Candidatus Neoehrlichia mikurensis in ticks and rodents from urban and natural habitats of South-Western Slovakia

The Occurrence and Diversity of Tick-Borne Pathogens in Small Mammals from Serbia

Background: Despite abundance of small mammals in Serbia, there is no information on their role in the epidemiology of tick-borne diseases (TBDs). This retrospective study aimed to identify different tick-borne pathogens (TBPs) in small mammals in Serbia collected during 2011. Materials and Methods: A total of 179 small mammals were collected from seven different localities in Serbia. The five localities belong to the capital city of Serbia-Belgrade: recreational areas-Ada Ciganlija, Titov gaj, and Košutnjak as well as mountainous suburban areas used for hiking-Avala and Kosmaj. The locality Veliko Gradište is a tourist place in northeastern Serbia, whereas the locality Milošev Do is a remote area in western Serbia with minor human impact on the environment. Results: The results of the presented retrospective study are the first findings of Rickettsia helvetica, Rickettsia monacensis, Neoehrlichia mikurensis, Borrelia afzelii, Borrelia miyamotoi, Babesia microti, Hepatozoon canis, and Coxiella burnetii in small mammals in Serbia. The presence of R. helvetica was confirmed in two Apodemus flavicollis, the presence of one of the following pathogens, R. monacensis, B. afzelii, H. canis, Ba. microti, and N. mikurensis was confirmed in one A. flavicollis each, whereas the presence of B. miyamotoi was confirmed in one Apodemus agrarius. Coinfection with B. afzelii and Ba. microti was confirmed in one A. flavicollis. DNA of C. burnetii was detected in 3 of 18 pools. Conclusions: The results confirm that detected pathogens circulate in the sylvatic cycle in Serbia and point to small mammals as potential reservoir hosts for the detected TBPs. Further large-scale studies on contemporary samples are needed to clarify the exact role of particular small mammal species in the epidemiology of TBDs caused by the detected pathogens.

Candidatus Neoehrlichia mikurensis and Hepatozoon sp. in voles (Microtus spp.): occurrence and evidence for vertical transmission

Candidatus Neoehrlichia mikurensis (CNM) and Hepatozoon spp. are important vector-borne parasites of humans and animals. CNM is a relatively recently discovered pathogen of humans. Hepatozoon are parasites of reptiles, amphibians and mammals, commonly found in rodents and carnivores worldwide. The present study aimed to determine the prevalence of CNM and Hepatozoon spp. in three species of Microtus and to assess the occurrence of vertical transmission in naturally-infected voles. Molecular techniques were used to detect pathogen DNA in blood and tissue samples of captured voles and their offspring. The prevalence of CNM in the vole community ranged 24-47% depending on Microtus species. The DNA of CNM was detected in 21% of pups from three litters of six infected Microtus dams (two Microtus arvalis and one M. oeconomus) and in 3/45 embryos (6.6%) from two litters of eight CNM-infected pregnant females. We detected Hepatozoon infection in 14% of M. arvalis and 9% of M. oeconomus voles. Hepatozoon sp. DNA was detected in 48.7% of pups from seven litters (6 M. arvalis and 1 M. oeconomus) and in two embryos (14.3%) obtained from one M. arvalis litter. The high prevalence of CNM infections in the Microtus spp. community may be a result of a relatively high rate of vertical transmission among naturally infected voles. Vertical transmission was also demonstrated for Hepatozoon sp. in M. arvalis and M. oeconomus. Our study underlines the significance of alternative routes of transmission of important vector-borne pathogens.

Clinical Aspects and Detection of Emerging Rickettsial Pathogens: A "One Health" Approach Study in Serbia, 2020

Ticks carry numerous pathogens that, if transmitted, can cause disease in susceptible humans and animals. The present study describes our approach on how to investigate clinical presentations following tick bites in humans. To this aim, the occurrence of major tick-borne pathogens (TBPs) in human blood samples (n = 85) and the ticks collected (n = 93) from the same individuals were tested using an unbiased high-throughput pathogen detection microfluidic system. The clinical symptoms were characterized in enrolled patients. In patients with suspected TBP infection, serological assays were conducted to test for the presence of antibodies against specific TBPs. A field study based on One Health tenets was further designed to identify components of a potential chain of infection resulting in Rickettsia felis infection in one of the patients. Ticks species infesting humans were identified as Ixodes ricinus, Rhipicephalus sanguineus sensu lato (s.l.), Dermacentor reticulatus, and Haemaphysalis punctata. Five patients developed local skin lesions at the site of the tick bite including erythema migrans, local non-specific reactions, and cutaneous hypersensitivity reaction. Although Borrelia burgdorferi s.l., Babesia microti, Anaplasma phagocytophilum, and Candidatus Cryptoplasma sp. DNAs were detected in tick samples, different Rickettsia species were the most common TBPs identified in the ticks. The presence of TBPs such as Rickettsia helvetica, Rickettsia monacensis, Borrelia lusitaniae, Borrelia burgdorferi, Borrelia afzelii, A. phagocytophilum, and B. microti in ticks was further confirmed by DNA sequencing. Two of the patients with local skin lesions had IgG reactive against spotted fever group rickettsiae, while IgM specific to B. afzelii, Borrelia garinii, and Borrelia spielmanii were detected in the patient with erythema migrans. Although R. felis infection was detected in one human blood sample, none of the components of the potential chain of infection considered in this study tested positive to this pathogen either using direct pathogen detection in domestic dogs or xenodiagnosis in ticks collected from domestic cats. The combination of high-throughput screening of TBPs and One Health approaches might help characterize chains of infection leading to human infection by TBPs, as well as prevalence of emerging rickettsial pathogens in the Balkan region.

Ticks and their epidemiological role in Slovakia: from the past till present

In Slovakia, 22 tick species have been found to occur to date. Among them, Ixodes ricinus, Dermacentor reticulatus, D. marginatus and marginally Haemaphysalis concinna, H. inermis and H. punctata have been identified as the species of public health relevance. Ticks in Slovakia were found to harbour and transmit zoonotic and/or potentially zoonotic agents such as tick-borne encephalitis virus (TBEV), spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex, the relapsing fever sprirochaete Borrelia miyamotoi, bacteria belonging to the orders Rickettsiales (Rickettsia spp., Anaplasma phagocytophilum, Neoehrlichia mikurensis), Legionellales (Coxiella burnetii), and Thiotrichales (Francisella tularensis), and Babesia spp. parasites (order Piroplasmida). Ixodes ricinus is the principal vector of the largest variety of microorganisms including viruses, bacteria and piroplasms. TBEV, B. burgdorferi s.l., rickettsiae of the spotted fever group, C. burnetii and F. tularensis have been found to cause serious diseases in humans, whereas B. miyamotoi, A. phagocytophilum, N. mikurensis, Babesia microti, and B. venatorum pose lower or potential risk to humans. Distribution of TBEV has a focal character. During the last few decades, new tick-borne encephalitis (TBE) foci and their spread to new areas have been registered and TBE incidence rates have increased. Moreover, Slovakia reports the highest rates of alimentary TBE infections among the European countries. Lyme borreliosis (LB) spirochaetes are spread throughout the distribution range of I. ricinus. Incidence rates of LB have shown a slightly increasing trend since 2010. Only a few sporadic cases of human rickettsiosis, anaplasmosis and babesiosis have been confirmed thus far in Slovakia. The latest large outbreaks of Q fever and tularaemia were recorded in 1993 and 1967, respectively. Since then, a few human cases of Q fever have been reported almost each year. Changes in the epidemiological characteristics and clinical forms of tularaemia have been observed during the last few decades. Global changes and development of modern molecular tools led to the discovery and identification of emerging or new tick-borne microorganisms and symbionts with unknown zoonotic potential. In this review, we provide a historical overview of research on ticks and tick-borne pathogens in Slovakia with the most important milestones and recent findings, and outline future directions in the investigation of ticks as ectoparasites and vectors of zoonotic agents and in the study of tick-borne diseases.

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

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

Comparison of tick-borne pathogen prevalence in Ixodes ricinus ticks collected in urban areas of Europe

Tick-borne diseases are a major threat to human and animal health. An increasing number of natural habitats have been transformed into urban areas by human activity; hence, the number of reported tick bites in urban and suburban areas has risen. This retrospective analysis evaluated 53 scientific reports concerning infections of Ixodes ricinus ticks collected from urban and suburban areas of Europe between 1991 and 2017. The results indicate significant differences in many variables, including a higher number of Anaplasma phagocytophilum infections in Eastern Europe than in Western Europe. The opposite result was observed for Candidatus Neoehrlichia mikurensis infections. A comparison of climate zones revealed that Borrelia burgdorferi s.l. infections have the greatest median incidence rate in subtropical climate zones. No statistical significance was found when comparing other tick-borne pathogens (TBPs), such as Borrelia miyamotoi, Rickettsia spp., Babesia spp., Bartonella spp., Ehrlichia spp., Coxiella burnetii and Francisella tularensis. The analysis also showed significant differences in the overall prevalence of TBPs according to average temperatures and rainfall across Europe. This retrospective study contributes to the knowledge on the occurrence and prevalence of TBPs in urbanized areas of Europe and their dependence on the habitats and geographical distributions of ticks. Due to the increased risk of tick bites, it is of great importance to investigate infections in ticks from urban and suburban areas.

Candidatus Neoehrlichia mikurensis is widespread in questing Ixodes ricinus ticks in the Czech Republic

Candidatus Neoehrlichia mikurensis, the causative agent of tick-borne "neoehrlichiosis" has recently been reported in humans, mammals and ticks in Europe. The aim of this study was to map the distribution of this bacterium in questing ticks in the Czech Republic. A total of 13,325 Ixodes ricinus including 445 larvae, 5270 nymphs and 7610 adults were collected from vegetation by flagging in 140 Czech towns and villages from every region of the Czech Republic. The ticks were pooled into 2665 groups of 5 individuals respecting life stage or sex and tested for the presence of Ca. Neoehrlichia mikurensis by conventional PCR targeting of the groEL gene. The bacterium was detected in 533/2665 pools and 125/140 areas screened, showing an overall estimated prevalence of 4.4 % in ticks of all life stages. Phylogenetic analysis revealed only small genetic diversity among the strains found. Two pools of questing larvae tested positive, suggesting transovarial transmission. According to this study, Ca. Neoehrlichia mikurensis is another tick-borne pathogen widespread in I. ricinus ticks in the Czech Republic.

Highly prevalent bartonellae and other vector-borne pathogens in small mammal species from the Czech Republic and Germany

Background

Rodents are important reservoirs for zoonotic vector-borne agents. Thus, the distribution of rodents and their vicinity to humans and companion animals may have an important impact on human and animal health. However, the reservoir potential of some rodent genera, e.g. Microtus, has not yet been precisely examined concerning tick-borne pathogens in Central Europe. Therefore, we examined small mammals from Germany and the Czech Republic for the following vector-borne pathogens: Babesia spp., Bartonella spp., Anaplasma phagocytophilum, “Candidatus Neoehrlichia mikurensis” (CNM) and Coxiella burnetii. Spleen DNA from 321 small mammals belonging to four genera, Myodes (n = 78), Apodemus (n = 56), Microtus (n = 149), Sorex (n = 38), collected during 2014 in Germany and the Czech Republic were available for this study. DNA samples were examined for the presence of Babesia and Bartonella DNA by conventional PCR targeting the 18S rRNA gene and the 16S–23S rRNA intergenic spacer region, respectively. For the detection of CNM, A. phagocytophilum and C. burnetii real-time PCR assays were performed.

Results

Bartonella spp. DNA was detected in 216 specimens (67.3%) with 102/174 (58.6%) positive in Germany and 114/147 (77.6%) in the Czech Republic. The prevalence in each genus was 44.9% for Myodes, 63.2% for Sorex, 77.2% for Microtus and 75% for Apodemus. Four Bartonella species, i.e. Bartonella sp. N40, B. grahamii, B. taylorii and B. doshiae, as well as uncultured bartonellae, were detected. The Bartonella species diversity was higher in rodents than in shrews. In total, 27/321 (8.4%) small mammals were positive for CNM and 3/321 (0.9%) for A. phagocytophilum (S. coronatus and M. glareolus). All samples were negative for Babesia spp. and Coxiella spp.

Conclusions

While the detected high prevalence for Bartonella in Apodemus and Myodes spp. is confirmatory with previous findings, the prevalence in Microtus spp. was unexpectedly high. This indicates that individuals belonging to this genus may be regarded as potential reservoirs. Interestingly, only Sorex spp. and M. glareolus were positive for A. phagocytophilum in the present study, suggesting a possible importance of the latter for the maintenance of certain A. phagocytophilum strains in nature.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3576-7) contains supplementary material, which is available to authorized users.

Diverse tick-borne microorganisms identified in free-living ungulates in Slovakia

BACKGROUND

Free-living ungulates are hosts of ixodid ticks and reservoirs of tick-borne microorganisms in central Europe and many regions around the world. Tissue samples and engorged ticks were obtained from roe deer, red deer, fallow deer, mouflon, and wild boar hunted in deciduous forests of south-western Slovakia. DNA isolated from these samples was screened for the presence of tick-borne microorganisms by PCR-based methods.

RESULTS

Ticks were found to infest all examined ungulate species. The principal infesting tick was Ixodes ricinus, identified on 90.4% of wildlife, and included all developmental stages. Larvae and nymphs of Haemaphysalis concinna were feeding on 9.6% of wildlife. Two specimens of Dermacentor reticulatus were also identified. Ungulates were positive for A. phagocytophilum and Theileria spp. Anaplasma phagocytophilum was found to infect 96.1% of cervids, 88.9% of mouflon, and 28.2% of wild boar, whereas Theileria spp. was detected only in cervids (94.6%). Importantly, a high rate of cervids (89%) showed mixed infections with both these microorganisms. In addition to A. phagocytophilum and Theileria spp., Rickettsia helvetica, R. monacensis, unidentified Rickettsia sp., Coxiella burnetii, "Candidatus Neoehrlichia mikurensis", Borrelia burgdorferi (s.l.) and Babesia venatorum were identified in engorged I. ricinus. Furthermore, A. phagocytophilum, Babesia spp. and Theileria spp. were detected in engorged H. concinna. Analysis of 16S rRNA and groEL gene sequences revealed the presence of five and two A. phagocytophilum variants, respectively, among which sequences identified in wild boar showed identity to the sequence of the causative agent of human granulocytic anaplasmosis (HGA). Phylogenetic analysis of Theileria 18S rRNA gene sequences amplified from cervids and engorged I. ricinus ticks segregated jointly with sequences of T. capreoli isolates into a moderately supported monophyletic clade.

CONCLUSIONS

The findings indicate that free-living ungulates are reservoirs for A. phagocytophilum and Theileria spp. and engorged ixodid ticks attached to ungulates are good sentinels for the presence of agents of public and veterinary concern. Further analyses of the A. phagocytophilum genetic variants and Theileria species and their associations with vector ticks and free-living ungulates are required.

'Candidatus Neoehrlichia mikurensis' in Europe

'Candidatus Neoehrlichia mikurensis' is an uncultured emerging bacterium that is provisionally included in the family Anaplasmataceae. In Europe, it is transmitted by Ixodes ricinus ticks. Rodents are the reservoirs. It is widely distributed in mammals (both wild and domestic) and birds. It causes an inflammatory disease in humans with underlying diseases, but the microorganism also affects immunocompetent individuals in which asymptomatic infection has been recognized. A high degree of suspicion and the use of molecular tools are needed for the correct diagnosis. Efforts to cultivate it and to investigate its pathogenesis should be a priority.

Prevalence of tick-borne pathogens in questing Ixodes ricinus ticks in urban and suburban areas of Switzerland

Background

Throughout Europe, Ixodes ricinus transmits numerous pathogens. Its widespread distribution is not limited to rural but also includes urbanized areas. To date, comprehensive data on pathogen carrier rates of I. ricinus ticks in urban areas of Switzerland is lacking.

Results

Ixodes ricinus ticks sampled at 18 (sub-) urban collection sites throughout Switzerland showed carrier rates of 0% for tick-borne encephalitis virus, 18.0% for Borrelia burgdorferi (sensu lato), 2.5% for Borrelia miyamotoi, 13.5% for Rickettsia spp., 1.4% for Anaplasma phagocytophilum, 6.2% for "Candidatus Neoehrlichia mikurensis", and 0.8% for Babesia venatorum (Babesia sp., EU1). Site-specific prevalence at collection sites with n > 45 ticks (n = 9) significantly differed for B. burgdorferi (s.l.), Rickettsia spp., and "Ca. N. mikurensis", but were not related to the habitat type. Three hundred fifty eight out of 1078 I. ricinus ticks (33.2%) tested positive for at least one pathogen. Thereof, about 20% (71/358) were carrying two or three different potentially disease-causing agents. Using next generation sequencing, we could detect true pathogens, tick symbionts and organisms of environmental or human origin in ten selected samples.

Conclusions

Our data document the presence of pathogens in the (sub-) urban I. ricinus tick population in Switzerland, with carrier rates as high as those in rural regions. Carriage of multiple pathogens was repeatedly observed, demonstrating the risk of acquiring multiple infections as a consequence of a tick bite.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2500-2) contains supplementary material, which is available to authorized users.

Diversity and prevalence of Bartonella species in small mammals from Slovakia, Central Europe

Wild-living rodents are important hosts for zoonotic pathogens. Bartonella infections are widespread in rodents; however, in Slovakia, knowledge on the prevalence of these bacteria in small mammals is limited. We investigated the prevalence and diversity of Bartonella species in the spleens of 640 rodents of six species (Apodemus flavicollis, Apodemus sylvaticus, Myodes glareolus, Microtus arvalis, Microtus subterraneus, and Micromys minutus) and in the European mole (Talpa europaea) from three different habitat types in south-western and central Slovakia. Overall, the prevalence of Bartonella spp. in rodents was 64.8%; a rate of 73.8% was found in natural habitat (deciduous forest), 56.0% in suburban forest park and 64.9% in rural habitat. Bartonella spp. were detected in 63.0% of A. flavicollis, 69% of My. glareolus and 61.1% of M. arvalis and in T. europaea. However, Bartonella were not found in the other examined rodents. Molecular analyses of the 16S-23S rRNA intergenic spacer region revealed the presence of four different Bartonella spp. clusters. We identified B. taylorii, B. rochalimae, B. elizabethae, B. grahamii and Bartonella sp. wbs11 in A. flavicollis and My. glareolus. Bartonella genotypes ascribed to B. taylorii and B. rochalimae were found in M. arvalis. B. taylorii was identified in T. europaea. Questing Ixodes ricinus ticks that were collected at the study sites were not infected with Bartonella. This study improves our understanding of the ecoepidemiology of Bartonella spp. in Europe and underlines the necessity for further research on Bartonella-host-vector associations and their consequences on animal and human health in Slovakia.

Assessment of a quantitative 5' nuclease real-time polymerase chain reaction using groEL gene for Ehrlichia and Anaplasma species in rodents in Brazil

New genotypes of Anaplasmataceae agents have been detected in wild carnivores, birds and deer in Brazil. The present work aimed to investigate the presence of Ehrlichia and Anaplasma species in rodents sampled in Brazil. Additionally, a newly designed quantitative 5' nuclease real-time multiplex PCR for Ehrlichia and Anaplasma spp. detection based on groEL gene amplification was designed, showing high specificity and sensitivity (10 groEL fragment copy/μL). Between 2000 and 2011, different rodent species [n=60] were trapped in 5 Brazilian biomes. Among 458 rodent spleen samples, 0.4% (2/458) and 2.4% (11/458) were positive for Ehrlichia and Anaplasma spp., respectively. Of 458 samples, 2.0% (9/458) and 1.1% (5/458) were positive for Anaplasma sp. and Ehrlichia sp., respectively, using conventional 16S rRNA PCR assays. Maximum Likelihood phylogenetic analyse based on a small region of 16S rRNA genes positioned the Anaplasma genotypes in rodents near Anaplasma phagocytophilum or Anaplasma marginale and Anaplasma odocoilei isolates. Ehrlichia genotypes were closely related to E. canis. There was a low occurrence of Anaplasma and Ehrlichia in wild and synanthropic rodents in Brazil, suggesting the circulation of new genotypes of these agents in rodents in the studied areas.

Babesia spp. in ticks and wildlife in different habitat types of Slovakia

BACKGROUND

Babesiosis is an emerging and potentially zoonotic disease caused by tick-borne piroplasmids of the Babesia genus. New genetic variants of piroplasmids with unknown associations to vectors and hosts are recognized. Data on the occurrence of Babesia spp. in ticks and wildlife widen the knowledge on the geographical distribution and circulation of piroplasmids in natural foci. Questing and rodent-attached ticks, rodents, and birds were screened for the presence of Babesia-specific DNA using molecular methods. Spatial and temporal differences of Babesia spp. prevalence in ticks and rodents from two contrasting habitats of Slovakia with sympatric occurrence of Ixodes ricinus and Haemaphysalis concinna ticks and co-infections of Candidatus N. mikurensis and Anaplasma phagocytophilum were investigated.

RESULTS

Babesia spp. were detected in 1.5 % and 6.6 % of questing I. ricinus and H. concinna, respectively. Prevalence of Babesia-infected I. ricinus was higher in a natural than an urban/suburban habitat. Phylogenetic analysis showed that Babesia spp. from I. ricinus clustered with Babesia microti, Babesia venatorum, Babesia canis, Babesia capreoli/Babesia divergens, and Babesia odocoilei. Babesia spp. amplified from H. concinna segregated into two monophyletic clades, designated Babesia sp. 1 (Eurasia) and Babesia sp. 2 (Eurasia), each of which represents a yet undescribed novel species. The prevalence of infection in rodents (with Apodemus flavicollis and Myodes glareolus prevailing) with B. microti was 1.3 % in an urban/suburban and 4.2 % in a natural habitat. The majority of infected rodents (81.3 %) were positive for spleen and blood and the remaining for lungs and/or skin. Rodent-attached I. ricinus (accounting for 96.3 %) and H. concinna were infected with B. microti, B. venatorum, B. capreoli/B. divergens, Babesia sp. 1 (Eurasia), and Babesia sp. 2 (Eurasia). All B. microti and B. venatorum isolates were identical to known zoonotic strains from Europe. Less than 1.0 % of Babesia-positive ticks and rodents carried Candidatus N. mikurensis or A. phagocytophilum.

CONCLUSION

Our findings suggest that I. ricinus and rodents play important roles in the epidemiology of zoonotic Babesia spp. in south-western Slovakia. Associations with vertebrate hosts and the pathogenicity of Babesia spp. infecting H. concinna ticks need to be further explored.