In Europe, Ixodes ricinus is the most important vector of tick-borne zoonotic bacteria. It transmits spirochaetes from the Borrelia burgdorferi sensu lato complex, Anaplasma phagocytophilum and Rickettsia spp. Although spatial differences in the prevalence of tick-borne pathogens have been intensively studied, seasonal (within-year) fluctuations in the prevalence of these pathogens within sites are often overlooked. We analyzed the occurrence and seasonal dynamics of Ixodes ricinus in an urban forest in Bratislava, Slovakia. Furthemore, we examined temporal trends in the community structure of B. burgdorferi s.l., A. phagocytophilum and Rickettsia spp. in questing and bird-feeding ticks. The total prevalence for B. burgdorferi s.l. in questing I. ricinus was 6.8%, involving six genospecies with the dominance of bird-associated B. garinii and B. valaisiana. A. phagocytophilum, R. helvetica and R. monacensis occurred in 5.9%, 5.0% and 0.2% of questing ticks, respectively. In total, 12.5% and 4.4% of bird-feeding I. ricinus ticks carried B. burgdorferi s.l. and R. helvetica. The total prevalence of B. burgdorferi s.l. in our study site was two times lower than the mean prevalence for Europe. In contrast, A. phagocytophilum prevalence was significantly higher compared to those in other habitats of Slovakia. Our results imply that tick propagation and the transmission, suppression and seasonal dynamics of tick-borne pathogens at the study site were primarily shaped by abundance and temporal population fluctuations in ruminant and bird hosts.

Natural foci of tick-borne spotted fever group (SFG) rickettsiae of public health concern have been found in Slovakia, but the role of rodents in their circulation is unclear. Ticks (Ixodes ricinus, Ixodes trianguliceps, Dermacentor marginatus, Dermacentor reticulatus, Haemaphysalis concinna and Haemaphysalis inermis) and tissues of rodents (Apodemus flavicollis, Apodemus sylvaticus, Myodes glareolus, Microtus arvalis, Microtus subterraneus and Micromys minutus) were examined for the presence of SFG rickettsiae and Coxiella burnetii by molecular methods. Suburban, natural and rural habitats were monitored to acquire information on the role of ticks and rodents in the agents’ maintenance in various habitat types of Slovakia. The overall prevalence of rickettsial infection in questing I. ricinus and D. marginatus was 6.6% and 21.4%, respectively. Rickettsia helvetica, R. monacensis and non-identified rickettsial species were detected in I. ricinus, whereas R. slovaca and R. raoultii were identified in D. marginatus. Rickettsia spp.-infected I. ricinus occurred during the whole tick questing period. Rickettsia helvetica dominated (80.5%) followed by R. monacensis (6.5%). The species were present in all studied habitats. Rickettsia slovaca (66.7%) and R. raoultii (33.3%) were identified in D. marginatus from the rural habitat. Apodemus flavicollis was the most infested rodent species with I. ricinus, but My. glareolus carried the highest proportion of Rickettsia-positive I. ricinus larvae. Only 0.5% of rodents (A. flavicollis) and 5.2% of engorged I. ricinus removed from My. glareolus, A. flavicollis and M. arvalis were R. helvetica- and R. monacensis-positive. Coxiella burnetii was not detected in any of the tested samples. We hypothesize that rodents could play a role as carriers of infected ticks and contribute to the maintenance of rickettsial pathogens in natural foci. Long-term presence of SFG Rickettsia spp. was confirmed in questing ticks from different habitat types of Slovakia. The results suggest a human risk for infection with the pathogenic R. helvetica, R. monacensis, R. slovaca and R. raoultii.

Fleas (Siphonaptera) as obligate, blood-feeding ectoparasites are, together with ticks, hosted by small mammals and can transmit causative agents of serious infections. This study aimed to determine and characterize the presence and genetic diversity of Bartonella, Rickettsia, and apicomplexan parasites (Babesia, Hepatozoon) in fleas feeding on small mammals from three different habitat types (suburban, natural, and rural) in Slovakia. The most common pathogen in the examined fleas was Bartonella spp. (33.98%; 95% CI: 30.38–37.58), followed by Rickettsia spp. (19.1%; 95% CI: 16.25–22.24) and apicomplexan parasites (4.36%; 95% CI: 2.81–5.91). Bartonella strains belonging to B. taylorii, B. grahamii, B. elizabethae, Bartonella sp. wbs11, and B. rochalimae clades were identified in Ctenophthalmus agyrtes, C. congener, C. assimilis, C. sciurorum, C. solutus, C. bisoctodentatus, Palaeopsylla similis, Megabothris turbidus, and Nosopsyllus fasciatus within all habitats. The presence of Rickettsia helvetica, R. monacensis, and rickettsiae, belonging to the R. akari and R. felis clusters, and endosymbionts with a 96–100% identity with the Rickettsia endosymbiont of Nosopsyllus laeviceps laeviceps were also revealed in C. agyrtes, C. solutus, C. assimilis, C. congener, M. turbidus, and N. fasciatus. Babesia and Hepatozoon DNA was detected in the fleas from all habitat types. Hepatozoon sp. was detected in C. agyrtes, C. assimilis, and M. turbidus, while Babesia microti was identified from C. agyrtes, C. congener, and P. similis. The present study demonstrated the presence of zoonotic pathogens in fleas, parasitizing the wild-living small mammals of southwestern and central Slovakia and widens our knowledge of the ecology and genomic diversity of Bartonella, Rickettsia, Babesia, and Hepatozoon.

Haemosporidians are a group of vector-borne parasites belonging to the order Haemosporida. These parasites infect avian hosts and require blood-sucking insects (Diptera) for transmission. The occurrence and diversity of haemosporidian parasites are shaped primarily by the specificity of the parasite and the susceptibility of the host/vector. In this study, the presence and distribution of haemosporidians in blood samples from birds in urbanized and natural habitats were estimated using microscopic and molecular approaches. Birds in urbanized habitats were infected with four different species of Plasmodium, P. relictum, P. vaughani, P. matutinum, and P. circumflexum, and one species of Haemoproteus, H. parabelopolskyi, and Leucocytozoon sp. The species H. attenuatus, H. concavocentralis, H. minutus, H. pallidus, H. noctuae, and H. tartakovskyi were additionally identified in birds in natural habitats. Typically, juvenile birds are essential markers of parasite species transmitted in the study area. The juveniles in the urbanized habitats carried P. relictum, P. vaughani, P. circumflexum, H. parabelopolskyi, and Leucocytozoon species. The most abundant parasite was H. parabelopolskyi, which was found in both habitat types. The prevalence of Haemoproteus/Plasmodium species determined by nested PCR in birds in natural habitats (43.80%; 53/121) was significantly greater than that in birds in urbanized habitats (21.94%; 43/196) (p < 0.05). There was no significant difference in the infection rate of Leucocytozoon sp. between the habitat types (p > 0.05; 10/121 vs. 19/196).

Spontaneous tumor regression is a recognized phenomenon across various cancer types. Recent research emphasizes the alterations in autoantibodies against carbonic anhydrase I (CA I) (anti‐CA I) levels as potential prognostic markers for various malignancies. Particularly, autoantibodies targeting CA I and II appear to induce cellular damage by inhibiting their respective protein’s catalytic functions. Our study illuminates the profound impact of anti‐CA I autoantibodies from patient serum on the esterase activity of human CA I, exhibiting inhibitory effects akin to the acetazolamide inhibitor. Concurrently, our newly synthesized mouse monoclonal IgG antibody, mAb 2B8, against human CA I showcased a potent inhibitory action. An in‐depth exploration into mAb 2B8′s binding dynamics with its target enzyme was undertaken. Leveraging epitope extraction and phage display library techniques, we identified the amino acid sequence DFWTYP (positions 191–196 of CA I) as crucial for mAb 2B8′s interaction. In 3‐D structural analysis, this sequence is spatially adjacent to a previously identified epitope (DFWTYP) that interacts with patient‐derived autoantibodies. Critically, mAb 2B8 demonstrated an ability to infiltrate eukaryotic cells, engaging specifically with its intracytoplasmic target. This positions mAb 2B8 as a promising model for future studies aimed at tumor cell eradication.