Identification of Hard Ticks in the United States: A Practical Guide for Clinicians and Pathologists

ABSTRACT

According to guidelines published by the Infectious Disease Society of America, Lyme disease prophylaxis is possible if a tick can be identified as Ixodes scapularis (nymphal or adult) within 72 hours of tick removal. However, a recent survey of medical practitioners indicates generally poor proficiency in tick identification. In this study, we provide a simple, practical guide to aid medical practitioners in identifying the most commonly encountered human biting ticks of North America.

Proficiency at Tick Identification by Pathologists and Clinicians Is Poor

OBJECTIVES

Prompt accurate identification of tick species is required for appropriate administration of single dose antimicrobial prophylaxis for Lyme disease in selected patients. To determine the proficiency of clinicians at tick identification in the northeastern United States where Lyme disease has its highest incidence, we undertook a survey.

METHODS

We analyzed the results of a voluntary survey testing proficiency in identifying tick species using high-resolution photographs of ticks.

RESULTS

Only 35% of ticks were correctly identified. Although 60% of respondents could identify a nonengorged adult blacklegged tick, only 34% could correctly identify a partially engorged blacklegged tick. Participants performed even worse at classifying brown dog, American dog, and Lone Star ticks.

CONCLUSIONS

Proficiency of tick identification by pathologists and clinicians is poor.

Focus Stacking Images of Morphological Character States for Differentiating the Adults of Ixodes affinis and Ixodes scapularis (Acari: Ixodidae) in Areas of Sympatry

Adult females and males of Ixodes affinis and Ixodes scapularis are illustrated by focus stacking image photography, and morphological character states are described that reliably differentiate the two species. In conjunction with other environmental cues, such as the questing phenology of adults, these characteristics will enable the rapid identification of adults of either sex along the southern Coastal Plain of the United States, where these species are sympatric.

High-elevational occurrence of two tick species, Ixodes ricinus and I. trianguliceps, at their northern distribution range

BACKGROUND

During the last decades a northward and upward range shift has been observed among many organisms across different taxa. In the northern hemisphere, ticks have been observed to have increased their latitudinal and altitudinal range limit. However, the elevational expansion at its northern distribution range remains largely unstudied. In this study we investigated the altitudinal distribution of the exophilic Ixodes ricinus and endophilic I. trianguliceps on two mountain slopes in Norway by assessing larval infestation rates on bank voles (Myodes glareolus).

METHODS

During 2017 and 2018, 1325 bank voles were captured during the spring, summer and autumn at ten trapping stations ranging from 100 m to 1000 m.a.s.l. in two study areas in southern Norway. We used generalized logistic regression models to estimate the prevalence of infestation of both tick species along gradients of altitude, considering study area, collection year and season, temperature, humidity and altitude interactions as extrinsic variables, and host body mass and sex as intrinsic predictor variables.

RESULTS

We found that both I. ricinus and I. trianguliceps infested bank voles at altitudes up to 1000 m.a.s.l., which is a substantial increase in altitude compared to previous findings for I. ricinus in this region. The infestation rates declined more rapidly with increasing altitude for I. ricinus compared to I. trianguliceps, indicating that the endophilic ecology of I. trianguliceps may provide shelter from limiting factors tied to altitude. Seasonal effects limited the occurrence of I. ricinus during autumn, but I. trianguliceps was found to infest rodents at all altitudes during all seasons of both years.

CONCLUSIONS

This study provides new insights into the altitudinal distribution of two tick species at their northern distribution range, one with the potential to transmit zoonotic pathogens to both humans and livestock. With warming temperatures predicted to increase, and especially so in the northern regions, the risk of tick-borne infections is likely to become a concern at increasingly higher altitudes in the future.

Benefits and Drawbacks of Citizen Science to Complement Traditional Data Gathering Approaches for Medically Important Hard Ticks (Acari: Ixodidae) in the United States

Tick-borne diseases are increasing in North America. Knowledge of which tick species and associated human pathogens are present locally can inform the public and medical community about the acarological risk for tick bites and tick-borne infections. Citizen science (also called community-based monitoring, volunteer monitoring, or participatory science) is emerging as a potential approach to complement traditional tick record data gathering where all aspects of the work is done by researchers or public health professionals. One key question is how citizen science can best be used to generate high-quality data to fill knowledge gaps that are difficult to address using traditional data gathering approaches. Citizen science is particularly useful to generate information on human-tick encounters and may also contribute to geographical tick records to help define species distributions across large areas. Previous citizen science projects have utilized three distinct tick record data gathering methods including submission of: 1) physical tick specimens for identification by professional entomologists, 2) digital images of ticks for identification by professional entomologists, and 3) data where the tick species and life stage were identified by the citizen scientist. We explore the benefits and drawbacks of citizen science, relative to the traditional scientific approach, to generate data on tick records, with special emphasis on data quality for species identification and tick encounter locations. We recognize the value of citizen science to tick research but caution that the generated information must be interpreted cautiously with data quality limitations firmly in mind to avoid misleading conclusions.

Ixodes spp. from Dogs and Cats in the United States: Diversity, Seasonality, and Prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum

Ixodes spp. are commonly found on dogs and cats throughout the world. In the eastern United States, 16S rDNA sequence of Ixodes scapularis, the predominant species, reveals two clades-American and Southern. To confirm the species and clades of Ixodes spp. ticks submitted from pets, we examined ticks morphologically and evaluated 16S rDNA sequence from 500 ticks submitted from 253 dogs, 99 cats, 1 rabbit, and 1 ferret from 41 states. To estimate pathogen prevalence, flaB of Borrelia burgdorferi (Bb) sensu stricto and 16S rDNA of Anaplasma phagocytophilum (Ap) were amplified and sequenced. Most Ixodes spp. from the Northeast (n = 115/115; 100%) and the Midwest (n = 77/80; 96.3%) were I. scapularis, American clade. Borrelia spp. were identified in 34 of 192 (17.8%) and Ap in 5 of 192 (2.6%) I. scapularis. Two Ixodes cookei and one Ixodes texanus were identified from Ohio, Illinois, and Michigan. In contrast, 156 of 261 (59.8%) Ixodes spp. from the Southeast were I. scapularis, American clade; 86 of 261 (33.0%) were I. scapularis, Southern clade; 9 of 261 (3.4%) were Ixodes affinis; and 10 of 261 (3.8%) were I. cookei. Southern clade was significantly more common in Florida and less common in the upper South (p < 0.0001). One I. scapularis (1/242; 0.4%) from the Southeast (Kentucky) tested positive for Bb and 6 of 242 (2.5%) were positive for Ap. In the West, most (34/44; 77.3%) Ixodes spp. were Ixodes pacificus, with Ixodes angustus (n = 6) submitted from dogs in Alaska, Washington, and Oregon and Ixodes haerlei (n = 4) preliminarily identified from a dog in Montana. Pathogens were not detected in any ticks from the West. Although I. scapularis, American clade, predominated in the Northeast and Midwest, additional Ixodes spp. were found on dogs and cats in other regions and pathogens were less commonly detected. The role of less common Ixodes spp. as disease vectors, if any, warrants continued investigation.

Identification of closely related Ixodes species by protein profiling with MALDI-TOF mass spectrometry

Ticks are vectors of infectious diseases of major importance in human and veterinary medicine. For epidemiological studies, accurate identification of ticks is crucial to define their potential role as vectors and to develop control and prevention strategies. Although morphological and molecular methods are widely used to identify ticks, an innovative approach using MALDI-TOF MS technology recently emerged as an alternative tool. Previous works showed that MALDI-TOF MS was highly effective in identifying ticks, but these works mainly tested tick specimens of different genera. To confirm the accuracy of this new tool for tick identification, nine closely related tick species belonging to the Ixodes genus were analysed, specimens of the Dermacentor reticulatus species were also included in the analysis as an outer group. Three of the species used for the present study belonged to the I. ricinus species complex, which are known to transmit Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis. A total of 246 tick specimens were submitted to MALDI-TOF MS analysis, and two body parts (half-idiosoma and four legs) were individually investigated. For each body part, intraspecies reproducibility and interspecies specificity of the MS profiles were determined. The profile analysis revealed that the main determinant for spectra clustering was the tick species for both legs and half-idiosoma. For each body part, a reference database of spectra was set up including 2 to 5 specimens per species randomly selected, and genotyped using 16s rDNA and COI genes to confirm their morphological identification. Both created spectral databases were individually blind tested with their respective body part using the remaining specimens, which were correctly identified in 98.5% of the cases. MALDI-TOF MS is a reliable tool for tick identification, including specimens belonging to closely related species and hardly distinguishable using morphology. The 4-legs as well as the half-idiosoma of ticks can now be applied for specimen identification using two different databases. The combined use of these two body parts improves the rate of tick identification and their confidence level.

Clinical spectrum of Lyme disease

Lyme disease (borreliosis) is one of the most common vector-borne diseases worldwide. Its incidence and geographic expansion has been steadily increasing in the last decades. Lyme disease is caused by Borrelia burgdorferi sensu lato, a heterogeneous group of which three genospecies have been systematically associated to Lyme disease: B. burgdorferi sensu stricto Borrelia afzelii and Borrelia garinii. Geographical distribution and clinical manifestations vary according to the species involved. Lyme disease clinical manifestations may be divided into three stages. Early localized stage is characterized by erythema migrans in the tick bite site. Early disseminated stage may present multiple erythema migrans lesions, borrelial lymphocytoma, lyme neuroborreliosis, carditis, or arthritis. The late disseminated stage manifests with acordermatitis chronica atrophicans, lyme arthritis, and neurological symptoms. Diagnosis is challenging due to the varied clinical manifestations it may present and usually involves a two-step serological approach. In the current review, we present a thorough revision of the clinical manifestations Lyme disease may present. Additionally, history, microbiology, diagnosis, post-treatment Lyme disease syndrome, treatment, and prognosis are discussed.

Ixodes heathi n. sp. (Acari: Ixodidae), a co-endangered tick from the critically endangered mountain pygmy possum (Burramys parvus), with notes on its biology and conservation

A new species of co-endangered tick, Ixodes heathi n. sp., is described from specimens of the nymph collected on the critically endangered mountain pygmy possum (Burramys parvus Broom) from the alpine region of Victoria, Australia. Its biology is discussed along with strategies for its conservation.

Evidence for increasing densities and geographic ranges of tick species of public health significance other than Ixodes scapularis in Québec, Canada

Climate change is driving emergence and establishment of Ixodes scapularis, the main vector of Lyme disease in Québec, Canada. As for the black-legged tick, I. scapularis Say, global warming may also favor northward expansion of other species of medically important ticks. The aims of this study were to determine (1) current diversity and abundance of ticks of public health significance other than I. scapularis, (2) sex and age of the human population bitten by these ticks (3), and the seasonal and geographic pattern of their occurrence. From 2007 to 2015, twelve tick species other than I. scapularis were submitted in the Québec passive tick surveillance program. Of these 9243 ticks, 91.2% were Ixodes cookei, 4.1% were Dermacentor variabilis, 4.0% were Rhipicephalus sanguineus and 0.7% were Amblyomma americanum. The combined annual proportion of submitted I. cookei, D. variabilis, R. sanguineus and A. americanum ticks in passive surveillance rose from 6.1% in 2007 to 16.0% in 2015 and an annual growing trend was observed for each tick species. The number of municipalities where I. cookei ticks were acquired rose from 104 to 197 during the same period. Of the 862 people bitten by these ticks, 43.3% were I. cookei ticks removed from children aged < 10 years. These findings demonstrate the need for surveillance of all the tick species of medical importance in Québec, particularly because climate may increase their abundance and geographic ranges, increasing the risk to the public of the diseases they transmit.

First Report of Ixodes nipponensis Infection in Goats in China

Ticks are obligate blood-sucking ectoparasites that infect a wide range of animals and humans, causing a variety of both human and animal diseases around the world. Ixodes nipponensis is the most commonly reported tick in Korea and Japan, but it is very rare in China. In this study, six I. nipponensis samples were collected from three black goats in Hunan province, China. Ticks identified morphologically as I. nipponensis were then examined by PCR with two different molecular markers: mitochondrial cox1 and the second internal transcribed spacer of ribosomal DNA genes. Sequence comparison and phylogenetic analysis of the cox1 sequences confirmed that all of the examined hard Ixodes ticks represented I. nipponensis. This finding indicates a potential risk of zoonotic I. nipponensis infection in humans and animals in China. To our knowledge, this is the first report documenting the occurrence of I. nipponensis infection in goats in China.

Differential diagnosis of Ixodes ricinus and Ixodes persulcatus: nymphs and larvae

We developed a method for differential diagnosis of nymphs and larvae of sheep (Ixodes ricinus (L.)) and taiga (I. persulcatus Sch.) ticks (Parasitiformes: Ixodidae) which allows to identify live material in the field.

Description of a new species of Ixodes Latreille, 1795 (Acari: Ixodidae) and redescription of I. priscicollaris Schulze, 1932, parasites of New Guinea rodents (Rodentia: Muridae)

Ixodes goliath n. sp. (Acari: Ixodidae), is described based on females collected from the eastern hyomys, Hyomys goliath (Milne-Edwards) (Rodentia: Muridae) from Papua New Guinea. Females of I. goliath n. sp. are similar to those of I. priscicollaris Schulze, 1932 but can be distinguished by the overall size, porose areas sculpture and shape of palpal segment I ventrally. For comparative purposes, the female of I. priscicollaris is redescribed. Studied females of I. priscicollaris were found on murid rodents and Phascogale sp. (Dasyuromorphia: Dasyuridae) from Indonesia (Papua Province) and Papua New Guinea.

Redescription of the kiwi tick Ixodes anatis (Acari: Ixodidae) from New Zealand, with notes on its biology

Ixodes anatis Chilton is of veterinary and conservation importance in New Zealand due to its association with the threatened kiwi (Aves: Apterygidae: Apteryx spp.). Since the tick's description in 1904, there has been debate regarding its correct taxonomic position and nomenclature. Herein all life stages of this species are redescribed and accompanied by electron micrographs and drawings. The systematics, host preferences, distribution, disease relationships and conservation biology of the species are also discussed.

First record of the tick Ixodes (Pholeoixodes) kaiseri in Turkey

Nymphs and larvae belonging to Ixodes spp. were collected from a red fox in Turkey. The ticks were identified morphologically and molecularly (16S rDNA PCR and phylogenetic analysis) as I. kaiseri. Sequence and phylogenetic analyses show that our I. kaiseri isolate is very similar to I. kaiseri isolates collected from Germany, Serbia, Romania, and Hungary. Therefore, the existence of I. kaiseri has been demonstrated for the first time in Turkey. More studies relating to the regional distribution and vectorial competence of I. kaiseri are needed.

Contributions to the phylogeny of Ixodes (Pholeoixodes) canisuga, I. (Ph.) kaiseri, I. (Ph.) hexagonus and a simple pictorial key for the identification of their females

BACKGROUND

In Europe, hard ticks of the subgenus Pholeoixodes (Ixodidae: Ixodes) are usually associated with burrow-dwelling mammals and terrestrial birds. Reports of Pholeoixodes spp. from carnivores are frequently contradictory, and their identification is not based on key diagnostic characters. Therefore, the aims of the present study were to identify ticks collected from dogs, foxes and badgers in several European countries, and to reassess their systematic status with molecular analyses using two mitochondrial markers.

RESULTS

Between 2003 and 2017, 144 Pholeoixodes spp. ticks were collected in nine European countries. From accurate descriptions and comparison with type-materials, a simple illustrated identification key was compiled for adult females, by focusing on the shape of the anterior surface of basis capituli. Based on this key, 71 female ticks were identified as I. canisuga, 21 as I. kaiseri and 21 as I. hexagonus. DNA was extracted from these 113 female ticks, and from further 31 specimens. Fragments of two mitochondrial genes, cox1 (cytochrome c oxidase subunit 1) and 16S rRNA, were amplified and sequenced. Ixodes kaiseri had nine unique cox1 haplotypes, which showed 99.2-100% sequence identity, whereas I. canisuga and I. hexagonus had eleven and five cox1 haplotypes, respectively, with 99.5-100% sequence identity. The distribution of cox1 haplotypes reflected a geographical pattern. Pholeoixodes spp. ticks had fewer 16S rRNA haplotypes, with a lower degree of intraspecific divergence (99.5-100% sequence identity) and no geographical clustering. Phylogenetic analyses were in agreement with morphology: I. kaiseri and I. hexagonus (with the similar shape of the anterior surface of basis capituli) were genetically more closely related to each other than to I. canisuga. Phylogenetic analyses also showed that the subgenus Eschatocephalus (bat ticks) clustered within the subgenus Pholeoixodes.

CONCLUSIONS

A simple, illustrated identification key is provided for female Pholeoixodes ticks of carnivores (including I. hexagonus and I. rugicollis) to prevent future misidentification of these species. It is also shown that I. kaiseri is more widespread in Europe than previously thought. Phylogenetic analyses suggest that the subgenus Pholeoixodes is not monophyletic: either the subgenus Eschatocephalus should be included in Pholeoixodes, or the latter subgenus should be divided, which is a task for future studies.

Bacteria of the Family 'Candidatus Midichloriaceae' in Sympatric Zones of Ixodes Ticks: Genetic Evidence for Vertical Transmission

Ixodes ticks transmit infectious agents and also harbor their own parasites and symbionts. The presumptive endosymbiont of Ixodes ricinus, 'Candidatus Midichloria mitochondrii', has a unique ability to invade mitochondria within tick ovarian cells and is transovarially transmitted with 100% efficiency. A closely related bacterium, provisionally named Montezuma (now 'Candidatus Lariskella arthropodarum'), was isolated from the Ixodes persulcatus ticks and human blood in 2004 as well as from Ixodes pavlovskyi in 2015. These microorganisms belong to the family 'Candidatus Midichloriaceae fam. nov.' and were detected not only in tick salivary glands, but also in animal blood. Nevertheless, the relative importance of vertical and horizontal routes for their transmission or maintenance in natural tick populations remains unclear. We analyzed the prevalence of L. arthropodarum and M. mitochondrii in two sympatric zones, where I. persulcatus/I. ricinus and I. persulcatus/I. pavlovskyi cohabit and produce interspecific hybrids. A specificity of the associations of L. arthropodarum with I. persulcatus (100%) and M. mitochondrii with I. ricinus (96.2%) was observed in the sympatric zone in Estonia, possibly showing poor contribution of the horizontal route to the overall prevalence of endosymbionts. L. arthropodarum was observed probably multiplying in I. pavlovskyi and also subjected to transovarial transmission, but much less efficiently compared to I. persulcatus. We revealed two new genetic variants of the rrl-rrf intergenic spacer of L. arthropodarum isolated from I. pavlovskyi ticks that possibly could indicate an ongoing process of adaptation of the microorganism to a new host species.

The genus Ixodes (Acari: Ixodidae) in China with three new record species

Total 24 valid species belongs to 6 subgenera in genus Ixodes had been documented in China. Of them, Eschatocephalus (2 species), Scaphixodes (2 species); Partipalpiger (1 species), Pholeoixodes (3 species) Ixodiopsis (1 species) and the largest subgenus Ixodes (15 species) were involved. Fortunately, we found another 3 new record species, namely I. (Ixodes) apronophorus Schulze, 1924, I. (Ixodes)pavlovskyi Pomerantzav, 1946 and I. (Trichotoixodes) frontalis (Panzer, 1798), from the specimens deposited in medical entomology gallery of China, which increase a new subgenus Trichotoixodes to the tick fauna in China. In the present paper, the taxonomy characteristics of the new record species were described briefly based on the specimens examined and keys to the genus Ixodes were also updated.

Phylogenetic Lineages and Postglacial Dispersal Dynamics Characterize the Genetic Structure of the Tick, Ixodes ricinus, in Northwest Europe

Dispersal and gene flow are important mechanisms affecting the dynamics of vectors and their pathogens. Here, patterns of genetic diversity were analyzed in many North European populations of the tick, Ixodes ricinus. Population sites were selected within and between areas separated by geographical barriers in order to evaluate the importance of tick transportation by birds in producing genetic connectivity across open sea and mountain ranges. The phylogenetic analyses of the mitochondrial control region and the cytochrome b gene revealed two distinct clades with supported sub-clades, with three genetic lineages: GB and WNo associated with Great Britain and western Norway respectively, and Eu with a wider distribution across continental Europe in agreement with much lower efficiency of tick dispersal by birds than by large mammals. The results suggest different ancestry of I. ricinus colonizing Britain and the rest of northern Europe, possibly from different glacial refuges, while ticks from western Norway and continental Europe share a more recent common ancestry. Demographic history modeling suggests a period of strong increase in tick abundance coincident with progression of the European Neolithic culture, long after their post-glacial colonization of NW Europe.

Microtomography of the Baltic amber tick Ixodes succineus reveals affinities with the modern Asian disease vector Ixodes ovatus

BACKGROUND

Fossil ticks are extremely rare and Ixodes succineus Weidner, 1964 from Eocene (ca. 44-49 Ma) Baltic amber is one of the oldest examples of a living hard tick genus (Ixodida: Ixodidae). Previous work suggested it was most closely related to the modern and widespread European sheep tick Ixodes ricinus (Linneaus, 1758).

RESULTS

Restudy using phase contrast synchrotron x-ray tomography yielded images of exceptional quality. These confirm the fossil's referral to Ixodes Latreille, 1795, but the characters resolved here suggest instead affinities with the Asian subgenus Partipalpiger Hoogstraal et al., 1973 and its single living (and medically significant) species Ixodes ovatus Neumann, 1899. We redescribe the amber fossil here as Ixodes (Partipalpiger) succineus.

CONCLUSIONS

Our data suggest that Ixodes ricinus is unlikely to be directly derived from Weidner's amber species, but instead reveals that the Partipalpiger lineage was originally more widely distributed across the northern hemisphere. The closeness of Ixodes (P.) succineus to a living vector of a wide range of pathogens offers the potential to correlate its spatial and temporal position (northern Europe, nearly 50 million years ago) with the estimated origination dates of various tick-borne diseases.

Morphological features of Ixodes persulcatus and I. ricinus hybrids: nymphs and adults

Our aim was to reveal morphological features of first-generation Ixodes persulcatus and I. ricinus hybrids (nymphs and adults) obtained under laboratory conditions for further study of natural populations of these species in sympatry foci. In 65 nymphs of three groups I. ricinus (23 specimens), I. persulcatus (21 specimens), and hybrids (21 specimens), 16 parameters were evaluated (length/width of the scutum and capitulum, length of the hypostome, palp, tarsus I, coxa I, sternal setae, and various scutal and alloscutal setae) and discrimination analysis was performed allowing differentiation of hybrid nymphs from original species. General effectiveness of classification of I. ricinus, I. persulcatus, and hybrids was >95 %. Discriminant functions are presented allowing classification of I. persulcatus, I. ricinus, and hybrid nymphs. For description of morphology, 27 adult hybrids (13 males and 14 females) were examined under a stereo microscope at 14-28× (without preparation of permanent mounts). The following morphological distinctions of hybrids from original species were described: posterior marginal groove is not clear (as in I. ricinus) and absence of syncoxa on coxa I (as in I persulcatus). In hybrid males, simultaneous absence of syncoxa on coxa I (as in I. persulcatus) and a long internal spur on coxa I (as in I. ricinus) can be used as a diagnostic feature. Based on the detected characteristics, 10 of 157 ticks collected in Karelia in I. ricinus and I. persulcatus sympatry area were classified as hybrids.

Tick infestation in birds and prevalence of pathogens in ticks collected from different places in Germany

The importance of ticks and tick-borne pathogens for human and animal health has been increasing over the past decades. For their transportation and dissemination, birds may play a more important role than wingless hosts. In this study, tick infestation of birds in Germany was examined. Eight hundred ninety-two captured birds were infested with ticks and belonged to 48 different species, of which blackbirds (Turdus merula) and song thrushes (Turdus philomelos) were most strongly infested. Ground feeders were more strongly infested than non-ground feeders, sedentary birds more strongly than migratory birds, and short-distance migratory birds more strongly than long-distance migratory birds. Mean tick infestation per bird ranged between 2 (long-distance migratory bird) and 4.7 (sedentary bird), in some single cases up to 55 ticks per bird were found. With the exception of three nymphs of Haemaphysalis spp., all ticks belonged to Ixodes spp., the most frequently detected tick species was Ixodes ricinus. Birds were mostly infested by nymphs (65.1 %), followed by larvae (32.96 %). Additionally, ticks collected from birds were examined for several pathogens: Tick-borne encephalitis virus (TBEV) and Sindbisvirus with real-time RT-PCR, Flaviviruses, Simbuviruses and Lyssaviruses with broad-range standard RT-PCR-assays, and Borrelia spp. with a Pan-Borrelia real-time PCR. Interestingly, no viral pathogens could be detected, but Borrelia spp. positive ticks were collected from 76 birds. Borrelia (B.) garinii, B. valaisiaina, B. burgdorferi s.s. and B. afzelii were determined. The screening of ticks and birds for viral pathogens with broad range PCR-assays was tested and the use as an “early warning system” is discussed.

Passive surveillance for ticks on horses in Saskatchewan

Passive surveillance of ticks on horses in Saskatchewan revealed that the horses were parasitized by 3 species, Dermacentor albipictus, D. andersoni, and D. variabilis. The nymphs and adults of D. albipictus occurred on horses earlier in the year than did adults of the 2 other species.

Virome analysis of Amblyomma americanum, Dermacentor variabilis, and Ixodes scapularis ticks reveals novel highly divergent vertebrate and invertebrate viruses

A wide range of bacterial pathogens have been identified in ticks, yet the diversity of viruses in ticks is largely unexplored. In the United States, Amblyomma americanum, Dermacentor variabilis, and Ixodes scapularis are among the principal tick species associated with pathogen transmission. We used high-throughput sequencing to characterize the viromes of these tick species and identified the presence of Powassan virus and eight novel viruses. These included the most divergent nairovirus described to date, two new clades of tick-borne phleboviruses, a mononegavirus, and viruses with similarity to plant and insect viruses. Our analysis revealed that ticks are reservoirs for a wide range of viruses and suggests that discovery and characterization of tick-borne viruses will have implications for viral taxonomy and may provide insight into tick-transmitted diseases.

IMPORTANCE

Ticks are implicated as vectors of a wide array of human and animal pathogens. To better understand the extent of tick-borne diseases, it is crucial to uncover the full range of microbial agents associated with ticks. Our current knowledge of the diversity of tick-associated viruses is limited, in part due to the lack of investigation of tick viromes. In this study, we examined the viromes of three tick species from the United States. We found that ticks are hosts to highly divergent viruses across several taxa, including ones previously associated with human disease. Our data underscore the diversity of tick-associated viruses and provide the foundation for further studies into viral etiology of tick-borne diseases.

Population-based passive tick surveillance and detection of expanding foci of blacklegged ticks Ixodes scapularis and the Lyme disease agent Borrelia burgdorferi in Ontario, Canada

We identified ticks submitted by the public from 2008 through 2012 in Ontario, Canada, and tested blacklegged ticks Ixodes scapularis for Borrelia burgdorferi and Anaplasma phagocytophilum. Among the 18 species of ticks identified, I. scapularis, Dermacentor variabilis, Ixodes cookei and Amblyomma americanum represented 98.1% of the 14,369 ticks submitted. Rates of blacklegged tick submission per 100,000 population were highest in Ontario's Eastern region; D. variabilis in Central West and Eastern regions; I. cookei in Eastern and South West regions; and A. americanum had a scattered distribution. Rates of blacklegged tick submission per 100,000 population were highest from children (0-9 years old) and older adults (55-74 years old). In two health units in the Eastern region (i.e., Leeds, Grenville & Lanark District and Kingston-Frontenac and Lennox & Addington), the rate of submission for engorged and B. burgdorferi-positive blacklegged ticks was 47× higher than the rest of Ontario. Rate of spread for blacklegged ticks was relatively faster and across a larger geographic area along the northern shore of Lake Ontario/St. Lawrence River, compared with slower spread from isolated populations along the northern shore of Lake Erie. The infection prevalence of B. burgdorferi in blacklegged ticks increased in Ontario over the study period from 8.4% in 2008 to 19.1% in 2012. The prevalence of B. burgdorferi-positive blacklegged ticks increased yearly during the surveillance period and, while increases were not uniform across all regions, increases were greatest in the Central West region, followed by Eastern and South West regions. The overall infection prevalence of A. phagocytophilum in blacklegged ticks was 0.3%. This study provides essential information on ticks of medical importance in Ontario, and identifies demographic and geographic areas for focused public education on the prevention of tick bites and tick-borne diseases.

[The role of birds in the maintenance of tick-borne infections in the Tomsk anthropurgic foci]

The role of birds in the focus of tick-borne infections was studied from 2006 to 2011. The frequency index of ticks carried by ground dwelling birds is about 49.7%. The index of their abundance is 3.8. The larvae of ticks have been found on birds in 43.8% of cases. Nymphs and adult ticks have been found in 39.9 and 16.3%, respectively. It was revealed that Ixodex pavlovskyi was transferred and dominated in the urban microfoci because of its ornithophily. The markers of infectious agents have been recorded in 42 of 60 bird species under study.

Comparison of the DNA sequences and secondary structure of the mitochondrial 16S rRNA gene of Ixodes kingi, Ixodes sculptus and Ixodes angustus

The DNA sequences and predicted secondary structure of domains IV and V of the mitochondrial (mt) 16S rRNA gene were compared for three species of Ixodes: Ixodes kingi, Ixodes sculptus and Ixodes angustus. Each species had a unique set of DNA sequences for the 16S gene. Many of the differences in DNA sequence within and among species occurred in a "hypervariable" region of domain V, and either represented partial or full compensatory base pair changes that maintained the helices within the secondary structure, or nucleotide alterations at unpaired positions that had no effect on the secondary structure. The results of the phylogenetic analyses revealed that I. kingi, I. sculptus and I. angustus were placed in a clade with some other species of the subgenera Pholeoixodes and Ixodiopsis. In addition, individuals of I. sculptus from Saskatchewan (Canada) and Colorado (USA) did not form a monophyletic clade, suggesting the possible existence of cryptic species.

Evidence for Ixodes holocyclus (Acarina: Ixodidae) as a vector for human lyme Borreliosis infection in Australia

Ixodes holocyclus (Acarina: Ixodidae) and Ixodes cornuatus (Acarina: Ixodidae) are two tick species found in the more densely populated areas of Australia and are known to be the cause of the neurotoxic disease tick paralysis in humans and mammals. Borreliosis otherwise known as Lyme disease is an emerging infectious disease in humans in Australia. Borrelia burgdorferi sensu stricto (Spirochaetales: Spirochaetaceae) and sensu lato are closely related spirochetal species that are the causative agents of Lyme disease in humans. Clinical transmission of this tick-borne disease can be identified in several but not all cases by a characteristic rash known as erythema migrans. However, there has been no study of the tick vectors of this infection in Australia. We used morphological and molecular techniques to identify unequivocally the ticks on the patients of this study to be I. holocyclus and then show the presence of B. burgdorferi sensu stricto infection in erythema migrans biopsies. I. holocyclus has not previously been associated with erythema migrans or Lyme disease. Two patients presented to the lead author's medical practice with erythema migrans in mid and late 2012. The morphology and cytochrome oxidase 1 and ITS2 genes of the two ticks were studied. The skin at the attachment site was sampled by central biopsy for both real time and endpoint Borrelia polymerase chain reaction (PCR) analysis and subsequent sequencing. Morphologically, the two ticks were either I. holocyclus or I. cornuatus. Molecular studies and nucleotide sequencing revealed that both ticks were I. holocyclus. Real time and endpoint PCR on the central tissue biopsy samples returned positive results for B. burgdorferi DNA. Our results are evidence for transmission of B. burgdorferi sensu stricto species to humans by the tick I. holocyclus in Australia. I. holocyclus is commonly associated with human tick bites on virtually the entire eastern coastline of Australia.

Isolation and characterization of ten polymorphic microsatellite loci in Ixodes arboricola, and cross-amplification in three other Ixodes species

We characterized ten polymorphic microsatellite loci from the tree-hole tick, Ixodes arboricola. Loci were screened in 11-18 individuals from three Belgian populations and five to ten alleles were found at each locus. Seven loci did not show deviations from Hardy-Weinberg equilibrium conditions and there were no indications for null alleles at these loci. The three other loci showed significant heterozygote deficiencies in at least one population, and a high potential for the occurrence of null alleles. We observed no effect of potential host DNA on the scoring of the microsatellites. Cross-amplification of the microsatellites was tested in eight specimens of three congeneric species: I. ricinus, I. hexagonus and I. frontalis. Depending on the species, six or seven of the loci were amplified in ≥ 4 of the 8 specimens and were polymorphic in each of these species (except for Ixaf 11 in I. frontalis and I. ricinus). These loci thus provide a tool for population genetic analysis of I. arboricola. The suitability of these markers needs to be further investigated in its congeners.

Receptors for the neuropeptides, myoinhibitory peptide and SIFamide, in control of the salivary glands of the blacklegged tick Ixodes scapularis

Tick salivary glands are important organs that enable the hematophagous feeding of the tick. We previously described the innervation of the salivary gland acini types II and III by a pair of protocerebral salivary gland neurons that produce both myoinhibitory peptide (MIP) and SIFamide (Šimo et al., 2009b). In this study we identified authentic receptors expressed in the salivary glands for these neuropeptides. Homology-based searches for these receptors in the Ixodes scapularis genome sequence were followed by gene cloning and functional expression of the receptors. Both receptors were activated by low nanomolar concentrations of their respective ligands. The temporal expression patterns of the two ligands and their respective receptors suggest that the SIFamide signaling system pre-exists in unfed salivary glands, while the MIP system is activated upon initiation of feeding. Immunoreactivity for the SIFamide receptor in the salivary gland was detected in acini types II and III, surrounding the acinar valve and extending to the basal region of the acinar lumen. The location of the SIFamide receptor in the salivary glands suggests three potential target cell types and their probable functions: myoepithelial cell that may function in the contraction of the acini and/or the control of the valve; large, basally located dopaminergic granular cells for regulation of paracrine dopamine; and neck cells that may be involved in the control of the acinar duct and its valve.

[Concerning the problem of the northern limit of Ixodes persulcatus (Acari: Ixodidae) distribution in Karelia]

The influence of changes in climate conditions on the abundance and formation of the northern limit of Ixodes persulcatus distribution in Karelia has been studied. It has been demonstrated that the territory in which the heat provision is sufficient for the development of ixodid ticks significantly increased during 2000-2007. Thus, it favored an increase in the abundance and enhanced distribution of I. persulcatus.

Ixodes persulcatus, a major vector of Alphaproteobacteria in Russia

Ixodes persulcatus Schulze, 1930 (I. persulcatus) is distributed from the western to the eastern borders of Russia where it is found in the taiga and in mixed forests of the European type. This tick is a known vector of viral (tick-borne encephalitis virus), spirochetal (Borrelia spp.), and protozoan (Babesia spp.) agents. In this work, we analyzed the phylogenetic position of I. persulcatus within the Prostriata based on its 18S rRNA gene. Furthermore, we review the relationship of this tick with 9 Alphaproteobacteria from the genera Rickettsia, Ehrlichia, and Anaplasma which are found in I. persulcatus in the territory of Russia. These observations suggest that I. persulcatus may be one of the more important vectors and reservoirs of Alphaproteobacteria and other microorganisms in Russia.

[Changes in the ranges of pasture ixodid ticks of the genus Ixodes Latr., 1795 (Parasitiformes, Ixodinae) in Western Siberia]

The character of distribution of two species from the genus Ixodes, the Taiga tick Ixodes persulcatus and Ixodes pavlovskyi in the plain part of Western Siberia is analyzed. The northern border of the range of I. persulcatus in HMAO-Ugra was clarified on the basis of long-term data on the population density of adult and immature ticks (1960-2011). The shift of the southern border of the species range in Western Siberia at the background of anthropogenic transformation (forest restoring activity, stopped sanitary forest cutting, road construction etc) is demonstrated; peculiarities of the distribution of the Taiga tick in some localities of the southwestern Siberia is analyzed. The modern state of the tick population in the joint dwelling zone of I. persulcatus and I. pavlovskyi is characterized. Possible reasons of changes in the structure of tick communities toward total prevalence of I. pavlovskyi in recreation zones of Novosibirsk and Tomsk are discussed. It is noted that the most significant changes in the character of distribution of these two tick species in Western Siberia had evidently occurred after 1990. Just in this period, local stable populations of the Taiga tick to the south of its main range in Western Siberia (within Omsk and Novosibirsk Provinces) were formed; the character of its distribution in the right bank of the Ob River (Novosibirsk Province) and in the valley of the Tom River (Tomsk Province) had changed; I. pavlovskyi became the dominating species.

[Identification of Ixodes persulcatus and Ixodes pavlovskyi occidentalis (Ixodidae) by the analysis of the gene fragment COXI (cytochrome oxidase subunit I)]

Ticks of the genus Ixodes were collected in 2010 in the lowland part of Toguchinsk district of Novosibirsk Province (Russia) and in the forest-park area of Novosibirsk Scientific Centre and its outskirts (Sovetskiy district of Novosibirsk), and identified as Ixodes persulcatus (Schulze, 1930) (18 females and 13 males) and Ixodes pavlovskyi (13 females and 10 males). Ten specimens of each sex from each collecting site were examined. The following nine characters were used: the length and width of the scutum (conscutum) and of the gnathosoma in ventral view; the length of palpal segments II-III; the width of the hypostome; the length of idiosoma with scapula, of leg I, of the medial spur on fore coxa (Taiga..., 1985; Filippova, Musatov, 1996; Filippova, Panova, 1998). According to morphometric characters, specimens of Ixodes pavlovskyi collected in the forest-park area of the Novosibirsk Scientific Centre were identified as the subspecies I. p. occidentalis Filippova et Panova, 1998. Nucleotide sequences of the COI mitochondrial gene fragment were determined for 56 ticks. Phylogenetic analysis of the COI gene fragment in representatives of the persulcatus-ricinus species-group dwelling in Asia demonstrated high degree of conservatism. Molecular-genetic methods allow reliable identification of morphologically similar species I. pavlovskyi and I. persulcatus, pathogenic for humans.

Prevalence, distribution and risk associated with tick infestation of dogs in Great Britain

Current concerns over the potential impacts of climate change and the increased movement between countries of people and companion animals on the distribution of ectoparasites, highlight the need for accurate understanding of existing prevalence patterns. Without these future changes will not be detected. Here, the distribution and prevalence of tick infestations of domestic dogs in Great Britain were examined. A total of 173 veterinary practices were recruited to monitor tick attachment to dogs in their local areas between March and October 2009. Practices selected five dogs at random each week from those brought to the surgery and undertook a thorough, standardized examination for ticks. Each veterinary practice participated for 3 months before being replaced. Any ticks identified were collected and a sample sent to the investigators for identification, along with a clinical history of the dog. A total of 3534 dogs were examined; 810 dogs were found to be carrying at least one tick. Ixodes ricinus (Linnaeus) (Acari: Ixodidae) was identified in 72.1% of cases, Ixodes hexagonus Leach in 21.7% and Ixodes canisuga Johnston in 5.6% of cases. Five samples of Dermacentor reticulatus (Fabricius) (Acari: Ixodidae) were also found, adding to the growing evidence that an established population of D. reticulatus now exists in south-eastern England. Almost all the ticks found were adults. Overall, 19.2% of the veterinary practices reported no tick detections, 50% reported that ≥14.9% of the dogs seen were infested and 14.6% reported that >50% of the dogs inspected carried ticks. The estimated incidence of tick attachment was 0.013 per day in March (lowest) and 0.096 per day in June (highest). A number of risk factors affected the likelihood of tick attachment on dogs. Gundog, terrier and pastoral breed groups were more likely to carry ticks, as were non-neutered dogs. Dogs with shorter hair were less likely to have ticks, and dogs were most likely to carry a tick in June. This study is of value because, unusually, it presents the results of a randomized sample of dogs and gives a prevalence which is higher than those previously recorded in Great Britain.

Species identification of Ixodes granulatus (Acari: Ixodidae) based on internal transcribed spacer 2 (ITS2) sequences

To investigate the genetic specificity of Ixodes granulatus ticks collected from Taiwan, the genetic identities and phylogenetic relationships were analyzed by comparing the sequences of the internal transcribed spacer 2 (ITS2) region obtained from 27 strains of ticks representing twelve species of Ixodes. Five major clades can be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. All these I. granulatus ticks collected from Taiwan and Japan were genetically affiliated to a monophyletic group with highly homogeneous sequences (95.8-99.5% similarity), and can be discriminated from other species and subgenera of Ixodes ticks with a sequence divergence ranging from 13.6% to 62.9%. Moreover, interspecific analysis revealed that four distinct lineages are evident between Ixodes ticks, and all these I. granulatus ticks collected from Taiwan and Japan belong to the same lineage. Our results provide the first investigation on the genetic specificity of I. granulatus ticks, and demonstrate that all these I. granulatus ticks represent a unique lineage distinct from other species and subgenera of Ixodes ticks. The feasibility of ITS2-based genetic analysis for species-specific identification of I. granulatus ticks around East Asia was highly anticipated.

Ticks attacking domestic dogs in the area of the Rymanów district, Subcarpathian province, Poland

Domestic dogs in Poland are attacked by five species of ticks. The present study shows results of research on species of ticks, their intensity and prevalence of infection in the domestic dogs in the district of Rymanów (Subcarpathian province, Poland). Local research was conducted from 25 August 2005 to 27 October 2006 on 82 randomly selected dogs in the veterinarian centre in Rymanów. Collected ticks were put into tubes with 70% ethyl alcohol. Collected and full up ticks were examined straight after being taken out of the preserving liquid. Stereoscopic microscope for species identification was used. The study revealed that domestic dogs in the Rymanów district are hosts for two species of ticks from the Ixodidae family: Ixodes (Ixodes) ricinus (Linnaeus, 1758) and Ixodes (Pholeoixodes) hexagonus Leach, 1815. Only one dog was infected with both tick species simultaneously. The dogs were attacked mainly by females. Ticks usually attached to such places as the neck, ear conches or groin. In general, the prevalence of ticks infestation on domestic dogs was 48.78%; I. ricinus prevalence was 47.56%, whereas I. hexagonus--2.43%. On the basis of obtained results it can be claimed that I. ricinus is more prevalent in the Rymanów district than I. hexagonus, therefore the domestic dogs are more frequently attacked by this species of ticks.

Genetic characterization of ticks from southwestern Romania by sequences of mitochondrial cox1 and nad5 genes

In the present study, samples representing three hard tick species and one soft tick species, namely Dermacentor marginatus, Haemaphysalis punctata, Ixodes ricinus and Argas persicus from southwestern Romania, and one hard tick, Haemaphysalis longicornis, from China were characterized genetically by a portion of mitochondrial cytochrome c oxidase subunit 1 gene (pcox1) and a portion of nicotinamide adenine dinucleotide dehydrogenase subunit 5 gene (pnad5). The pcox1 and pnad5 were amplified separately from individual ticks by PCR, sequenced and analyzed. The length of pcox1 and pnad5 sequences of all samples was 732 and 519 bp, respectively. The intra-specific sequence variation in De. marginatus was 0.1-1.0% for pcox1 and 0.2-1.2% for pnad5, whereas in Ha. punctata it was 0.4-1.9% for pcox1 and 0.4-1.0% for pnad5. For the tick species examined in the present study, sequence comparison revealed that the inter-specific sequence differences were higher: 15.9-27.6% for pcox1 and 20.3-42.4% for pnad5. This suggests that the cox1 and nad5 sequences could provide useful genetic markers for the specific identification and genetic characterization of ticks in Romania and elsewhere.

Host range and geographical distribution of Ixodes sigelos (Acari: Ixodidae)

Larvae, nymphs and females of Ixodes sigelos Keirans, Clifford and Corwin (Ixodidae) were collected in 13 localities of the Patagonian region of Argentina parasitizing eight species of sigmodontine rodents. We report for the first time adults of I. sigelos for Argentina. Besides, we extend the southern limit of its geographical distribution, and six species of sigmodontines are added as new host species of I. sigelos (Phyllotis xanthopygus, Euneomys chinchilloides, Calomys musculinus, Reithrodon auritus, Loxodontomys micropus and Eligmodontia morgani). The presence of larvae, nymphs and females on sigmodontines, as well as more than 50% of the individuals engorged, indicate that I. sigelos can develop the complete parasitic phase of its life cycle on these small mammals. The geographical distribution of I. sigelos is restricted to the biogeographical Andean Region in Argentina and Chile.

[Pandora's Box: pathogens in Ixodes ricinus ticks in Central Europe]

Among the various species of hard ticks, Ixodes ricinus is the most frequently found tick throughout Europe. As with other ixodid ticks, the developmental cycle runs through three stages. In each stage a blood meal is required in order to develop to the next stage. Ixodes ricinus has been found to feed on more than 300 different vertebrate species. Usually, larval ticks feed on small mammals such as mice and become infected with various microorganisms and viruses, of which some are substantial pathogens to humans. The pathogens remain in the tick during molting and are thus transstadially transmitted to the next developmental stage. Pathogens transmitted to humans are the agents of Lyme borreliosis, the tick-borne encephalitis virus, Rickettsia species, Anaplasma phagocytophilum, occasionally Francisella tularensis, and protozoal Babesia species. Within the scope of an EU project Ixodes ricinus ticks from all federal states of Austria were searched by means of PCR methods for bacterial pathogens such as Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Coxiella burnetii, Ehrlichia spp., Francisella tularensis, Rickettsia spp., and protozoal Babesia. Additionally, the prevalence of Bartonella spp. in this tick species was also determined. Besides the singular detection of Coxiella burnetii and Francisella tularensis in one tick collection site the overall prevalence of Anaplasma phagocytophilum, borreliae, rickettsae and babesiae in Ixodes ricinus amounted to 15%, 14%, 6% and surprising 36% and 51%, respectively. Bartonellae were detected in about 7%.

Confirmation of occurrence of Ixodes (Pholeoixodes) rugicollis Schulze et Schlottke, 1929 (Acari: Ixodidae) in Poland, including the morphological description and diagnostic features of this species

Research on feline and canine ticks was conducted in the years 2004-2005 in the vicinities of Przemyśl, in the village of Torki (Medyka region) and in Przemyśl. Ticks were collected by examining thoroughly the bodies of cats and dogs. Ticks were preserved in 70% ethyl alcohol and their taxonomic identity was determined. It was confirmed that dogs and cats in the study sites carried four species of ticks: Ixodes (Ph.) rugicollis, I. (Ph.) hexagonus, I. (Ph.) crenulatus and I. (I.) ricinus. Ixodes (Ph.) rugicollis was shown to be a common species among the ectoparasites on these hosts and therefore is considered now to be a regular component of the Polish fauna. Morphological characteristics of all the development stages of I. rugicollis are given in the paper.

[Mapping of parasitological environmental data: the tick Ixodes ricinus--a case of study]

While the mapping of health data is not new for epidemiologists the incorporation of differentiated environmental factors, e.g., temperature, rainfall, humidity, elevation, vegetation type, host abundance and distribution, zoonotic reservoirs of infection can create a new opportunities for parasitologists. Suitable tools for spatial modeling of health problems and pathogen occurrence in space and time are provided by geographic information system (GIS). It is computer-based system which integrates, storages, edits, analyses, shares and displays information. This software system is based on connection between information--data and their location. GIS applications allow users to create interactive queries, analyze spatial information, edit data and maps. GIS is very useful to define the habitats of parasites, especially for the ticks which are strong depended on environmental conditions. Mapping not only enables to create maps based on field monitoring but also to create forecasting maps for prevention and control strategies on small and large scale. Up to now ticks and tick-borne diseases (TBD) having strong relationship with the ecosystem are highly amenable to predictive mapping. The aim of study is the characterization of procedural steps with regard to entering field environmental data to GIS database and their visualization on digital maps. The field date of tick monitoring conducted in April 2008 in the Wrocław area (the Osobowicki Forest) made possible to create digital database. ArcView as one of three separate software products of ArcGIS (a scalable framework for implementing GIS) was used to create an interactive maps. Visualization of the data which are stored in tables of attributes made possible to show legibly the distribution of I. ricinus on the analysed area. Mapping of I. ricinus occurrence on digital maps enable to indicate areas of the highest risk of biting and potential tick-borne diseases.

Ticks (Acari: Ixodida) parasitizing bats in Poland and Slovakia

We summarize the previously published reports and the results of our own research about distribution of ticks parasitizing bats in Poland and Slovakia. Five species of ticks infesting bats were recorded: Carios vespertilionis, Ixodes (E.) vespertilionis, I. (P.) simplex, I. (I.) ricinus and I. (Ex.) trianguliceps. Two last species were observed only on bats in Poland. C. vespertilionis, I. vespertilionis and I. simplex are specific parasites of bats. C. vespertilionis was recorded on 37 sites in Poland and 7 in Slovakia. Fourteen species of bats in Poland and 5 in Slovakia were parasitized by this species. I. vespertilionis was collected from 6 bat species both in Poland and Slovakia respectively on 22 and 11 sites, respectively. The remaining species have been reported very rarely.

The estimation scale of endangerment with tick attacks on recreational towns areas

The 5-classed scale of threats with tick's attacks was modelled on the ground diversification of the number of tick collected. The areas above 50 ticks collected per hour, was named as the very high class, minimal level of endangerment (1 to 3 ticks) named low class, medium values were established: medium low class of endangerment, medium class of endangerment, high class of endangerment respectively.

Co-phylogenetic analysis of Anaplasma phagocytophilum and its vectors, Ixodes spp. ticks

The coevolutionary history of Ixodes spp. ticks, the obligately tick-transmitted bacterial pathogen Anaplasma phagocytophilum, and its various rodent reservoir hosts world-wide is not known. According to coevolution theory, the most recently evolved of tick-bacterial complexes could have difficulty maintaining A. phagocytophilum in nature, because transmissibility has not been efficiently maximized. This study was intended to examine the phylogeographic history of I. ricinus-subgroup ticks and A. phagocytophilum, provide an estimate for the date of the divergence of A. marginale and A. phagocytophilum, and evaluate whether there is correspondence between tick and Anaplasma spp. trees. Analysis of Ixodes spp. ticks showed a New World clade consisting of I. scapularis and I. pacificus, European I. ricinus as a sister group to this clade, and Asian I. persulcatus as basal. Of the three A. phagocytophilum genes evaluated, the most resolution was provided by the ankA gene. ankA sequences formed an Old World clade with eastern North America strains as a sister clade. California strains were highly diverse and did not form a clade. Base substitution rates were very comparable along both A. marginale and A. phagocytophilum lineages. Based on 16S rDNA analysis, maximum and minimum divergence times of A. phagocytophilum and A. marginale were calculated to be 78,296,703 and 43,415,708 years, respectively. If A. phagocytophilum did closely coevolve with specific I. ricinus-subgroup tick species, then A. phagocytophilum strains could have specialized on local tick species and optimized local infectivity in the Old World and eastern US. However, lack of absolute resolution of tick trees and conflicting prevalence data (with low prevalence in Asia and western North America) preclude us from inferring a tight coevolutionary relationship of tick species from this phylogeographic analysis.

[Detection of the West Nile Virus and its genetic typing in ixodid ticks (Parasitiformes: Ixodidae) in Tomsk City and its suburbs]

Four tick species, Ixodes persulcatus, I. pavlovskyi, I. trianguliceps, and Dermacentor reticulatus, were found in Tomsk and its suburbs in 2006. The species I. pavlovskyi was found to be dominant in the localities situated in Tomsk City, and I. persulcatus was dominant in its suburbs. Viral RNA and viral antigen of the West Nile virus (WNV) were detected in the ticks I. pavlovskyi and I. persulcatus collected in the city and its suburbs by the RT PCR method and enzyme immunoassay with monoclonal antibodies against protein E of the WNV. Average rate of the WNV infected ticks varied from 5.2 up to 11.7% in different localities. Identification of the nucleotide sequence of the protein E gene fragment allowed classifying the cDNA obtained as genotype Ia of the WNV. The sequences are proved similar to the strain LEIV-Vlg99-27889-human of the WNV isolated in Volgograd. The obtained data showed that natural foci of the WNV virus can appear in the city and its suburbs probably involving two dominant tick species. The WNV infected imagoes, larvae, and nymphs of I. persulcatus and I. pavlovskyi were collected from small mammals, lizards, and birds. Therefore we presume that these hosts can be involved in the circulation and distribution of WNV on the territory of Tomsk Region.

Case report: Borrelia valaisiana infection in a Japanese man associated with traveling to foreign countries

A 78-year-old Japanese man who had clinical symptoms and a flu-like illness with fever, chills, diarrhea, and arthralgia had traveled to Cambodia and Khabarovsk, Russia, before the onset of symptoms and illness. He had been bitten by an Ixodes persulcatus tick in which the DNA of Borrelia valaisiana was detected. The patient's symptoms improved rapidly after treatment with minocycline. Serologic examination detected antibodies to Lyme disease Borrelia. An flaB polymerase chain reaction with the patient's plasma amplified a DNA fragment similar to that of B. valaisiana.

Description of the immature stages and redescription of the female of Ixodes schulzei Aragão & Fonseca, 1951 (Acari: Ixodidae), an endemic tick species of Brazil

Ixodes schulzei Aragão & Fonseca, 1951 is a tick endemic to Brazil, where nine species of Ixodes Latreille, 1796 are currently known to occur. Larvae, nymphs and females of I. schulzei were obtained from a laboratory colony originating from an engorged female collected on a free-living water rat Nectomys squamipes from the Santa Branca municipality, São Paulo State. Only female ticks were obtained from engorged nymphs. Unfed immature and female adult specimens were measured and the descriptions were based on optical and scanning electron microscopy, as were drawings of some features of the larva. Both immature stages present the very long palpi and basis capituli, and the female has large, contiguous porose areas. However, the basis capituli is triangular, with a slight central elevation in the larva and nymph, whereas in the female this area is depressed. The I. schulzei types deposited at the FIOCRUZ (Instituto Oswaldo Cruz) were also examined, as was other material from collections, such as the IBSP (Coleção Acarológica do Instituto Butantan), CNC-FMVZ/USP (Coleção Nacional de Carrapatos da Faculdade de Medicina Veterinária e Zootecnia da USP) and USNTC (United States National Tick Collection). In addition, the relationship between I. schulzei and other immature neotropical species of Ixodes is discussed.