae and Borrelia burgdorferi sensu lato in the sand lizard Lacerta agilis and co-infection of these bacteria in hosted Ixodes ricinus ticks

BACKGROUND

Anaplasmataceae and Borrelia burgdorferi s.l. are important tick-borne bacteria maintained in nature by transmission between ticks and vertebrate hosts. However, the potential role of lizards as hosts has not been sufficiently studied.

RESULTS

The current study showed that 23 of 171 examined sand lizards Lacerta agilis were PCR positive for Anaplasmataceae. The nucleotide sequences of the several selected PCR products showed 100% homology with Anaplasma spp. found in Ixodes ricinus collected in Tunisia and Morocco (AY672415 - AY672420). 1.2% of lizard collar scale samples were PCR positive for B. lusitaniae. In addition, 12 of 290 examined I. ricinus were PCR positive for B. burgdorferi s.l. and 82 were PCR positive for Anaplasmatacea. The number of ticks per lizard and the number of ticks PCR positive for both microorganisms per lizard were strongly correlated. Moreover, we found a significant correlation between numbers of ticks infected with Anaplasmataceae and with B. burgdorferi s.l. living on the same lizard. However, there was no significant correlation between detection of both bacteria in the same tick.

CONCLUSIONS

To the best of our knowledge, this is the first report of Anaplasmataceae DNA and additionally the second report of B. burgdorferi s.l DNA detection in the sand lizard.

Blood parasites in two co-existing species of lizards (Zootoca vivipara and Lacerta agilis)

We investigated the occurrence of blood parasites of two lizard species: the common or viviparous lizard (Zootoca vivipara) and the sand lizard (Lacerta agilis) in western Poland. Selected traits of lizard body morphology were studied with respect to the presence and intensity of haematozoan infection in blood samples collected from 218 adult lizards; 88 of the common lizard and 130 of the sand lizard. Haemogregarinid blood parasites were found to be the common parasite of both lizard species in studied locality with prevalence 39.8 (95% CL, 29.5-50.8) for Z. vivipara and 22.3 (95% CL, 15.5-30.4) for L. agilis. Incidence of parasitemia did not differ between sexes and was not correlated with morphological traits or presence of ectoparasites--Ixodes ricinus ticks. However, a significant difference between the two species of lizards was a greater frequency of haemogregarinid parasitism in Z. vivipara.

Transmission dynamics of Borrelia lusitaniae and Borrelia afzelii among Ixodes ricinus, lizards, and mice in Tuscany, central Italy

To estimate the basic reproduction number (R(0)) of Borrelia lusitaniae and Borrelia afzelii, we formulated a mathematical model considering the interactions among the tick vector, vertebrate hosts, and pathogens in a 500-ha enclosed natural reserve on Le Cerbaie hills, Tuscany, central Italy. In the study area, Ixodes ricinus were abundant and were found infected by B. lusitaniae and B. afzelii. Lizards (Podarcis spp.) and mice (Apodemus spp.), respectively, are the reservoir hosts of these two Borrelia burgdorferi sensu lato (s.l.) genospecies and compete for immature ticks. B. lusitaniae R(0) estimation is in agreement with field observations, indicating the maintenance and diffusion of this genospecies in the study area, where lizards are abundant and highly infested by I. ricinus immature stages. In fact, B. lusitaniae shows a focal distribution in areas where the tick vector and the vertebrate reservoir coexist. Mouse population dynamics and their relatively low suitability as hosts for nymphs seem to determine, on the other hand, a less efficient transmission of B. afzelii, whose R(0) differs between scenarios in the study area. Considering host population dynamics, the proposed model suggests that, given a certain combination of the two host population sizes, both spirochete genospecies can coexist in our study area. Additional incompetent hosts for B. burgdorferi s.l. have a negative effect on B. afzelii maintenance, whose R(0) results > 1 only with high mouse population densities and/or low lizards abundance, but they do not seem to influence B. lusitaniae transmission cycle on Le Cerbaie. Secondly, our model confirms the importance of nymphs' infestation, of host population density and diversity, and spirochetes host association for the maintenance of the transmission cycle of B. burgdorferi s.l.

Role of sand lizards in the ecology of Lyme and other tick-borne diseases in the Netherlands

Background

Lizards are considered zooprophylactic for almost all Borrelia burgdorferi species, and act as dilution hosts in parts of North America. Whether European lizards significantly reduce the ability of B. burgdorferi to maintain itself in enzootic cycles, and consequently decrease the infection rate of Ixodes ricinus ticks for B. burgdorferi and other tick-borne pathogens in Western Europe is not clear.

Results

Ticks were collected from sand lizards, their habitat (heath) and from the adjacent forest. DNA of tick-borne pathogens was detected by PCR followed by reverse line blotting. Tick densities were measured at all four locations by blanket dragging. Nymphs and adult ticks collected from lizards had a significantly lower (1.4%) prevalence of B. burgdorferi sensu lato, compared to questing ticks in heath (24%) or forest (19%). The prevalence of Rickettsia helvetica was significantly higher in ticks from lizards (19%) than those from woodland (10%) whereas neither was significantly different from the prevalence in ticks from heather (15%). The prevalence of Anaplasma and Ehrlichia spp in heather (12%) and forest (14%) were comparable, but significantly lower in ticks from sand lizards (5.4%). The prevalence of Babesia spp in ticks varied between 0 and 5.3%. Tick load of lizards ranged from 1 - 16. Tick densities were ~ 5-fold lower in the heather areas than in woodlands at all four sites.

Conclusions

Despite their apparent low reservoir competence, the presence of sand lizards had insignificant impact on the B. burgdorferi s.l. infection rate of questing ticks. In contrast, sand lizards might act as reservoir hosts for R. helvetica. Remarkably, the public health risk from tick-borne diseases is approximately five times lower in heather than in woodland, due to the low tick densities in heather.