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.     

Frequent isolation of Francisella tularensis from Dermacentor reticulatus ticks in an enzootic focus of tularaemia

Abstract. A total of 924 questing Dermacentor reticulatus (Fabricius), 504 Ixodes ricinus (L.), sixty Haemaphysalis concinna Koch and 718 mosquitoes (Aedes spp.) were examined in a floodplain forest ecosystem during the 1994-95 outbreak of tularaemia in South Moravia, Czech Republic. Francisella tularensis was not isolated from H.concinna ticks or Aedes spp. mosquitoes, whereas twenty-one isolates were recovered from the other haematophagous arthropods. Dermacentor reticulatus revealed a significantly higher infection rate (2.6%) than I.ricinus (0.2%). This tick species acts as principal vector for tularaemia in the enzootic focus. Monitoring of D.reticulatus for F.tularensis thus seems to be a very efficient approach in the surveillance of tularaemia in the flood-plain forest ecosystems of Europe.     

Distribution of Borrelia burgdorferi s.l. spirochaete DNA in British ticks (Argasidae and Ixodidae) since the 19th Century, assessed by PCR

The distribution of Borrelia burgdorferi sensu lato , the Lyme borreliosis agent, was surveyed in British ticks in the collection of the Natural History Museum, London. Alcohol-preserved specimens of eight species of ticks known to attack humans were studied: Ixodes ricinus , I. hexagonus , I. uriae , I. trianguliceps , Dermacentor reticulatus , Haemaphysalis punctata , Rhipicephalus sanguineus and Argas vespertilionis. The sample comprised all life stages and originated from a wide range of host species, collection dates (1896–1994) and geographical localities in England, Scotland and Wales.
Borrelia burgdorferi s. l. DNA, detected by a polymerase chain reaction that targeted the outer surface protein A gene, was found in all eight species. The overall proportion of PCR-positive specimens ranged from 7.8% for I. hexagonus (mostly from mustelids and hedgehogs) to 98.3% for I. uriae (mostly from seabirds). Borrelia burgdorferi s. l. DNA was found for the first time in the bat parasite A. vespertilionis (85.3%). The spirochaete is newly recorded in British populations of I. trianguliceps (97.4%, mostly from voles, mice and shrews), D. reticulatus (12.5% from dog and man) and R. sanguineus (30% from dogs and human dwellings). Of the four tick species with larvae available for testing, examples of I. ricinus, I. uriae and A. vespertilionis were PCR positive, as were significantly more nymphs than adults of I. ricinus, I. hexagonus and A. vespertilionis. Analyses showed that B. burgdorferi s. l. has been consistently present in British tick populations since at least 1897. Ticks positive for B. burgdorferi s. l. DNA were collected in all months of the year, throughout Britain, and were found on a wide range of mammal and bird species. PCR positivity does not prove vector or reservoir competence, but the use of archived material has demonstrated an extensive range of host–tick relationships involving B. burgdorferi s.l. in Britain for >100 years.     

The taxonomic aspects of the transmission of the causative agent of Lyme disease

According to world literature data 17 species of ixodid ticks have been studied for natural infection with the Lyme disease agent. Analysis of the data on the level of the infection, transovarial and transphase transmission has shown that main biological vectors of Borrelia burgdorferi are the species of the subgenus Ixodes s. str. - I. ricinus, I. persulcatus (Eurasia), I. dammini, I. pacificus (North America). Potential vectors are I. scapularis, I. dentatus, Amblyomma americanum, Dermacentor variabilis. Single isolations were registered for I. neotomae, Haemaphysalis leporispalustris, D. occidentalis. Nonidentified spirocheta was isolated from A. americanum, D. variabilis, D. parumapertum, Rhipicephalus sanguineus. No agent was isolated from I. cookey, D. albipictus, R. reticulatus, H. concinna. On the basis of comparative and ontogenetic data the species from a group of main vectors: I. ricinus, I. persulcatus, I. pacificus had been attributed by me to the phyletic group persulcatus before Lyme disease was discovered and its causative agent isolated. The question whether I. scapularis belongs to the group persulcatus was also discussed at that time but left open due to somewhat aberrant structure of gnathosoma at preimaginal phases (Filippova, 1969, 1971, 1973). 6 Palaearctic, 2 Indomalayan and 3 Nearctic species were referred to the group persulcatus at the time. I. dammini was described later, in 1979. Gnathosoma of its preimaginal phases has an intermediate structure between I. scapularis and other species of the group persulcatus. Sexually mature phase and nymph of I. dentatus have much in common with Palaearctic members of the group, I. pavlovskyi, I. kazakstani, I. kashmicus. Preimaginal phases of I. scapularis and nymph of I. dentatus were studied by me on the collection material. Thus, it is possible to speak of the belonging of main vectors of B. burgdorferi to a common phyletic group within the subgenus Ixodes s. str. and, therefore, of common origin of ecological medium for the agent. At the same time each species of the vector is an evolutionally developed difference of ecological medium for B. burgdorferi. Roots of the group persulcatus could originate as far as in Paleocene before the land connection between North America and Europe disappeared. Conditions for the existence of recent species, however, appeared considerably later and their flourishing is dated by Pliocene. The main epidemiological role belongs now to I. ricinus, I. persulcatus, I. dammini, I. pacificus.(ABSTRACT TRUNCATED AT 400 WORDS)     

Acarological studies in two protected areas of Central Italy

In the present note are reported the results of preliminary studies on tick distribution in two wildlife areas of Abruzzo (National Park of Abruzzo, a mountainous area, approximately 40,000 ha, in Central Apennines, interesting Abruzzo, Latium and Molise regions) and Latium (Capocotta-Castel Porziano Presidential reserve, on the Tyrrhenian coast, 30 km from Rome). Sampling of ticks from domestic and wild mammals as well as from vegetation, was performed in three different areas of the National Park in 1995. Tick species identified include Rhipicephalus bursa, R. sanguineus, Hyalomma marginatum, Haemaphysalis punctata, Dermacentor marginatus, Ixodes ricinus, I. hexagonus. The presence of I. ricinus was discontinuous and sporadic. In Capocotta estate, samplings were performed bimonthly from March to November 1997 in an restricted area (1 ha) with typical Mediterranean flora and fauna. The following species were collected: I. ricinus, Haemaphysalis concinna, D. marginatus, R. bursa, Hy. marginatum. There was a high dominance of I. ricinus and H. concinna.     

Distribution and molecular detection of Theileria and Babesia in questing ticks from northern Spain

Abstract.  A total of 562 questing adult ixodid ticks, collected during 2003−05 in 10 recreational mountain areas in northern Spain, were analysed for piroplasm infection. Reverse line blot (RLB) analysis using a panel of probes for 23 piroplasm species identified 16 different piroplasms, with an overall prevalence of 9.3%. Most were Theileria spp.-positive (7.7%), 3.0% were positive for Babesia spp. and 1.4% of ticks harboured both genera. Ixodes ricinus (Linnaeus, 1758), the most abundant tick in the vegetation, ranked third with regard to piroplasm infection prevalence (11.4%) after Rhipicephalus bursa (Canestrini & Fanzago, 1878) (16.0%) and Haemaphysalis punctata (Canestrini & Fanzago, 1878) (13.5%). Infection was detected in 6.2% of Dermacentor reticulatus (Fabricius, 1794) and in 1.1% of Haemaphysalis inermis (Birula, 1895), but was absent from Haemaphysalis concinna (Koch, 1844). Ixodes ricinus carried more piroplasm species (13), followed by H. punctata (10), D. reticulatus (8), R. bursa (3) and H. inermis (1). Although most of the positive ticks harboured a single infection (76.9%), mixed infections with two or three different piroplasm species were also detected (23.1%). The various tick−pathogen associations found are discussed and prevalences of infection in ticks are compared with previous results on piroplasms infecting animals in the same region.     

Ixodid ticks of Pavlodar Province and their participation in the circulation of tularemia infection

Investigations carried out in Pavlodar Province have shown that 7 species of ixodid ticks, Ixodes crenulatus, I. lividus, I. persulcatus, I. laguri laguri, Dermacentor marginatus, D. reticulatus, Haemaphysalis concinna, and one brought species, Hyalomma asiaticum, parasitize domestic animals and wild mammals. Maximum activity of pasture ticks of the genus Dermacentor falls on the end of April--beginning of May, that of H. concinna on the beginning of June. The growth in the abundance of pasture ticks, recorded during the last years, is favoured by the increase in the cattle live stock, its seasonal movements and pasture area reduction. Natural nidi of tularemia become more active. Since 1977 221 cultures of tularemia agent have been isolatid from pasture ticks. H. concinna takes the most active part in the infection circulation.     

Effect of forest clearing on the abundance of Ixodes ricinus ticks and the prevalence of Borrelia burgdorferi s.l

Questing Ixodes ricinus L. (Acari: Ixodidae) ticks were collected on a forest trail that had been completely cleared of shrubs and ground vegetation in winter 2002 and on a nearby control uncleared forest transect in South Moravia (Czech Republic). Samples were collected each May in 2003, 2004 and 2005. Nymphal ticks were 3.4 times, 1.9 times and 1.2 times less frequent on cleared forest than on uncleared forest trails in the three respective years, whereas adult tick abundance was 27.2 times, 4.0 times and 2.2 times lower, respectively. The ticks were examined for borreliae by dark-field microscopy: prevalence of nymphal ticks infected with Borrelia burgdorferi sensu lato (12.6% to 20.0%) did not differ significantly between the cleared and uncleared trail during the 3 years. In conclusion, the habitat modification appeared to result in a decreased abundance of I. ricinus as well as a reduced frequency of infected ticks (and thus indirectly a lower potential risk of Lyme borreliosis), which lasted, however, for only 2 years. Eight cultures of borreliae isolated from the ticks were all identified as the 'ornithophilic' genomic species Borrelia garinii, possibly indicating a greater role of forest birds than that of forest rodents as the hosts of immature I. ricinus in the tick (and borrelial) colonization of the cleared part of the forest.     

Borrelia burgdorferi sensu lato detected in skin of Norwegian mountain hares (Lepus timidus) without signs of dissemination

The mountain hare (Lepus timidus) population in southern Norway appears to be in decline. Necropsy and laboratory examinations of 36 hares found dead or diseased during 2007-2009 in Vest- and Aust-Agder counties showed that disease and deaths were attributed to multiple causes, with no specific etiology emerging as a cause for population decline. To investigate whether Borrelia burgdorferi sensu lato (s.l.) infection is associated with mortality in mountain hares, tissues and ticks collected from hares were investigated for infection with the spirochete. Borrelia burgdorferi s.l. DNA was not detected in samples from internal organs, whereas Borrelia afzelii, B. burgdorferi sensu stricto (s.s.), and the not-yet-defined Borrelia sp. SV1 were found in skin samples from hares and in adult and nymphal Ixodes ricinus feeding on hares. Only B. burgdorferi s.s. and Borrelia sp. SV1 were detected in larvae feeding on hares. Our results indicate that disseminated Borrelia infection in hares rarely occurs and, presumably, does not play a central role in the suspected population decline. The results also suggest that the mountain hare to some degree functions as a transmission host for B. burgdorferi s.s. and Borrelia sp. SV1.     

Lyme borreliosis situation in North Africa

Many epidemiological studies were conducted for studying Lyme borreliosis (LB) which represents a new global public health problem. It is now the most common vector-borne disease in Europe and North America. The causative agent Borrelia burgdorferi sl is a bacterial species complex comprising 12 delineated and named species. In North Africa, few studies based on clinical and serological features, have suggested that LB could occur. Indeed, recent studies conducted in Tunisia, Algeria and Morocco have showm that Ixodes ricinus is present in cooler and humid area of these regions. These studies also revealed that this species is a vector of B. burgdorferi sl with high prevalence of infection. Using IFI and PCR tests, the mean rate of Borrelia-infection ranged from 50 to 60% in I. ricinus adult collected in Tunisia and Morocco and from 30 to 40% in nymphs; in contrast, the prevalence in larvae is less than 2.5%. Several strains of B. burgdorfer were isolated from adult and nymph I ricinus collected in Tunisia and Morocco. The identification of these strains and DNAs directly extracted from Ixodes was done by PCR-RFLP and sequence analysis. The results showed that B. lusitaniae (genotypes Poti B2 and Poti B3) is the predominant species circulating in I. ricinus in Tunisia and Morocco, B. garinii and B. burgdorferi ss and B lusitaniae were also present but very rare. These results provide the evidence for the existence of B. burgdorferi sl in North Africa; however, the impact of LB in the human population seem to be negligible and the seroprevalence of Borrelia in forest workers (considered as population at high risk) in Tunisia is less than 4%.     

Borreliae in Ixodes ricinus ticks feeding on humans

A total of 298 Ixodes ricinus (L.) ticks (Acari: Ixodidae) feeding on humans in the Czech Republic were tested for borreliae (Borrelia burgdorferi sensu lato) by darkfield microscopy between 1997 and 2003. A majority (68%) of the supplied I. ricinus ticks were nymphs, 25% were females and 7% were larvae. Overall, 20% of 74 examined females and 9% of 203 examined nymphs (but none of 21 examined larvae) were infected with borreliae. The proportion of ticks with a high infection load (>100 spirochetes) was 4% in females and 2% in nymphal I. ricinus. During the year, the highest numbers and proportions of infected nymphal and female ticks were taken from humans in June. Detection of borreliae in the ticks feeding on humans might be helpful in the prophylaxis of Lyme borreliosis.     

Local variations in the distribution and prevalence of Borrelia burgdorferi sensu lato genomospecies in Ixodes ricinus ticks.

Unfed nymphal and adult Ixodes ricinus ticks were collected from five locations within the 10,000-ha Killarney National Park, Ireland. The distribution and prevalence of the genomospecies of Borrelia burgdorferi sensu lato in the ticks were investigated by PCR amplification of the intergenic spacer region between the 5S and 23S rRNA genes and by reverse line blotting with genomospecies-specific oligonucleotide probes. The prevalence of ticks infected with B. burgdorferi sensu lato was significantly variable between the five locations, ranging from 11.5 to 28.9%. Four genomospecies were identified as B. burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii, and VS116. Additionally, untypeable B. burgdorferi sensu lato genomospecies were identified in two nymphs. VS116 was the most prevalent of the genomospecies and was identified in 50% of the infected ticks. Prevalences of B. garinii and B. burgdorferi sensu stricto were similar (17 and 18%, respectively); however, significant differences were observed in the prevalence of these genomospecies in mixed infections (58.8 and 23.5%, respectively). Notably, the prevalence of B. afzelii was low, comprising 9.6 and 7.4%, respectively, of single and mixed infections. Significant variability was observed in the distribution and prevalence of B. burgdorferi sensu lato genomospecies between locations in the park, and the diversity and prevalence of B. burgdorferi sensu lato genomospecies was typically associated with woodland. The distributions of B. burgdorferi sensu lato genomospecies were similar in wooded areas and in areas bordering woodland, although the prevalence of B. burgdorferi sensu lato infection was typically reduced. Spatial distributions vegetation composition, and host cenosis of the habitats were identified as factors which may affect the distribution and prevalence of B. burgdorferi sensu lato genomospecies within the park.     

Ability of Ixodes persulcatus, Haemaphysalis concinna and Dermacentor silvarum ticks to acquire and transstadially transmit Borrelia garinii

In China, the ability of Ixodes persulcatus, Haemaphysalis concinna and Dermacentor silvarum to transmit Borrelia spirochetes was determined under laboratory conditions. Results showed that all three tick species can acquire spirochetes by feeding on infected mice. However, the capability of the three species to maintain spirochetes was different. Only I. persulcatus is able to maintain spirochetes alive during molting, and subsequent tick stages transmitted the infection to naive mice. In H. concinna and D. silvarum ticks, spirochetes could not survive after the digestion period of blood and after the molting process was finished, spirochetes were no longer detected. Contrary to H. concinna and D. silvarum, I. persulcatus should be considered the principal vector of Lyme disease in north China.     

Density of deer in relation to the prevalence of Borrelia burgdorferi s.1. in Ixodes ricinus nymphs in Rambouillet forest, France

The Rambouillet Forest, a Lyme disease-endemic area near Paris, France, was surveyed from September 1994 to October 1995 to determine the risk periods and zones for humans. Firstly, during the period of Ixodes ricinus activity, abundance of nymphs is greater in spring than in autumn. Secondly, we observed significant variation in nymphal abundance between zones according to the density of cervids. The polymerase chain reaction (PCR) was used to detect DNA of Borrelia burgdorferi sensu lato in 461 unfed nymphs. DNA was detected in 38 nymphs (8.2%). By genospecific PCR based on the OspA gene, we detected the three pathogenic spirochetes with occurrences of 10.3, 31.1 and 58.6 for B. burgdorferi s.s., Borrelia garinii and Borrelia afzelii, respectively, indicating that B. afzelii is probably the main Borrelia species in the Rambouillet Forest. Finally, 11.5% of positive nymphs exhibited a double infection. Infection rates of I. ricinus nymphs by B. burgdorferi s.l. were not significantly different throughout the year for a given area, indicating that the risk periods of acquiring Lyme disease are mainly linked to nymph activity and correspond to spring and autumn. Likewise infection rates of nymphs were not significantly different between zones with a high density of deer (more than 100 animals per 100 ha) and zones with lower deer density (less than 20 animals per 100 ha). In addition to the role of deer as an amplifier of tick populations, these data indicate that zones with a high density of cervids should be considered as higher risk areas. © Rapid Science Ltd. 1998     

Immunity of dogs against Babesia canis, its vector tick Dermacentor reticulatus, and Ixodes ricinus in endemic area

Previous epidemiological studies allowed us to accurately define endemic areas of canine babesiosis and tick distribution in southeastern France (Martinod, 1983). Using a micro-ELISA test 100 dogs sera were tested with 3 antigens: Babesia canis, Dermacentor reticulatus and Ixodes ricinus. Antibodies against B. canis and its vector D. reticulatus were detected in an endemic area, sometimes with high levels (optical density 1.38 and 0.80 respectively). A correlation factor and regression lines were found between ELISA activity of B. canis and vector tick antigens, even for dogs which never showed any babesiosis symptoms. These results were compared with those of an area without any babesiosis. Furthermore I. ricinus antigens detected ELISA activity in sera of dogs; some cross reactions were observed between I. ricinus and D. reticulatus antigen.     

A molecular marker for the identification of the zoonotic reservoirs of Lyme borreliosis by analysis of the blood meal in its European vector Ixodes ricinus.

The efficacy of the mitochondrially encoded cytochrome b gene as a molecular marker for the discrimination of the reservoir host species of the Lyme borreliosis spirochete, Borrelia burgdorferi sensu lato (s.l.), in its European vector Ixodes ricinus (Acari: Ixodidae) was determined. Degenerate PCR primers were designed which amplified orthologous regions of the cytochrome b gene in several animal species which act as B. burgdorferi s.l. reservoirs and hosts for I. ricinus. PCR products were amplified and characterized by hybridization and restriction fragment length polymorphism analysis. Restriction fragment length polymorphism analysis of a 638-bp PCR product with HaeIII and DdeI revealed unique restriction fragment profiles, which allowed the taxonomic identification of animals to the genus level. A system was devised for the detection of the larval host blood meal from the remnants in unfed nymphal I. ricinus ticks by nested PCR amplification. An inverse correlation was demonstrated between amplicon size and successful PCR amplification of host DNA from the nymphal stage of the tick. The stability of the cytochrome b product as a marker for the identification of the larval host species in the nymphal instar was demonstrated up to 200 days after larval ingestion (approximately 165 days after molting) by reverse line blotting with a host-specific probe. This assay has the potential for the determination of the reservoir hosts of B. burgdorferi s.l. by using extracts from the same individual ticks for both the identification of the host species and the detection of the Lyme borreliosis spirochete.     

Infections and coinfections of questing Ixodes ricinus ticks by emerging zoonotic pathogens in Western Switzerland

In Europe, Ixodes ricinus is the vector of many pathogens of medical and veterinary relevance, among them Borrelia burgdorferi sensu lato and tick-borne encephalitis virus, which have been the subject of numerous investigations. Less is known about the occurrence of emerging tick-borne pathogens like Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and Anaplasma phagocytophilum in questing ticks. In this study, questing nymph and adult I. ricinus ticks were collected at 11 sites located in Western Switzerland. A total of 1,476 ticks were analyzed individually for the simultaneous presence of B. burgdorferi sensu lato, Rickettsia spp., Babesia spp., "Candidatus Neoehrlichia mikurensis," and A. phagocytophilum. B. burgdorferi sensu lato, Rickettsia spp., and "Candidatus Neoehrlichia mikurensis" were detected in ticks at all sites with global prevalences of 22.5%, 10.2%, and 6.4%, respectively. Babesia- and A. phagocytophilum-infected ticks showed a more restricted geographic distribution, and their prevalences were lower (1.9% and 1.5%, respectively). Species rarely reported in Switzerland, like Borrelia spielmanii, Borrelia lusitaniae, and Rickettsia monacensis, were identified. Infections with more than one pathogenic species, involving mostly Borrelia spp. and Rickettsia helvetica, were detected in 19.6% of infected ticks. Globally, 34.2% of ticks were infected with at least one pathogen. The diversity of tick-borne pathogens detected in I. ricinus in this study and the frequency of coinfections underline the need to take them seriously into consideration when evaluating the risks of infection following a tick bite.     

Problems of isolating Borrelia burgdorferi from ticks collected in United Kingdom foci of Lyme disease

Abstract. Many isolates of Borrelia burgdorferi have been obtained from ticks and vertebrate tissues collected in North America and continental Europe but only one established culture of United Kingdom Borrelia burgdorferi has been recorded. In this paper we report the isolation of B.burgdorferi from one of 108 tick pools representing 733 ticks and eighty-four tissue samples from twenty-six rodents collected in the U.K., and the subsequent failure to establish the isolate (from ticks collected in Fordingbridge) in culture. In contrast, using identical techniques and culture medium, B.burgdorferi was isolated from one of seven tick pools collected in Switzerland, and from a single pool of ticks collected in Slovakia, and both isolates were successfully passaged. Analysis of questing I.ricinus collected from Fordingbridge by direct immunofluorescence showed 6/32 (19%) of adults and 8/108 (7%) of nymphs were positive for B. burgdorferi , although only one nymph contained ≥ 1000 spirochaetes. To examine further the problem of isolating U.K. B.burgdorferi , twelve Ixodes ricinus tick samples from Fordingbridge, a recognized focus of Lyme disease, were subjected to isolation and culturing techniques, and the procedures monitored by use of the polymerase chain reaction (PCR). Whereas 11/12 samples were PCR positive after 2 weeks in culture, only one was PCR positive after 4 weeks. Motile spirochaetes were not visible by dark-field microscopy in any of the cultures. The results indicate that the standard BSK II medium routinely used to isolate and culture B. burgdorferi does not readily support the replication of the Borrelia species endemic to the U.K.     

Spirochetes in mammals and ticks (Acari: Ixodidae) from a focus of Lyme borreliosis in California

In northern California, antibodies to Borrelia burgdorferi were detected in 58 of 73 (79%), and spirochetemias in one of 26 (4%) black-tailed jackrabbits (Lepus californicus californicus), by indirect and direct immunofluorescence, respectively. Five species of ticks (Dermacentor occidentalis, D. parumapertus, Ixodes neotomae, I. pacificus, and Haemaphysalis leporispalustris) were collected from rabbits. Two of these species of ticks were found to contain spirochetes; two of 10 (20%) I. neotomae and two of 174 (1%) H. leporispalustris. A strain of B. burgdorferi was recovered from I. neotomae. One infected H. leporispalustris female passed spirochetes via eggs to about 67% of her progeny. The widespread distribution of the black-tailed jackrabbit, its infestation by at least four ticks (D. occidentalis, D. parumapertus, I. neotomae, and I. pacificus) known to be infected naturally with B. burgdorferi, and the high prevalence of spirochetal antibody in this lagomorph suggest that it might be useful as a sentinel for surveillance of Lyme borreliosis. Spirochetes were detected in 15% of 40 Columbian black-tailed deer (Odocoileus hemionus columbianus) by direct immunofluorescence bound with a Borrelia-specific monoclonal antibody (H9724), but not with a monoclonal antibody (H5332) specific for B. burgdorferi. The geographical overlap of different borreliae in ticks that bite wildlife such as deer may confound spirochetal serosurveys, and underscores the need for more specific serologic tests than those currently available.     

Diversity of Ixodes ricinus tick-associated bacterial communities from different forests

Nymphal Ixodes ricinus ticks (n=180) were collected from three different areas in the Netherlands to investigate the effect of forest composition on tick-associated microbial communities. Sampled habitats differed in thickness of leaf litter and humus layers and vegetation associations and were located near Amsterdam (Beech-Oak), Ede (Birch-Oak) and Veldhoven (Birch-Oak). Analysis of nine 16S rRNA gene clone libraries made from individual ticks showed nearest matches with presumed pathogens Candidatus Neoehrlichia mikurensis and Rickettsia australis and arthropod endosymbionts Wolbachia pipientis and Candidatus Midichloria mitochondrii. Total bacterial species diversity (Shannon index) and Borrelia species infections were determined in I. ricinus by, respectively, PCR-denaturing gradient gel-electrophoresis and PCR-reverse line blot with probes specific for Borrelia burgdorferi sensu stricto, Borrelia afzelii, Borrelia garinii, Borrelia valaisiana, Borrelia lusitaniae and Borrelia ruski. Bacterial diversity differed significantly per area and was lowest in Ede. In contrast, Borrelia species-infected ticks were more abundant in Ede, Candidatus Neoehrlichia mikurensis-infected ticks in Ede and Veldhoven, and R. australis-infected ticks in Amsterdam. Borrelia afzelii was the most common Borrelia species found in all three areas. Bacterial tick diversity was influenced by local differences in forest structure, which is proposed to modulate animal populations that are commonly parasitized by I. ricinus.