Cutaneous borreliosis in children - a challenging problem.

Borreliosis, also known as Lyme disease, is a vector-borne disease caused by different species of the Borrelia burgdorferi complex. It is frequent in Europe and Northern America. The major vectors are ixodoid ticks. Paediatric borreliosis is common and peaks in children between five to nine years. In Europe, the leading symptom of early infection is erythema migrans, in contrast to Northern America where arthritis is the dominating clinical finding. In this review, we focus on Europe, where cutaneous borreliosis is mainly caused by infection with B. afzelii. The cutaneous symptoms include erythema migrans, lymphocytoma, chronic atrophic dermatitis and juxta-articular nodules. In children, lymphocytoma is very common but chronic atrophic dermatitis is rare. Clinical symptoms, diagnosis, peculiarities of childhood disease and treatment are also reviewed. It is important to note that after haematogeneic spread, signs of infection may be non-specific, and this is a challenge for diagnosis.

Knowledge, protective behaviours, and perception of Lyme disease in an area of emerging risk: results from a cross-sectional survey of adults in Ottawa, Ontario.

BACKGROUND: The number of Lyme disease risk areas in Canada is growing. In regions with emerging tick populations, it is important to emphasize peridomestic risk and the importance of protective behaviours in local public health communication. This study aims to identify characteristics associated with high levels of Lyme disease knowledge and adoption of protective behaviours among residents in the Ottawa, Ontario region. METHODS: A geographically stratified web survey was conducted in November 2020 (n = 2018) to determine knowledge, attitudes, and practices regarding Lyme disease among adult residents. Responses were used to calculate: (i) composite scores for knowledge and adoption of protective practices; and (ii) an exposure risk index based on reported activity in woodlands during the spring-to-fall tick exposure risk period. RESULTS: 60% of respondents had a high knowledge of Lyme disease, yet only 14% indicated they often use five or more measures to protect themselves. Factors strongly associated with a high level of Lyme disease knowledge included being 55 or older (Odds Ratio (OR) = 2.04), living on a property with a yard (OR = 3.22), having a high exposure index (OR = 1.59), and knowing someone previously infected with Lyme disease (OR = 2.05). Strong associations with the adoption of a high number of protective behaviours were observed with membership in a non-Indigenous racialized group (OR = 1.70), living on a property with a yard (OR = 2.37), previous infection with Lyme disease (OR = 2.13), prior tick bite exposure (OR = 1.62), and primarily occupational activity in wooded areas (OR = 2.31). CONCLUSIONS: This study highlights the dynamics between Lyme disease knowledge, patterns of exposure risk awareness, and vigilance of personal protection in a Canadian region with emerging Lyme disease risk. Notably, this study identified gaps between perceived local risk and protective behaviours, presenting opportunities for targeted enhanced communication efforts in areas of Lyme disease emergence.

Effects of rodent abundance on ticks and Borrelia: results from an experimental and observational study in an island system.

BACKGROUND: Lyme borreliosis is the most common tick-borne disease in Europe and is often caused by Borrelia afzelii, which is transmitted by Ixodes ricinus ticks. The prevalence and abundance of infected ticks fluctuate in time and space, influencing human infection risk. Rodents are reservoir hosts for B. afzelii and important feeding hosts for larval ticks. In the study reported here, we examined how variation in rodent abundance is associated with B. afzelii infection prevalence in ticks, the density of nymphs (DON) and the density of infected nymphs (DIN) in the following year. We further analysed the relationships between the abundance of infected rodents and nymphal infection prevalence (NIP) and DIN. METHODS: We conducted a study that combined experimental and observational approaches on 15 islands (10 small islands and 5 large islands) in Finland. On all of the islands, ticks and rodents were monitored and sampled during the summer of 2019, with the monitoring of tick abundance and sampling continuing into the spring of 2020. On five of the 10 small islands, captured rodents were removed from the island ("removal" islands), and on the other five small islands, captured rodents were released back to the trapping site after marking and sampling ("control" islands). On the five large islands, captured rodents were released back to the trapping site after marking and sampling. The presence of B. afzelii from nymph and rodent samples was examined. RESULTS: The results of the experimental study showed that neither treatment (removal), rodent abundance index nor abundance index of infected rodents in 2019 was associated with DON, NIP or DIN in 2020. Based on data from the observational study, the NIP in 2020 decreased with increasing rodent abundance index and abundance index of infected rodents in 2019. However, the DIN in 2020 was not associated with the rodent abundance index or the abundance index of infected rodents in 2019. In addition, in the observational study, DON in 2020 increased with increasing rodent abundance index. CONCLUSIONS: Our results suggest that low rodent abundance during the tick activity period is not sufficient for reducing the disease hazard and, hence, rodent removal may not be a feasible control measure in natural ecosystems.

Lyme borreliosis and medical wandering: what do patients think about multidisciplinary management? A qualitative study in the context of scientific and social controversy.

INTRODUCTION: To answer to patients' medical wandering, often due to "unexplained symptoms" of "unexplained diseases" and to misinformation, multidisciplinary care centers for suspected Lyme borreliosis (LB), such as the 5 Tick-Borne Diseases (TBDs) Reference Centers (TBD-RC), were created a few years ago in France, the Netherlands and Denmark. Our study consisted of a comprehensive analysis of the satisfaction of the patients managed at a TBD-RC for suspected LB in the context of scientific and social controversy. METHODS: We included all adults who were admitted to one of the TBD-RC from 2017 to 2020. A telephone satisfaction survey was conducted 12 months after their first consultation. It consisted of 5 domains, including 2 free-text items: "What points did you enjoy?" and "What would you like us to change or to improve?". In the current study, the 2 free-items were analyzed with a qualitative method called reflexive thematic analysis within a semantic and latent approach. RESULTS: The answer rate was 61.3% (349/569) and 97 distinctive codes from the 2-free-text items were identified and classified into five themes: (1) multidisciplinarity makes it possible to set up quality time dedicated to patients; (2) multidisciplinarity enables seamless carepaths despite the public hospital crisis compounded by the COVID-19 pandemic; (3) multidisciplinarity is defined as trust in the team's competences; (4) an ambivalent opinion and uncertainty are barriers to acceptance of the diagnosis, reflecting the strong influence of the controversy around LB; and (5) a lack of adapted communication about TBDs, their management, and ongoing research is present. CONCLUSION: The multidisciplinary management for suspected LB seemed an answer to medical wandering for the majority of patients and helped avoid misinformation, enabling better patient-centered shared information and satisfaction, despite the context of controversy.

Prevalence of Powassan Virus Seropositivity Among People with History of Lyme Disease and Non-Lyme Community Controls in the Northeastern United States.

Introduction: Lyme disease (LD) affects ∼476,000 people each year in the United States. Symptoms are variable and include rash and flu-like symptoms. Reasons for the wide variation in disease outcomes are unknown. Powassan virus (POWV) is a tick-borne flavivirus that causes disease ranging from asymptomatic infection to encephalitis, neurologic damage, and death. POWV and LD geographic case distributions overlap, with Ixodes species ticks as the common vectors. Clinical ramifications of coinfection or sequential infection are unknown. Objectives: This study's primary objective was to determine the prevalence of POWV-reactive antibodies in sera samples collected from previously studied cohorts of individuals with self-reported LD history residing in the Northeastern United States. As a secondary objective, we studied clinical differences between people with self-reported LD history and low versus high POWV antibody levels. Methods: We used an enzyme-linked immunosorbent assay (ELISA) to quantify IgG directed at the POWV envelope (E) protein domain III in 538 samples from individuals with self-reported LD history and 16 community controls. The samples were also tested with an ELISA assay to quantify IgG directed at the POWV NS1 protein. Results: The percentage of individuals with LD history and possible evidence of POWV exposure varied depending on the assay utilized. We found no significant difference in clinical symptoms between those with low or high POWV IgG levels in the in-house assay. Congruence of the EDIII and NS1 assays was low with only 12% of those positive in the in-house EDIII ELISA testing positive in the POWV NS1 ELISA. Conclusions: The results highlight the difficulty in flavivirus diagnostic testing, particularly in the retrospective detection of flavivirus exposure. The findings suggest that a prospective study with symptomatic patients using approved clinical testing is necessary to address the incidence and clinical implications of LD and POWV co-infection or sequential infection.

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.

Cranial nerve involvement, visual complications and headache syndromes in Lyme disease.

PURPOSE OF REVIEW: To provide a summary of the visual manifestations and cranial neuropathies seen in Lyme disease. RECENT FINDINGS: Lyme facial palsy remains the most common manifestation of Lyme neuroborreliosis. Recent investigations show likely evidence of vagal involvement in Lyme disease. SUMMARY: The literature on Lyme neuroborreliosis continues to evolve. Lyme disease can affect nearly any cranial nerve in addition to causing various headache syndromes. The most common manifestation is Lyme disease facial palsy, occurring in up to 5-10% of patients with documented Lyme disease. Headache syndromes are common in the context of facial palsy but can occur in isolation, and more specific headache syndromes including trigeminal and geniculate neuralgias can occur rarely. Signs and symptoms indicative of vestibulocochlear nerve involvement are relatively common, although it could be that these represent other vestibular involvement rather than a specific cranial neuropathy. Optic neuritis is a controversial entity within Lyme disease and is likely overdiagnosed, but convincing cases do exist. Physicians who see any cranial neuropathy, including optic neuritis, in an endemic area can consider Lyme disease as a possible cause.

Lyme disease and Whipple's disease: a comprehensive review for the rheumatologist.

Despite their rarity, Lyme disease and Whipple's disease are of significant importance in rheumatology, as both can manifest as chronic arthritis, presenting challenges in the differential diagnosis of inflammatory arthropathies. In Lyme disease, arthritis typically emerges as a late manifestation, usually occurring six months after the onset of erythema migrans. The predominant presentation involves mono- or oligoarthritis of large joints, with a chronic or remitting-recurrent course. Even with appropriate antimicrobial treatment, arthritis may persist due to inadequate immunological control triggered by the disease. In contrast, Whipple's disease may present with a migratory and intermittent seronegative poly- or oligoarthritis of large joints, preceding classic gastrointestinal symptoms by several years. Both disorders, particularly Whipple's disease, can be misdiagnosed as more common autoimmune rheumatic conditions such as rheumatoid arthritis and spondyloarthritis. Epidemiology is crucial in suspecting and diagnosing Lyme disease, as the condition is transmitted by ticks prevalent in specific areas of the United States, Europe, and Asia. On the contrary, the causative agent of Whipple's disease is widespread in the environment, yet invasive disease is rare and likely dependent on host genetic factors. In addition to erythema migrans in Lyme disease and gastrointestinal manifestations in Whipple's disease, neurological and cardiac involvement can further complicate the course of both. This article offers a comprehensive review of the epidemiological, pathophysiological, clinical, and therapeutic aspects of both diseases.

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.

Estimating the Incidence and Economic Cost of Lyme Disease Cases in Canada in the 21st Century with Projected Climate Change.

BACKGROUND: Lyme disease (LD) is emerging in Canada owing to the range expansion of the tick vector Ixodes scapularis (I. scapularis). OBJECTIVES: Our objective was to estimate future LD incidence in Canada, and economic costs, for the 21st century with projected climate change. METHODS: Future regions of climatic suitability for I. scapularis were projected from temperature output of the North American Coordinated Regional Climate Downscaling Experiment regional climate model ensemble using greenhouse gas Representative Concentration Pathways (RCPs) 4.5 and 8.5. Once regions became climatically suitable for ticks, an algorithm derived from tick and LD case surveillance data projected subsequent increasing LD incidence. Three scenarios (optimistic, intermediate, and pessimistic) for maximum incidence at endemicity were selected based on LD surveillance, and underreporting estimates, from the United States. Health care and productivity cost estimates of LD cases were obtained from the literature. RESULTS: Projected annual LD cases for Canada ranged from 120,000 to >500,000 by 2050. Variation in incidence was mostly due to the maximum incidence at endemicity selected, with minor contributions from variations among climate models and RCPs. Projected annual costs were substantial, ranging from CA$0.5 billion to $2.0 billion a year by 2050. There was little difference in projected incidence and economic cost between RCPs, and from 2050 to 2100, because projected climate up to 2050 is similar for RCP4.5 and RCP8.5 (mitigation of greenhouse gas emissions captured in RCP4.5 does not impact climate before the 2050s) and by 2050 the most densely populated areas of the study region are projected to be climatically suitable for ticks. CONCLUSIONS: Future incidence and economic costs of LD in Canada are likely to be substantial, but uncertainties remain. Because densely populated areas of Canada are projected to become endemic under conservative climate change scenarios, mitigation of greenhouse gas emissions is unlikely to provide substantial health co-benefits for LD. https://doi.org/10.1289/EHP13759.

The four most frequently diagnosed vector-borne diseases among service member and non-service member beneficiaries in the geographic combatant commands, 2010-2022.

Vector-borne diseases (VBDs) may pose an increased risk for U.S. service members during recurring military training exercises, operations, and response missions, in addition to residence in endemic regions within and outside the continental U.S. Prior MSMR reports address VBD surveillance, described by surveillance data for 23 reportable medical events (RMEs), among active duty and reserve component service members. This report covers a 13-year surveillance period, from January 2010 to December 2022, and provides linear trends of selected VBDs among Armed Forces service and non-service member beneficiaries diagnosed at installations within the Northern Command (NORTHCOM), Africa Command (AFRICOM), Central Command (CENTCOM), European Command (EUCOM), Indo-Pacific Command (INDOPACOM), or Southern Command (SOUTHCOM). Trends of only the 4 mostfrequently reported VBDs were evaluated, as Lyme disease, malaria, Rocky Mountain Spotted Fever (RMSF), and dengue fever comprised 90% (n=5,199) of all 23 VBDs (n=5,750) among Military Health System (MHS) beneficiaries documented as RMEs during the surveillance period.

Density of host-seeking Ixodes scapularis nymphs by region, state, and county in the contiguous United States generated through national tick surveillance.

The majority of vector-borne disease cases reported annually in the United States are caused by pathogens spread by the blacklegged tick, Ixodes scapularis. The number and geographic distribution of cases have increased as the geographic range and abundance of the tick have expanded in recent decades. A large proportion of Lyme disease and other I. scapularis-borne diseases are associated with nymphal tick bites; likelihood of such bites generally increases with increasing nymphal densities. National tick surveillance was initiated in 2018 to track changes in the distribution and abundance of medically important ticks at the county spatial scale throughout the United States. Tick surveillance records, including historical data collected prior to the initiation of the national program, are collated in the ArboNET Tick Module database. Through exploration of ArboNET Tick Module data, we found that efforts to quantify the density of host-seeking I. scapularis nymphs (DON) were unevenly distributed among geographic regions with the greatest proportion of counties sampled in the Northeast and Upper Midwest. Submissions covering tick collections from 2004 through 2022 revealed extensive variation in DON estimates at collection site, county, state, and regional spatial scales. Throughout the entire study period, county DON estimates ranged from 0.0 to 488.5 nymphs/1,000 m2 . Although substantial variation was recorded within regions, DON estimates were greatest in the Northeast, Upper Midwest, and northern states within the Southeast regions (Virginia and North Carolina); densities were intermediate in the Ohio Valley and very low in the South and Northern Rockies and Plains regions. The proportion of counties classified as moderate or high DON was lower in the Northeast, Ohio Valley, and Southeast regions during the 2004 through 2017 time period (prior to initiation of the national tick surveillance program) compared to 2018 through 2022; DON estimates remained similarly low between these time periods in the South and the Northern Rockies and Plains regions. Despite the limitations described herein, the ArboNET Tick Module provides useful data for tracking changes in acarological risk across multiple geographic scales and long periods of time.

History of the geographic distribution of the western blacklegged tick, Ixodes pacificus, in the United States.

Ixodes pacificus (the western blacklegged tick) occurs in the far western United States (US), where it commonly bites humans. This tick was not considered a species of medical concern until it was implicated in the 1980s as a vector of Lyme disease spirochetes. Later, it was discovered to also be the primary vector to humans in the far western US of agents causing anaplasmosis and hard tick relapsing fever. The core distribution of I. pacificus in the US includes California, western Oregon, and western Washington, with outlier populations reported in Utah and Arizona. In this review, we provide a history of the documented occurrence of I. pacificus in the US from the 1890s to present, and discuss associations of its geographic range with landscape, hosts, and climate. In contrast to Ixodes scapularis (the blacklegged tick) in the eastern US, there is no evidence for a dramatic change in the geographic distribution of I. pacificus over the last half-century. Field surveys in the 1930s and 1940s documented I. pacificus along the Pacific Coast from southern California to northern Washington, in the Sierra Nevada foothills, and in western Utah. County level collection records often included both immatures and adults of I. pacificus, recovered by drag sampling or from humans, domestic animals, and wildlife. The estimated geographic distribution presented for I. pacificus in 1945 by Bishopp and Trembley is similar to that presented in 2022 by the Centers for Disease Control and Prevention. There is no clear evidence of range expansion for I. pacificus, separate from tick records in new areas that could have resulted from newly initiated or intensified surveillance efforts. Moreover, there is no evidence from long-term studies that the density of questing I. pacificus ticks has increased over time in specific areas. It therefore is not surprising that the incidence of Lyme disease has remained stable in the Pacific Coast states from the early 1990s, when it became a notifiable condition, to present. We note that deforestation and deer depredation were less severe in the far western US during the 1800s and early 1900s compared to the eastern US. This likely contributed to I. pacificus maintaining stable, widespread populations across its geographic range in the far western US in the early 1900s, while I. scapularis during the same time period appears to have been restricted to a small number of geographically isolated refugia sites within its present range in the eastern US. The impact that a warming climate may have had on the geographic distribution and local abundance of I. pacificus in recent decades remains unclear.

Delayed Diagnosis of Locally Acquired Lyme Disease, Central North Carolina, USA.

Healthcare providers in North Carolina, USA, have limited experience diagnosing and managing Lyme disease because few cases occur annually statewide. We outline the prolonged diagnostic course for a patient with locally acquired Lyme disease in North Carolina. This case highlights the need for greater awareness and professional education.

Surveillance for Lyme Disease After Implementation of a Revised Case Definition - United States, 2022.

Lyme disease, a tickborne zoonosis caused by certain species of Borrelia spirochetes, is the most common vectorborne disease in the United States. Approximately 90% of all cases are reported from 15 high-incidence jurisdictions in the Northeast, mid-Atlantic, and upper-Midwest regions. After the implementation of a revised surveillance case definition in 2022, high-incidence jurisdictions report cases based on laboratory evidence alone, without need for additional clinical information. In 2022, 62,551 Lyme disease cases were reported to CDC, 1.7 times the annual average of 37,118 cases reported during 2017-2019. Annual incidence increased most in older age groups, with incidence among adults aged ≥65 years approximately double that during 2017-2019. The sharp increase in reported Lyme disease cases in 2022 likely reflects changes in surveillance methods rather than change in disease risk. Although these changes improve standardization of surveillance across jurisdictions, they preclude detailed comparison with historical data.

High Prevalence of Borrelia burgdorferi Antibodies in Jaworzno, Poland: A Retrospective Study Revealing Endemic Lyme Borreliosis.

BACKGROUND This retrospective study of 704 adult residents of Jaworzno, Poland, aimed to evaluate medical personnel awareness of episodes of Lyme borreliosis and serum antibody levels for Borrelia burgdorferi sensu lato. MATERIAL AND METHODS This study included 704 residents of Jaworzno, Poland, who had no more than 12 months between tick bite and screening. The study consisted of a self-designed questionnaire survey and an analysis of IgG and IgM antibodies against B. burgdorferi sensu lato using an enzyme-linked assay (ELISA) and Western blot analysis, when necessary, to confirm the results. RESULTS A total of 558 residents (79.3%) confirmed having contact with a tick, 84 (11.9%) responded that they did not remember having contact with a tick, and 62 (8.8%) denied having contact with a tick. Regarding IgG, the ELISA showed 183 (25.99%) positive, 440 (62.5%) negative, and 81 (11.5%) equivocal results. Regarding IgM, the ELISA showed 180 (25.57%) positive, 435 (61.79%) negative, and 89 (12.64%) equivocal results. Positive and equivocal results for the IgG and IgM classes using the ELISA test were confirmed in 36 cases (13.64%) for IgG and in 53 cases (19.70%) for IgM using Western blot analysis. CONCLUSIONS The ELISA method obtained similar values for positive, negative, and equivocal results in the serological test. This was reflected in the survey conducted on residents who reported a tick bite and later received a positive result in the ELISA test as well as an approximate time between the bite and removal of the tick.

IxPopDyMod: an R package to write, run, and analyze tick population and infection dynamics models.

Given the increasing prevalence of tick-borne diseases, such as Lyme disease, modeling the population and infection dynamics of tick vectors is an important public health tool. These models have applications for testing the effects of control methods or climate change on tick populations. There is an established history of tick population models, but code for them is rarely shared, especially not in a convenient format for others to modify and use. We present an R package, called IxPopDyMod, intended to function as a flexible and consistent framework for reproducible Ixodidae (hard-bodied ticks) population dynamics models. Here we focus on two key parts of the package: a function to create valid model configurations and a function to run a configured model and return the daily population over time. We provide three examples in appendices: one reproducing an existing Ixodes scapularis population model, one providing a novel Dermacentor albipictus model, and one showing Borrelia burgdorferi infection in ticks. Together these examples show the flexibility of the package to model scenarios of interest to tick researches.

Tick-borne infections in children in North America.

PURPOSE OF REVIEW: Because both incidence and awareness of tick-borne infections is increasing, review of major infections and recent advances related to their diagnosis and management is important. RECENT FINDINGS: A new algorithm, termed modified two-tier testing, for testing for antibodies to Borrelia burgdorferi , the cause of Lyme disease, has been approved and may replace traditional two-tier testing. In addition, doxycycline is now acceptable to use for treatment of and/or prophylaxis for Lyme disease for up to 21 days in children of any age. Borrelia miyamotoi , a bacterium in the relapsing fever type of Borrelia, is the first of this type of Borrelia that is transmitted by hard-bodied ticks such as Ixodes scapularis. SUMMARY: Awareness of these infections and advances in their diagnosis and treatment is important to assure the best outcomes for affected patients. Table 1 contains a summary of infections discussed.

Developing a Prospective Gestational Lyme Disease Study.

Lyme disease in pregnancy is understudied. The few available reports of Borrelia infection during pregnancy collecting clinical outcomes, with or without confirmed fetal infection both in utero and neonatal, are limited to case reports and small series. Population-based studies are not available. We propose a prospective study of Borrelia infection during pregnancy based in obstetrical practices in both endemic and nonendemic areas, with long term follow-up of pregnancy outcomes and development assessment of offspring infected or exposed to Borrelia in utero using current serological, microscopic, culture, and molecular techniques. In addition to detection of Borrelia burgdorferi sensu stricto, additional Borrelia species and other pathogens known to be transmitted by ticks will be tested. Serial biospecimens including maternal and cord blood, maternal peripheral blood mononuclear cells and urine, and, when clinically indicated, amniotic fluid, chorionic villi, intrauterine cord blood, will be collected with clinical data, imaging, and for infections treatment medications. Offspring will be followed until age 5 years with annual developmental assessments to assess pregnancy outcomes. The study will require parallel development of a biorepository with strategies for management, data security and data sharing. A public-private partnership will be required to support the study.

Lyme Disease Models of Tick-Mouse Dynamics with Seasonal Variation in Births, Deaths, and Tick Feeding.

Lyme disease is the most common vector-borne disease in the United States impacting the Northeast and Midwest at the highest rates. Recently, it has become established in southeastern and south-central regions of Canada. In these regions, Lyme disease is caused by Borrelia burgdorferi, which is transmitted to humans by an infected Ixodes scapularis tick. Understanding the parasite-host interaction is critical as the white-footed mouse is one of the most competent reservoir for B. burgdorferi. The cycle of infection is driven by tick larvae feeding on infected mice that molt into infected nymphs and then transmit the disease to another susceptible host such as mice or humans. Lyme disease in humans is generally caused by the bite of an infected nymph. The main aim of this investigation is to study how diapause delays and demographic and seasonal variability in tick births, deaths, and feedings impact the infection dynamics of the tick-mouse cycle. We model tick-mouse dynamics with fixed diapause delays and more realistic Erlang distributed delays through delay and ordinary differential equations (ODEs). To account for demographic and seasonal variability, the ODEs are generalized to a continuous-time Markov chain (CTMC). The basic reproduction number and parameter sensitivity analysis are computed for the ODEs. The CTMC is used to investigate the probability of Lyme disease emergence when ticks and mice are introduced, a few of which are infected. The probability of disease emergence is highly dependent on the time and the infected species introduced. Infected mice introduced during the summer season result in the highest probability of disease emergence.