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Early stages of deadly respiratory diseases including COVID-19 are challenging to elucidate in humans. Here, we define cellular tropism and transcriptomic effects of SARS-CoV-2 virus by productively infecting healthy human lung tissue and using scRNA-seq to reconstruct the transcriptional program in "infection pseudotime" for individual lung cell types. SARS-CoV-2 predominantly infected activated interstitial macrophages (IMs), which can accumulate thousands of viral RNA molecules, taking over 60% of the cell transcriptome and forming dense viral RNA bodies while inducing host profibrotic (TGFB1, SPP1) and inflammatory (early interferon response, CCL2/7/8/13, CXCL10, and IL6/10) programs and destroying host cell architecture. Infected alveolar macrophages (AMs) showed none of these extreme responses. Spike-dependent viral entry into AMs used ACE2 and Sialoadhesin/CD169, whereas IM entry used DC-SIGN/CD209. These results identify activated IMs as a prominent site of viral takeover, the focus of inflammation and fibrosis, and suggest targeting CD209 to prevent early pathology in COVID-19 pneumonia. This approach can be generalized to any human lung infection and to evaluate therapeutics.

Abstract: Rock glaciers are common in alpine landscapes, but their evolution over time and their significance as agents of debris transport are not well‐understood. Here, we assess the movement of an ice‐cemented rock glacier over a range of timescales using GPS surveying, satellite‐based radar, and cosmogenic 10Be surface‐exposure dating. GPS and InSAR measurements indicate that the rock glacier moved at an average rate of ∼10 cm yr−1 in recent years. Sampled boulders on the rock glacier have cosmogenic surface‐exposure ages from 1.2 to 10 ka, indicating that they have been exposed since the beginning of the Holocene. Exposure ages increase linearly with distance downslope, suggesting a slower long‐term mean surface velocity of 3 ± 0.3 cm yr−1. Our findings suggest that the behavior of this rock glacier may be dominated by episodes of dormancy punctuated by intervals of relatively rapid movement over both short and long timescales. Our findings also show that the volume of the rock glacier corresponds to ∼10 m of material stripped from the headwall during the Holocene. These are the first cosmogenic surface‐exposure ages to constrain movement of a North American rock glacier, and together with the GPS and satellite radar measurements, they reveal that rock glaciers are effective geomorphic agents with dynamic multi‐millennial histories.

Parents boost STEM skills by scaffolding children's attention and discovery during play, but many need support doing so. Using human-centered design (HCD) methods, we created activity kits fostering parents' (a) involvement in and (b) valuing of parent-child play to promote preschoolers' STEM skills. Study 1 documents how HCD methods informed the design of guided activity kits. In initial home visits, we videorecorded six parent-child dyads playing with basic building materials. Play revealed minimal parental STEM scaffolding and talk. Collaborating with 18 families and drawing on prior research, parent interviews, videotaped play sessions, and advisory-board members' expertise, the interdisciplinary research team designed and refined activity kit prototypes. Study 2 was a randomized field test comparing use and evaluation of final guided kits (n = 50) versus basic kits (n = 25) that contained identical building materials and challenges but omitted scaffolding guides. Both groups received kits by mail every other week for 10 weeks. Relative to parents given basic kits, parents given guided kits (a) reported significantly more sustained use of the kits across the 10 weeks, (b) felt more self-efficacy in fostering their child's STEM learning, and (c) judged that their child had achieved greater STEM-skill learning from program use.

Small group social skills training (SST) is recommended to improve the social behavior and peer relations of rejected children, but child responses vary. This study explored variation in intervention experiences that emerged in a large study of a school-based SST program for peer-rejected children and associations with program outcomes. One hundred and seven peer-rejected elementary students (60% White, 15% Black, 22% Latinx, 3% Multi-racial, and 65% male) were identified by classroom sociometrics and randomly assigned to a year-long small group SST program. Normative classmates served as partners. Among the peer-rejected targets of the intervention, those with relatively better pretreatment social skills received more SST sessions and were more positively engaged, whereas those with fewer social skills and more behavior problems experienced more negative peer responses during SST sessions and less collateral support from teachers and parents. Hierarchical regressions (controlling for pretreatment scores) revealed attenuated intervention benefits for children who received more negative peer responses during SST and less parent and teacher support. The findings suggest that, within a sample of peer-rejected children, those with more severe skill deficits and elevated behavior problems at pretreatment have lower-quality SST experiences that reduce intervention benefits, even when normative classmates serve as peer partners. These issues warrant careful attention in future SST intervention design and research.

Although tremendous advances have been made in the development of evidence-based services and strategies to prevent and treat emotional and behavioral disorders (EBDs) in children, often such programs may be necessary but not sufficient to address the circumstances and needs of a specific student. The purpose of this introductory article and this broader special issue on the adaptation and individualization of evidence-based approaches for students with EBD is to consider innovations for tailoring multifactored interventions within tiered systems of support. In this article, we discuss potential ways that current tiered models may be strengthened using information and research strategies from developmental science to more rigorously link intervention to long-term outcomes of youth. We center this discussion on the concepts of developmental cascades and correlated constraints. We then present Tiered Systems of Adaptive Supports (TSAS) as a framework that is developmentally informed to guide individualized intervention. In this model, Tier 1 focuses on adapting general classroom strategies to support the routine daily functioning of all students; Tier 2 focuses on preventing the negative reorganization of a student's developmental system; and Tier 3 focuses on promoting the positive reorganization of a student's developmental system.

Social-cognitive and emotional factors as well as behavior problems contribute to the social difficulties experienced by many students with or at high risk for emotional and behavioral disorders (EBDs). The way that teachers and peers treat and respond to these students can either mitigate or exacerbate their challenges in establishing and maintaining positive social relationships and adjusting adaptively to the school context. Managing behavior alone does not address the self-regulatory skills deficits that contribute to social maladjustment, nor does it create socializing contexts that can support self-regulatory skill development. This article reviews research on neurodevelopmental processes and contextual constraints that contribute to the social-emotional difficulties of students with or at high risk for EBD. Implications for intervention design are explored, with a focus on the need for more consistent use of tiered social-emotional learning programs in schools to promote the self-regulation skills and social competence of vulnerable students with or at risk of EBDs. The authors also highlight the need for future research to enhance capacity to support tiered systems of intervention in schools and tailor them effectively to meet the varied needs of these students. [For the corresponding grantee submission, see ED610547.]

Psychotic-like experiences (PLEs) are common throughout childhood, and the presence of these experiences is a significant risk factor for poor mental health later in development. Given the association of PLEs with a broad number of mental health diagnoses, these experiences serve as an important malleable target for early preventive interventions. However, little is known about these experiences across childhood. While these experiences may be common, longitudinal measurement in non-clinical settings is not. Therefore, in order to explore longitudinal trajectories of PLEs in childhood, we harmonized three school-based randomized control trials with longitudinal follow-up to identify heterogeneity in trajectories of these experiences. In an integrative data analysis (IDA) using growth mixture modeling, we identified three latent trajectory classes. One trajectory class was characterized by persistent PLEs, one was characterized by high initial probabilities but improving across the analytic period, and one was characterized by no reports of PLEs. Compared to the class without PLEs, those in the improving class were more likely to be male and have higher levels of aggressive and disruptive behavior at baseline. In addition to the substantive impact this work has on PLE research, we also discuss the methodological innovation as it relates to IDA. This IDA demonstrates the complexity of pooling data across multiple studies to estimate longitudinal mixture models.

Developmental research suggests that peer rejection has negative spillover effects which strain parent-child relationships and parent attitudes toward the child's school. This study tested whether a school-based social skill training program could reverse these effects and improve parent-child closeness and parent attitudes toward the school. Participants included 217 children who were rejected by peers (57% White, 17% Black, 20% Latinx, 5% multiracial; 68% male; M[subscript age] = 8.1 years old) identified with sociometric social preference scores and randomized to intervention or control groups. Parents rated parent-child closeness and parent attitudes toward school at the start and end of the intervention year. Multilevel path analyses indicated that intervention improved parent-child closeness and, for children in the older grade levels only, enhanced parent attitudes toward the school. Additional analyses revealed that intervention effects on parent-child closeness were direct whereas effects on attitudes toward school were mediated by intervention-related increases in teacher support and peer liking. Implications for intervention design and future research are discussed.

A latent profile analysis was applied to explore heterogeneity in the social and classroom behaviors of 224 peer-rejected elementary school students (56% White, 68% male, Grades 1-4, M age = 8.1 years). Profile indicators included teacher ratings of social skills and problem behaviors on the Social Skills Improvement System (SSIS) and peer nominations of prosocial, aggressive, and withdrawn behavior. Four profiles emerged. Two profiles where characterized by elevated externalizing problems by peer and teacher report, one with multiple co-occurring difficulties (multiproblem, 21% of the sample) and one characterized primarily by aggression (domineering, 32% of the sample). Another profile was characterized by deficits in social skills and viewed by teachers as internalizing and disruptive (internalizing-dysregulated, 26% of the sample.) The final profile was nondistinct on teacher ratings but defined by low rates of prosocial behavior by peers (teacher preferred, 21% of the sample.) Group comparisons revealed that students in the multiproblem and internalizing-dysregulated profile classes had lower-quality relationships with teachers and more academic difficulties than students in the other two profile classes. The findings are discussed in terms of implications for identifying peer-rejected students for Tier 2 interventions and tailoring those interventions to enhance impact. [For the corresponding grantee submission, see ED622111.]

Conductive biomaterials provide an important control for engineering neural tissues, where electrical stimulation can potentially direct neural stem/progenitor cell (NS/PC) maturation into functional neuronal networks. It is anticipated that stem cell-based therapies to repair damaged central nervous system (CNS) tissues and ex vivo, "tissue chip" models of the CNS and its pathologies will each benefit from the development of biocompatible, biodegradable, and conductive biomaterials. Here, technological advances in conductive biomaterials are reviewed over the past two decades that may facilitate the development of engineered tissues with integrated physiological and electrical functionalities. First, one briefly introduces NS/PCs of the CNS. Then, the significance of incorporating microenvironmental cues, to which NS/PCs are naturally programmed to respond, into biomaterial scaffolds is discussed with a focus on electrical cues. Next, practical design considerations for conductive biomaterials are discussed followed by a review of studies evaluating how conductive biomaterials can be engineered to control NS/PC behavior by mimicking specific functionalities in the CNS microenvironment. Finally, steps researchers can take to move NS/PC-interfacing, conductive materials closer to clinical translation are discussed.

Biomaterials are being developed as therapeutics for spinal cord injury (SCI) that can stabilize and bridge acute lesions and mediate the delivery of transgenes, providing a localized and sustained reservoir of regenerative factors. For clinical use, direct injection of biomaterial scaffolds is preferred to enable conformation to unique lesions and minimize tissue damage. While an interconnected network of cell-sized macropores is necessary for rapid host cell infiltration into-and thus integration of host tissue with-implanted scaffolds, injectable biomaterials have generally suffered from a lack of control over the macrostructure. As genetic vectors have short lifetimes in vivo, rapid host cell infiltration into scaffolds is a prerequisite for efficient biomaterial-mediated delivery of transgenes. We present scaffolds that can be injected and assembled in situ from hyaluronic acid (HA)-based, spherical microparticles to form scaffolds with a network of macropores (∼10 μm). The results demonstrate that addition of regularly sized macropores to traditional hydrogel scaffolds, which have nanopores (∼10 nm), significantly increases the expression of locally delivered transgene to the spinal cord after a thoracic injury. Maximal cell and axon infiltration into scaffolds was observed in scaffolds with more regularly sized macropores. The delivery of lentiviral vectors encoding the brain-derived neurotrophic factor (BDNF), but not neurotrophin-3, from these scaffolds further increased total numbers and myelination of infiltrating axons. Modest improvements to the hindlimb function were observed with BDNF delivery. The results demonstrate the utility of macroporous and injectable HA scaffolds as a platform for localized gene therapies after SCI.

Research Findings: Children's readiness to handle the expectations of elementary school depends heavily on their self-regulation skills. Self-regulation includes both cognitive and behavioral elements; however, past studies have typically looked at cognitive and behavioral self-regulation in isolation or as a composite score rather than examining self-regulation profiles. Conceptually, a profile characterized by pervasive cognitive and behavioral self-regulation difficulties may have different developmental roots than a profile limited to behavioral regulation difficulties and children displaying these different profiles likely require different intervention supports. In the current study, latent profile analysis with cognitive and behavioral self-regulation indicators revealed four unique self-regulation profiles for preschool children (N=566): Pervasive Dysregulation (cognitively and behaviorally dysregulated), Behavioral Dysregulation (behaviorally dysregulated only), Average Self-Regulation, and High Self-Regulation. Practice or Policy: Latent moderational analyses indicated that while both the Pervasive and Behavioral Dysregulation group were at increased risk for less desirable kindergarten and 2nd grade outcomes, this risk was offset to a greater extant for children from the Behavioral Dysregulation profile when they experienced a close, non-conflictual teacher-student relationship in preschool. Ultimately, high-quality teacher-student relationships may be effective for supporting children who present behavioral challenges without cognitive self-regulatory challenges, but pervasively dysregulated children may require more intensive support.

Background: Childcare programs serving preschool children are generally of poorer quality than publicly-funded preschools both in terms of their classroom processes and structural features. Research on childcare programs has typically collapsed them into a single group, yet these programs vary greatly in neighborhood disadvantage and organization as they are managed by for-profit chains, non-profit community organizations, faith-based organizations, or individual owners. Little is known about variations in childcare program quality and what factors are associated with quality. Objective: The current study utilized latent profile analysis (LPA) with classroom process, structural features, and neighborhood disadvantage indicators to identify patterns of quality and neighborhood disadvantage within a diverse sample of childcare programs serving preschool children. Methods: Classroom processes (instructional support, emotional support, classroom management, positive discipline) and structural features (teacher age, experience, education, and satisfaction) data was collected from preschool teachers (N = 127) from 76 childcare programs. Neighborhood disadvantage (median income; rates of unemployment, single parents, and education) was measured using census tract data. Results: LPA indicated two profiles of childcare programs with high-quality classroom processes and two with poorer processes. Both of the high-quality profiles were in low-to-moderate income neighborhoods and the two low-quality profiles were in more affluent neighborhoods. Subsequent analyses suggested quality covaried with management type with the lowest quality centers often run by for-profit chains. Conclusions: Connections between classroom processes, structural features, and neighborhood disadvantage are complex making it extremely challenging for parents to identify high-quality care for their children.

Originating in the brain, glioblastoma (GBM) is a highly lethal and virtually incurable cancer, in large part because it readily develops resistance to treatments. While numerous studies have investigated mechanisms enabling GBM cells to evade chemotherapy-induced apoptosis, few have addressed how their surrounding extracellular matrix (ECM) acts to promote their survival. Here, we employed a biomaterial-based, 3D culture platform to investigate systematically how interactions between patient-derived GBM cells and the brain ECM promote resistance to alkylating chemotherapies - including temozolomide, which is used routinely in clinical practice. Scaffolds for 3D culture were fabricated from hyaluronic acid (HA) - a major structural and bioactive component of the brain ECM - and functionalized with the RGD (arginine-glycine-aspartic acid) tripeptide to provide sites for integrin engagement. Data demonstrate that cooperative engagement of CD44, through HA, and integrin αV, through RGD, facilitates resistance to alkylating chemotherapies through co-activation of Src, which inhibited downstream expression of BCL-2 family pro-apoptotic factors. In sum, a bioengineered, 3D culture platform was used to gain new mechanistic insights into how ECM in the brain tumor microenvironment promotes resistance to chemotherapy and suggests potential avenues for the development of novel, matrix-targeted combination therapies designed to suppress chemotherapy resistance in GBM.

Spinal cord injury (SCI) is a serious problem that primarily affects younger and middle-aged adults at its onset. To date, no effective regenerative treatment has been developed. Over the last decade, researchers have made significant advances in stem cell technology, biomaterials, nanotechnology, and immune engineering, which may be applied as regenerative therapies for the spinal cord. Although the results of clinical trials using specific cell-based therapies have proven safe, their efficacy has not yet been demonstrated. The pathophysiology of SCI is multifaceted, complex and yet to be fully understood. Thus, combinatorial therapies that simultaneously leverage multiple approaches will likely be required to achieve satisfactory outcomes. Although combinations of biomaterials with pharmacologic agents or cells have been explored, few studies have combined these modalities in a systematic way. For most strategies, clinical translation will be facilitated by the use of minimally invasive therapies, which are the focus of this review. In addition, this review discusses previously explored therapies designed to promote neuroregeneration and neuroprotection after SCI, while highlighting present challenges and future directions. Impact Statement To date there are no effective treatments that can regenerate the spinal cord after injury. Although there have been significant preclinical advances in bioengineering and regenerative medicine over the last decade, these have not translated into effective clinical therapies for spinal cord injury. This review focuses on minimally invasive therapies, providing extensive background as well as updates on recent technological developments and current clinical trials. This review is a comprehensive resource for researchers working towards regenerative therapies for spinal cord injury that will help guide future innovation.

Neural stem/progenitor cell (NS/PC)-based therapies have shown exciting potential for regeneration of the central nervous system (CNS) and NS/PC cultures represent an important resource for disease modeling and drug screening. However, significant challenges limiting clinical translation remain, such as generating large numbers of cells required for model cultures or transplantation, maintaining physiologically representative phenotypes ex vivo and directing NS/PC differentiation into specific fates. Here, we report that culture of human NS/PCs in 3D, hyaluronic acid (HA)-rich biomaterial microenvironments increased differentiation toward oligodendrocytes and neurons over 2D cultures on laminin-coated glass. Moreover, NS/PCs in 3D culture exhibited a significant reduction in differentiation into reactive astrocytes. Many NS/PC-derived neurons in 3D, HA-based hydrogels expressed synaptophysin, indicating synapse formation, and displayed electrophysiological characteristics of immature neurons. While inclusion of integrin-binding, RGD peptides into hydrogels resulted in a modest increase in numbers of viable NS/PCs, no combination of laminin-derived, adhesive peptides affected differentiation outcomes. Notably, 3D cultures of differentiating NS/PCs were maintained for at least 70 days in medium with minimal growth factor supplementation. In sum, results demonstrate the use of 3D, HA-based biomaterials for long-term expansion and differentiation of NS/PCs toward oligodendroglial and neuronal fates, while inhibiting astroglial fates. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 704-718, 2019.

Klinefelter syndrome (47,XXY) is associated with problems in social interaction and behavioral adaptation. Sixteen adolescents and adult men with 47,XXY enrolled in a pilot-study evaluating the effectiveness of Social Management Training (SMT), a novel neurocognitive-behavioral treatment program targeted at improving social, emotional, and behavioral functioning. Participants reported improved emotional stability from pre- to post-test (5 months). Informants reported reductions in internalizing and externalizing symptoms, including improvement in self-regulation. Although informants did not report changes in autism-like symptoms, increased awareness of social challenges was found. SMT may improve emotional stability, self-regulation, and self-reflection in people males with Klinefelter syndrome. This potentially efficacious treatment approach may prove to be a promising psychosocial therapeutic intervention for this population.

In the U.S., one-third of preschool children attend programs run by childcare centers. Childcare centers are generally isolated and under-resourced businesses, often challenged by high rates of teacher turnover and inconsistent financial support. Correspondingly, childcare centers often struggle to provide high-quality educational experiences for preschool children. This study introduced an evidence-based curriculum (REDI) to improve the educational experiences of preschool children in childcare centers and used a novel professional development (PD) model in which center directors were trained to serve as local coaches. Open-ended interviews with 45 teachers and 31 center directors evaluated the acceptability, feasibility, and effectiveness of the REDI intervention and coaching model. Participants also described their workplace and rated their intentions regarding future program use. Participants described multiple challenges in the workplace but generally positive perceptions of the REDI intervention. Perceptions regarding the feasibility of the coaching model were mixed. Workplace descriptions were associated with intervention experiences which, in turn, predicted intentions for future program use. Findings validate the importance of addressing the unique workplace challenges faced by childcare staff when designing classroom interventions and PD supports. Attending to program acceptability, feasibility, and perceived effectiveness in these settings may be critical to support sustained use.

Two hundred ninety-four children from low-income families (58% White, 17% Latinx, 25% Black; 54% girls; M[subscript age] = 4.49 years old at study entry) were recruited from Head Start classrooms to participate in a randomized-controlled trial of the project Research-based, Developmentally Informed (REDI) preschool intervention and then followed longitudinally for 10 years through 9th grade. At study entry, parents reported on their children's exposure to adverse childhood experiences (ACEs). Youth reported on their feelings of social-emotional distress and school bonding after making the transition into middle school (7th grade) and high school (9th grade). Multilevel latent profile analyses revealed three profiles of adolescent distress and school bonding. Increased rates of ACEs in early childhood predicted membership in adolescent profiles characterized by heightened social-emotional distress and reduced levels of school bonding. The REDI intervention that focused on promoting early social-emotional and language skills in preschool moderated the impact of early ACEs on adolescent adjustment and promoted youth resilience, significantly buffering children from the negative impact of early ACEs on their levels of social-emotional distress and school bonding.

Children with externalizing symptoms typically show dysregulated arousal when facing emotional challenges and are at risk for antisocial outcomes later in life. The model of emotion socialization (Eisenberg, Cumberland, & Spinrad, 1998) points to supportive emotion-related parenting as central to promoting children's regulatory capability and behavioral adjustment. However, the role of emotion-related parenting is less clear for children living in disadvantaged conditions and already displaying behavioral problems, and little is known about how these parenting practices shape the physiological underpinnings of behavioral adjustment. This study examined the relation between supportive emotion-related parenting and the trajectories of physiological regulation and externalizing symptoms across early school years among 207 children (66% male) from high-risk urban communities, who showed aggressive/oppositional behaviors at school entry. Mothers' supportive emotion-related parenting was observed in kindergarten during structured interactions. Children's respiratory sinus arrhythmia (RSA), an indicator of parasympathetic influence over cardiac arousal, was measured at rest and during an anger scene each year from kindergarten to the 2nd grade. Teacher ratings of externalizing symptoms were also obtained every year. Over time, supportive emotion-related parenting was related to a developmental trend from RSA augmentation toward RSA withdrawal during the anger scene as well as lower risk for escalating externalizing symptoms. The developmental changes of RSA reactivity partially accounted for the relation between parenting and trajectories of externalizing symptoms. Findings underscore the potential of supportive emotion-related parenting for diverting at-risk children from antisocial trajectories by shaping their physiological regulation and behavioral adjustment.

Lyme disease, caused by the spirochetal bacterium, Borrelia burgdorferi sensu lato (Bbsl), is typically transmitted by hard-bodied ticks (Acari: Ixodidae). Whenever this tick-borne zoonosis is mentioned in medical clinics and emergency rooms, it sparks a firestorm of controversy. Denial often sets in, and healthcare practitioners dismiss the fact that this pathogenic spirochetosis is present in their area. For distribution of Bbsl across Canada, we conducted a 4-year, tick⁻host study (2013⁻2016), and collected ticks from avian and mammalian hosts from Atlantic Canada to the West Coast. Overall, 1265 ticks representing 27 tick species belonging to four genera were collected. Of the 18 tick species tested, 15 species (83%) were positive for Bbsl and, of these infected ticks, 6 species bite humans. Overall, 13 of 18 tick species tested are human-biting ticks. Our data suggest that a 6-tick, enzootic maintenance cycle of Bbsl is present in southwestern B.C., and five of these tick species bite humans. Biogeographically, the groundhog tick, Ixodes cookei, has extended its home range from central and eastern Canada to southwestern British Columbia (B.C.). We posit that the Fox Sparrow, Passerella iliaca, is a reservoir-competent host for Bbsl. The Bay-breasted Warbler, Setophaga castanea, and the Tennessee Warbler, Vermivora peregrina, are new host records for the blacklegged tick, Ixodes scapularis. We provide the first report of a Bbsl-positive Amblyomma longirostre larva parasitizing a bird; this bird parasitism suggests that a Willow Flycatcher is a competent reservoir of Bbsl. Our findings show that Bbsl is present in all provinces, and that multiple tick species are implicated in the enzootic maintenance cycle of this pathogen. Ultimately, Bbsl poses a serious public health contagion Canada-wide.

Lyme disease has been documented in northern areas of Canada, but the source of the etiological bacterium, Borrelia burgdorferi sensu lato (Bbsl) has been in doubt. We collected 87 ticks from 44 songbirds during 2017, and 24 (39%) of 62 nymphs of the blacklegged tick, Ixodes scapularis, were positive for Bbsl. We provide the first report of Bbsl-infected, songbird-transported I. scapularis in Cape Breton, Nova Scotia; Newfoundland and Labrador; north-central Manitoba, and Alberta. Notably, we report the northernmost account of Bbsl-infected ticks parasitizing a bird in Canada. DNA extraction, PCR amplification, and DNA sequencing reveal that these Bbsl amplicons belong to Borrelia burgdorferi sensu stricto (Bbss), which is pathogenic to humans. Based on our findings, health-care providers should be aware that migratory songbirds widely disperse B. burgdorferi-infected I. scapularis in Canada's North, and local residents do not have to visit an endemic area to contract Lyme disease.