Babesia microti in adult Dermacentor reticulatus ticks from eastern Poland

Prevalence of Borrelia, Neoehrlichia mikurensis and Babesia in ticks collected from vegetation in eastern Poland

In Poland, tick-borne diseases constitute the majority of diseases related to exposure to biological agents with a predominance of Lyme borreliosis; therefore, research on ticks as a reservoir of various pathogens remains crucial in the epidemiology of human diseases after tick bites. This study aimed to identify the occurrence of Borrelia burgdorferi sensu lato, Borrelia miyamotoi, Neoehrlichia mikurensis, and Babesia spp. in ticks collected from vegetation in eastern Poland. Additionally, the prevalence of co-infections in the adult Ixodes ricinus ticks was determined. Among I. ricinus ticks the predominantly detected pathogen was B. burgdorferi s.l. (23%) with B. burgdorferi sensu stricto as the most frequently identified species, followed by B. garinii. In 2013, the double or triple infections of B. burgdorferi s.s., B. afzelii, and B. garinii species did not exceed 9% in adult ticks, whereas in 2016, the prevalence of mixed infections reached 29%. The prevalence of N. mikurensis and B. miyamotoi in I. ricinus was determined at the same level of 2.8%. Four Babesia species were identified in the examined I. ricinus population: B. microti (1.5%), B. venatorum (1.2%), B. divergens (0.2%), and B. capreoli (0.1%). Co-infections were detected in 10.1% of all infected ticks with the highest prevalence of co-infections with B. burgdorferi s.l. and Babesia species. The changes in the prevalence and the distribution of particular pathogens within tick populations indicate the need for monitoring the current situation related to tick-borne pathogens from the aspect of risk to human health.

Prevalence of Tick-Borne Pathogens in Questing Ixodes ricinus and Dermacentor reticulatus Ticks Collected from Recreational Areas in Northeastern Poland with Analysis of Environmental Factors

Ticks, such as Ixodes ricinus and Dermacentor reticulatus, act as vectors for multiple pathogens posing a threat to both human and animal health. As the process of urbanization is progressing, those arachnids are being more commonly encountered in urban surroundings. In total, 1112 I. ricinus (n = 842) and D. reticulatus (n = 270) ticks were collected from several sites, including recreational urban parks, located in Augustów and Białystok, Poland. Afterwards, the specimens were examined for the presence of Borrelia spp., Babesia spp., Anaplasma phagocytophilum, Rickettsia spp., Bartonella spp., and Coxiella burnetii using the PCR method. Overall obtained infection rate reached 22.4% (249/1112). In total, 26.7% (225/842) of I. ricinus was infected, namely with Borrelia spp. (25.2%; 212/842), Babesia spp. (2.0%; 17/842), and A. phagocytophilum (1.2%; 10/842). Among D. reticulatus ticks, 8.9% (24/270) were infected, specifically with Babesia spp. (7.0%; 19/270), A. phagocytophilum (1.1%; 3/270), and Borrelia burgdorferi s.l. (0.7%; 2/270). No specimen tested positively for Rickettsia spp., Bartonella spp., or Coxiella burnetii. Co-infections were detected in 14 specimens. Results obtained in this study confirm that I. ricinus and D. reticulatus ticks found within the study sites of northeastern Poland are infected with at least three pathogens. Evaluation of the prevalence of pathogens in ticks collected from urban environments provides valuable information, especially in light of the growing number of tick-borne infections in humans and domesticated animals.

Infection rates, species diversity, and distribution of zoonotic Babesia parasites in ticks: a global systematic review and meta-analysis

Zoonotic Babesia species are emerging public health threats globally, and are the cause of a mild to severe malaria-like disease which may be life threatening in immunocompromised individuals. In this study, we determine the global infection rate, distribution, and the diversity of zoonotic Babesia species in tick vectors using a systematic review and meta-analysis. We used the random-effects model to pool data and determined quality of individual studies using the Joanna Briggs Institute critical appraisal instrument for prevalence studies, heterogeneity using Cochran's Q test, and across study bias using Egger's regression test. Herein, we reported a 2.16% (3915/175345, 95% CI: 1.76-2.66) global infection rate of zoonotic Babesia species (B. divergens, B. microti, and B. venatorum) in tick vectors across 36 countries and 4 continents. Sub-group infection rates ranged between 0.65% (95% CI: 0.09-4.49) and 3.70% (95% CI: 2.61-5.21). B. microti was the most prevalent (1.79%, 95% CI: 1.38-2.31) species reported in ticks, while Ixodes scapularis recorded the highest infection rate (3.92%, 95% CI: 2.55-5.99). Larvae 4.18% (95% CI: 2.15-7.97) and females 4.08% (95% CI: 2.56-6.43) were the tick stage and sex with the highest infection rates. The presence of B. divergens, B. microti, and B. venatorum in tick vectors as revealed by the present study suggests possible risk of transmission of these pathogens to humans, especially occupationally exposed population. The control of tick vectors through chemical and biological methods as well as the use of repellants and appropriate clothing by occupationally exposed population are suggested to curtail the epidemiologic, economic, and public health threats associated with this emerging public health crisis.

The specificity of Babesia-tick vector interactions: recent advances and pitfalls in molecular and field studies

Background

Babesia spp. are protozoan parasites of great medical and veterinary importance, especially in the northern Hemisphere. Ticks are known vectors of Babesia spp., although some Babesia-tick interactions have not been fully elucidated.

Methods

The present review was performed to investigate the specificity of Babesia-tick species interactions that have been identified using molecular techniques in studies conducted in the last 20 years under field conditions. We aimed to indicate the main vectors of important Babesia species based on published research papers (n = 129) and molecular data derived from the GenBank database.

Results

Repeated observations of certain Babesia species in specific species and genera of ticks in numerous independent studies, carried out in different areas and years, have been considered epidemiological evidence of established Babesia-tick interactions. The best studied species of ticks are Ixodes ricinus, Dermacentor reticulatus and Ixodes scapularis (103 reports, i.e. 80% of total reports). Eco-epidemiological studies have confirmed a specific relationship between Babesia microti and Ixodes ricinus, Ixodes persulcatus, and Ixodes scapularis and also between Babesia canis and D. reticulatus. Additionally, four Babesia species (and one genotype), which have different deer species as reservoir hosts, displayed specificity to the I. ricinus complex. Eco-epidemiological studies do not support interactions between a high number of Babesia spp. and I. ricinus or D. reticulatus. Interestingly, pioneering studies on other species and genera of ticks have revealed the existence of likely new Babesia species, which need more scientific attention. Finally, we discuss the detection of Babesia spp. in feeding ticks and critically evaluate the data on the role of the latter as vectors.

Conclusions

Epidemiological data have confirmed the specificity of certain Babesia-tick vector interactions. The massive amount of data that has been thus far collected for the most common tick species needs to be complemented by more intensive studies on Babesia infections in underrepresented tick species.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05019-3.

Detection of Borrelia burgdorferi s.l., Anaplasma phagocytophilum and Babesia spp. in Dermacentor reticulatus ticks found within the city of Białystok, Poland-first data

Pathogens carried by ticks pose a threat to both human and animal health across the world. Typically associated with rural landscapes, ticks appear to adapt well to life in urban recreational areas. Although Dermacentor reticulatus is commonly found across Europe, data on the prevalence of pathogens in this tick species, in an urban environment, are very limited. PCR was used to examine 368 D. reticulatus individuals collected in the Zwierzyniecki Forest Nature Reserve in Białystok, Poland. In total, 10.3% of ticks were infected, with Babesia spp. (9.2%), Anaplasma phagocytophilum (0.8%) and Borrelia burgdorferi sensu lato (0.3%). Rickettsia spp., Bartonella spp., and Coxiella burnetii were not detected. Sequence analysis for Babesia-positive samples identified 79.4% of them as Babesia canis, 8.8% as Babesia microti, 5.9% as Babesia spp., 2.9% as Babesia venatorum, and 2.9% as Babesia vogeli. Results obtained in this study indicate that D. reticulatus ticks found within the urban premises of the study area are infected with at least three pathogens and therefore are an important factor in public health risk for tick-borne diseases.

Global Distribution of Babesia Species in Questing Ticks: A Systematic Review and Meta-Analysis Based on Published Literature

Babesiosis caused by the Babesia species is a parasitic tick-borne disease. It threatens many mammalian species and is transmitted through infected ixodid ticks. To date, the global occurrence and distribution are poorly understood in questing ticks. Therefore, we performed a meta-analysis to estimate the distribution of the pathogen. A deep search for four electronic databases of the published literature investigating the prevalence of Babesia spp. in questing ticks was undertaken and obtained data analyzed. Our results indicate that in 104 eligible studies dating from 1985 to 2020, altogether 137,364 ticks were screened with 3069 positives with an estimated global pooled prevalence estimates (PPE) of 2.10%. In total, 19 different Babesia species of both human and veterinary importance were detected in 23 tick species, with Babesia microti and Ixodesricinus being the most widely reported Babesia and tick species, respectively. Regardless of species, adult ticks with 2.60% had the highest infection rates, while larvae had the least with 0.60%. Similarly, female ticks with 4.90% were infected compared to males with 3.80%. Nested-polymerase chain reaction (PCR) 2.80% had the highest prevalence among the molecular techniques employed. In conclusion, results obtained indicate that Babesia species are present in diverse questing tick species at a low prevalence, of which some are competent vectors.

The Discovery of Zoonotic Protozoans in Fleas Parasitizing on Pets as a Potential Infection Threat

PURPOSE

Fleas are insects with a high medical and veterinary importance. They may participate in spreading of many pathogenic agents, but still there is limited information about their possible reservoir or vector role for protozoans. The main aim of this study was an attempt of detection zoonotic pathogens, such as Babesia microti and Toxoplasma gondii in fleas Ctenocephalides felis felis and Ctenocephalides canis.

METHODS

In 2013-2017, 155 fleas were captured from domestic dogs and cats in veterinary clinics, animal shelters and pet grooming salons in Upper Silesia Region in Poland. Then, the DNA was extracted from each Ctenocephalides flea by using the ammonia method. Samples were screened for the presence of B. microti and T. gondii using PCR and nested PCR methods.

RESULTS

B. microti was reported in 6.6% of C. felis felis and 9.1% of C. canis, whereas the prevalence of coinfection with B. microti and T. gondii was 1.9% in cat fleas and 2.3% in dog fleas.

CONCLUSION

This study shows the first cases of B. microti occurrence and B. microti and T. gondii coinfection in Ctenocephalides fleas. The estimation of prevalence of examined protozoans may be useful considering the possibility of infection among companion animals, as well as during presentation of the potential risk of infection in humans. In order to clarify the role of C. felis felis and C. canis in transmission of B. microti and T. gondii, the another studies with in vitro cultures and laboratory animals are needed.

Collection of immature Dermacentor reticulatus (Fabricius, 1794) ticks from vegetation and detection of Rickettsia raoultii in them

It is commonly assumed that Dermacentor reticulatus immature life stages are nidicolous and therefore cannot be collected from vegetation. However, in June and July of 2018 and 2019, a total of 47 questing D. reticulatus larvae and two nymphs were collected by the flagging method in two different sites close to the city of Leipzig, Germany. To confirm their role in the transmission of tick-borne pathogens, 45 larvae (pooled by 2 in 21 pools and 1 pool with three individuals) and one nymph were tested either by conventional or real-time PCR for the presence of Bartonella spp., Neoehrlichia mikurensis, Rickettsia spp., and Babesia spp. All samples tested negative for Bartonella spp., N. mikurensis, and Babesia spp.; while the minimal infection rate of larvae for Rickettsia spp. was 42%, and the one tested nymph was also positive. Sequencing partial ompB genes revealed the presence of Rickettsia raoultii in larvae and nymph. Further research needs to be done to determine under which circumstances immature D. reticulatus ticks are found outside the burrows of their hosts and can be collected from vegetation.

Zoonotic Babesia: A scoping review of the global evidence

BACKGROUND

Babesiosis is a parasitic vector-borne disease of increasing public health importance. Since the first human case was reported in 1957, zoonotic species have been reported on nearly every continent. Zoonotic Babesia is vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes scapularis, the tick species responsible for transmitting the pathogens that also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted climate change is expected to impact the spread of vectors, which is likely to affect the distribution of vector-borne diseases including human babesiosis.

METHODS

A scoping review has been executed to characterize the global evidence on zoonotic babesiosis. Articles were compiled through a comprehensive search of relevant bibliographic databases and targeted government websites. Two reviewers screened titles and abstracts for relevance and characterized full-text articles using a relevance screening and data characterization tool developed a priori.

RESULTS

This review included 1394 articles relevant to human babesiosis and/or zoonotic Babesia species. The main zoonotic species were B. microti, B. divergens, B. duncani and B. venatorum. Articles described a variety of study designs used to study babesiosis in humans and/or zoonotic Babesia species in vectors, animal hosts, and in vitro cell cultures. Topics of study included: pathogenesis (680 articles), epidemiology (480), parasite characterization (243), diagnostic test accuracy (98), mitigation (94), treatment (65), transmission (54), surveillance (29), economic analysis (7), and societal knowledge (1). No articles reported predictive models investigating the impact of climate change on Babesia species.

CONCLUSION

Knowledge gaps in the current evidence include research on the economic burden associated with babesiosis, societal knowledge studies, surveillance of Babesia species in vectors and animal hosts, and predictive models on the impact of climate change. The scoping review results describe the current knowledge and knowledge gaps on zoonotic Babesia which can be used to inform future policy and decision making.

Dermacentor reticulatus in Berlin/Brandenburg (Germany): Activity patterns and associated pathogens

Dermacentor reticulatus is one of the most important European tick species. However, its spatial distribution, seasonality and regional vector role are not well known. This study aimed to gather information about abundance patterns of questing ticks and associated pathogens in unfed female adult D. reticulatus in the Berlin/Brandenburg area. Using the flagging method, questing ticks were collected at four sites in 2010-2012 and 2000 D. reticulatus were analysed regarding infection with Rickettsia, Babesia, Borrelia and Anaplasmataceae by conventional or real-time PCR. Dermacentor reticulatus showed a bimodal activity pattern: highest numbers of adult ticks were recorded between March and end of May (mean 50 ticks/h) and from mid-August until end of November (mean 102 ticks/h). During summer, almost complete inactivity was observed (mean 0.4 ticks/h). Sporadic samplings from December to February revealed tick activity also during winter (mean 47 ticks/h), which was characterised by large fluctuations. Using negative binomial regression analysis, significant influences of the variables sampling site, season and temperature on the abundance of questing D. reticulatus were determined. The parameters relative humidity and year were not of significant importance. PCR analyses showed an average prevalence of 64% for Rickettsia sp. Large differences in pathogen frequencies were observed between sampling sites (31.4-78.3%). Regression analysis demonstrated a significant influence of the sampling site but not of season and year. Examinations regarding other pathogen groups indicated prevalences of 0.25% (Borrelia sp.) and 0.05% (Anaplasmataceae) but absence of Babesia sp. Sequencing of positive samples revealed infections with Rickettsia raoultii, Borrelia miyamotoi, Borrelia afzelii and Anaplasma phagocytophilum. The study shows stable populations of D. reticulatus in Berlin/Brandenburg. People should be aware of ticks throughout the year since Ixodes ricinus is co-endemic and active in spring, summer and autumn while adult D. reticulatus are active throughout the year and even in winter during periods of frost as long as it is warming up during the day. Prevalence of R. raoultii in the present study is among the highest described for D. reticulatus. Borrelia miyamotoi was detected for the first time in D. reticulatus, illustrating the importance of screening studies to evaluate the pathogen structure in D. reticulatus populations.

Evaluation on Infectivity of Babesia microti to Domestic Animals and Ticks Outside the Ixodes Genus

Babesiosis caused by Babesia microti parasite is an emerging tick borne zoonotic disease that was confirmed recently in China. To understand the epidemiology characteristics of this emerging disease, infectivity of B. microti to domestic animals and ticks outside the genus Ixodes was evaluated in this study. Different domestic animals, chick, pig, goat, dog and the reference host rat were experimentally inoculated with B. microti-infected erythrocytes and the parasite infection was monitored daily by blood smear observation, real-time PCR detection, nested-PCR and special antibody responses during 55 days period. The results showed that rats infected with B. microti showed a typical sustained infection with strongly antibody responses; however, both goats and dogs infected with B. microti only showed transient antibody responses and the parasite was not found by blood smear observation or PCR; neither the parasite nor the special antibodies were detected in experimental chicks and pigs. On the other hand, the present study also experimentally investigated the infectivity of B. microti to Rhipicephalus haemaphysaloides, Haemaphysalis longicornis, and Hyalomma asiaticum three species of ticks outside the genus Ixodes and the transmission experiment of B. microti between H. longicornis ticks and mice. Results showed that B. microti can be detected in the nymph and adult of these species after molting from engorged tick fed on infected mice, but the parasite was not detected in larvae hatching from eggs of engorged female tick fed on the infected mice. Transmission of B. microti to mice by infected H. longicornis nymphs was confirmed. These results indicated that these domestic animals do not have reservoir competence for B. microti, however, three species of ticks out of the genus Ixodes, common in China were successfully infected by B. microti, with H. longicornis showing the potential of transmitting the parasite to the vertebrate host.

Dermacentor reticulatus, a putative vector of Babesia cf. microti (syn. Theileria annae) piroplasm

Babesia cf. microti (syn. Theileria annae, Babesia microti-like, Babesia vulpes) is a recently recognized tick-borne piroplasm that infects domestic and wild carnivores. Although Ixodes hexagonus is considered as the leading candidate responsible for the transmission, its capacity to act as a competent vector has not yet been confirmed. This study reports the occurrence of B.cf. microti in unfed Dermacentor reticulatus for the first time, suggesting that this tick species may be implicated in the life cycle of this canine parasite. Out of 128 questing D. reticulatus ticks collected in eastern Austria, nine (7%) and four (3%) of them were found to be PCR positive for B. canis and B. cf. microti, respectively. Although the data presented here are not sufficient to explicitly state that D. reticulatus is a competent vector of B. cf. microti, our results can at least give a hint for future studies, which need to include experimental transmission in order to confirm its vector competence and possible involvement in the transmission of this babesial species.

The PCR and nested PCR detection of Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum and Babesia microti in Dermacentor reticulatus F. collected in a new location in Poland (Trzciel, Western Poland)

The study was performed in the Trzciel Forest Districts which is located in the west part of Poland. The Scots pine is the main tree species creating forest landscape there. Dermacentor reticulatus, usually found in wet, boggy and damp habitat, in this case was discovered in fresh mixed coniferous forest and fresh coniferous forest. In Central Europe the Dermacentor reticulatus is after Ixodes ricinus the second most important vector for tick-borne diseases in Europe. The ticks were collected by flagging from lower vegetation during the autumn peak of their activity. All Dermacentor reticulatus were checked for presence of tickborne pathogens using PCR and nested PCR. In total 125 Dermacentor reticulatus ticks were collected. Among the pathogens examined, only Babesia microti has been found in 4% of them whereas Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum have not been found. In this research the presence of Babesia. microti in Dermacentor reticulatus has been proved. It should be stressed that it is a new focus for the Dermacentor reticulatus tick in Western Poland.

Detection of selected pathogens in ticks collected from cats and dogs in the Wrocław Agglomeration, South-West Poland

Background

Tick-borne infections are no longer confined to rural areas, they are documented with increasing frequency in urban settlements across the world. They are known to cause diseases in humans as well as in their companion animals.

Methods

During a period of 2 years, from January 2013 until December 2014, ticks were collected from dogs and cats in 18 veterinary clinics in the Wrocław Agglomeration, Poland. In total, 1455 ticks were found on 931 pets: 760 domestic dogs and 171 cats. For molecular examinations 127 I. ricinus ticks (115 females and 12 males) were randomly selected, all collected I. hexagonus (n = 137, 32 females, 98 nymphs, 7 larvae) and all collected D. reticulatus (n = 46, 31 females, 15 males) were taken. Ixodes ricinus and I. hexagonus ticks were tested for Rickettsia spp., Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis and Babesia spp., while D. reticulatus ticks were investigated for Rickettsia spp. and Babesia spp. only.

Results

In total, 65.4 % I. ricinus ticks were infected with at least one pathogen. Over 50 % of I. ricinus were positive for Rickettsia spp. (R. helvetica and R. monacensis). The infection level with A. phagocytophilum was 21.3 %. DNA of Cand. N. mikurensis was detected in 8.1 % I. ricinus ticks. Interestingly only female ticks were infected. The prevalence of Babesia spp. was confirmed in 9.0 % of I. ricinus involving the species B. microti and B. venatorum. A total of nineteen double, one triple and two quadruple infections were found in I. ricinus ticks only. Almost 11 % of I. hexagonus ticks were positive for at least one of the tested pathogens. Rickettsia spp. infection was found in 2.2 %, while A. phagocytophilum was detected in 8.1 % of I. hexagonus ticks. Only one nymph was positive for Cand. N. mikurensis and none of I. hexagonus ticks harbored a Babesia spp. Over 60 % of D. reticulatus ticks were positive for rickettsial DNA, exclusively belonging to the species R. raoultii.

Conclusion

The high tick infestation rates and the prevalence of pathogens found in these ticks demonstrate a serious level of encounter to tick-borne diseases in urban dogs in the Wroclaw area, and provide evidence that dogs and cats themselves may substantially contribute to the circulation of the ticks and pathogens in the urban area.

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.

Experimental transmission of Babesia microti by Rhipicephalus haemaphysaloides

Background

Human babesiosis is considered an emerging threat in China. Dozens of human infections with Babesia microti have been reported recently, especially in southern China. However, the transmission vectors of this parasite in these areas are not well understood. Rhipicephalus haemaphysaloides, which is one of the dominant tick species in southern China, is a major vector of bovine babesiosis in China. However, whether this tick has the potential to transmit B. microti has not been tested. The present study experimentally investigated the transmission competence of B. microti through R. haemaphysaloides ticks.

Methods

Larvae and nymphs of R. haemaphysaloides ticks were fed on laboratory mice infected by B. microti. The infection was detected by PCR at 4 weeks post-molting. BALB/c and NOD/SCID mice were infested by nymphs molting from larvae that ingested the blood of infective mice, and blood samples were then analyzed by PCR.

Results

Experimental transstadial transmission of R. haemaphysaloides for B. microti was proved in both the larvae to nymph and the nymph to adult transstadial routes. The positive rate of B. microti was 43.8 % in nymphs developed from larvae consumed infected mice and 96.7 % in adults developed from nymphs exposed to positive mice. Among the mice infested by infective nymphs, B. microti was detected in 16.7 % (2/12) of the BALB/c mice and in all of the NOD/SCID (6/6). However, the parasite was not observed to persist beyond more than one molt, and transovarial transmission did not occur.

Conclusions

This is the first study to demonstrate that B. microti can be transmitted artificially by R. haemaphysaloides. This tick species might be a potential vector of human babesiosis in southern China, which represents a public health concern.

Genetic diversity and molecular characterization of Babesia motasi-like in small ruminants and ixodid ticks from China

Ovine babesioses, an important tick-borne disease of sheep and goats in China, is caused by the reproduction of intraerythrocytic protozoa of the Babesia genus. Babesia motasi-like is a Babesia parasite that infects small ruminant in China, and two sub-groups of B. motasi-like can be subdivided based on differences in the rhoptry-associated-protein-1 gene. This study aimed to characterize the distribution, epidemiology and genetics of B. motasi-like in animals and ticks. A molecular investigation was carried out from 2009 to 2015 in 16 provinces in China. In total, 1081 blood samples were collected from sheep and goats originating from 27 different regions, and 778 ixodid tick samples were collected from 8 regions; the samples were tested for the presence of B. motasi-like using a specific nested PCR assay based on the rap-1b gene. The results indicated that 139 (12.9%), 91 (8.4%), 48 (4.4%) and 6 (0.7%) of the blood samples were positive for general B. motasi-like, Babesia sp. BQ1 (Lintan and Ningxian), Babesia sp. Tianzhu and Babesia sp. Hebei sub-groups, mixed infections, respectively. Among the collected 778 ixodid ticks (including Haemaphysalis longicornis, Haemaphysalis qinghaiensis, Dermacentor silvarum, Ixodes persulcatus, Rhipicephalus sanguineus and Rhipicephalus (Boophilus) microplus), the most frequently infected with Babesia were D. silvarum and I. persulcatus (35.7%), followed by H. longicornis (26.8%), H. qinghaiensis (24.8%) and R. sanguineus (9.3%). The PCR results were confirmed by DNA sequencing. The positive rates of B. motasi-like infection in ticks were found to be higher in China, compared with previous studies in other countries. B. motasi-like infections have not previously been reported in D. silvarum, I. persulcatus or R. sanguineus. The findings obtained in this study could be used for planning effective control strategies against babesiosis in China.

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.

Toxoplasma gondii (Nicolle et Manceaux, 1908) detected in Dermacentor reticulatus (Fabricius) (Ixodidae)

The aim of the present work was to determine whether Dermacentor reticulatus (Fabricius), tick species common in eastern Poland could be infected with Toxoplasma gondii (Nicolle et Manceaux, 1908). A total of 664 unfed D. reticulatus ticks were collected from six localities of Lublin province (eastern Poland) within the framework of study for the presence of bacterial, viral and parasitological infections, with use of PCR and confirmed by sequencing analysis. The prevalence of T. gondii DNA of B1 gene in the total examined D. reticulatus ticks was 3.2%. The infection varies greatly depending on the locality of tick collection (0-16.7%). Preliminary identification of clonal type (I or II/III) by Restriction Fragments Length Polymorphism PCR (RFLP-PCR) with use B1 gene showed that all isolates of T. gondii belonged to type I. RFLP analysis using genetic markers SAG1, 5'-SAG2, 3'-SAG2, SAG3, and GRA6 on B1-positive samples showed that only a single isolate proved to be type I with all five markers, another type was classified to type I according to four markers, while another five isolates had only type I alleles at GRA6, which cannot be regarded as type I confirmation. It must be pointed out that the used DNA isolation method by boiling with ammonium hydroxide enables to receive the total DNA from ticks, but may be not quite suitable for genotyping. In conclusion, this study indicates that besides Ixodes ricinus (Linnaeus), also D. reticulatus should be considered as a potential vector of T. gondii. The presumption of tick-borne transmission as an alternative pathway of disease spreading could well explain the high prevalence of toxoplasmosis among the herbivorous mammals and birds. However, this hypothesis needs verification by further experimental and ecological studies.

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.

Novel foci of Dermacentor reticulatus ticks infected with Babesia canis and Babesia caballi in the Netherlands and in Belgium

Background

Autochthonous populations of Dermacentor reticulatus ticks in the Netherlands were discovered after fatal cases of babesiosis occurred in resident dogs in 2004. The presence of D. reticulatus in the Netherlands has also linked with the emergence of piroplasmosis in the resident horse population. The aim of this study was to put together results of continued surveillance of field sites and hosts for this tick in the Netherlands and also in Belgium and determine their infection status for Babesia and Theileria species.

Methods

Ticks were collected from the vegetation at 11 locations between 2011 and 2013. D. reticulatus ticks were also collected from different hosts between 2007 and 2013. Ticks were screened by PCR and reverse line blot (RLB).

Results

A total of 1368 D. reticulatus ticks were collected from 4 previously known field locations and from 5 new locations in the Netherlands and from 2 sites in Belgium (one old and one new location). A total of 855 ticks collected from 8 locations in the Netherlands and 2 locations in Belgium were tested. Fourteen ticks (1,64%) collected at 4 field locations (Dintelse Gorzen, Rozenburg, Slikken van de Heen and St. Philipsland) were positive for Babesia canis, whereas two ticks were positive for Babesia caballi, one tick in the Dintelse Gorzen in the Netherlands and one tick was found positive in De Panne in Belgium.

A further 1092 D. reticulatus ticks were collected between 2007 and 2013 from 40 dogs (132 ticks), two ticks from two humans, 51 ticks from 15 horses, two ticks from two cats, one tick from a roe deer, whereas most ticks (904) were collected from cattle (n = 25). Ticks were found throughout the year on dogs in nearly all provinces of the Netherlands. None of the ticks collected from these hosts were infected.

Conclusions

D. reticulatus is continuing its spread into novel areas. The finding that some autochthonous ticks are infected with B. canis and B. caballi poses a threat to the resident dog and horse population and justifies year-round tick control measures.

Changes in the activity of adult stages of Dermacentor reticulatus (Ixodida: Amblyommidae) induced by weather factors in eastern Poland

Background

The host-seeking activity in Dermacentor reticulatus ticks undergoes rhythmical changes correlated with environmental conditions. Therefore, this study is focused on investigating the activity of adult stages of the species during weather changes occurring in winter months in eastern Poland, i.e. a period of tick diapause.

Methods

D. reticulatus ticks were collected in a meadow ecosystem near Lublin (eastern Poland, 51°36'N, 22°58'E) between the third decade of November 2011 and the third decade of January 2012. During each collection, temperature and humidity were measured at the soil surface and at a height of 25 cm and the differences (delta) in the parameters between the two measurement points were calculated.

Results

During one hour of our observation, from 0 to 42 specimens were collected, with the greatest numbers (25-40 specimens) between late November and mid- December. The activity of adult D. reticulatus (females and males in total) depended on soil and air temperature (r = -0.6986, p < 0.05). Soil and air humidity did not exert an impact on the questing behaviour of adult stages. In turn, the greater the moisture delta between these two measurement points was, the greater the activity of the adult tick stages was observed.

Our investigations have demonstrated differences in the questing behaviour between D. reticulatus females and males correlated with environmental conditions. The temperatures of soil and air increased the migratory activity in females but did not affect migration of male ticks. In turn, the deltas of temperatures (r = -0.6986, p < 0.05) and humidity (r = 0.6829, p < 0.05) did not have a statistically significant effect on stimulation of female activity but they induced significant changes on the behaviour of males, for which we found a highly negative correlation between the number of active specimens and the temperature delta (r = -0.7276, p < 0.05) and a highly positive correlation with the humidity delta (r = 0.8199, p < 0.01).

Conclusions

Weather changes can be accompanied by activity of adult D. reticulatus even in their winter diapause period. Therefore, there is an increased threat to human and animal health posed by tick-borne diseases.

A molecular survey of Babesia spp. and Theileria spp. in red foxes (Vulpes vulpes) and their ticks from Thuringia, Germany

Wild canines which are closely related to dogs constitute a potential reservoir for haemoparasites by both hosting tick species that infest dogs and harbouring tick-transmitted canine haemoparasites. In this study, the prevalence of Babesia spp. and Theileria spp. was investigated in German red foxes (Vulpes vulpes) and their ticks. DNA extracts of 261 spleen samples and 1953 ticks included 4 tick species: Ixodes ricinus (n=870), I. canisuga (n=585), I. hexagonus (n=485), and Dermacentor reticulatus (n=13) were examined for the presence of Babesia/Theileria spp. by a conventional PCR targeting the 18S rRNA gene. One hundred twenty-one out of 261 foxes (46.4%) were PCR-positive. Out of them, 44 samples were sequenced, and all sequences had 100% similarity to Theileria annae. Similarly, sequencing was carried out for 65 out of 118 PCR-positive ticks. Theileria annae DNA was detected in 61.5% of the sequenced samples, Babesia microti DNA was found in 9.2%, and Babesia venatorum in 7.6% of the sequenced samples. The foxes were most positive in June and October, whereas the peak of tick positivity was in October. Furthermore, the positivity of the ticks was higher for I. canisuga in comparison to the other tick species and for nymphs in comparison to adults. The high prevalence of T. annae DNA in red foxes in this study suggests a reservoir function of those animals for T. annae. To our knowledge, this is the first report of T. annae in foxes from Germany as well as the first detection of T. annae and B. microti in the fox tick I. canisuga. Detection of DNA of T. annae and B. microti in three tick species collected from foxes adds new potential vectors for these two pathogens and suggests a potential role of the red fox in their natural endemic cycles.

Natural history of Zoonotic Babesia: Role of wildlife reservoirs

Babesiosis is an emerging zoonotic disease on all inhabited continents and various wildlife species are the principal reservoir hosts for zoonotic Babesia species. The primary vectors of Babesia are Ixodid ticks, with the majority of zoonotic species being transmitted by species in the genus Ixodes. Species of Babesia vary in their infectivity, virulence and pathogenicity for people. Various factors (e.g., increased interactions between people and the environment, increased immunosuppression, changes in landscape and climate, and shifts in host and vector species abundance and community structures) have led to an increase in tick-borne diseases in people, including babesiosis. Furthermore, because babesiosis is now a reportable disease in several states in the United States, and it is the most common blood transfusion-associated parasite, recognized infections are expected to increase. Because of the zoonotic nature of these parasites, it is essential that we understand the natural history (especially reservoirs and vectors) so that appropriate control and prevention measures can be implemented. Considerable work has been conducted on the ecology of Babesia microti and Babesia divergens, the two most common causes of babesiosis in the United States and Europe, respectively. However, unfortunately, for many of the zoonotic Babesia species, the reservoir(s) and/or tick vector(s) are unknown. We review the current knowledge regarding the ecology of Babesia among their reservoir and tick hosts with an emphasis of the role on wildlife as reservoirs. We hope to encourage the molecular characterization of Babesia from potential reservoirs and vectors as well from people. These data are necessary so that informed decisions can be made regarding potential vectors and the potential role of wildlife in the ecology of a novel Babesia when it is detected in a human patient.

Human babesiosis in Europe: what clinicians need to know

Although best known as an animal disease, human babesiosis is attracting increasing attention as a worldwide emerging zoonosis. Humans are commonly infected by the bite of ixodid ticks. Rare ways of transmission are transplacental, perinatal and transfusion-associated. Infection of the human host can cause a very severe host-mediated pathology including fever, and hemolysis leading to anemia, hyperbilirubinuria, hemoglobinuria and possible organ failure. In recent years, apparently owing to increased medical awareness and better diagnostic methods, the number of reported cases in humans is rising steadily worldwide. Hitherto unknown zoonotic Babesia spp. are now being reported from geographic areas where babesiosis was not previously known to occur and the growing numbers of travelers and immunocompromised individuals suggest that the frequency of cases in Europe will also continue to rise. Our review is intended to provide clinicians with practical information on the clinical management of this rare, but potentially life-threatening zoonotic disease. It covers epidemiology, phylogeny, diagnostics and treatment of human babesiosis and the potential risk of transfusion-transmitted disease with a special focus on the European situation.