First cases of canine babesiosis in the Slovak Republic

The role of wildlife in the epidemiology of tick-borne diseases in Slovakia

Tick-borne diseases (TBD) represent an important challenge for human and veterinary medicine. In Slovakia, studies on the epidemiology of tick-borne pathogens (TBP) regarding reservoir hosts have focused on small mammals and to a lesser extent on birds or lizards, while knowledge of the role of the remaining vertebrate groups is limited. Generally, wild ungulates, hedgehogs, small- and medium-sized carnivores, or squirrels are important feeding hosts for ticks and serve as reservoirs for TBP. Importantly, because they carry infected ticks and/or are serologically positive, they can be used as sentinels to monitor the presence of ticks and TBP in the environment. With their increasing occurrence in urban and suburban habitats, wild ungulates, hedgehogs or foxes are becoming an important component in the developmental cycle of Ixodes ricinus and of TBP such as Anaplasma phagocytophilum or Babesia spp. On the other hand, it has been postulated that cervids may act as dilution hosts for Borrelia burgdorferi (sensu lato) and tick-borne encephalitis virus. In southwestern Slovakia, a high prevalence of infection with Theileria spp. (100%) was observed in some cervid populations, while A. phagocytophilum (prevalence of c.50%) was detected in cervids and wild boars. The following pathogens were detected in ticks feeding on free-ranging ungulates, birds, and hedgehogs: A. phagocytophilum, Rickettsia spp., Coxiella burnetii, Neoehrlichia mikurensis, B. burgdorferi (s.l.), and Babesia spp. The growing understanding of the role of wildlife as pathogen reservoirs and carriers of pathogen-infected ticks offers valuable insights into the epidemiology of TBP, providing a foundation for reducing the risk of TBD.

Babesiosis in Southeastern, Central and Northeastern Europe: An Emerging and Re-Emerging Tick-Borne Disease of Humans and Animals

There is now considerable evidence that in Europe, babesiosis is an emerging infectious disease, with some of the causative species spreading as a consequence of the increasing range of their tick vector hosts. In this review, we summarize both the historic records and recent findings on the occurrence and incidence of babesiosis in 20 European countries located in southeastern Europe (Bosnia and Herzegovina, Croatia, and Serbia), central Europe (Austria, the Czech Republic, Germany, Hungary, Luxembourg, Poland, Slovakia, Slovenia, and Switzerland), and northern and northeastern Europe (Lithuania, Latvia, Estonia, Iceland, Denmark, Finland, Sweden, and Norway), identified in humans and selected species of domesticated animals (cats, dogs, horses, and cattle). Recorded cases of human babesiosis are still rare, but their number is expected to rise in the coming years. This is because of the widespread and longer seasonal activity of Ixodes ricinus as a result of climate change and because of the more extensive use of better molecular diagnostic methods. Bovine babesiosis has a re-emerging potential because of the likely loss of herd immunity, while canine babesiosis is rapidly expanding in central and northeastern Europe, its occurrence correlating with the rapid, successful expansion of the ornate dog tick (Dermacentor reticulatus) populations in Europe. Taken together, our analysis of the available reports shows clear evidence of an increasing annual incidence of babesiosis across Europe in both humans and animals that is changing in line with similar increases in the incidence of other tick-borne diseases. This situation is of major concern, and we recommend more extensive and frequent, standardized monitoring using a "One Health" approach.

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.

Variability of species of Babesia Starcovici, 1893 in three sympatric ticks (Ixodes ricinus, Dermacentor reticulatus and Haemaphysalis concinna) at the edge of Pannonia in the Czech Republic and Slovakia

The distribution, variability and host specificity of species of Babesia Starcovici, 1893 were studied in questing ticks collected on the northwestern edge of the Pannonian Basin in the south-easternmost part of the Czech Republic and in western Slovakia. The area is characterised by relatively natural floodplain habitats and the sympatric occurrence of three tick species possessing wide host spectra, namely Ixodes ricinus (Linnaeus), Dermacentor reticulatus (Fabricius) and Haemaphysalis concinna Koch. Analysis was carried out on 1,408 I. ricinus, 2,999 D. reticulatus and 150 H. concinna altogether, collected from 59 localities. We documented the presence of Babesia spp. not only in I. ricinus but also in H. concinna in the Czech Republic. Two isolates from I. ricinus were classified as B. venatorum Herwaldt, Cacciò, Gherlinzoni, Aspöck, Slemenda, Piccaluga, Martinelli, Edelhofer, Hollenstein, Poletti, Pampiglione, Löschenberger, Tura et Pieniazek, 2003 (formerly determined as Babesia sp. EU1), which is a zoonotic parasite and can cause human babesiosis. The rest of our amplicons were very similar to B. canis (Piana et Galli-Valerio, 1895), which is usually transmitted by D. reticulatus. Despite the huge amount of examined samples, all D. reticulatus ticks were Babesia-free. Due to this finding, we did not consider our obtained isolates to be B. canis, but other closely related species possessing a similar sequence of the studied portion of 18S rDNA. Although this genetic marker is most frequently used in PCR-based diagnostic methods of babesias, its low variability compromises its reliability in studies based only on this marker.

Epizootiological Study of the Occurrence of Canine Babesiosisin Southwestern Slovakia

This epizootiological study was carried out to investigate the occurrence of canine babesiosis in southwestern Slovakia. The study focused on the proportion of the species of ticks serving as babesia vectors of babesiosis in the ticks collected from selected locations close to Komárno, in southwestern Slovakia. Additionally, observations were made on the health and overall clinical signs in dogs suspected of having babesiosis. In 2014 we collected ticks from vegetation by the drag cloth (flagging) method and also directly from dogs. A totally of 622 ticks were collected: 491 Dermacentor reticulatus and 131 Ix-odes ricinus. Representative samples of ticks (n = 103) were examined by the molecular method and the presence of Babesia spp. DNA was identified in 12.5 % of the Ixodes ricinus ticks collected by flagging and in 9.5 % of the Ixodes ricinus ticks collected from the dogs. Babesia canis (KU681325) with 90 bp sequence, 100 % identical with Babesia canis isolates from dogs for example from: Turkey (KF499115), Rumania (HQ662634), Croatia (FJ209025), Poland (EU622792) and Russia (AY962186), was confirmed after sequencing in one Ixodes ricinus female obtained from a dog. This was the first confirmation of the occurrence of B. canis in Ixodes ricinus ticks in Slovakia. In 2.2 % of the Dermacentor reticulatus ticks obtained from vegetation by flagging, we were able to diagnose the DNA of Babesia canis. In 4.8 % of the Dermacentor reticulatus ticks collected from dogs, the presence of Babesia spp. was confirmed. Thirty three dogs with suspicion of babesiosis were observed in an ambulance by their health and clinical signs. The loss of appetite was observed in 22 patients (66.7 %), apathy in 19 cases (57.6 %), and fever in 19 cases. Closer specification indicating babesiosis was finding engorged ticks on the dog bodies which occurred in 21 cases (63.6 %), haematuria in 8 cases (24.2 %), anaemia in 4 cases (12.1 %), and tremor in 6 cases (18.2 %). Other non-specific signs, such as diarrhoea, vomitus, slowed-down movement, ataxia and lacrimation were also observed in less than 18 % of the examined dogs. On the basis of the specific clinical signs, blood was withdrawn from 33 dogs for preparation of blood smears and in 19 of them (57.6 %) babesia in erythrocytes were confirmed microscopically.

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.

First molecular identification of Babesia gibsoni in dogs from Slovakia, central Europe

Canine babesiosis is a severe and potentially life threatening infection. In Europe, Babesia canis is considered to be the most common species responsible for the disease. We report two cases of babesiosis caused by Babesia gibsoni. The polymerase chain reaction, restriction fragment length polymorphism analysis and further sequencing of 18S rRNA gene fragments from blood samples of both dogs revealed the identity of isolates with B. gibsoni genotypes from other dogs worldwide. This species was previously not known to infect dogs in Slovakia. It is resistant to traditional anti-babesial therapy. Therefore, correct diagnosis is crucial for the successful treatment, especially in dogs with hemolytic anemia and febrile conditions.

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.

Molecular detection of co-infections with Anaplasma phagocytophilum and/or Babesia canis canis in Dirofilaria-positive dogs from Slovakia

Recently, several arthropod-borne infections have been introduced into previously non-endemic regions in Europe as the result of various global changes. At the same time, endemic regions are expanding and the risk of co-infections is rising, due to climate change that allows vectors to move and spread infectious diseases into new areas. The aim of the current study was to confirm simultaneous infections with Anaplasma phagocytophilum and/or Babesia canis canis in Dirofilaria-infected dogs from Slovakia, central Europe. Genomic DNA was isolated from 366 blood samples of microfilaraemic dogs without clinical signs of infection. Samples were further screened for the presence of canine tick-borne pathogens using PCR and sequencing. This survey revealed co-infection with four arthropod-borne pathogens, in particular, Dirofilaria repens, Dirofilaria immitis, A. phagocytophilum, and B. canis canis. While D. repens, responsible for canine subcutaneous dirofilariosis, is scattered through the whole territory of the country, D. immitis occurs only in endemic areas of southeastern and southwestern Slovakia in mixed infection with D. repens. Co-infection with A. phagocytophilum was reported in 3.27% of the dogs positive for D. repens; mixed infection with D. repens and B. canis canis was detected in 3.55% of the tested blood samples. Eastern Slovak Lowland represents a natural focus of B. canis canis and is a highly endemic area for canine dirofilariosis. The presence of triple infection with D. repens, A. phagocytophilum, and B. canis canis was detected in one dog originating from the eastern lowland region of Slovakia. This study highlights the importance of co-infected, clinically healthy dogs in the spreading of several different arthropod-borne pathogens and the necessity for detailed epidemiological surveys, especially in newly infested areas.

Contribution to canine babesiosis in the Czech Republic

From March to November 2010, a total of 68 samples of blood from 41 hunting and working dogs that never left the Czech Republic were examined. Some dogs were sampled repeatedly. Blood samples were examined by polymerase chain reaction for the presence of DNA of piroplasms with negative results. Specific IgG antibodies against Babesia canis were detected by indirect immunofluorescence test, and five dogs (12.21%) were seropositive. Titres ranged from 50 to 200. One dog was positive in two samplings within 3 months. The highest number of positive samples was taken in June. The results of this study suggest a likely contact of the examined dogs with the parasite; although in 2005, a total of 340 adult unfed Dermacentor reticulatus ticks in 34 pools screened by PCR for babesiae were negative.

Polymerase chain reaction confirmation of Babesia canis canis and Anaplasma phagocytophilum in dogs suspected of babesiosis in Slovakia

Canine babesiosis was considered an imported tick transmitted disease until the first case of autochthonous canine babesiosis in Slovakia was described in 2002. Since then, the number of cases kept increasing every year. The causative agent of babesiosis in dogs is not yet characterized; therefore, the aim of our study was to determine the agent and the rate of infection in the vector tick D. reticulatus in Slovakia. Babesia canis canis was detected in 80 out of 87 blood samples from dogs with clinical manifestations of babesiosis. Six dogs suspected of babesiosis tested positive for presence of Anaplasma phagocytophilum, and one mixed infection of B. c. canis and A. phagocytophilum was detected. B. c. canis was detected in 35.6% questing adults of D. reticulatus. The obtained sequences from blood samples showed 99.7% and from D. reticulatus, 99.4% similarity with the B. c. canis (AY072926) from dogs infected in Croatia. In our study, we characterized the agent of canine babesiosis from blood samples of naturally infected dogs and D. reticulatus, the vector tick. Further, the presence of A. phagocytophilum, bacterium responsible for the canine granulocytic anaplasmosis, was recorded in dogs for the first time in Slovakia.

West-to-east differences of Babesia canis canis prevalence in Dermacentor reticulatus ticks in Slovakia

Babesia canis canis is the most frequent causative agent of canine babesiosis in Central Europe, frequently causing severe disease. Recently, many new endemic foci of this disease have been reported from European countries. Growing incidence of canine babesiosis was recorded also in Slovakia during the last decade, from first cases in eastern Slovakia ten years ago to recent cases all over the south of the country. We have used nested PCR-RFLP method to study prevalence of B. c. canis in its natural tick vector Dermacentor reticulatus, collected at three geographically isolated lowland areas of southern Slovakia situated in the southeast, southwest, and west of Slovakia, respectively. The highest prevalence of B. c. canis was observed in D. reticulatus from eastern Slovakia (14.7%; n=327), whereas the prevalence in southwest was significantly lower (2.3%; n=1205). Notably, all 874 D. reticulatus ticks collected at Záhorská nížina lowland (W Slovakia) were B. c. canis-negative. Recorded differences in Babesia prevalence concurs well with the shift in incidence of clinical cases of canine babesiosis as observed by vet practitioners. Presented results revealed that eastern Slovakia represents an area of high risk of B. c. canis infection, whereas western areas of the country still remain Babesia canis-free.

Spatial distribution of Dermacentor reticulatus tick in Slovakia in the beginning of the 21st century

A new field survey monitoring the spatial distribution of Dermacentor (D.) reticulatus (Fabricius, 1794) tick in Slovakia was carried out in 2005-2008 in order to record changes in its distribution when compared to former studies. Last surveys on the geographical distribution were conducted in 1950s and 1970s and the presence of D. reticulatus was determined along the rivers in the south-east (Latorica) as well as in the south-west (Morava, Dunaj) Slovakia. In the present survey new areas with D. reticulatus occurrence were detected, providing evidence that this tick species has extended its range in the surroundings of its former habitats but also by at least 200 km further North and by 300 m of elevation into higher altitudes. D. reticulatus is known to transmit Babesia spp. causing babesiosis in cattle and dogs. Expansion of D. reticulatus range is therefore likely to bring a spread of babesiosis, which can be severe or fatal especially for dogs.

Seroprevalence of canine babesiosis in Hungary suggesting breed predisposition

Six hundred fifty-one blood samples were collected from urban and rural dogs in various parts of Hungary to measure antibody levels to Babesia canis with indirect fluorescent antibody test. Thirty-seven (5.7%) of the sera showed positivity with titers between 1:80 and 1:10,240. Seroconverted dogs were found in 13 locations of the country. It is concluded that canine babesiosis is becoming more prevalent in Eastern Hungary. Seropositivity increased then declined with age, reaching a maximum in case of 3.1- to 5-year-old dogs. Prevalence of antibodies to B. canis was significantly higher among german shepherds and komondors. This suggests a genetic predisposition of german shepherd dogs to chronic babesiosis (carrier status) with long-term maintenance of their seropositivity. On the other hand, heavy-coated komondors are phenotypically more suitable for repeated exposure to ticks, potentially infected with B. canis. This is the first report on the seroprevalence of canine babesiosis in Hungary.

Evidence for an increased geographical distribution of Dermacentor reticulatus in Germany and detection of Rickettsia sp. RpA4

Two studies were performed to elucidate the current distribution of the tick Dermacentor reticulatus in Germany. In the first one in 2003, a total of 365 dogs from 171 sites in the states of Berlin and Brandenburg was screened for ticks, and the corresponding outdoor sites that the dogs usually visited were searched for host-seeking ticks by the flagging method. A total of 1155 ticks was removed from the dogs. The majority were Ixodes ricinus (88.5%), followed by D. reticulatus (9.1%) and I. hexagonus (2.4%). Altogether, 222 dogs carried I. ricinus (60.8%), 41 D. reticulatus (11.2%) and 15 I. hexagonus (4.1%) ticks. Based on scutal index determination, the removed I. ricinus and D. reticulatus had been feeding on the dogs for a mean of 4.0 and 4.5 days, respectively. The dogs infested with D. reticulatus lived at 26 different sites, all previously unknown as Dermacentor sites. Seven of the sites could be confirmed subsequently by flagging the vegetation for ticks. In the second study, a total of 721 deer was shot at 201 different sites from a total of 160 districts all over Germany during the autumn hunting season 2004. A total of 23 deer (3.2%) originating from 14 sites was infested with D. reticulatus. Hereby, significantly more red deer (Cervus elaphus elaphus) than roe deer (Capreolus capreolus) or fallow deer (Dama dama) harboured D. reticulatus ticks. Only two of the sites found had already been known as D. reticulatus areas, whereas all other sites in Brandenburg, Saxony Anhalt, Hesse and Bavaria had been unknown. The results of both studies show that D. reticulatus presently occurs at far more sites than previously known in Germany and thus most likely has expanded its range. Additionally, a total of 135 D. reticulatus removed from deer was screened for Babesia canis and Rickettsia sp. by PCR. A total of 31 D. reticulatus (23%) were positive for Rickettsia. Sequencing revealed in all cases 100% identity with the strain RpA4 that was first isolated from Rhipicephalus ticks in Russia.

Spatial distribution of Dermacentor reticulatus and Ixodes ricinus in Hungary: evidence for change?

A survey was conducted to investigate the spatial distribution of Ixodes ricinus and Dermacentor reticulatus in Hungary and to compare these data with the results of a previous large-scale survey. In the survey conducted in the 1950s, D. reticulatus adults were detected in two isolated areas of two counties, and the presence of these ticks in the collection was explained by accidental introduction. In the present survey, D. reticulatus became the second most common species occurring in all 16 counties involved in the monitoring and showed high prevalence. The change in the spatial distribution of this tick species, the increase of incidence of Babesia canis infection in Hungary, and the increasing number of canine babesiosis case reports from other Central and Central Eastern European countries since the 1970s suggest an expansion of the geographic range of D. reticulatus and intensification of the transmission rate of B. canis and probably other D. reticulatus-borne diseases (e.g. tularemia and tick-borne lymphadenopathy) in the region. The spatial distribution of I. ricinus was roughly in line with the results of the earlier survey. I. ricinus was the most common tick species being present in all 16 counties with the highest prevalence. Nevertheless, the comparison of the data of the previous and current survey cannot be used for fine-scale analysis; thus, it cannot be dismissed that the spatial distribution of I. ricinus also changed during the past decades. The spatial distribution patterns of tick-borne encephalitis in Hungary and other Central Eastern European countries may indicate such a change.