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Dirofilaria repens is an expanding vector-borne zoonotic parasite of canines and other carnivores. Sub-clinically infected dogs constitute the most important reservoir of the parasite and the source of infection for its mosquito vectors. However, occurrence of D. repens infection in wild animals may contribute to the transmission of the parasite to humans and may explain the endemicity of filariae in newly invaded regions. The aim of the current study was to determine the occurrence of D. repens in 511 blood and spleen samples from seven species of wild carnivores (wolves, red foxes, Eurasian badgers, raccoons, raccoon dogs, stone martens, and pine martens) from different regions of Poland by means of a PCR protocol targeting the 12S rDNA gene. Dirofilaria repens–positive hosts were identified in seven of fourteen voivodeships in four of the seven regions of Poland: Masovia, Lesser Poland, Pomerania and Warmia-Masuria. The highest prevalence was found in Masovia region (8%), coinciding with the highest previously recorded prevalence in dogs in Central Poland. The DNA of Dirofilaria was detected in 16 samples of three species (total prevalence 3.13%). A low and similar percentage of positive samples (1.9%, 4.2% and 4.8%) was recorded among badgers, red foxes, and wolves, respectively. Dirofilaria repens–positive hosts were identified in seven of fourteen voivodships. Based on detection in different voivodeships, D. repens–positive animals were recorded in four out of the seven regions of Poland: in Masovia, Lesser Poland, Pomerania, and Warmia-Masuria. The highest prevalence of filariae was found in Masovia region (8%), reflecting the highest previously recorded prevalence in dogs (12–50%) in Central Poland. In summary, we conducted the first comprehensive study on the epidemiology of D. repens in seven species of wild hosts in all seven regions of Poland and identified the first case of D. repens infection in Eurasian badgers in Poland and the second in Europe. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In recent years, a new focus of the relict tick Haemaphysalis concinna was discovered in Western Poland, near Wolsztyn, Greater Poland voivodeship. This species may play an important role in the circulation of pathogens of medical and veterinary importance. In the present study we tested 880 juvenile ticks collected from rodents, including 427 H. concinna, 443 Ixodes ricinus and 10 Dermacentor reticulatus for three of the most common pathogens vectored by ticks in Poland: Rickettsia and Babesia spp. and Borrelia burgdorferi s.l. Additionally, molecular techniques were applied for accurate identification of tick host species (the voles Microtus and Alexandromys). Our study found differences in the range and prevalence of vectored pathogens between the three tick species. DNA of all three pathogens was found in I. ricinus. In juvenile H. concinna, DNA of Babesia microti, Borrelia afzelii and Rickettsia sp. was identified. Moreover, DNA of a new unnamed Babesia species related to B. crassa, was found in two H. concinna nymphs. This genotype of Babesia was previously identified in H. concinna in the Far East and then in Central Europe. DNA of Rickettsia raoulti and B. afzelii was detected in D. reticulatus nymphs. Among rodent hosts, Alexandromys oeconomus seems to be host of the highest significance for juvenile tick stages and was the only host species with B. afzelii detected in blood samples. Using phylogenetic methods, we confirmed a clear division between rodents from the genera Microtus and Alexandromys. Moreover, we found that A. oeconomus trapped in Western Poland clustered with a Central European A. oeconomus allopatric phylogroup. [ABSTRACT FROM AUTHOR]

Dirofilariasis is a fast-spreading disease of dogs and humans in Europe. We investigated whether Dirofilaria spp. have spread northwards in Europe, invading the Baltic countries. Altogether, 424 blood samples were collected from eight countries in the period 2017–2019, including 227 samples from sled dogs and 197 samples from other dogs. PCR amplification and sequencing were conducted employing three genetic markers (mitochondrial [mt] 12S rDNA, mt cytochrome c oxidase subunit I [COI] gene and mt dehydrogenase subunit I [NAD1] gene). The SNAP test (IDEXX) for detection of D. immitis infections was also implemented. The DNA of D. repens was detected in 59 of 424 dogs (prevalence 13.9%). D. repens was found in sled dogs from Lithuania, Latvia, Poland and Belarus. Only one dog from Estonia was infected, apparently an imported case. The highest prevalence was recorded in Lithuania (38%). Among pet dogs from the Ukraine, six dogs tested positive (3.8%). Our study has revealed a high prevalence of D. repens infections in Lithuania and Latvia, but no evidence for spread of the heartworm D. immitis. We conclude that sled dog kennels constitute hot spots for D. repens transmission. [ABSTRACT FROM AUTHOR]

Juvenile Dermacentor reticulatus ticks inhabit nests and burrows of their rodent hosts and cannot be collected from vegetation. To detect vertical transmission of Babesia canis in D. reticulatus, we studied larvae and nymphs collected from rodents. However, the molecular techniques used for detection of pathogen DNA are sensitive enough to detect not only pathogens vectored by ticks but also those taken up with current or previous blood meals ('meal contamination') or just present in the environment and on the tick or host surface ('environmental contaminations'). Thus, an additional aim of our study was to evaluate the extent of such contamination while studying feeding ticks collected from rodents. Juvenile D. reticulatus were collected from 140 rodents: 91 bank voles trapped in two forest sites in the Mazury Lake District and 49 rodents (Apodemus and Microtus spp.) from an open habitat near the town of Białobrzegi in Central Poland. Altogether 504 D. reticulatus ticks, comprising 266 individually evaluated nymphs and 238 larvae assigned to 50 larval pools, were studied for the presence of Babesia, Bartonella and Rickettsia spp. DNA. Statistical analyses were conducted to (1) evaluate the effect of rodent host factors (species, sex and age) on prevalence of infection in ticks, and (2) to compare the frequency of positive samples between groups of pathogen-positive and pathogen-negative rodent hosts. To complete the last aim, blood samples obtained from 49 rodents from Białobrzegi were studied for the presence of Babesia and Bartonella DNA. Infestation of rodent hosts with juvenile ticks ranged between 46 and 78%, with a mean abundance of 3.6 ticks/rodent for D. reticulatus and 4.8 ticks/rodent for Ixodes ricinus. The highest prevalence of PCR-positive D. reticulatus samples was obtained for Rickettsia spp. (28%) and R. raoultii was identified in 22 sequenced PCR products. Babesia DNA was detected in 20 (7.5%), including B. microti in 18 (6.8%) and B. canis in two (0.8%) of 266 D. reticulatus nymphs that were analyzed. Babesia microti DNA was also detected in four pools of D. reticulatus larvae (4/50 pools = 8%). The detection success of B. microti in D. reticulatus was associated with the species of the rodent hosts of the ticks (much higher for typical B. microti-host-species such as Microtus spp. than for Apodemus spp.) and host age (3 × higher in ticks collected from adult hosts in comparison to juvenile ones). Moreover, the DNA of B. microti was detected in 68% of D. reticulatus nymphs collected from B. microti-positive rodents in comparison to only 1.6% of nymphs collected from B. microti-negative rodents. Bartonella DNA was detected in 18% of D. reticulatus tick samples (38% of larval pools, 14% of nymphs). Again, host factors played important roles for 'tick positivity'-the highest prevalence of positive ticks was on Apodemus spp., which are regarded as Bartonella reservoirs. Bartonella DNA was detected in 42% of nymphs and 57% of larval pools collected from Bartonella-positive rodents in comparison to 28% of nymphs and 11% of larvae collected from Bartonella-negative rodents. Vertical transmission of B. canis in D. reticulatus ticks was confirmed in the field. Additionally, we demonstrated that 'meal contamination' generates a confounding signal in molecular detection of pathogen DNA extracted from ticks collected from infected hosts and must be taken into account in evaluating the competence of tick species as vectors. [ABSTRACT FROM AUTHOR]

The relict tick Haemaphysalis concinna has a fragmented and focal distribution in Central Europe and Asia. Although in the majority of neighboring countries the occurrence of this tick species is well-documented (i.e., in Germany, Czech Republic, Slovakia, Ukraine), to-date its occurrence in Poland has been registered only once, in 1953 in Troszyn in North-Western Pomerania, close to the German-Polish border. In the present study we report the first documented finding of H. concinna in Western Poland, confirmed both by collection of juvenile ticks from rodent hosts and questing ticks from vegetation. Trapping of rodents took place in the summer of 2018 in three locations in Western Poland (Słonin, Nowy Młyn 1, Nowy Młyn 2). Rodents were inspected for ectoparasites, which were detached and fixed in 70% ethanol. All the collected ticks were assigned to species and developmental stages using appropriate morphological keys, and representative individuals were genotyped by molecular methods. A total of 1482 feeding ticks were collected from 106 rodents from three sites. The common tick Ixodes ricinus was found in abundance on small rodents at all three sites; Dermacentor reticulatus ticks were identified at two sites in small numbers and, finally, numerous juvenile H. concinna (n = 427) were found at one of our study sites (Nowy Młyn 2). The highest prevalence and abundance of H. concinna were recorded on voles, Microtus agrestis and M. oeconomus, from this site in August. Additionally, questing nymphs and adult H. concinna were collected locally from vegetation (n = 20). Genotyping and phylogenetic analysis confirmed the species as H. concinna. A new focus of H. concinna has been described in Western Poland. Our long-term field work monitoring the expansion of the distribution of D. reticulatus in Poland, during which all collected ticks are identified, suggests that H. concinna is still very rare in the country. [ABSTRACT FROM AUTHOR]

Following the description of Babesia behnkei in the region of St. Katherine, Sinai, the present study was undertaken to determine the role of local tick species as vectors of piroplasms. First we assessed the local fauna of ticks, especially species occurring on rodents, camels and encountered in the environment, and then we compared genotypes of ticks from isolated wadis. Finally, we assessed the role of local tick species as potential vectors of Babesia spp. During our expedition to the Sinai Massif in a 4-week period in August-September 2012, 393 ticks were collected, including 235 adult questing ticks collected from the environment (ground level in the wadis) and 158 engorging ticks from camels and rodents. Amplification and sequencing of a 600 bp fragment of the conservative 18S rDNA and a 440 bp fragment of the more variable mitochondrial (mt) 16S rDNA were carried out to enable the identification of 54 ticks and to assess the genetic variability of ticks collected from two distant isolated wadis. The camel tick Hyalomma dromedarii constituted the majority (80-90%) of adult ticks collected from three wadis in the Sinai Mountains near St. Katherine. Among juvenile ticks collected from rodents, three genotypes were identified: H. dromedarii; Hyalomma sp. showing low homology with H. dromedarii, H. lusitanicum or H. aegyptium; and Rhipicephalus sp. A new genotype of Hyalomma was identified in an isolated montane valley, W. Gebal. Babesia/Theileria DNA was not detected in any of the ticks, which is likely due to the low infection rate in the limited number of ticks that were examined. [ABSTRACT FROM AUTHOR]

Long-term field studies on parasite communities are rare but provide a powerful insight into the ecological and evolutionary processes shaping host-parasite interactions. The aim of our study was to identify the principal factors regulating long-term trends in the haemoparasite communities of bank voles, and to this end, we sampled three semi-isolated populations of bank voles ( n = 880) in 1999, 2002, 2006 and 2010 in the Mazury lake district region of NE Poland. Overall, 90.8 % of the bank voles harboured at least one of the species of haemoparasites studied. Whilst overall prevalence (all species combined) did not vary significantly between the surveys, different temporal changes were detected among voles in each of the three sites. In voles from Urwitałt, prevalence increased consistently with successive surveys, whereas in Tałty, the peak years were 2002 and 2006, and in Pilchy, prevalence oscillated without a clear pattern. Across the study, bank voles harboured a mean of 1.75 ± 0.034 haemoparasite species, and species richness remained stable with no significant between-year fluctuations or trends. However, each of the five constituent species/genera showed a different pattern of spatio-temporal changes. The overall prevalence of Babesia microti was 4.9 %, but this varied significantly between years peaking in 2006 and declining again by 2010. For Bartonella spp., overall prevalence was 38.7 %, and this varied with year of study, but the temporal pattern of changes differed among the three sites. The overall prevalence of Haemobartonella ( Mycoplasma) was 68.3 % with an increase in prevalence with year of study in all three sites. Hepatozoon erhardovae had an overall prevalence of 46.8 % but showed a marked reduction with each successive year of the study, and this was consistent in all three sites. The overall prevalence of Trypanosoma evotomys was 15.4 % varying significantly between sites, but showing temporal stability. While overall prevalence of all haemoparasites combined and species richness remained stable over the period of study, among the five haemoparasites, the pattern of spatiotemporal changes in prevalence and abundance of infections differed depending on parasite species. For some genera, host age was shown to play an important role, but a significant effect of host sex was found only for Haemobartonella spp. [ABSTRACT FROM AUTHOR]