Prevalence of tick-borne pathogens in Ixodes ricinus and Dermacentor reticulatus ticks from different geographical locations in Belarus

First detection of murine herpesvirus 68 in adult Ixodes ricinus ticks

Murine herpesvirus 68 (MHV-68) is a natural pathogen that infects murid rodents, which serves as hosts for Ixodes ricinus ticks. For the first time, MHV-68 was detected in immature I. ricinus ticks feeding on Lacerta viridis lizards trapped in Slovakia, which supports the idea that ticks can acquire the virus from feeding on infected hosts. The recent discovery of MHV-68 infection and MHV-68 M3 gene transcripts in Dermacentor reticulatus ticks collected in Slovakia also supports this suggestion. Here, for the first time, we report MHV-68 infection, which was detected by nested PCR, in I. ricinus adults collected from the vegetation, and the viral load in infected ticks was determined by quantitative PCR. The viral incidence in ticks was 38.1% (21/55), and the viral load varied from 1.5 × 10³ to 2.85 × 10⁴ genome copies per tick. These results suggest that the I. ricinus ticks became infected with MHV-68 from biting infected rodents; thus, I. ricinus ticks may play a role in the spread of this virus in nature.

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

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

Tick infestation in human beings in the Nilgiris and Kancheepuram district of Tamil Nadu, India

Thirteen human beings were infested with ticks at Sandynallah and Gudalur of the Nilgiris district and Mottur Suruvakkam of Kancheepuram district of Tamil Nadu from January 2016 to December 2016. The collected ticks were identified as Rhipicephalus haemaphysaloides, Otobius megnini and Hyalomma isaaci. The tick infestation was observed more on the persons working with animals (sheep and goats) than those working in tea estate. The person infested with R. haemaphysaloides revealed erythematous papule (2 mm size) and inflammatory lesion up to 16 days whereas, the people infested with H. isaaci showed continuous itching and irritation for > 6 months and wound formation (0.5 cm) at the biting site. The people infested with O. megnini showed irritation, vomiting sensation and fever.

Investigation of Babesia spp. in sympatric populations of Dermacentor reticulatus and Ixodes ricinus ticks in Lithuania and Latvia

The objectives of the present study were to investigate the presence of the Babesia parasites in Dermacentor reticulatus ticks along its current distribution range in Lithuania and Latvia, and Ixodes ricinus in Lithuania, to characterize the detected Babesia spp. using partial sequencing of 18S rRNR gene, and to determine the prevalence of the Babesia pathogens in ticks from different locations of Lithuania and Latvia. From 2013 to 2015, four D. reticulatus nymphs and 2255 questing adults were collected from 40 locations in Lithuania, and 181 questing adult D. reticulatus specimens from 11 locations in Latvia. In Lithuania, 16 questing I. ricinus nymphs and 354 questing adults were collected from 12 locations with the sympatric existence of D. reticulatus and I. ricinus. In Lithuania, Babesia spp. were detected in 1.2% (26/2259) of D. reticulatus and in 9.5% (35/370) of I. ricinus ticks. The overall prevalence of Babesia in D. reticulatus ticks from Latvia was 2.8% (5/181). Sequence analysis of partial 18S rRNA gene of positive samples indicated the presence of B. canis and B. venatorum in D. reticulatus ticks, whereas B. microti and B. venatorum were detected in I. ricinus ticks. Our study is the first investigation on the prevalence and molecular characterization of zoonotic B. canis, B. venatorum, and B. microti in ixodid ticks in Lithuania, and of B. canis in D. reticulatus ticks in Latvia. It is also the first report of B. venatorum in D. reticulatus ticks.

Tick-borne pathogens and their reservoir hosts in northern Italy

The aim of this study was to determine the occurrence of Anaplasma phagocytophilum, Rickettsia spp., Babesia spp., and Candidatus Neoehrlichia mikurensis in Ixodes spp. ticks removed from wildlife, domestic animals and humans in the Province of Trento (northern Italy) in order to better understand their ecology and provide public health professionals with an updated list of pathogens which should be considered during their diagnostic procedures after a tick bite. During 2011-2012, 848 feeding ticks at all life stages (adults, nymphs and larvae) from various hosts (wild ungulates, birds and rodents; domestic sheep, dogs and humans) were collected. The highest prevalences of A. phagocytophilum and Rickettsia spp. were detected in adult and nymphal tick stages feeding on wild ungulates (11.4% prevalence for both pathogens), while the Babesia spp. prevailed in nymphal and larval ticks feeding on wild birds (7.7%). A wide spectrum of tick-borne agents was present in larval ticks: those detached from wild ungulates were positive for A. phagocytophilum, B. venatorum, R. helvetica, R. monacensis and R. raoultii, while those removed from wild rodents were positive for B. venatorum, R. helvetica, R. monacensis and Ca. N. mikurensis, and ticks from wild birds carried A. phagocytophilum, B. venatorum, B. capreoli and R. helvetica. This study provides evidence of circulation of five tick-borne pathogens not reported in this region before, specifically R. raoultii, R. monacensis, B. venatorum, B. capreoli and B. microti. Furthermore, it discusses the epidemiological role of the animal species from which the ticks were collected highlighting the needs for more experimental studies especially for those pathogens where transovarial transmission in ticks has been demonstrated.

Infection of Ixodes ricinus by Borrelia burgdorferi sensu lato in peri-urban forests of France

Lyme borreliosis is the most common tick-borne disease in the northern hemisphere. In Europe, it is transmitted by Ixodes ticks that carry bacteria belonging to the Borrelia burgdorferi sensu lato complex. The objective of this work was to explore eco-epidemiological factors of Lyme borreliosis in peri-urban forests of France (Sénart, Notre-Dame and Rambouillet). We investigated whether the introduction of Tamias sibiricus in Sénart could alter the density of infected ticks. Moreover, the density and tick infection were investigated according to the tree species found in various patches of Sénart forest. For this purpose, ticks were sampled during 3 years. In the Sénart forest, the density of nymph and adult ticks showed no significant difference between 2008, 2009 and 2011. The nymph density varied significantly as a function of the month of collection. Regarding the nymphs, a higher rate of infection and infected density were found in 2009. Plots with chipmunks (C) presented a lower density of both nymphs and adult ticks than plots without chipmunks (NC) did. A higher rate of infection of nymphs with Borrelia was seen in C plots. The prevalence of the various species of Borrelia was also found to vary between C and NC plots with the year of the collect. The presence of chestnut trees positively influenced the density of both nymphs and adults. The infected nymph density showed a significant difference depending on the peri-urban forest studied, Sénart being higher than Rambouillet. The prevalence of Borrelia species also differed between the various forests studied. Concerning the putative role that Tamias sibiricus may play in the transmission of Borrelia, our results suggest that its presence is correlated with a higher rate of infection of questing ticks by Borrelia genospecies and if its population increases, it could play a significant role in the risk of transmission of Lyme borreliosis.

Europe-Wide Meta-Analysis of Borrelia burgdorferi Sensu Lato Prevalence in Questing Ixodes ricinus Ticks

Lyme borreliosis is the most common zoonotic disease transmitted by ticks in Europe and North America. Despite having multiple tick vectors, the causative agent, Borrelia burgdorferisensu lato, is vectored mainly by Ixodes ricinus in Europe. In the present study, we aimed to review and summarize the existing data published from 2010 to 2016 concerning the prevalence of B. burgdorferi sensu lato spirochetes in questing I. ricinus ticks. The primary focus was to evaluate the infection rate of these bacteria in ticks, accounting for tick stage, adult tick gender, region, and detection method, as well as to investigate any changes in prevalence over time. The data obtained were compared to the findings of a previous metastudy. The literature search identified data from 23 countries, with 115,028 ticks, in total, inspected for infection with B. burgdorferi sensu lato We showed that the infection rate was significantly higher in adults than in nymphs and in females than in males. We found significant differences between European regions, with the highest infection rates in Central Europe. The most common genospecies were B. afzelii and B. garinii, despite a negative correlation of their prevalence rates. No statistically significant differences were found among the prevalence rates determined by conventional PCR, nested PCR, and real-time PCR.IMPORTANCEBorrelia burgdorferisensu lato is a pathogenic bacterium whose clinical manifestations are associated with Lyme borreliosis. This vector-borne disease is a major public health concern in Europe and North America and may lead to severe arthritic, cardiovascular, and neurological complications if left untreated. Although pathogen prevalence is considered an important predictor of infection risk, solitary isolated data have only limited value. Here we provide summarized information about the prevalence of B. burgdorferi sensu lato spirochetes among host-seeking Ixodes ricinus ticks, the principal tick vector of borreliae in Europe. We compare the new results with previously published data in order to evaluate any changing trends in tick infection.

The enzootic life-cycle of Borrelia burgdorferi (sensu lato) and tick-borne rickettsiae: an epidemiological study on wild-living small mammals and their ticks from Saxony, Germany

BACKGROUND

Borrelia burgdorferi (sensu lato) and rickettsiae of the spotted fever group are zoonotic tick-borne pathogens. While small mammals are confirmed reservoirs for certain Borrelia spp., little is known about the reservoirs for tick-borne rickettsiae. Between 2012 and 2014, ticks were collected from the vegetation and small mammals which were trapped in Saxony, Germany. DNA extracted from ticks and the small mammals' skin was analyzed for the presence of Rickettsia spp. and B. burgdorferi (s.l.) by qPCR targeting the gltA and p41 genes, respectively. Partial sequencing of the rickettsial ompB gene and an MLST of B. burgdorferi (s.l.) were conducted for species determination.

RESULTS

In total, 673 small mammals belonging to eight species (Apodemus agrarius, n = 7; A. flavicollis, n = 214; Microtus arvalis, n = 8; Microtus agrestis, n = 1; Mustela nivalis, n = 2; Myodes glareolus, n = 435; Sorex araneus, n = 5; and Talpa europaea, n = 1) were collected and examined. In total, 916 questing ticks belonging to three species (Ixodes ricinus, n = 741; Dermacentor reticulatus, n = 174; and I. trianguliceps, n = 1) were collected. Of these, 474 ticks were further investigated. The prevalence for Rickettsia spp. and B. burgdorferi (s.l.) in the investigated small mammals was 25.3 and 31.2%, respectively. The chance of encountering Rickettsia spp. in M. glareolus was seven times higher for specimens infested with D. reticulatus than for those which were free of D. reticulatus (OR: 7.0; 95% CI: 3.3-14.7; P < 0.001). In total, 11.4% of questing I. ricinus and 70.5% of D. reticulatus were positive for Rickettsia spp. DNA of B. burgdorferi (s.l.) was detected only in I. ricinus (5.5%). Sequence analysis revealed 9 R. helvetica, 5 R. raoultii, and 1 R. felis obtained from 15 small mammal samples.

CONCLUSION

Small mammals may serve as reservoirs for Rickettsia spp. and B. burgdorferi (s.l.). While the prevalence for Rickettsia spp. in M. glareolus is most likely depending on the abundance of attached D. reticulatus, the prevalence for B. burgdorferi (s.l.) in small mammals is independent of tick abundance. Dermacentor reticulatus may be the main vector of certain Rickettsia spp. but not for Borrelia spp.

Novel Rickettsia raoultii strain isolated and propagated from Austrian Dermacentor reticulatus ticks

Background

Continuous culture of tick cell lines has proven a valuable asset in isolating and propagating several different vector-borne pathogens, making it possible to study these microorganisms under laboratory conditions and develop serological tests to benefit public health. We describe a method for effective, cost- and labor-efficient isolation and propagation of Rickettsia raoultii using generally available laboratory equipment and Rhipicephalus microplus cells, further demonstrating the usefulness of continuous tick cell lines. R. raoultii is one of the causative agents of tick-borne lymphadenopathy (TIBOLA) and is, together with its vector Dermacentor reticulatus, emerging in novel regions of Europe, giving rise to an increased threat to general public health.

Methods

Dermacentor reticulatus ticks were collected in the Donau-Auen (Lobau) national park in Vienna, Austria. The hemolymph of ten collected ticks was screened by PCR-reverse line blot for the presence of rickettsial DNA. A single tick tested positive for R. raoultii DNA and was used to infect Rhipicephalus microplus BME/CTVM2 cells.

Results

Sixty-five days after infection of the tick-cell line with an extract from a R. raoultii-infected tick, we observed intracellular bacteria in the cultured cells. On the basis of microscopy we suspected that the intracellular bacteria were a species of Rickettsia; this was confirmed by several PCRs targeting different genes. Subsequent sequencing showed 99–100 % identity with R. raoultii. Cryopreservation and resuscitation of R. raoultii was successful. After 28 days identical intracellular bacteria were microscopically observed.

Conclusions

R. raoultii was successfully isolated and propagated from D. reticulatus ticks using R. microplus BME/CTVM2 cells. The isolated strain shows significant molecular variation compared to currently known sequences. Furthermore we show for the first time the successful cryopreservation and resuscitation of R. raoultii.

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

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

Emergence of tick-borne pathogens (Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Ricketsia raoultii and Babesia microti) in the Kyiv urban parks, Ukraine

To date, only limited data about the presence of ticks and circulation of tick-borne pathogens in urban parks of Kyiv in northern Ukraine are available. In total, 767 ticks (696 Ixodes ricinus and 69 Dermacentor reticulatus) collected in seven urban parks and one suburban oak wood park in Kyiv were individually analyzed by the PCR assays. Tick-borne pathogens, namely spirochetes from Borrelia burgdorferi sensu lato complex, Anaplasma phagocytophilum, and Babesia microti, were detected in 11.1% of tested I. ricinus ticks. In total, 4% of I. ricinus ticks tested positive for the presence of B. burdorferi s.l. (Borrelia afzelii and Borrelia garinii), 5.2% for A. phagocytophilum, and Ba. microti was confirmed in 1.9% of examined ticks. Mixed infections were recorded in four DNA samples, representing the prevalence of 0.6%. One female and two I. ricinus nymphs were simultaneously infected with B. afzelii and A. phagocytophilum, and one female carried B. afzelii and Ba. microti. In addition, 10.1% of D. reticulatus ticks tested positive for Rickettsia raoultii. Identification of infectious agents and their diversity, assessment of the relative epidemiological importance and determination of the prevalence in questing ticks from central parts of the cities are crucial steps towards the tick-borne diseases surveillance in urban environment.

Coxiella burnetii in central Italy: novel genotypes are circulating in cattle and goats

Genotyping of bacteria is critical for diagnosis, treatment, and epidemiological surveillance. Coxiella burnetii, the etiological agent of Q fever, has been recognized to have a potential for bioterrorism purposes. Because few serosurveys have been conducted in Italy, there is still limited information about the distribution of this pathogen in natural conditions. In this paper, we describe the genotyping of C. burnetii strains by multispacer sequence typing (MST) detected in cattle and goat farms in the Abruzzi region of Italy. Biological samples (milk, aborted fetus) positive for C. burnetii DNA were sequenced in the spacer regions and compared with those already publicly available ( http://ifr48.timone.univ-mrs.fr/MST_Coxiella/mst/group_detail ). The MST profile of C. burnetii detected in milk samples demonstrated the presence of a new allele, whereas the C. burnetii spacer sequences from fetus and milk goat samples displayed a new allelic combination. The results suggest the circulation of novel genotypes of C. burnetii in Italy.

Dermacentor reticulatus: a vector on the rise

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

Infection with Babesia microti in humans with non-specific symptoms in North East Poland

AIM

The aim of the study was to evaluate the clinical course and effectiveness of diagnostics tools for Babesia spp. infection in patients bitten by ticks.

MATERIALS AND METHODS

Five hundred and forty-eight patients hospitalised or seen in outpatients department because of various symptoms after a tick bite were included in the study. PCR, nucleotide sequencing of Babesia 18S rRNA gene fragment, blood smears and serological tests for Babesia spp., TBEV, A. phagocytophilum and B. burgdorferi were performed in all patients. Six patients infected with Babesia were included in the final analysis. They had PCR, Babesia 18S rRNA gene fragment nucleotide sequencing, blood smears and serological tests for Babesia spp., TBEV, A. phagocytophilum and B. burgdorferi performed twice.

RESULTS

Tick-borne infection with Babesia microti in six immunocompetent patients with non-specific symptoms was confirmed for the first time in Poland. No severe course of the disease was seen. No piroplasm forms were noticed within erythrocytes on blood smear. Three patients developed a serological response.

CONCLUSIONS

Immunocompetent patients may be unaware of infection with Babesia microti after a tick bite. It must be included in the differential diagnosis after the tick bite. In patients with low parasitaemia PCR and serology seem useful when blood smear is negative. Self-elimination of Babesia spp. is possible, especially in cases with low parasitaemia.

Prevalence and phylogenetic analysis of Babesia spp. in Ixodes ricinus and Ixodes persulcatus ticks in Latvia

Babesia spp. are tick-borne protozoan parasites that have been reported in many European countries and are considered to be emerging pathogens. Several Babesia spp. have been identified in ticks in Latvia. Recently, canine babesiosis cases were diagnosed for the first time in Latvia; therefore, continued studies on the prevalence and occurrence of new species are warranted. In the present study, questing tick samples collected in 2005-2007 were screened for the presence of Babesia spp.; in total, 432 Ixodes ricinus and 693 Ixodes persulcatus ticks were analyzed. Babesia spp. were detected in 1.4% of the I. ricinus ticks and in 1.9% of I. persulcatus ticks. Sequencing revealed that ixodid ticks in Latvia contained Babesia microti, Babesia capreoli, and Babesia venatorum. Babesia microti was the most prevalent species, accounting for 58% of all positive samples; moreover, two distinct B. microti genotypes were identified. Phylogenetic analysis of the full-length 18S rRNA gene of two B. capreoli/B. divergens isolates indicated a closer relationship to the B. capreoli clade than B. divergens. This is the first report of B. venatorum in I. persulcatus ticks in Latvia. Our results suggest that both I. ricinus and I. persulcatus ticks play important roles in the epidemiology of these zoonotic pathogens in Latvia.

First Molecular Evidence of Zoonotic Bacteria in Ticks in Bosnia and Herzegovina

In Bosnia and Herzegovina, the tick fauna is very diverse, but data on the occurrence of zoonotic tick-borne bacteria are lacking. Thus, the aim of this study was to investigate the presence of Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, 'Candidatus Neoehrlichia mikurensis', spotted fever group (SFG) rickettsiae and Francisella tularensis in questing ticks. In 19 (21.8%) of 87 ticks (Ixodes ricinus, n = 30; Dermacentor reticulatus, n = 54; D. marginatus, n = 3) collected by flagging the vegetation at the collection site in the Glamoč Municipality (south-western Bosnia and Herzegovina), Rickettsia monacensis (1.1%), R. helvetica (5.7%), R. raoultii (5.7%), R. slovaca (8.0%), A. phagocytophilum (1.1%) and F. tularensis subsp. holartica (1.1%) were detected and identified by molecular methods. None of the tested ticks were positive for B. burgdorferi s.l. and 'Candidatus N. mikurensis', and co-infection of R. slovaca and F. tularensis subsp. holarctica was detected in only one D. marginatus (1.1%). This study reports the occurrence of emerging zoonotic bacteria in ticks from Bosnia and Herzegovina for the first time, indicating a public health threat to humans. Therefore, physicians and practitioners should be aware of the presence of these tick-borne bacteria, especially when they are faced with acute febrile illnesses after tick exposure.

Detection of Babesia venatorum, Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis in Ixodes persulcatus ticks from Mongolia

Information about the prevalence and geographical distribution of tick-borne pathogens Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, and Babesia spp. is still rare in Mongolia. We tested 275 Ixodes persulcatus ticks for A. phagocytophilum, Cand. N. mikurensis and Babesia spp. and 125 Dermacentor nuttalli ticks especially for Babesia spp. using different PCR methods. Ticks were collected from three provinces (Selenge, Arkhangai, Khentii) in Mongolia. DNA of A. phagocytophilum, Cand. N. mikurensis and Babesia spp. were found with a prevalence of 6.2%, 1.5% and 3.3% in each case in I. persulcatus ticks. This is the first time Cand. N. mikurensis was found in ticks from Mongolia. Sequence analysis of Babesia spp.-positive amplicons showed exclusively B. venatorum, which had also not been mentioned in Mongolia before. On the contrary, all D. nuttalli ticks tested negatively for Babesia spp. This study demonstrates that all three zoonotic pathogens are present in I. persulcatus ticks in Mongolia, and justify the need for further investigations of a more detailed genetic characterization of these pathogens.

Molecular methods routinely used to detect Coxiella burnetii in ticks cross-react with Coxiella-like bacteria

BACKGROUND

Q fever is a widespread zoonotic disease caused by Coxiella burnetii. Ticks may act as vectors, and many epidemiological studies aim to assess C. burnetii prevalence in ticks. Because ticks may also be infected with Coxiella-like bacteria, screening tools that differentiate between C. burnetii and Coxiella-like bacteria are essential.

METHODS

In this study, we screened tick specimens from 10 species (Ornithodoros rostratus, O. peruvianus, O. capensis, Ixodes ricinus, Rhipicephalus annulatus, R. decoloratus, R. geigy, O. sonrai, O. occidentalis, and Amblyomma cajennense) known to harbor specific Coxiella-like bacteria, by using quantitative PCR primers usually considered to be specific for C. burnetii and targeting, respectively, the IS1111, icd, scvA, p1, and GroEL/htpB genes.

RESULTS

We found that some Coxiella-like bacteria, belonging to clades A and C, yield positive PCR results when screened with primers initially believed to be C. burnetii-specific.

CONCLUSIONS

These results suggest that PCR-based surveys that aim to detect C. burnetii in ticks by using currently available methods must be interpreted with caution if the amplified products cannot be sequenced. Future molecular methods that aim at detecting C. burnetii need to take into account the possibility that cross-reactions may exist with Coxiella-like bacteria.

Geographical distribution of Dermacentor marginatus and Dermacentor reticulatus in Europe

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

Detection of Murine Herpesvirus 68 (MHV-68) in Dermacentor reticulatus Ticks

Murid herpesvirus 4 (MuHV 4) strain 68 (MHV-68) is a natural pathogen of murid rodents, which serves as hosts to Dermacentor reticulatus ticks. These ticks are known to transmit multiple pathogens, which can cause diseases in humans and animals. Recently, the detection of MHV-68 antibodies in the blood of animals living in the same biotope as virus-infected mice has suggested the role of ticks in pathogen circulation in nature. Herein, to identify MHV-68 in D. reticulatus ticks, DNA samples from 432 adults were collected at two sites in southwestern Slovakia from 2011 to 2014. Samples were examined by polymerase chain reaction (PCR), targeting ORF50 of MHV-68. Ignoring season and locality, we have found 25.9 % of the male and 44.9 % of the female ticks to be positive. Within ticks collected in Vojka, 40 % (125/312) became positive, at a rate of approximately 6.8 times higher in spring than in autumn (66 vs 9.7 %). In addition, in the spring, 1.4 times more females were positive than males. Within ticks collected in Gabčíkovo, 23.3 % (28/120) became positive, with positive females being twice as frequent. The infecting virus was identified by analyzing amplified products via sequencing and restriction fragment length polymorphism (RFLP) analyses. Using an explantation/co-cultivation procedure, we examined the salivary glands, intestines, and ovaries of five females for live MHV-68. In all organs of two ticks, we identified a virus capable of replication in mammalian cells. This is the first report of MHV-68 detection in D. reticulatus ticks and of a live virus in their organs. Findings encourage further study to determine whether this potential arbovirus, found in salivary glands, is transmissible. It further supports the hypothesis regarding the mediating role of ticks in MHV-68 circulation in nature.

Pathogens vectored by the tick, Dermacentor reticulatus, in endemic regions and zones of expansion in Poland

Background

Dermacentor reticulatus plays an important role in the maintenance of pathogens of medical and veterinary importance in the environment. Currently two isolated populations of D. reticulatus are present in Poland –Western and Eastern. The range of the Eastern population covers endemic areas in eastern Poland but this population is expanding westwards creating an expansion zone in the centre of the country. The expansion zone in western Poland is occupied by the recently discovered Western population, spreading eastwards.

Methods

Questing adult ticks (n = 2585) were collected in 2012–2014 in endemic regions of north-eastern (Warmińsko-Mazurskie Voivodeship) and central Poland (Masovian Voivodeship) and in the expansion zones in central and western Poland, in the region between the Vistula River and the western border of the country. Amplification of Babesia, Rickettsia spp. and Borrelia burgdorferi sensu lato DNAs was performed using specific starters. RNA of the TBE virus was detected using RT-PCR and representative PCR products were sequenced and compared with sequences deposited in GenBank.

Results

Of the total 2585 examined ticks, 1197 (46.3 %) were infected with at least one pathogen. Overall prevalence of pathogens was 4.18 % (108/2585) for Babesia spp., 44.10 % (1140/2585) for Rickettsia spp., 0.09 % (1/1107) for Borrelia afzelii and 7.6 % (7/92) for TBEV. Sequence analysis of DNA showed 99.86 % similarity to R. raoulti and 99.81 % to B. canis. One male from north-eastern Poland was infected with B. microti.

Prevalence of R. raoulti was highest in the Western population (52.03 %) and lowest in the Eastern population in north-eastern Poland (34.18 %). Babesia canis was not detected in 592 ticks collected in the Western population, while in the Eastern population overall prevalence was 5.42 %. There were significant differences in the prevalence of B. canis between tick samples from northern (0.68 %), central (1.18 %) and southern (14.8 %) areas of the expansion zone in central Poland.

Conclusions

Our study found significant differences between the range and prevalence of vectored pathogens in D. reticulatus from the endemic areas and newly inhabited expansion zones. The differences were likely associated with the different time of settlement or ‘source’ of ticks populations, the Eastern and the Western one.

Epidemiology and ecology of tularemia in Sweden, 1984-2012

Geographic distribution of cases was correlated with the locations of lakes and rivers.

The zoonotic disease tularemia is endemic in large areas of the Northern Hemisphere, but research is lacking on patterns of spatial distribution and connections with ecologic factors. To describe the spatial epidemiology of and identify ecologic risk factors for tularemia incidence in Sweden, we analyzed surveillance data collected over 29 years (1984–2012). A total of 4,830 cases were notified, of which 3,524 met all study inclusion criteria. From the first to the second half of the study period, mean incidence increased 10-fold, from 0.26/100,000 persons during 1984–1998 to 2.47/100,000 persons during 1999–2012 (p<0.001). The incidence of tularemia was higher than expected in the boreal and alpine ecologic regions (p<0.001), and incidence was positively correlated with the presence of lakes and rivers (p<0.001). These results provide a comprehensive epidemiologic description of tularemia in Sweden and illustrate that incidence is higher in locations near lakes and rivers.

Mapping of Dermacentor reticulatus expansion in Poland in 2012-2014

Rapid expansion of the tick Dermacentor reticulatus (Fabricius) has been reported in many European countries. In Poland its range was limited to the area on the eastern side of the Vistula River up until the 1990s. However, new foci were recently discovered, while the centre of the country and mountain regions are believed to be free of this tick and are known as "the gap". A few unconfirmed factors, like unfavourable weather conditions, changes in land cover and absence of competent hosts have previously been reported as possible reasons for the absence of D. reticulatus in this area. Since D. reticulatus plays an important role for the maintenance and the circulation of tick-borne pathogens, we (1) determined its actual range in Poland, (2) monitored its expansion in 2012-2014 and (3) correlated abiotic conditions on its known range. Dragging was conducted in the area between the Vistula River and the western border of Poland in 2012-2014, along the three major Polish rivers and their tributaries. Temperature and humidity on the ground were recorded 4 times a day at a total of 32 sites. D. reticulatus was found in 21 new locations on the western side of the Vistula River and in 22 locations in western Poland. The presence of this tick species was confirmed for the first time in Wielkopolskie, Kujawsko-Pomorskie and Łódzkie voivodeships. Existence of 'the gap' was confirmed on a strip of land along the northwest-southeast axis (an area of approximately 151000km(2)), that extends between Zachodniopomorskie and Pomorskie in the North, and the mountain areas with foothills in the South, in Opolskie, Śląskie, Małopolskie and Podkarpackie voivodeships. This gap divides the tick population in Poland into two separated populations - Western and Eastern. The lowest abundance of ticks was found in the newly established foci in central and western Poland. Our study showed the need for the monitoring of the D. reticulatus expansion. Early detection of new foci is crucial for taking proper prevention measures.

Detection and identification of Rickettsia species in Ixodes tick populations from Estonia

A total of 1640 ticks collected in different geographical parts of Estonia were screened for the presence of Rickettsia species DNA by real-time PCR. DNA of Rickettsia was detected in 83 out of 1640 questing ticks with an overall prevalence of 5.1%. The majority of the ticks infected by rickettsiae were Ixodes ricinus (74 of 83), while 9 of the 83 positive ticks were Ixodes persulcatus. For rickettsial species identification, a part of the citrate synthase gltA gene was sequenced. The majority of the positive samples were identified as Rickettsia helvetica (81 out of 83) and two of the samples were identified as Rickettsia monacensis and Candidatus R. tarasevichiae, respectively. Genetic characterization based on the partial gltA gene showed that the Estonian sequences within the R. helvetica, R. monacensis and Candidatus R. tarasevichiae species demonstrated 100% similarity with sequences deposited in GenBank, originating from Rickettsia species distributed over large territories from Europe to Asia.

Bartonella henselae in eastern Poland: the relationship between tick infection rates and the serological response of individuals occupationally exposed to tick bites

To explore the potential role of Ixodes ricinus as the presumed vector of Bartonella henselae in eastern Poland, ticks collected in various geographic locations were examined for the presence of B. henselae, and the results were matched against the prevalence of anti-B. henselae antibodies in individuals occupationally exposed to tick bites. The presence of Bartonella DNA was investigated by PCR in a total of 1,603 unfed Ixodes ricinus ticks. The presence of IgG antibodies against B. henselae was investigated in serum samples from 332 people occupationally exposed to tick bites (94 farmers and 238 forestry workers). The total prevalence of B. henselae in ticks was 1.7%; the infection rates in males (3.1%) and females (2.7%) were nearly ten times greater than in nymphs (0.3%). The prevalence of seropositive results in the risk group (30.4%), farmers (27.7%) and forestry workers (31.5%), was significantly greater compared to the control group (8.9%). The results showed a weak positive correlation between the degree of infection of ticks and humans living in the same geographic region. The lack of a direct relationship indicates that exposure to tick bites is only one of the factors contributing to the significant preponderance of a seropositive response to B. henselae in the forestry workers and farmers over the control group. Other factors must be considered, such as contact with cats, which are popular domestic animals in Polish villages, and exposure to cat fleas.

Babesia spp. in questing ticks from eastern Poland: prevalence and species diversity

A total of 853 questing Ixodes ricinus males, females, and nymphs and of 582 questing Dermacentor reticulatus males and females were collected from vegetation on the territory of the Lublin province (eastern Poland). The ticks were examined for the presence of Babesia by PCR detecting part of 18S ribosomal RNA (rRNA) gene and nuclear small subunit rRNA (SS-rDNA) for determining of Babesia spp. and Babesia microti, respectively. The overall incidence of Babesia strains in I. ricinus ticks was 4.6 %. Three species of Babesia were identified. The prevalent species was B. microti which occurred in 2.8 % of ticks, while Babesia venatorum, Babesia divergens, and unidentified Babesia species were found at the frequency of 1.2, 0.2, and 0.3 %, respectively. Altogether, B. microti constituted 61.5 % of the total strains detected in I. ricinus, B. venatorum—25.7 %, B. divergens—5.1 %, and unidentified Babesia species—7.7 %. The prevalence of Babesia species in I. ricinus did not depend significantly on locality (χ² = 1.885, P = 0.390) nor on the tick stage (χ² = 4.874, P = 0.087). The incidence of Babesia strains in D. reticulatus ticks was 2.7 %. Two species of Babesia were identified. Again, the prevalent species was B. microti which occurred in 2.1 % of ticks, while B. canis was found in 0.7 % of ticks. In one D. reticulatus female, B. canis and B. microti co-infection was found. Altogether, B. microti constituted 75 % of the total strains detected in D. reticulatus while B. canis formed 25 % of the total strains. The frequency of the occurrence of Babesia species in D. reticulatus did not depend significantly on locality (χ² = 0.463, P = 0.793). The difference between the prevalence of Babesia in males and females of D. reticulatus was insignificant (P = 0.0954); nymphs were not found. The dominance of B. microti in the species composition of tick-borne Babesia found in this study was typical for eastern Europe. In conclusion, the results revealed that the population inhabiting the forested area of eastern Poland could be exposed to Babesia parasites, especially to those from the species B. microti, by a bite of I. ricinus, a competent vector of human babesiosis, and probably also by a bite of D. reticulatus whose role in the transmission of human babesiosis needs to be clarified.

Dominance of Dermacentor reticulatus over Ixodes ricinus (Ixodidae) on livestock, companion animals and wild ruminants in eastern and central Poland

The most common tick species parasitizing animals in Poland are Ixodes ricinus and Dermacentor reticulatus. These tick species differ in their distribution, habitats, seasonal activity and host specificity. Ixodes ricinus is the most prevalent and widely distributed, whereas the range of D. reticulatus is limited to eastern and central parts of the country with several new foci in the middle-west and the west. However, as in many central European countries, the range of D. reticulatus is expanding, and some authors have correlated this expansion with an increasing number of available hosts. The aim of the present study was to determine the tick fauna on domestic and livestock animals in two areas endemic for I. ricinus and D. reticulatus and to compare the risk of infestation with different tick species in open and forest areas. Over a 14 month period, 732 ticks were collected from five host species including domestic animals (dogs and cats), livestock (cows and horses) and wildlife (European bison) in two areas, central and NE Poland, endemic for D. reticulatus. Three tick species were recorded: D. reticulatus (623 individuals; 85.1% of all collected ticks), I. ricinus (106 individuals; 14.5%) and three females of Ixodes hexagonus (0.4%) from a dog. Dermacentor reticulatus was the dominant tick species found on four host species and constituted 86, 81, 97 and 100% of all ticks from dogs, horses, cows and bison, respectively, and was collected from animals throughout the year, including during the winter. The common tick, I. ricinus, was the dominant tick collected from cats (94%). Fully-engorged, ready-for-reproduction females of D. reticulatus were collected from all host species. In May 2012, questing ticks were collected by dragging in forest or open habitats. The density of adult marsh ticks in open areas was around 2 ticks/100 m(2) in the majority of locations, with a maximum of 9.5 ticks/100 m(2). The density of adult I. ricinus was much lower in its typical habitat (forests: range 0.8-2.2 ticks/100 m(2)) between three and seven times lower than the density of D. reticulatus in its typical habitat. In regions endemic for marsh ticks, this tick species constitutes the main risk of tick infestation for livestock and dogs throughout the year. Livestock and companion animals are competent hosts for D. reticulatus, enabling the completion of the tick's life cycle. Anti-tick treatment should be adjusted to marsh tick seasonal activity and drug sensitivity.

Detection and quantification of Anaplasma phagocytophilum and Babesia spp. in Ixodes ricinus ticks from urban and rural environment, northern Poland, by real-time polymerase chain reaction

Anaplasma phagocytophilum and Babesia spp. are emerging tick-borne pathogens which can threaten human health. A duplex real-time PCR and qPCRs with primers and probes targeting 97 and 116 bp fragments of 16S rRNA and 18S rRNA genes, respectively, were used for qualitative and quantitative detection of both pathogens in Ixodes ricinus ticks. Altogether 1875 ticks (1084 adults and 791 nymphs) were collected from rural and urban habitats in northern Poland. Of them, at least 0.9% were found to be infected with A. phagocytophilum while 2.5% with Babesia spp. A comparison of the infection rates by the tick stage, the type of area, the collection site, habitats of different tick density and by the month of collection was done. The prevalence of pathogens was significantly lower in nymphs than in adult ticks (p = 0.02) and in rural areas than in urban areas (p = 0.007). Four different 16S rRNA gene variants of A. phagocytophilum were determine, however none of them showed 100% identity with compared sequences isolated from human patients. The dominant Babesia species was B. venatorum. Results of qPCRs with circular and linearized forms of plasmids used as the standards showed significant difference in the pathogen loads (p = 0.001). The copy numbers of A. phagocytophilum and Babesia spp. estimated from the linear plasmids were 28.7 and 5.1 times lower, respectively, when compared with their circular forms, and were accepted as more reliable. The average number of copies of 16S rRNA gene of A. phagocytophilum in the positive I. ricinus samples were 3.39 × 10(5) ± 6.09 × 10(5). The mean copy number of 18S rRNA gene of Babesia spp. was ~2.55 × 10(5) ± 1.04 × 10(6). We confirmed the presence of A. phagocytophilum and Babesia spp. in I. ricinus in both rural and urban environments. The determined low infection rates suggests, however, that the risk for local population and tourists to acquire infection is also low. Moreover, we confirmed recent findings that serious overestimation by circular plasmid DNA makes it less suitable as a standard and that the linear standards should be recommended for qPCR.

Occurrence of Francisella spp. in Dermacentor reticulatus and Ixodes ricinus ticks collected in eastern Poland

A total of 530 questing Dermacentor reticulatus ticks and 861 questing Ixodes ricinus ticks were collected from Lublin province (eastern Poland) and examined for the presence of Francisella by PCR for 16S rRNA (rrs) and tul4 genes. Only one female D. reticulatus tick out of 530 examined (0.2%) was infected with Francisella tularensis subspecies holarctica, as determined by PCR of the rrs gene. None of 861 I. ricinus ticks were infected with F. tularensis. In contrast, the presence of Francisella-like endosymbionts (FLEs) was detected in more than half of the D. reticulatus ticks (50.4%) and 0.8% of the I. ricinus ticks. The nucleotide sequences of the FLEs detected in D. reticulatus exhibited 100% homology with the nucleotide sequence of the FLE strain FDrH detected in Hungary in D. reticulatus. In conclusion, our results suggest a low contribution of D. reticulatus and I. ricinus ticks to the circulation of F. tularensis in eastern Poland. This finding, however, needs to be confirmed by further studies in other areas. Our study confirmed the common infection of D. reticulatus with Francisella-like endosymbionts (FLEs) of unknown pathogenic potential and revealed, for the first time, a low grade of infection of I. ricinus with FLEs.

Sympatric occurrence of Ixodes ricinus, Dermacentor reticulatus and Haemaphysalis concinna ticks and Rickettsia and Babesia species in Slovakia

Vojka nad Dunajom in the south-west of the Slovak Republic is a locality with sympatric occurrence of 3 species of ticks. This study investigated the spatial distribution of Dermacentor reticulatus, Ixodes ricinus, and Haemaphysalis concinna ticks in this area and determined the prevalence of Babesia and Rickettsia species in questing adults of these tick species considered as potential risk for humans and animals. Ticks were collected by blanket dragging over the vegetation from September 2011 to October 2012. All ticks were subjected to DNA extraction and individually assayed with PCR-based methods targeting the gltA, sca4, 23S rRNA genes of Rickettsia spp. and the 18S rRNA gene of Babesia spp. D. reticulatus was the dominant species occurring in this area (67.7%, n=600), followed by I. ricinus (31.8%, n=282) and H. concinna (0.5%, n=4) ticks. Rickettsial infection was determined in 10.8% (n=65) and 11.7% (n=33) of D. reticulatus and I. ricinus ticks, respectively. Babesia spp. infection was confirmed in 1.8% (n=11) of D. reticulatus and 0.4% (n=1) of I. ricinus ticks. DNA of 6 different pathogenic tick-borne species, Rickettsia helvetica, Rickettsia monacensis, Rickettsia slovaca, Rickettsia raoultii, Babesia canis, and Babesia venatorum were identified in this locality with sympatric occurrence of I. ricinus, D. reticulatus, and H. concinna ticks.

Comparison of tick-borne microorganism communities in Ixodes spp. of the Ixodes ricinus species complex at distinct geographical regions

Characterizing the tick-borne microorganism communities of Ixodes ricinus (sheep tick) and Ixodes persulcatus (taiga tick) from the I. ricinus species complex in distinct geographical regions of Eastern Europe and European Russia, we demonstrated differences between the two ticks. Taiga ticks were more frequently mono- and co-infected than sheep ticks: 24.4 % (45/184 tested ticks) versus 17.5 % (52/297) and 4.3 % (8/184) versus 3.4 % (10/297), respectively. Ginsberg co-infection index values were significant at the various sites. Diversity of the tick-borne microorganism communities was estimated by the Shannon index, reaching values of 1.71 ± 0.46 and 1.20 ± 0.15 at the sheep-tick and the taiga-tick harbored sites, respectively. Richness of the tick-borne microorganism community in the sheep tick collection sites was about twice the value of the taiga tick collection sites. Future investigations are warranted to further characterize the peculiarities of the tick-borne microorganism communities among the ticks of the Ixodes ricinus complex.

Rickettsiaceae and Anaplasmataceae infections in Ixodes ricinus ticks from urban and natural forested areas of Poland

Background

Ixodes ricinus is a major vector for a range of microbial pathogens and the most prevalent and widely distributed tick species on the European continent, occurring in both natural and urban habitats. Nevertheless, little is known about the relative density of ticks in these two ecologically distinct habitats and the diversity of tick-borne pathogens that they carry.

Methods

We compared densities of questing I. ricinus nymphs and adults in urban and natural habitats in Central and Northeastern Poland, assessed the prevalence and rate of co-infection with A. phagocytophilum, Rickettsia, Ehrlichia and ‘Ca. Neoehrlichia spp.’ in ticks, and compared the diversity of tick-borne pathogens using molecular assays (PCR).

Results

Of the 1325 adults and nymphs, 6.2% were infected with at least one pathogen, with 4.4%, 1.7% and less than 0.5% being positive for the DNA of Rickettsia spp., A. phagocytophilum, Ehrlichia spp. and Ca. N. mikurensis, respectively. Although tick abundance was higher in natural habitats, the prevalence of the majority of pathogens was higher in urban forested areas.

Conclusion

We conclude that: (i) zoonotic genetic variants of A. phagocytophilum are widely distributed in the Polish tick population, (ii) although the diversity of tick borne pathogens was higher in natural habitats, zoonotic species/strains were detected only in urban forests, (iii) and we provide the first description of Ca. N. mikurensis infections in ticks in Poland.

A seventeen-year epidemiological surveillance study of Borrelia burgdorferi infections in two provinces of northern Spain

This paper reports a 17-year seroepidemiological surveillance study of Borrelia burgdorferi infection, performed with the aim of improving our knowledge of the epidemiology of this pathogen. Serum samples (1,179) from patients (623, stratified with respect to age, sex, season, area of residence and occupation) bitten by ticks in two regions of northern Spain were IFA-tested for B. burgdorferi antibodies. Positive results were confirmed by western blotting. Antibodies specific for B. burgdorferi were found in 13.3% of the patients; 7.8% were IgM positive, 9.6% were IgG positive, and 4.33% were both IgM and IgG positive. Five species of ticks were identified in the seropositive patients: Dermacentor marginatus (41.17% of such patients) Dermacentor reticulatus (11.76%), Rhiphicephalus sanguineus (17.64%), Rhiphicephalus turanicus (5.88%) and Ixodes ricinus (23.52%). B. burgdorferi DNA was sought by PCR in ticks when available. One tick, a D. reticulatus male, was found carrying the pathogen. The seroprevalence found was similar to the previously demonstrated in similar studies in Spain and other European countries.

Update on tick-borne rickettsioses around the world: a geographic approach

Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases.

Anaplasma phagocytophilum--a widespread multi-host pathogen with highly adaptive strategies

The bacterium Anaplasma phagocytophilum has for decades been known to cause the disease tick-borne fever (TBF) in domestic ruminants in Ixodes ricinus-infested areas in northern Europe. In recent years, the bacterium has been found associated with Ixodes-tick species more or less worldwide on the northern hemisphere. A. phagocytophilum has a broad host range and may cause severe disease in several mammalian species, including humans. However, the clinical symptoms vary from subclinical to fatal conditions, and considerable underreporting of clinical incidents is suspected in both human and veterinary medicine. Several variants of A. phagocytophilum have been genetically characterized. Identification and stratification into phylogenetic subfamilies has been based on cell culturing, experimental infections, PCR, and sequencing techniques. However, few genome sequences have been completed so far, thus observations on biological, ecological, and pathological differences between genotypes of the bacterium, have yet to be elucidated by molecular and experimental infection studies. The natural transmission cycles of various A. phagocytophilum variants, the involvement of their respective hosts and vectors involved, in particular the zoonotic potential, have to be unraveled. A. phagocytophilum is able to persist between seasons of tick activity in several mammalian species and movement of hosts and infected ticks on migrating animals or birds may spread the bacterium. In the present review, we focus on the ecology and epidemiology of A. phagocytophilum, especially the role of wildlife in contribution to the spread and sustainability of the infection in domestic livestock and humans.

Borrelia burgdorferi sensu lato prevalence in tick populations in Estonia

Background

Estonia is located in a unique area of co-distribution of Ixodes ricinus and I. persulcatus, which are the main tick vectors of Borrelia burgdorferi sensu lato. In the last decade, the incidence rate of Lyme borreliosis in Estonia has increased dramatically up to 115.4 per 100,000 in 2012. Here we present the first survey of the presence, the prevalence and genetic characteristics of B. burgdorferi s.l. complex spirochetes in the tick population in Estonia.

Methods

During the years 2006–2009, 2833 unfed Ixodes ricinus and I. persulcatus were collected from 43 sites in 7 counties in mainland Estonia as well as in 10 sites on the Saaremaa Island. DNA samples from ticks were analyzed individually using nested PCR of the ribosomal 5S-23S spacer region followed by bidirectional sequencing.

Results

The overall estimated prevalence of B. burgdorferi s.l was 9.7% and varied from 4.9% to 24.2% on the mainland and to 10.7% in Saaremaa Island. Ixodes persulcatus ticks showed significantly higher prevalence rates compared to that in I. ricinus-16.3% and 8.2%, respectively. The most prevalent genospecies was B. afzelii which was detected in 53.5% of Borrelia-positive ticks, followed by B. garinii and B. valaisiana with 26.2% and 5.5%, respectively. Also, B. bavariensis and B. burgdorferi s.s. DNA in single I. ricinus ticks were detected. Borrelia afzelii, B. garinii and B. valaisiana were detected in both tick species. Two genetic subgroups of B. garinii (NT29 and 20047) and two genetic subgroups of B. afzelii (NT28 and VS461) were found to be circulating in all studied regions as well as in both tick species, except B. garinii subgroup NT29, which was found only in I. persulcatus ticks.

Conclusions

In the current study we detected the circulation of five B. burgdorferi s.l. genospecies and estimated the prevalence in ticks in different regions of Estonia. Detection and genetic characterization of Borrelia genospecies, especially those of public health importance, in the natural foci may help assessing high risk areas of human exposure to B. burgdorferi s.l.

Bartonella henselae bacteremia in a mother and son potentially associated with tick exposure

BACKGROUND

Bartonella henselae is a zoonotic, alpha Proteobacterium, historically associated with cat scratch disease (CSD), but more recently associated with persistent bacteremia, fever of unknown origin, arthritic and neurological disorders, and bacillary angiomatosis, and peliosis hepatis in immunocompromised patients. A family from the Netherlands contacted our laboratory requesting to be included in a research study (NCSU-IRB#1960), designed to characterize Bartonella spp. bacteremia in people with extensive arthropod or animal exposure. All four family members had been exposed to tick bites in Zeeland, southwestern Netherlands. The mother and son were exhibiting symptoms including fatigue, headaches, memory loss, disorientation, peripheral neuropathic pain, striae (son only), and loss of coordination, whereas the father and daughter were healthy.

METHODS

Each family member was tested for serological evidence of Bartonella exposure using B. vinsonii subsp. berkhoffii genotypes I-III, B. henselae and B. koehlerae indirect fluorescent antibody assays and for bacteremia using the BAPGM enrichment blood culture platform.

RESULTS

The mother was seroreactive to multiple Bartonella spp. antigens and bacteremia was confirmed by PCR amplification of B. henselae DNA from blood, and from a BAPGM blood agar plate subculture isolate. The son was not seroreactive to any Bartonella sp. antigen, but B. henselae DNA was amplified from several blood and serum samples, from BAPGM enrichment blood culture, and from a cutaneous striae biopsy. The father and daughter were seronegative to all Bartonella spp. antigens, and negative for Bartonella DNA amplification.

CONCLUSIONS

Historically, persistent B. henselae bacteremia was not thought to occur in immunocompetent humans. To our knowledge, this study provides preliminary evidence supporting the possibility of persistent B. henselae bacteremia in immunocompetent persons from Europe. Cat or flea contact was considered an unlikely source of transmission and the mother, a physician, reported that clinical symptoms developed following tick exposure. To our knowledge, this is the first time that a B. henselae organism has been visualized in and amplified from a striae lesion. As the tick bites occurred three years prior to documentation of B. henselae bacteremia, the mode of transmission could not be determined.