The aim of the study was to determine prevalence of Anaplasmataceae-infected ticks in the Black Sea Coast and the Pleven regions of Bulgaria. A total of 350 ticks from different tick species were collected. Two hundred fifty-five ticks were removed from dogs in the Black Sea Coast region, and 95 Ixodes ricinus ticks were collected by flagging vegetation with a white flannel cloth in two areas in the region of Pleven. After the DNA isolation of the ticks, a genus-specific polymerase chain reaction (PCR) was performed to identify Anaplasmataceae. Second PCRs were performed with species-specific primers to identify Ehrlichia canis (E. canis) and Anaplasma phagocytophilum (A. phagocytophilum). The results showed that 26.9% of the Ixodes ricinus ticks were infected with Anaplasmataceae in the Black Sea Coast region and 36.8% in the Pleven region. The infection with E. canis was detected in 35.7% and A. phagocytophilum in 25.0% of positive ticks from the Black Sea Coast region. In the Pleven region, 22.9% of ticks were positive for E. canis, while 42.9% were positive for A. phagocytophilum. The molecular identification of E. canis in ticks collected from Bulgaria was performed for the first time. In conclusion, the present study revealed a higher prevalence of ticks infected with Anaplasmataceae, particularly A. phagocytophilum, in the Pleven region than in the Black Sea Coast region.

In our study, we focused on the role of the immunosuppressive cytokines TGF-β1 and IL-10 in RA and, in particular, the influence of the IL10-1082 A/G (rs1800896) and TGFB1-509C/T (rs1800469) promoter polymorphisms on their levels as a prerequisite for RA and disease activity clinical features. We found significantly higher IL-10 and lower TGF-β1 serum levels in women with RA than in controls. Patients who carried the -1082AA and AG genotypes had significantly higher levels of lnIL-10 compared to GG in contrast to healthy women carrying the same genotypes. The heterozygous -1082AG genotype was less frequent in RA cases (45.4%) than in healthy women (56.1%) and could be a protective factor for RA development (over-dominant model, OR = 0.66 95% CI 0.38–1.57). In addition, RA patients carrying the heterozygous -1082AG genotype were less likely to be anti-CCP positive than those carrying the homozygous AA/GG genotypes (37.1% vs. 62.9%; OR = 0.495. 95% CI 0.238–1.029, p = 0.058). There was no association between TGFB1 -509C/T SNP and susceptibility to RA and no relation between systemic TGF-β1 levels and rs1800469 genotypes. In conclusion, the IL10-1082 genotypes affect the serum levels of IL-10 in women with RA in a different way from that in healthy women and appear to play a role in the genetic predisposition and autoantibody production in the Bulgarian population.

We aimed to determine the presence and distribution of Borrelia burgdorferi sensu lato (s.l.) in Ixodes ricinus ticks collected from urbanized and wild areas in Kaylaka Park (Bulgaria). A total of 546 ticks were collected over three years (2017–2019). The presence of Borrelia in 334 of the collected I. ricinus was detected by dark-field microscopy (DFM) and two nested PCRs (nPCR) targeting the borrelial 5S-23S rRNA intergenic spacer and Flagellin B (FlaB) gene. DFM was performed on a total of 215 ticks, of which 86 (40%) were positive. PCR was performed on 153 of the ticks. In total, 42.5% of the 5S-23S rRNA intergenic spacer and 49% of FlaB were positive. Considering as positive any single tick in which Borrelia sp. was detected regardless of the used method, the infection rate reached 37% (10/27) in the nymphs and 48.5% (149/307) in the adults (48.7% (77/158) females, 48.3% (72/149) males). The incidence of B. burgdorferi infection in I. ricinus did not differ statistically significantly between female, male, and nymph. This study provides evidence that Lyme disease spirochetes are present in various regions of Kaylaka Park with extremely high prevalence in their vectors.

Infection of dogs with the tick-borne rickettsiae Ehrlichia and Anaplasma provokes an immune response mediating the pathology and bacterial resistance. IL-10 is the main anti-inflammatory cytokine and plays a multifaceted role in host protection. The study aimed to investigate circulating IL-10 in 32 dogs naturally infected with A. phagocytophilum and E. canis, identified by PCR positivity, and 33 PCR-negative animals which tested positive for antibodies against these pathogens, as well as 22 healthy animals. The highest quantity of IL-10, measured by ELISA, was observed among dogs positive simultaneously for anti-E. canis and anti-A. phagocytophilum IgG antibodies, followed by dogs positive for anti-E. canis only. The concentration of IL-10 in PCR-positive dogs was almost three and a half times higher than that measured in the control group (77.09 ± 23.61 pg./mL vs. 21.55 ± 4.61 pg./mL; p = 0.0015) and five times higher than the concentration of interleukin in PCR-negative animals (77.09 ± 23.61 pg./mL vs. 14.86 ± 3.01 pg./mL; p = 0.000016). The highest level of IL-10 was observed in PCR-positive dogs with mixed infection (120.54 ± 44.18), followed by the level in PCR-positive dogs for E. canis only (78.81 ± 16.92). The lowest level of IL-10 was observed in PCR-positive dogs for A. phagocytophilum only (56.32 ± 12.68). We may suggest that infection with E. canis and A. phagocytophilum stimulates the IL-10 production in dogs, which may facilitate specific antibody responses.

A parasitological survey was conducted during May 2026 on captive Aldabra giant tortoises (Aldabrachelys gigantea) housed at three zoological facilities on Zanzibar Island, Tanzania: the Prison Island Giant Tortoise Sanctuary (Changuu Island), Zanzibar Park, and Zanzibar Nungwi Zoo. This study investigated the occurrence of gastrointestinal parasite stages in faecal samples from captive Aldabra giant tortoises and compared the proportion of positive samples among the three zoological facilities. A total of 84 fresh faecal samples were examined using Fülleborn’s flotation and sedimentation techniques. Because individual tortoises could not always be reliably identified during sampling, repeated sampling of the same animal cannot be excluded. Therefore, the reported values represent sample-level proportions rather than individual-level prevalence. Oxyurid-type nematode eggs were detected only in samples collected from tortoises housed at Zanzibar Nungwi Zoo, whereas no gastrointestinal helminth eggs or larvae were detected using the applied coprological methods in samples from the Prison Island Giant Tortoise Sanctuary and Zanzibar Park. The overall proportion of positive faecal samples was 13.1% (11/84; 95% CI: 6.7–22.2%), while 42.3% (11/26; 95% CI: 23.4–63.1%) of samples from Zanzibar Nungwi Zoo were positive. Differences in the proportion of positive faecal samples were observed among the three zoological facilities. These findings provide baseline data on gastrointestinal parasites in captive Aldabra giant tortoises on Zanzibar Island and support future parasite surveillance, health monitoring, and management in zoological collections.

The tick species Ixodes ricinus is the most widely distributed throughout Europe and serves as the primary vector for the spirochete Borrelia burgdorferi sensu lato (s.l.), which is responsible for Lyme borreliosis. The present study evaluated the prevalence of B. burgdorferi (s.l.) in I. ricinus ticks using nPCR amplification. Ticks were collected from three geographical regions in Bulgaria: the Black Sea Coast in the east, the Pleven region in the north, and the Stara Zagora region in the central south. This study focused on urban and peri-urban areas, including heavily traveled trails in parks. The results indicated statistically significant differences in infection rates, with the highest percentage of infected ticks found in Pleven (52.34%), followed by Stara Zagora (35.46%) and the lowest on the Black Sea Coast (23.08%). Furthermore, we conducted genospecies molecular identification of B. afzelii and B. garinii by PCR amplification of genospecies-specific nucleotide sequences in the 16S rRNA gene. The lowest prevalence of B. afzelii was recorded in Stara Zagora at 10.64%, followed by the Black Sea region at 12.5%, while the statistically highest frequency was observed in Pleven at 21.03%. The prevalence of B. garinii among the total number of I. ricinus ticks was greatest in Pleven at 15.89%, followed by the Black Sea region at 8.65%, and the lowest in the Stara Zagora region at 4.96%. Statistically significant differences were found only between Pleven and Stara Zagora (p = 0.002), but no significant differences in infection rates were observed between adults and nymphs in the regions examined. Overall, the prevalence of B. afzelii in each region exceeds that of B. garinii, and when considered collectively for Bulgaria, the frequency of B. afzelii (15.9%) is higher than that of B. garinii (10.89%) in infected ticks. In a controlled epidemiological context, managing the population of I. ricinus infected with B. burgdorferi s.l. can mitigate the health burden of Lyme disease, although this preventive strategy may not guarantee complete protection.