Incidence Of Lyme Borreliosis Research Articles

Spatiotemporal trends and covariates of Lyme borreliosis incidence in Poland, 2010–2019

Lyme borreliosis (LB) is the most commonly diagnosed tick-borne disease in the northern hemisphere. Since an efficient vaccine is not yet available, prevention of transmission is essential. This, in turn, requires a thorough comprehension of the spatiotemporal dynamics of LB transmission as well as underlying drivers. This study aims to identify spatiotemporal trends and unravel environmental and socio-economic covariates of LB incidence in Poland, using consistent monitoring data from 2010 through 2019 obtained for 320 (aggregated) districts. Using yearly LB incidence values, we identified an overall increase in LB incidence from 2010 to 2019. Additionally, we observed a large variation of LB incidences between the Polish districts, with the highest risks of LB in the eastern districts. We applied spatiotemporal Bayesian models in an all-subsets modeling framework to evaluate potential associations between LB incidence and various potentially relevant environmental and socio-economic variables, including climatic conditions as well as characteristics of the vegetation and the density of tick host species. The best-supported spatiotemporal model identified positive relationships between LB incidence and forest cover, the share of parks and green areas, minimum monthly temperature, mean monthly precipitation, and gross primary productivity. A negative relationship was found with human population density. The findings of our study indicate that LB incidence in Poland might increase as a result of ongoing climate change, notably increases in minimum monthly temperature. Our results may aid in the development of targeted prevention strategies.

A comprehensive genetic map of cytokine responses in Lyme borreliosis

The incidence of Lyme borreliosis has risen, accompanied by persistent symptoms. The innate immune system and related cytokines are crucial in the host response and symptom development. We characterized cytokine production capacity before and after antibiotic treatment in 1,060 Lyme borreliosis patients. We observed a negative correlation between antibody production and IL-10 responses, as well as increased IL-1Ra responses in patients with disseminated disease. Genome-wide mapping the cytokine production allowed us to identify 34 cytokine quantitative trait loci (cQTLs), with 31 novel ones. We pinpointed the causal variant at the TLR1-6-10 locus and validated the regulation of IL-1Ra responses at transcritpome level using an independent cohort. We found that cQTLs contribute to Lyme borreliosis susceptibility and are relevant to other immune-mediated diseases. Our findings improve the understanding of cytokine responses in Lyme borreliosis and provide a genetic map of immune function as an expanded resource.

Incidence of Lyme Borreliosis in Germany: A retrospective observational healthcare claims study

Lyme borreliosis (LB) is the most common tick–borne disease in Germany. Although the incidence of LB in Germany has been assessed in several studies, those studies either used data from statutory surveillance, which frequently underreport cases, or data from health claims databases, which may overestimate cases due to non–specific LB case definitions. Here, using a more specific case definition, we describe the incidence of medically–attended LB by disease manifestation, age group, and federal state for the period 2015–2019. Both inpatient and outpatient cases were analyzed from a claims database. To be eligible for inclusion, patients were required to have an LB specific ICD–10 GM diagnosis code plus an antibiotic prescription, and for disseminated manifestations, a laboratory test order additionally. LB cases were classified as erythema migrans (EM), or disseminated disease including Lyme arthritis (LA), Lyme neuroborreliosis (LNB), and all other disease manifestations (OTH). Between 2015 and 2019, the incidence of medically–attended LB cases ranged from 195.7/100,000 population per year (95% confidence interval [CI], 191.0 – 200.5) to 254.5/100,000 population per year (95% CI, 249.0 – 260.0) per year. The majority of cases (92.2%) were EM, while 2.8% presented as LA, 3.8% as LNB, and 1.2% as OTH. For both EM and disseminated disease, the incidence peaked in children aged 5–9 years and in older adults. By federal state, the incidence of medically–attended EM ranged from 74.4/100,000 population per year (95% CI, 71.9 – 77.0) per year in Hamburg, to 394.1/100,000 population per year (95% CI, 370.7 – 417.6) per year in Saxony, whereas for medically–attended disseminated disease, the highest incidence was in Thuringia, Saxony, and Bavaria (range: 22.0 [95% CI, 19.9 – 24.0] to 35.7 [95% CI, 34.7 – 36.7] per 100,000 population per year). This study comprehensively estimated the incidence of all manifestations of medically–attended LB and showed a high incidence of LB throughout Germany. Results from the study support performing epidemiological studies in all federal states to measure the burden of LB and to invest in public health interventions for prevention.

Seroprevalence of Infection by Borrelia Species Responsible for Lyme Disease in the French Alps: Analysis of 27,360 Serology Tests, 2015-2020.

Objectives: Lyme borreliosis incidence is increasing in several areas; moreover, it has recently gained the public's attention. Apart from erythema migrans, Lyme disease diagnosis relies (among others) on serology test; however, the prevalence of positive enzyme-linked immunosorbent assay (ELISA) and western blot (WB) assay has been poorly studied in the general population. We aimed to approach the seroprevalence of infection by Borrelia species responsible for Lyme disease in the French Isere department using city laboratories data. Patients and Methods: We retrieved all serological tests for Borrelia species responsible for Lyme disease performed in the two main networks of city laboratories between 2015 and 2020. All patients with both ELISA and WB IgG were considered seropositive. Results: We analyzed 27,360 tests (ELISA/ELISA+WB). Mean age was 50.9 ± 20.3 years (ranges: 0-101), with 57.1% females. Overall, 11.7% had IgG detected by ELISA, and 4.7% had IgG detected by both ELISA and WB assay. Seropositive status was more frequent in males (7.0% vs. 2.9%, p < 0.001). Seropositivity rate increased with age after a first peak in childhood; men aged 61-70 years had the highest seropositivity rate (10.3%). In addition, seropositivity rate was higher in persons from a rural area. In multivariate analysis, older age, male gender and living in a rural area were independently associated with seropositivity. Seropositivity rate was stable on the 2017-2020 period. Conclusion: The seroprevalence of infection by Borrelia species responsible for Lyme disease is high in Isere; this probably reduces the predictive positive value for Lyme disease of ELISA and WB IgG, suggesting that this serological test should not be performed for nonspecific symptoms.

Crowdsourced tick observation data from across 60 years reveals major increases and northwards shifts in tick contact areas in Finland

There is mounting evidence of increases in tick (Acari: Ixodidae) contacts in Finland during the past few decades, highlighted by increases in the incidence of Lyme borreliosis and tick-borne encephalitis (TBE). While nationwide field studies to map distributions of ticks are not feasible, crowdsourcing provides a comprehensive method with which to assess large-scale changes in tick contact areas. Here, we assess changes in tick contact areas in Finland between 1958 and 2021 using three different nationwide crowdsourced data sets. The data revealed vast increases in tick contact areas, with ticks estimated to be contacted locally approximately 400 km further north in western and approximately 100 km further north in eastern Finland in 2021 than 1958. Tick contact rates appeared to be highest along the coastline and on the shores of large lakes, possibly indicating higher tick abundance therein. In general, tick observations per inhabitant increased from 2015 to 2021. Tick contact areas have expanded in Finland over the past 60 years. It appears that taiga ticks (Ixodes persulcatus) are behind most of the northwards shifts in tick contact areas, with Ixodes ricinus contributing mostly to new contact areas in the south. While ticks are now present in most of Finland, there are still areas where tick abundance is low and/or establishment not possible, mainly in northern Finland.

Аналіз захворюваності на Лайм-бореліоз під час епідемії COVID-19

The global pandemic caused by the SARS-CoV-2 virus has created unprecedented health, social and economic challenges, and has led to a sharp decline in official statistical reporting of many infectious diseases, including Lyme borreliosis (LB), especially in children, due to COVID-19-related health, anti-epidemic and quarantine measures. Purpose - to assess the completeness of statistical accounting of LB in children against the background of the COVID-19 situation in the context of the epidemic in the Ternopil region of Ukraine that began in the spring of 2020. Materials and methods. A PubMed search was conducted for analytical articles on LB and COVID-19 for the period from 2020 to February 2023. Epidemiological analysis and forecasting were performed using statistical methods. The search included 300 publications. After the selection process, 25 publications were included in the review. The results of long-term epidemiologic surveillance of tick-borne infectious diseases in the Ternopil region, including data from official statistics, epidemiologic investigations, and laboratory studies, were analyzed. To predict the incidence of LB in the first half of 2023 for the age group 0-17 years, over 17 years and all age groups, increasing polynomial trends of the second order with approximation coefficients equal to 1 were used. To predict the incidence of COVID-19 in the first half of 2023 for the age group 0-17 years, an increasing linear trend with an approximation coefficient equal to 0.8 was used. To predict the incidence of COVID-19 in the first half of 2023 for the age groups 18-29 years, 30-49 years, 50-65 years, over 65 years and all age groups, we used decreasing polynomial trends of the second order with approximation coefficients equal to 1. The vast majority of the highest values of the approximation coefficients confirm the high accuracy of predicting the incidence of VL and COVID-19 in the first half of 2023 in the Ternopil region. Results and conclusions. The officially registered number of cases of pulmonary disease, including among children, during the COVID-19 epidemic in Ternopil region is likely incomplete and does not reflect the actual incidence rate. This is due to the problem of identifying patients with pulmonary disease during the COVID-19 epidemic. After a sharp decline in reported cases of LB in 2020 compared to previous years, in 2021-2023, there was an improvement in its detection and diagnosis, but at levels lower than before the COVID-19 epidemic. However, the proportion of children is decreasing. No conflict of interests was declared by the authors.

Estimated Incidence of Symptomatic Lyme Borreliosis Cases in Lublin, Poland in 2021.

Lyme borreliosis (LB), the most common tick-borne disease in Europe, is endemic to Poland. Despite public health surveillance with mandatory reporting of LB cases by physicians and laboratories, many symptomatic LB cases are not included in surveillance in Poland. We estimated the extent of the under-ascertainment of symptomatic LB cases via surveillance in the Polish province of Lublin to better understand Poland's LB burden. The number of incident symptomatic LB cases in Lublin in 2010 was estimated from two seroprevalence studies conducted among adults in Lublin, as well as estimates of the proportion of asymptomatic LB cases and the duration of LB antibody persistence. The estimated number of incident symptomatic LB cases was compared to the number of surveillance-reported cases in Lublin to derive an under-ascertainment multiplier. This multiplier was applied to the number of surveillance-reported cases in 2021 to estimate the number and population-based incidence of symptomatic LB cases in Lublin in 2021. We estimate that there are 5.9 symptomatic LB cases for every surveillance-reported LB case in Lublin. Adjusting for under-ascertainment, the estimated number of symptomatic LB cases in Lublin in 2021 was 6204 (population-based incidence: 467.6/100,000). After adjustment for under-ascertainment, the incidence of symptomatic LB in Lublin, Poland, is high.

Centres de référence des maladies vectorielles liées aux tiques : activités et perspectives

IntroductionFor about ten years, ticks and the diseases they can transmit appear to be a major concern, due to increased tick abundance in some areas, tick-bites and the incidence of Lyme borreliosis in the northern hemisphere. In addition to these epidemiological data, controversies about the recognition of tick-borne diseases (TBDs) and the management of patients exist. The Tick-borne Diseases Reference Centers (TBD-RC) were created in 2019 to address patients' concerns and to organise high-quality care paths accessible to all people with symptoms attributed to a TBD. MethodWe carried out a review of the activities of the TBD-RC. Results – conclusionsThis patient-centered multidisciplinary approach demonstrated its effectiveness, including in complex situations where the suspicion of TBD is the gateway to the healthcare system but not the final diagnosis. The challenge is then to develop, disseminate and implement sustainable and reproducible care strategies throughout the country. TBD-RCs face other challenges, as there are many different types of TBDs, some uncommon, others emerging. Research is necessarily multimodal, with a One Health approach in which veterinarians, physicians and biologists, ecosystem specialists, human and social scientists and users work together. Finally, social appeasement regarding TBDs will require the dissemination of reliable information, to citizens as well as health care professionals alike, to limit medical wandering, break with this history of controversy and reduce the overall impact of these diseases.

Citizen Science on Lyme Borreliosis in Spain Reveals Disease-Associated Risk Factors and Control Interventions.

Background: Lyme borreliosis (LB) caused by Borrelia burgdorferi sensu lato complex spirochetes is one of the tick-borne diseases with high prevalence and social/economic burden in the United States, Spain, and other European countries. The objective is to address limited information available about the incidence, prevalence, and symptoms of LB, current prevention, and treatment interventions that are not adequately focused and thus not very effective against this disease. Methods: To address these limitations, in this study, we used a citizen science approach to evaluate the LB-associated risks and implementation of control interventions in Spain. A total of 405 participants in the survey were included in the analysis. Responses to the questionnaire were received during January-July 2022. The questionnaire contained qualitative and quantitative questions. Homogeneity among binary variables was analyzed using a Fisher's exact test. Results: Despite limitations of the study associated with response to the questionnaire and information on tick species, the results evidenced the effect of factors such as age, gender, tick bites, disease clinical signs, comorbidities such as alpha-gal syndrome, health care services, and treatment effectiveness affecting LB. Conclusions: The main conclusions of the study highlight the need for better surveillance of tick infestations, pathogen infection, and diagnosis of LB and related comorbidities. To advance in disease prevention, diagnosis, and treatment, new interventions need to be developed and implemented in both public and private health care services. Providing access to these results to the society, health care system, and scientists is important to further advance in disease surveillance, diagnosis, control, and prevention.

Demographic patterns in Lyme borreliosis seasonality over 25 years.

Lyme borreliosis, the most common vector-borne disease in Europe and North America, is attracting growing concern due to its expanding geographic range. The growth in incidence and geographic spread is largely attributed to climate and land-use changes that support the tick vector and thereby increase disease risk. Despite a wide range of symptoms displayed by Lyme borreliosis patients, the demographic patterns in clinical manifestations and seasonal case timing have not been thoroughly investigated and may result from differences in exposure, immunity and pathogenesis. We analysed 25 years of surveillance data from Norway, supplemented by population demography data, using a Bayesian modelling framework. The analyses aimed to detect differences in case seasonality and clinical manifestations of Lyme borreliosis across age and sex differentiated patient groups. The results showed a bimodal pattern of incidence over age, where children (0-9 years) had the highest incidence, young adults (20-29 years) had low incidence and older adults had a second incidence peak in the ages 70-79 years. Youth (0-19 years) presented with a higher proportion of neuroborreliosis cases and a lower proportion of arthritic manifestations compared to adults (20+ years). Adult males had a higher overall incidence than adult females and a higher proportion of arthritis cases. The seasonal timing of Lyme borreliosis consistently occurred around 4.4 weeks earlier in youth compared to adults, regardless of clinical manifestation. All demographic groups exhibited a shift towards an earlier seasonal timing over the 25-year study period, which appeared unrelated to changes in population demographics. However, the disproportionate incidence of Lyme borreliosis in seniors requires increased public awareness and knowledge about this high-risk group as the population continues to age concurrently with disease emergence. Our findings highlight the importance of considering patient demographics when analysing the emergence and seasonal patterns of vector-borne diseases using long-term surveillance data.

Similarities and differences in the characteristics of the epidemical process tick-borne encephalitis and Lyme borreliosis

Objective: To identify common and distinctive characteristics of the epidemical process of tick-borne encephalitis and Lyme borreliosis on the example of the Republic of Karelia.Materials and methods. The frequency of infected tick bites, dynamics, intensity, territorial, gender, age and social features of the incidence of tick-borne encephalitis and Lyme borreliosis in 2000–2021 were analyzed according to official statistics, epidemiological examination of foci and laboratory studies. The results of studies of 2379 blood samples of adults who were not ill and not vaccinated against tick-borne encephalitis for the presence of antibodies to the virus were analyzed.Results. The virulence of ticks in 2000–2021 decreased from 23.6 to 1.3%, infection with borrelia at the level of 13.4– 38.4%. The average long-term incidence rates of tick-borne encephalitis and Lyme borreliosis were 6.2 and 6.6 per 100 thousand, the dynamics of incidence had an average pronounced downward trend, correlated with the dynamics of requests for medical care of the population affected by ticks. The main clinical form of tick–borne encephalitis is meningeal (48%). Non-erythemic forms of borreliosis in recent years amounted to 39.1%. Antibodies of class G to tick-borne encephalitis virus were detected in 11.8±0.7% of the examined individuals. The territory of risk of infection with tick-borne encephalitis and Lyme borreliosis is the central and eastern part of the south of the Republic, where I.persulcatus dominates. The proportion of urban residents among patients with both infections is higher, but the incidence of urban and rural populations did not have significant differences. The incidence rates of tick-borne borreliosis in persons aged 40-49, 50-59 and 60 years and older are 1.6-2.2 times higher than those of tick-borne encephalitis, but the difference is not significant. At working age, the percent of men is higher than women, there are no differences among the elderly.Conclusions: Similar and different features of the epidemic process of tick-borne encephalitis and tick-borne borreliosis have been identified, which should be taken to improving the detection of diseases, predicting the situation and planning preventive measures.

The Incidence of Lyme Borreliosis Among Children.

First recognized in children in the United States, Lyme borreliosis (LB) is the most prevalent tickborne illness in North America and Europe. However, the incidence of LB in children, including geographic variation and difference from that in adults, is incompletely described. We compiled surveillance data from public health agency websites reporting age-stratified LB case data, which was combined with census data to derive incidence estimates. Additional incidence estimates were obtained through a systematic literature review. We identified 18 surveillance systems and 15 published studies for derivation of LB incidence in children. National incidence of >10 cases in children per 100,000 per year were estimated for the United States and parts of Eastern, Western and Northern Europe. However, there was substantial variation in incidence among countries in some European regions. National incidence estimates from the literature largely aligned with estimates from surveillance. Surveillance-reported pediatric incidence was lower than adult incidence in adults in 8 countries, similar to adult incidence in 3 countries, and higher than adult incidence in 1 country. Among all pediatric age strata, the 5-9 years of age stratum had the highest proportion of pediatric cases in most countries. As pediatric LB represents a substantial proportion of overall LB incidence across countries in Europe and North America, LB prevention and control efforts should target pediatric as well as adult populations. However, better data are needed to fully characterize the difference in incidence across geographic regions.

Which trial do we need? Treatment of multiple erythema migrans with doxycycline for 7 days versus 14 days

Which trial do we need? Treatment of multiple erythema migrans with doxycycline for 7 days versus 14 days

Characteristics of the epidemic process of Lyme borreliosis in the Sverdlovsk district over a 20-year period

Relevance. The Sverdlovsk district is a tense natural focus for Lyme borreliosis (LB) with a constantly recorded incidence that exceeds these indicators in the Russian Federation and the Ural Federal region several times. LB is registered on 56 of 59 administrative territories of the district. Currently, the count of LB in the Russian Federation includes both infections caused by Borrelia burgdorferi sensu lato group Borrelia and infections caused by Borrelia miyamotoi sensu lato group Borrelia.Aim. To characterize the epidemic process of LB in the territory of the Sverdlovsk district over a 20-year period (2002–2021).Materials and methods. The paper uses data from federal and regional statistical observations, reporting materials of the Department of Rospotrebnadzor in the Sverdlovsk district for 2002–2021, methods of statistical analysis.Results and discussion. During the follow–up period (2002–2021), the incidence rate of BL in the Sverdlovsk district exceeded the average long-term level in the Russian Federation by almost 3 times, and in the Ural Federal region – by 1.8 times. Among the mechanisms and ways of transmission of LB pathogens, the vector-borne mechanism dominated (84.5%), the share of the unidentified pathway was 15.4%, alimentary (when using raw goat's milk) – 0.1%. The duration of the epidemic season for LB in the district was 10 months (from March to December) with a peak incidence in June. Cases of LB were registered among people of different ages, with a predominance in the group of 60 years and older (39.1%). An analysis of the distribution of people with LB by social composition showed that pensioners prevailed among them – 36.3%, officials made up 27.8%, unemployed – 14.1%. Among the cases, a high proportion of schoolchildren and children under 7 years old were noted. It was found that erythematous and non-erythematous forms of LB are registered in the district, with a predominance of erythematous (64.5%). The main etiological agent of the erythematous form is Borrelia garinii, while the non-erythematous form is Borrelia miyamotoi and B. garinii. In the general structure of morbidity, the number of cases of LB is largely determined by the city inhabitants (92.9%). There were no fatal outcomes in LB in the territory of the district during the studied period.Conclusions. Due to the lack of vaccination of LB worldwide, the only strategy to reduce the incidence of LB is non-specific prevention and timely diagnosis of the disease, including data from epidemiological history, clinical and laboratory diagnostics. The long-term clinical and epidemiological and laboratory studies conducted by us in the Sverdlovsk district allowed us to characterize the main manifestations of the epidemic process of LB and to improve the diagnosis of the disease.

Estimated number of symptomatic Lyme borreliosis cases in Germany in 2021 after adjusting for under-ascertainment

BackgroundAlthough nine of 16 federal states in Germany conduct public health surveillance for Lyme borreliosis (LB), the extent of under-ascertainment is unknown. ObjectiveAs a model for European countries that conduct LB surveillance, we sought to estimate the population-based incidence of symptomatic LB after adjusting for under-ascertainment. MethodsEstimating seroprevalence-derived under-ascertainment relies on data from seroprevalence studies, public health surveillance, and published literature. The number of symptomatic LB cases in states that conduct LB surveillance was estimated from studies reporting the seroprevalence of antibodies against Borrelia burgdorferi sensu lato, the proportion of LB cases that are asymptomatic, and the duration of antibody detection. The number of estimated incident symptomatic LB cases was compared with the number of surveillance-reported LB cases to derive under-ascertainment multipliers. The multipliers were applied to the number of 2021 surveillance-reported LB cases to estimate the population-based incidence of symptomatic LB in Germany. ResultsAdjusting for seroprevalence-based under-ascertainment multipliers, the estimated number of symptomatic LB cases in states that conducted surveillance was 129,870 (408 per 100,000 population) in 2021. As there were 11,051 surveillance-reported cases in 2021 in these states, these data indicate there were 12 symptomatic LB cases for every surveillance-reported LB case. ConclusionsWe demonstrate that symptomatic LB is underdetected in Germany and that this seroprevalence-based approach can be applied elsewhere in Europe where requisite data are available. Nationwide expansion of LB surveillance would further elucidate the true LB disease burden in Germany and could support targeted disease prevention efforts to address the high LB disease burden.

Spatial and seasonal determinants of Lyme borreliosis incidence in France, 2016 to 2021.

BackgroundLyme borreliosis (LB) is the most widespread hard tick-borne zoonosis in the northern hemisphere. Existing studies in Europe have focused mainly on acarological risk assessment, with few investigations exploring human LB occurrence.AimWe explored the determinants of spatial and seasonal LB variations in France from 2016 to 2021 by integrating environmental, animal, meteorological and anthropogenic factors, and then mapped seasonal LB risk predictions.MethodsWe fitted 2016-19 LB national surveillance data to a two-part spatio-temporal statistical model. Spatial and temporal random effects were specified using a Besag-York-Mollie model and a seasonal model, respectively. Coefficients were estimated in a Bayesian framework using integrated nested Laplace approximation. Data from 2020-21 were used for model validation.ResultsA high vegetation index (≥ 0.6) was positively associated with seasonal LB presence, while the index of deer presence (> 60%), mild soil temperature (15-22 °C), moderate air saturation deficit (1.5-5 mmHg) and higher tick bite frequency were associated with increased incidence. Prediction maps show a higher risk of LB in spring and summer (April-September), with higher incidence in parts of eastern, midwestern and south-western France.ConclusionWe present a national level spatial assessment of seasonal LB occurrence in Europe, disentangling factors associated with the presence and increased incidence of LB. Our findings yield quantitative evidence for national public health agencies to plan targeted prevention campaigns to reduce LB burden, enhance surveillance and identify further data needs. This approach can be tested in other LB endemic areas.

Incidence of Lyme Borreliosis in Germany: Exploring Observed Trends Over Time Using Public Surveillance Data, 2016–2020

Background: Public surveillance of Lyme borreliosis (LB) occurs in 9 out of 16 federal states of Germany and remains a critical facet of disease epidemiology and trends. We describe the incidence, time trends, seasonality, and geographic distribution of LB in Germany using publicly reported surveillance data. Methods: We obtained LB cases and incidence (2016-2020) from the online platform SurvStat@RKI 2.0, maintained by the Robert Koch Institute (RKI). Data included clinically diagnosed and laboratory-confirmed LB reported by nine out of 16 federal states of Germany where LB notification is mandatory. Results: During 2016-2020, the nine federal states reported 63,940 LB cases, of which 60,570 (94.7%) were clinically diagnosed, and 3370 (5.3%) also had laboratory confirmation, with an average of 12,789 cases annually. Incidence rates were mostly stable over time. The average annual LB incidence was 37.2/100,000 person-years and varied by spatial level, ranging from 22.9 to 64.6/100,000 person-years among nine states; from 16.8 to 85.6/100,000 person-years among 19 regions; and from 2.9 to 172.8/100,000 person-years among 158 counties. Incidence was lowest among persons 20-24 years old (16.1/100,000 person-years) and highest among those 65-69 years old (60.9/100,000 person-years). Most cases were reported between June and September, with a peak in July of every year. Conclusion: The risk of LB varied substantially at the smallest geographic unit and by age group. Our results underscore the importance of presenting LB data at the most spatially granular unit and by age to allow implementation of efficient preventive interventions and reduction strategies.

Incidence of Lyme Borreliosis in Finland: Exploring Observed Trends Over Time Using Public Surveillance Data, 2015-2020.

Background: Lyme borreliosis (LB) is a tick-borne zoonotic disease endemic in many European countries, including Finland. We describe the incidence, time trends, and geographical distribution of LB in Finland for the period 2015-2020. The data generated can help inform public health policy, including prevention strategies. Methods: We retrieved online-available LB cases and incidence from two Finnish national databases. Microbiologically confirmed LB cases were identified from the National Infectious Disease Register and clinically diagnosed LB cases from the National Register of Primary Health Care Visits (Avohilmo), with the total LB cases equal to the sum from these two sources. Results: A total of 33,185 LB cases were reported for the 2015-2020 period, of which 12,590 (38%) were microbiologically confirmed and 20,595 (62%) were clinically diagnosed. The average annual national incidences for total, microbiologically confirmed, and clinically diagnosed LB were, respectively, 99.6, 38.1, and 61.4 per 100,000 population. The total LB incidence was highest in the south to southwestern coastal areas by the Baltic Sea and in eastern areas, with average annual incidences of 109.0 to 207.3/100,000. The Åland Islands were a hyperendemic region with an average annual incidence of 2473.9/100,000. The highest incidence was among persons aged >60 years, peaking at age 70-74 years. Most cases were reported between May and October, with a peak in July and August. Conclusions: The incidence of LB varied substantially by hospital district, and many regions reached incidences comparable with other high incidence countries, suggesting preventive measures such as vaccines may be an efficient use of resources.

Incidence of Lyme Borreliosis in Europe: A Systematic Review (2005-2020).

Background: Lyme borreliosis (LB) is the most common tick-borne disease in Europe, but the burden of disease is incompletely described. Methods: We conducted a systematic review across PubMed, EMBASE, and CABI Direct (Global Health) databases, from January 1, 2005, to November 20, 2020, of epidemiological studies reporting incidence of LB in Europe (PROSPERO, CRD42021236906). Results: The systematic review yielded 61 unique articles describing LB incidence (national or subnational) in 25 European countries. Substantial heterogeneity in study designs, populations sampled, and case definitions restricted data comparability. The European Union Concerted Action on Lyme Borreliosis (EUCALB)-published standardized LB case definitions were used by only 13 (21%) of the 61 articles. There were 33 studies that provided national-level LB incidence estimates for 20 countries. Subnational LB incidence was available from an additional four countries (Italy, Lithuania, Norway, and Spain). The highest LB incidences (>100 cases per 100,000 population per year [PPY]) were reported in Belgium, Finland, the Netherlands, and Switzerland. Incidences were 20-40/100,000 PPY in the Czech Republic, Germany, Poland, and Scotland and <20/100,000 PPY in Belarus, Croatia, Denmark, France, Ireland, Portugal, Russia, Slovakia, Sweden, and the United Kingdom (England, Northern Ireland, and Wales); markedly higher incidences were observed at the subnational level (up to 464/100,000 PPY in specific local areas). Conclusions: Although countries in Northern (Finland) and Western (Belgium, the Netherlands, and Switzerland) Europe reported the highest LB incidences, high incidences also were reported in some Eastern European countries. There was substantial subnational variation in incidence, including high incidences in some areas of countries with low overall incidence. This review, complemented by the incidence surveillance article, provides a comprehensive view into LB disease burden across Europe that may guide future preventive and therapeutic strategies-including new strategies on the horizon.

Incidence of Lyme Borreliosis in the Dutch General Practice Population: A Large-Scale Population-Based Cohort Study Across the Netherlands Between 2015 and 2019

Background: There is a need for updated incidence rates (IRs) of Lyme borreliosis (LB) in Europe, including the Netherlands. We estimated LB IRs stratified by geographic area, year, age, sex, immunocompromised status, and socioeconomic status (SES). Methods: All subjects registered in the PHARMO General Practitioner (GP) Database without prior diagnosis of LB or disseminated LB and having ≥1 year of continuous database enrolment were included. IRs and corresponding confidence intervals (CIs) of GP-recorded LB, erythema migrans (EM), and disseminated LB were estimated during the period 2015‒2019. Results: We identified 14,794 events (suspected, probable, or confirmed) with a diagnostic code for LB that included 8219 with a recorded clinical manifestation: 7985 (97%) with EM and 234 (3%) with disseminated LB. National annual LB IRs were relatively consistent, ranging from 111 (95% CI 106‒115) in 2019 to 131 (95% CI 126‒136) in 2018 per 100,000 person-years. Incidence of LB showed a bimodal age distribution, with peak IRs observed among subjects aged 5‒14 and 60‒69 years in men and women. Higher LB incidence was found in subjects who were residents of the provinces of Drenthe and Overijssel, immunocompromised, or of lower SES. Similar patterns were observed for EM and disseminated LB. Conclusions: Our findings confirm that LB incidence remains substantial throughout the Netherlands with no indication of decline in the past 5 years. Foci in two provinces and among vulnerable populations suggest potential initial target groups for preventive strategies such as vaccination.