Tick-Borne Encephalitis Virus and Borrelia burgdorferi Seroprevalence in Balkan Tick-Infested Individuals: A Two-Centre Study

Abstract

Lyme borreliosis (LB) and tick-borne encephalitis (TBE) are important tick-borne diseases in Europe. This study aimed to investigate the seroreactivity against Borrelia burgdorferi and TBE virus (TBEV) in tick-infested individuals in North Macedonia and Serbia. Serum samples were collected from tick-infested individuals and from healthy individuals in the same regions. Samples were tested for anti-Borrelia IgG reactivity and TBEV-neutralizing antibodies. Results showed higher seroreactivity against Borrelia antigens in patients and healthy donors from Novi Sad compared to those from the Skopje region. However, there was no statistically significant difference between tick-infested patients and healthy donors within each region. No TBEV-neutralizing antibodies were detected in participants from Novi Sad or in the control groups, except for one person from North Macedonia who had a moderate TBEV-neutralizing reaction. The study highlights the need for improved surveillance and diagnostic capabilities for LB and TBE in these regions. It also suggests the potential existence of TBEV foci in North Macedonia. The findings provide a complementary understanding of the LB and TBE epidemiology in the studied regions; however, further research is needed to investigate the presence and distribution of Borrelia spp. and TBEV in ticks to assess the significance of detected seroreactivity.

Evidence of tick-borne encephalitis virus neutralizing antibodies in Serbian individuals exposed to tick bites

“…In addition, TBEV-Nabs are only a subset of total anti-TBEV antibodies generated after exposure to TBEV. Although, TBEV-Nab seroprevalence in our cohort is higher compared to Norwegian, Romanian and Serbian blood donors (0.66 vs. 0.4% and 0.08 and 0%, respectively; Marvik et al, 2021 ; Coroian et al, 2022 ; Jakimovski et al, 2023 ) and much lower compared to residents of Czechia (0.66% vs. 26.3%; Kriz et al, 2015 ).…”

“…However, a significant limitation of these studies is that TBEV exposure was inferred through assays not designed to differentiate anti-TBEV antibodies from the humoral response generated against other orthoflaviviruses circulating in Serbia (e.g., Orthoflavivirus usutuense and WNV). Indeed, when a neutralization assay was applied in a two-center seroprevalence study conducted in Novi Sad (Serbia) and Skopje (North Macedonia), no TBEV-neutralizing antibodies were found in the Serbian cohort exposed to tick bites ( Jakimovski et al, 2023 ). This result may be influenced by the small number of participants included in the Serbian cohort ( n = 51), compared with the cohort examined in this study ( n = 450).…”

Serosurvey of Tick-Borne Encephalitis Virus Infection in Romania

“…The incidence rate and implied identification of new natural foci are strongly dependent on national diagnostic guidelines and diagnostic resources [ 21 ]. Patients presenting to the hospital with a confirmed TBEV infection may play a role in detecting new natural foci, and a precise history of the medical case may generate a trace to the origin of the infection and the detection of new areas of interest.…”

Ixodid ticks and zoonotic tick-borne pathogens of the Western Balkans

“…The seroprevalence in the patients who reported a tick bite was 28.9% (13/45) [ 134 ]. Recently, Jakimovski et al [ 135 ] observed that tick-infested individuals had lower seroreactivity against specific Borrelia proteins OspC and VlsE of 8.88% and 2.17%, respectively, and found TBEV-neutralizing antibodies in only one sample (2.22%) from the tick-exposed group from Skopje.…”