Background: Lyme borreliosis (LB) is the most common tick-borne disease in Europe. Incidence is increasing partly due to climate change and changing human behaviors. This review compiled updated national European LB surveillance data to assess recent incidence trends from 2015 to 2023. Methods: Publicly available LB surveillance data sources were identified for 29 European countries. Cases were collected from reports and dashboards. Estimates of population-based incidence were calculated. Countries were categorized based on their case classification criteria and geographic region. Subnational regions were classified as high-incidence areas if they reported ≥10 cases per 100,000 population per year (PPY) over a three-year period. The percentage of people residing in these high-incidence regions was calculated. Results: An average of 132,000 LB cases were reported to surveillance systems annually. Countries that included both erythema migrans and laboratory-confirmed LB cases in their reporting had the highest incidence rates—particularly Estonia, Finland, and Slovenia, exceeding 100 cases per 100,000 PPY. Overall, variation of incidence at the subnational level was observed, showing incidence at the national level can mask subnational differences in rates. Temporary decreases in incidence were observed during 2019–2021, but incidence increased from 2021 to 2023. A minimum of 223 million people, equating to 30% of the entire European population and 51% of those living in a European country with available subnational data, live in an area with high LB incidence. Conclusion: High LB incidence across Europe was observed from 2015 to 2023, particularly in parts of Northern, Eastern, and Western Europe. For nearly 70% of countries with recently published LB surveillance, incidence increased an average of 36% in the last two years of reporting. These findings emphasize the need for continued monitoring of LB across Europe and new public health prevention tools, such as enhanced tick prevention campaigns, improved education among health care providers, and effective vaccines.

Introduction: Lyme disease (LD) is caused by infection with the bacteria Borrelia burgdorferi sensu lato (Bb) through the bite of an infected Ixodes spp. tick. LD has emerged as a public and animal health issue in Canada, with human incidence increasing in part due to the expansion of Ixodes scapularis ticks and their vertebrate hosts. We sought to provide the first comprehensive summary of published tick and animal surveillance literature regarding LD in Canada to describe changes in LD over time.Methods: We conducted a review to identify peer‐reviewed LD‐focused tick, mammal, and bird surveillance articles in three online databases between 1975 and 2023. Data on study characteristics, data collection years, and surveillance methods and findings were extracted. Descriptive statistics were reported.Results: In total, 115 studies were included for review. Results showed an increase in published surveillance literature and changes in study approaches and their provincial distribution over time, coinciding with increased LD cases in Canada. Seventy‐four studies were published after 2014 when Canada's Federal Framework on Lyme Disease Act was introduced, and two‐thirds of these studies focused on tick surveillance only. Overall, 58% of studies involved surveillance in Ontario but increases in all other provinces were observed after 2009.Conclusions: Observed changes in five decades of LD‐related tick and animal surveillance literature helps document the historical rapid spread of Ixodes and Bb across provinces. This can provide lessons for other regions that may transition from emerging to endemic status for LD in the coming years.

Lyme borreliosis (LB) is the most common tick-borne disease in Europe. Many European countries conduct LB surveillance, but these data do not always capture the complete burden on the healthcare system and are difficult to compare across countries due to unstandardized reporting procedures. In this study, we combined data from public health surveillance and published literature to estimate the incidence of patients with LB seeking healthcare by clinical manifestation in Norway, Finland, and Poland. Surveillance data in each country were combined with medical administrative datasets (e.g., public health registries, claims databases, electronic medical records) to estimate the incidence of medically-attended LB. These estimates were adjusted to exclude cases that were not prescribed LB-specific antibiotics, and remove cases present in multiple datasets. Country-specific distributions of clinical manifestations were used to obtain medically-attended incidence by clinical manifestation. We estimated a high incidence of medically-attended LB in Norway (213.2 / 100,000 population per year [PPY]), Finland (116.4 / 100,000 PPY), and Poland (130.9 / 100,000 PPY). This corresponds to 67,578 annual cases or 2.7 times more than reported by surveillance in these countries. Incidence of disseminated LB was also substantial with 9.9, 36.3 and 6.2/ 100,000 PPY in Norway, Finland and Poland respectively corresponding to a total of 4,920 annual cases. This study provides estimates for incidence of medically-attended LB, including disseminated LB, in three European countries and highlights the limitations of surveillance data alone in assessing LB burden.

Lyme borreliosis (LB) is the most common tick-borne disease in Europe and can manifest as localized erythema migrans (EM) or further disseminate into Lyme neuroborreliosis (LNB), Lyme arthritis (LA) or other manifestations. However, public health surveillance in Denmark and Ireland only captures LNB, while published LB data for Sweden only includes LNB. To enhance the understanding of LB disease burden in these countries, this study aimed to estimate LB incidence by clinical manifestation using the ratio of each manifestation to LNB. These ratios were derived using random effects meta-analysis of published data from other European countries. We estimated the ratios for EM/LNB, LA/LNB and other manifestations/LNB to be 42.8 (95 % confidence interval [CI]: 36.4-50.4), 0.9 (95 % CI: 0.7-1.0), and 0.8 (95 % CI; 0.4-1.4), respectively. Applying these ratios to the LNB incidence resulted in an estimated overall LB incidence of 151.5 cases per 100,000 population per year (PPY) in Denmark, 285.2 per 100,000 PPY in Sweden and 9.5 per 100,000 PPY in Ireland. These correspond to >36,000 LB cases per year compared to approximately 800 LNB cases reported in these three countries. Furthermore, the estimated incidence of disseminated manifestations was 8.7 and 16.4 per 100,000 PPY in Denmark and Sweden, respectively. These estimates across LB manifestations highlight the LB health burden on the national healthcare systems. Future studies that directly estimate the incidence of medically-attended LB from healthcare registries, claims data or administrative medical records may help validate these estimates.

Lyme borreliosis (LB) is the most common vector-borne disease in Europe. At least 29 European Economic Area (EEA) countries publish online LB surveillance reports. However, countries have different criteria for what is notifiable for LB surveillance, limiting comparability. EEA countries began reporting Lyme neuroborreliosis (LNB) cases, a disseminated LB manifestation, to the European Centre for Disease Prevention and Control (ECDC) in 2018, using a uniform case definition. This analysis compared LNB data from ECDC and national surveillance reports to evaluate their utility in monitoring LB in Europe. LNB surveillance data from 2018 to 2023 were downloaded from ECDC. Nationally reported online LB surveillance data from EEA countries were identified and reviewed. Countries that reported LNB cases in national surveillance and to ECDC were included and case data were compared. Of 31 EEA countries during 2018 to 2023, 11 (35 %) differentiated LNB cases in their national published LB surveillance; eight of these also reported to ECDC. The number of LNB cases published in national reports in these eight countries did not exactly match the number of LNB cases reported to ECDC but overall disease trends were similar. Comparing the LNB cases from eight countries in ECDC and national surveillance demonstrates that both capture evolving LNB disease trends despite some differences in the number of cases reported to each. To allow for more robust comparisons of LB burden and trends across Europe, harmonizing case definitions and reporting mechanisms for LB would provide great value.

Slovenia has a high tick-borne encephalitis (TBE) incidence and TBE vaccination is recommended for all residents ≥1 year-of-age. Despite widespread TBE vaccine use in Slovenia, TBE vaccine effectiveness (VE) has not been reported for Slovenia. We defined individuals who received ≥3 TBE vaccine doses in accordance with the recommended vaccination schedule as fully vaccinated. Using the screening method, TBE VE was determined by comparing the proportions of TBE cases and survey respondents who were fully vaccinated. TBE incidence and VE were used to estimate the number of TBE cases prevented by TBE vaccination. Of 637 surveillance-reported TBE cases in 2019–2024, 332 (52.1%) had a known vaccination history. Of these 332 TBE cases, 322 (97.0%) were unvaccinated and 10 (3.0%) received ≥1 doses of a TBE vaccine. Among 25,242 persons surveyed with known TBE vaccination history, 57.9% were unvaccinated. VE of ≥3 TBE doses for the prevention of TBE was 93.4% (84.0–97.3%). TBE vaccination prevented 426 TBE cases in 2019–2024. If the entire population was vaccinated against TBE, vaccination would have prevented 994 TBE cases in 2019−2024. TBE vaccination in Slovenia was highly effective, preventing hundreds of TBE cases a year. Most of the Slovenian population, however, is not vaccinated against TBE. To prevent additional TBE cases in Slovenia, further efforts are needed to enhance TBE vaccine uptake.