Active Forest Management Reduces Blacklegged Tick and Tick-Borne Pathogen Exposure Risk

In the northeastern USA, active forest management can include timber harvests designed to meet silvicultural objectives (i.e., harvesting trees that meet certain maturity, height, age, or quality criteria). Timber harvesting is an important tool in enhancing regeneration and maintaining forest health. It also has considerable potential to influence transmission dynamics of tick-borne pathogens, which are deeply embedded in the forest ecosystem. We conducted a 2-year study to test the hypotheses that recent timber harvesting impacts blacklegged tick density and infection prevalence in managed nonindustrial forests. We found that (1) recent harvesting reduces the presence of nymphal and density of adult blacklegged ticks, (2) recently harvested stands are characterized by understory microclimate conditions that may inhibit tick survival and host-seeking behavior, (3) capture rates of small mammal species frequently parasitized by immature ticks are lower in recently harvested stands compared to control stands with no recent harvest history. In addition, a 1-year pilot study suggests that harvesting does not affect nymphal infection prevalence. Collectively, our results demonstrate that forest structure and understory conditions may impact ticks and the pathogens they transmit via a range of mechanistic pathways, and moreover, active forest management may offer sustainable tools to inhibit entomological risk of exposure to tick-borne pathogens in the landscape.

Clinical Practice Guidelines by the Infectious Diseases Society of America (IDSA), American Academy of Neurology (AAN), and American College of Rheumatology (ACR): 2020 Guidelines for the Prevention, Diagnosis and Treatment of Lyme Disease

This evidence-based clinical practice guideline for the prevention, diagnosis, and treatment of Lyme disease was developed by a multidisciplinary panel representing the Infectious Diseases Society of America (IDSA), the American Academy of Neurology (AAN), and the American College of Rheumatology (ACR). The scope of this guideline includes prevention of Lyme disease, and the diagnosis and treatment of Lyme disease presenting as erythema migrans, Lyme disease complicated by neurologic, cardiac, and rheumatologic manifestations, Eurasian manifestations of Lyme disease, and Lyme disease complicated by coinfection with other tick-borne pathogens. This guideline does not include comprehensive recommendations for babesiosis and tick-borne rickettsial infections, which are published in separate guidelines. The target audience for this guideline includes primary care physicians and specialists caring for this condition such as infectious diseases specialists, emergency physicians, internists, pediatricians, family physicians, neurologists, rheumatologists, cardiologists and dermatologists in North America.

Do-It-Yourself Tick Control: Granular Gamma-Cyhalothrin Reduces Ixodes scapularis (Acari: Ixodidae) Nymphs in Residential Backyards

Lyme disease is the most common vector-borne disease in the United States with hotspots in the Northeast and Midwest. Integrated vector control for mosquito-borne disease prevention is often organized at the community level, but tick control is primarily coordinated at the household and individual level. Management of the blacklegged tick, Ixodes scapularis (Say), the vector of the causative agent of Lyme disease in the Midwest and eastern United States in peridomestic environments may be critical as many tick encounters are reported to occur in the yard. Therefore, we assessed the effectiveness of a widely available and low-cost pesticide that targets common lawn pests and is labeled for use against ticks. In June 2019, we evaluated a granular form of gamma-cyhalothrin in a placebo-controlled residential backyard study (n = 90) in two communities in Wisconsin. The product applied by the research team reduced nymphal blacklegged ticks in plots established in the lawn part of the ecotone by 97% one week after application at both communities and by 89-97% three to four weeks postapplication. The proportion of homes with at least one nymphal tick postapplication was significantly lower at acaricide-treated homes and ranged from 4.2 to 29.2% compared with placebo homes where at least one nymphal tick was found at 50-81.5% of homes. These results support the efficacy of a low-cost do-it-yourself strategy for homeowners seeking to reduce blacklegged ticks in the yard.

Assessing Recognition of the Vector of Lyme Disease Using Resin-Embedded Specimens in a Lyme Endemic Area

Lyme disease (LD) is the most common vector-borne disease in the United States. To assess whether a tick bite puts someone at risk for LD, adequate tick identification skills are needed. We surveyed residents of a high LD-incidence state, Wisconsin, on their ability to distinguish ticks from insects and to identify the specimens that could transmit the LD causative agent. Surveys were conducted using resin blocks with four insects and four tick specimens embedded. About half of the participants (64 of 130) recognized all of the ticks, and 60% of those individuals chose only ticks and no insects. Younger participants (18- to 44-yr old) were more likely to identify ticks correctly compared with those 45 yr and older. Participants who agreed strongly with the statement 'I know a lot about ticks` were also likelier to correctly identify ticks. When asked to identify which specimens could transmit LD, less than 25% of participants chose both the Ixodes scapularis Say adult female and nymph and about half of those (15% of participants) picked only those two and no other specimens. Although the relatively small convenience sample was biased toward younger participants who consider themselves 'outdoorsy', results showed that further assessments of tick recognition skills are needed to understand what determines whether people can recognize medically important ticks and to evaluate the potential benefits of enhanced education. In addition to the value of the resin blocks as research tools, the blocks may be useful as training tools to improve tick check efficacy.

Spray Safe, Play Safe: Story-Based Films Increase Homeowner Confidence About Backyard Tick Management

Lyme disease incidence is increasing in the United States despite myriad efforts to educate individuals about effective prevention practices to reduce exposure to nymphal Ixodes scapularis Say (Acari: Ixodidae) (blacklegged tick), the primary vector of the pathogen causing Lyme disease. Furthermore, Lyme prevention educational needs currently exceed the ability of public health professionals to deliver the information in person. Past work has shown there is especially high confusion regarding the use of acaricides for tick management by homeowners. Story-based education is known to engage individuals and change behaviors. To increase the reach and engagement regarding Lyme disease prevention practices, especially residential acaricide use, we created short, story-based educational films (Spray Safe, Play Safe) and evaluated their educational benefit with a survey pre- and post-viewing. We determined that after viewing the films, a significantly higher percentage of respondents reported increased confidence in identifying the riskiest areas in their yards for ticks, using personal protective measures to prevent tick bites, using tick-safe landscaping, and using tick control products. This study also suggests that using short, engaging films that can be posted to popular websites and social media outlets could be employed more frequently for successful and engaging Lyme disease education, as creative and up-to-date educational methods are needed.

Interactions Between Ticks and Lyme Disease Spirochetes

Borrelia burgdorferi sensu lato causes Lyme borreliosis in a variety of animals and humans. These atypical bacterial pathogens are maintained in a complex enzootic life cycle that primarily involves a vertebrate host and Ixodes spp. ticks. In the Northeastern United States, I. scapularis is the main vector, while wild rodents serve as the mammalian reservoir host. As B. burgdorferi is transmitted only by I. scapularis and closely related ticks, the spirochete-tick interactions are thought to be highly specific. Various borrelial and arthropod proteins that directly or indirectly contribute to the natural cycle of B. burgdorferi infection have been identified. Discrete molecular interactions between spirochetes and tick components also have been discovered, which often play critical roles in pathogen persistence and transmission by the arthropod vector. This review will focus on the past discoveries and future challenges that are relevant to our understanding of the molecular interactions between B. burgdorferi and Ixodes ticks. This information will not only impact scientific advancements in the research of tick- transmitted infections but will also contribute to the development of novel preventive measures that interfere with the B. burgdorferi life cycle.

Protective Effectiveness of Long-Lasting Permethrin Impregnated Clothing Against Tick Bites in an Endemic Lyme Disease Setting: A Randomized Control Trial Among Outdoor Workers

Tick-borne diseases are a growing threat to public health in the United States, especially among outdoor workers who experience high occupational exposure to ticks. Long-lasting permethrin-impregnated clothing has demonstrated high initial protection against bites from blacklegged ticks, Ixodes scapularis Say (Acari: Ixodidae), in laboratory settings, and sustained protection against bites from the lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae), in field tests. However, long-lasting permethrin impregnation of clothing has not been field tested among outdoor workers who are frequently exposed to blacklegged ticks. We conducted a 2-yr randomized, placebo-controlled, double-blinded trial among 82 outdoor workers in Rhode Island and southern Massachusetts. Participants in the treatment arm wore factory-impregnated permethrin clothing, and the control group wore sham-treated clothing. Outdoor working hours, tick encounters, and bites were recorded weekly to assess protective effectiveness of long-lasting permethrin-impregnated garments. Factory-impregnated clothing significantly reduced tick bites by 65% in the first study year and by 50% in the second year for a 2-yr protective effect of 58%. No significant difference in other tick bite prevention method utilization occurred between treatment and control groups, and no treatment-related adverse outcomes were reported. Factory permethrin impregnation of clothing is safe and effective for the prevention of tick bites among outdoor workers whose primary exposure is to blacklegged ticks in the northeastern United States.

Availability and Nature of Commercial Tick Control Services in Three Lyme Disease Endemic States

In an update of earlier surveys conducted in Connecticut and New Jersey in the mid-1990s, an online survey of private commercial pest control firms engaged in residential tick control showed that the application of synthetic acaricides continues to be the primary method of control used. The carbamate and organophospate acaricides, previously the most commonly used against ticks, have given way to synthetic pyrethroids and, to a lesser extent, the use of natural product/organic acaricides. Typical costs for a single acaricide application today ($100-$200 for a 1 acre [0.4 ha] property) remain similar to those reported from the earlier surveys, although the frequency of applications and, therefore, also the overall annual cost has increased. The application habitats within residential properties, life stages targeted, and application equipment used have not changed appreciably since the mid-1990s. While most survey respondents expressed knowledge of natural product acaricides and Damminix Tick Tubes, many reported that they either did not employ or knew very little about other alternative tick control methods (including entomopathogenic fungus and topical application of acaricides to tick hosts via 4-Poster deer treatment stations or Select TCS rodent bait boxes). This suggests either a failure to adequately inform the pest management industry and their potential client base of the availability of alternate methods, and/or industry concerns about cost and effectiveness of the alternatives.

Protective Immunity and New Vaccines for Lyme Disease

Lyme disease, caused by some Borrelia burgdorferi sensu lato, is the most common tick-borne illness in the Northern Hemisphere and the number of cases, and geographic spread, continue to grow. Previously identified B. burgdorferi proteins, lipid immunogens, and live mutants lead the design of canonical vaccines aimed at disrupting infection in the host. Discovery of the mechanism of action of the first vaccine catalyzed the development of new strategies to control Lyme disease that bypassed direct vaccination of the human host. Thus, novel prevention concepts center on proteins produced by B. burgdorferi during tick transit and on tick proteins that mediate feeding and pathogen transmission. A burgeoning area of research is tick immunity as it can unlock mechanistic pathways that could be targeted for disruption. Studies that shed light on the mammalian immune pathways engaged during tick-transmitted B. burgdorferi infection would further development of vaccination strategies against Lyme disease.

Development and optimization of OspC chimeritope vaccinogens for Lyme disease

Experimental Outer surface protein (Osp) C based subunit chimeritope vaccinogens for Lyme disease (LD) were assessed for immunogenicity, structure, ability to elicit antibody (Ab) responses to divergent OspC proteins, and bactericidal activity. Chimeritopes are chimeric epitope based proteins that consist of linear epitopes derived from multiple proteins or multiple variants of a protein. An inherent advantage to chimeritope vaccinogens is that they can be constructed to trigger broadly protective Ab responses. Three OspC chimeritope proteins were comparatively assessed: Chv1, Chv2 and Chv3. The Chv proteins possess the same set of 18 linear epitopes derived from 9 OspC type proteins but differ in the physical ordering of epitopes or by the presence or absence of linkers. All Chv proteins were immunogenic in mice and rats eliciting high titer Ab. Immunoblot and enzyme linked immunosorbent assays demonstrated that the Chv proteins elicit IgG that recognizes a diverse array of OspC type proteins. The panel included OspC proteins produced by N. American and European strains of the LD spirochetes. Rat anti-Chv antisera uniformly labeled intact, non-permeabilized Borreliella burgdorferi demonstrating that vaccinal Ab can bind to targets that are naturally presented on the spirochete cell surface. Vaccinal Ab also displayed potent complement dependent-Ab mediated killing activity. This study highlights the ability of OspC chimeritopes to serve as vaccinogens that trigger potentially broadly protective Ab responses. In addition to the current use of an OspC chimeritope in a canine LD vaccine, chimeritopes can serve as key components of human LD subunit vaccines.

Field evaluation of a novel oral reservoir-targeted vaccine against Borrelia burgdorferi utilizing an inactivated whole-cell bacterial antigen expression vehicle

Blacklegged ticks (Ixodes scapularis) are the principal vector for Borrelia burgdorferi, among other infectious agents, in the northeastern, mid-Atlantic, and upper midwestern USA. White-footed mice (Peromyscus leucopus) are the primary and most competent reservoir host of B. burgdorferi in the Northeast. Live reservoir-targeted vaccines (RTVs) to limit enzootic transmission of B. burgdorferi were previously developed and successfully evaluated in laboratory and controlled field trials. A novel, inactivated RTV was developed to minimize regulatory and market challenges facing previous RTVs based on live bacterial or viral vehicles. Thirty-two residential properties in Redding, Connecticut, participated in a field trial of an orally delivered, inactivated RTV efficacy study (2015-2016). During the two-year vaccination period, a significant decrease in the percentage of B. burgdorferi-infected I. scapularis larvae parasitizing P. leucopus was observed, as was a significant reduction in the percentage of infected P. leucopus on RTV-treated properties when compared to control properties. This novel inactivated RTV was effective in reducing numbers of B. burgdorferi-infected I. scapularis and B. burgdorferi-infected P. leucopus on properties where it was distributed.

A study with a commercial vaccine against Lyme borreliosis in horses using two different vaccination schedules: Characterization of the humoral immune response

A total of 143 horses were included in a study to test a commercial vaccine against Lyme borreliosis. The vaccine contained three different antigens (outer surface protein A, OspA) to prevent the infection with spirochetes - B.burgdorferi sensu stricto, B. afzelii and B. garinii. Horses in Group A (49 animals) received two vaccinations on days 0 and 14 and a booster on day 365, whereas 50 horses in Group B received an additional booster vaccination on day 180. Group C (44 animals) was not immunized. Total antibody levels and specific OspA antibody responses were assessed quantitatively and qualitatively in two-month intervals over 13-month period. Vaccinees in Groups A and B developed high OspA antibodies levels, whereas horses in Group C did not show specific antibody responses. The additional vaccination applied in Group B enhanced the specific OspA antibody response significantly and prevented its rapid decline.

Exposure to ticks and undertaking Lyme borreliosis prevention activities among students from Poland and Slovakia

INTRODUCTION AND OBJECTIVE

The incidence of Lyme borreliosis (LB) is increasing in many countries in Europe, including Poland and Slovakia. The aim of the study was to analyze the exposure to tick bites and undertaking LB prevention activities among students of medical fields of studies in Poland (PL) and Slovakia (SK).

MATERIAL AND METHODS

The study was conducted among 611 students from Poland (296 students) and Slovakia (315 students). The applied research tool was the questionnaire. It consisted of questions about exposure to ticks (occurrence of an episode of tick bites, bite site, methods used for tick removal) and the frequency of undertaking preventive actions (using repellents, checking the body after returning from green areas). Pearson Chi-square statistics were calculated to assess significant differences between students from the study countries PL/SK and gender in each country.

RESULTS

Among surveyed students the episode of a tick bite was reported by 352 persons (57.6%). Students from PL most frequently removed ticks with tweezers with a swift, steady movement (26.6%), while students from SK removed the tick by applying a fatty substance so that it would come off by itself (30.1%). Most of the surveyed students, being outdoors, did not apply ticks repellents (34.7%) or used them rarely (48.9%). At the same time, 49.4% of students stated that they always checked the body to search for any attached tick after returning from green areas.

CONCLUSIONS

Considering the fact that the surveyed people were the students of medical fields of studies, and in the future became qualified medical personnel, the frequency of using the analyzed methods of prophylaxis of LB appears to be too small. The results obtained can help in the education of students of medical fields.

Can Protected Areas Mitigate Lyme Disease Risk in Fennoscandia?

This Forum article synthesizes the current evidence on the links between predator-prey interactions, protected areas and spatial variations in Lyme disease risk in Fennoscandia. I suggest key research directions to better understand the role of protected areas in promoting the persistence of diverse predator guilds. Conserving predators could help reducing host populations and Lyme disease risk in northern Europe. There is an urgent need to find possible win-win solutions for biodiversity conservation and human health in ecosystems facing rapid global environmental change.

Counterattacking the tick bite: towards a rational design of anti-tick vaccines targeting pathogen transmission

Hematophagous arthropods are responsible for the transmission of a variety of pathogens that cause disease in humans and animals. Ticks of the Ixodes ricinus complex are vectors for some of the most frequently occurring human tick-borne diseases, particularly Lyme borreliosis and tick-borne encephalitis virus (TBEV). The search for vaccines against these diseases is ongoing. Efforts during the last few decades have primarily focused on understanding the biology of the transmitted viruses, bacteria and protozoans, with the goal of identifying targets for intervention. Successful vaccines have been developed against TBEV and Lyme borreliosis, although the latter is no longer available for humans. More recently, the focus of intervention has shifted back to where it was initially being studied which is the vector. State of the art technologies are being used for the identification of potential vaccine candidates for anti-tick vaccines that could be used either in humans or animals. The study of the interrelationship between ticks and the pathogens they transmit, including mechanisms of acquisition, persistence and transmission have come to the fore, as this knowledge may lead to the identification of critical elements of the pathogens' life-cycle that could be targeted by vaccines. Here, we review the status of our current knowledge on the triangular relationships between ticks, the pathogens they carry and the mammalian hosts, as well as methods that are being used to identify anti-tick vaccine candidates that can prevent the transmission of tick-borne pathogens.

[Ecology of Lyme disease]

Diseases spread by ticks are complex and typically come under the One Health approach because the implications for human, animal and environmental health are so intricately interconnected. In Europe and North America, these diseases, particularly the emblematic case of Lyme disease, are constantly on the rise. They are associated with a very strong emotional element in Western societies, where citizens are preoccupied by this upsurge and call on governments and health services to act. There is no vaccine against Lyme disease. This is the backdrop against which scientists are looking for alternative solutions based on the identification of ecological factors that are liable to better control tick populations and the movements of pathogens within ecosystems. This article describes the main knowledge already acquired about the ecology of Lyme disease and then provides a list of a number of instruments that can be leveraged to limit the risks and improve control.

[Prevention and management of Lyme disease: On complexity and the need to take into consideration various psycho-social factors]

OBJECTIVE

This paper aims to present a psychosocial analysis on the scientific literature concerning Lyme disease prevention and care.

METHODS

We performed a literature review on Lyme disease, especially on prevention and care, both through physicians and patients' perspective.

RESULTS

A total of 31 documents were included in our literature review. Literature shows that the acceptability of preventive measures, which is relatively poor, has to be associated with the behavioral nature, and not medical one, of these interventions. Moreover, the Lyme disease care is characterized by a condition of uncertainty - especially because of the controversy about the existence of the chronical form and the treatment to adopt - provoking important consequences on patient's quality of life. That is why the acknowledgment of profane knowledge's legitimacy is strongly demanded by patients, especially through the research of an empowered condition in the relation with the physicians. In this sense, the construction of a solid relation between caregiver and patient seems to be essential.

CONCLUSIONS

The invisibility of most symptoms, the patient's subjective experience and the social representations about Lyme disease show the need and the contribution of a psychosocial approach, in order to better understand the life experience of this uncertain condition and, more in general, of this disease.

Mice Against Ticks: an experimental community-guided effort to prevent tick-borne disease by altering the shared environment

Mice Against Ticks is a community-guided ecological engineering project that aims to prevent tick-borne disease by using CRISPR-based genome editing to heritably immunize the white-footed mice ( Peromyscus leucopus) responsible for infecting many ticks in eastern North America. Introducing antibody-encoding resistance alleles into the local mouse population is anticipated to disrupt the disease transmission cycle for decades. Technology development is shaped by engagement with community members and visitors to the islands of Nantucket and Martha's Vineyard, including decisions at project inception about which types of disease resistance to pursue. This engagement process has prompted the researchers to use only white-footed mouse DNA if possible, meaning the current project will not involve gene drive. Instead, engineered mice would be released in the spring when the natural population is low, a plan unlikely to increase total numbers above the normal maximum in autumn. Community members are continually asked to share their suggestions and concerns, a process that has already identified potential ecological consequences unanticipated by the research team that will likely affect implementation. As an early example of CRISPR-based ecological engineering, Mice Against Ticks aims to start small and simple by working with island communities whose mouse populations can be lastingly immunized without gene drive. This article is part of a discussion meeting issue 'The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems'.

Azithromycin nanocrystals for dermal prevention of tick bite infections

Azithromycin was optimized as nanocrystals with a drug content of 10.0 % (w/w) and a surfactant D-^α -tocopheryl polyethylenglycol 1000 succinate (TPGS) content of 1.0 % (w/w) using bead milling for 10 min. The photon correlation spectroscopy (PCS) diameter of the bulk population was 189 nm, laser diffraction (LD) diameter 90 % was 370 nm. Spherical morphology of the optimal nanocrystals was observed by transmission electron microscope (TEM). They were stable over 1 year of storage at 4 °C with the particle size within the nanometer range which was confirmed by PCS, LD and light microscope. An acceptable physical stability of 2 years was also obtained when stored at 4 °C. No microbial attack to the nanocrystals was observed before 3 years storage at 4 °C. The saturation solubility of the nanocrystals was up to triple compared to the raw drug powder (RDP) in water. When incorporated into the gel base, highest penetration efficacy was achieved by the optimal nanocrystals compared to 1) the clinically effective ethanol-solution-gel, 2) the gel with propylene glycol and 3) the gel with RDP in the ex vivo porcine ear penetration study. Even though propylene glycol improved saturation solubility of nanocrystals, it could not bring benefit to nanocrystals in the penetration study. Based on these optimized azithromycin nanocrystals, topical administration for enhanced dermal bioavailability of azithromycin seems to be feasible.

Factors Leading Municipal Authorities to Implement Preventive Interventions for Lyme Disease

The aim of this study is to document climate change adaptation interventions targeting Lyme disease at the municipal level in the province of Quebec (Canada). This exploratory study relies on the theory of planned behavior and certain constructs from the health belief model to identify the factors leading municipal authorities to implement preventive interventions for Lyme disease (PILD). Data were obtained from an online survey sent, during the summer of 2018, to municipal officers in 820 municipalities in Quebec, in all health regions where the population is at risk of contracting Lyme disease (response rate = 36%). The questionnaire was used to measure the implementation of PILD, the intention to implement these interventions, attitudes, perceived social pressure, perceived control (levers and barriers) over interventions, perceived effectiveness of preventive measures, risk, and perceived vulnerability. Results of structural equation analyses showed that attitudes were significantly associated with municipal authorities' intention to implement PILD, while the intention to implement PILD was a significant predictor of the implementation of PILD. Additional analyses showed that perceived barriers added a moderating effect in the intention-implementation relationship. The prediction of behaviors or practices that municipal authorities could implement to prevent Lyme disease will enable the evaluation over time of the evolution of Quebec municipalities' adaptation to Lyme disease. Moreover, the examination of the associations of specific psychosocial factors revealed important implications for the design of effective behavior-change interventions, which would allow health officials doing awareness work to create personalized interventions better suited to municipal officers and their specific contexts.

A Multiple Streams Approach to Understanding the Issues and Challenges of Lyme Disease Management in Canada's Maritime Provinces

This study examines potential challenges facing Lyme disease patients in Canada’s Maritime provinces—New Brunswick, Nova Scotia, Prince Edward Island—and considers how issues could be addressed. Reviews of both the academic and grey literature are complemented by surveys targeting both medical professionals and decision makers in government. Combined, the literature reviews and surveys demonstrate that there is considerable debate surrounding the effectiveness of testing, treatment options, and the existence of chronic Lyme disease. As the focus on the Maritimes demonstrates, these debates often pit the medical community against patients and patient advocates and, thus far, governments have been unable to produce policy that entirely pleases either side. Moving forward, this study recommends the creation of a discussion forum via a federal Commission of inquiry to review best practise guidelines for Lyme disease. The key is to foster an unbiased probe of central issues surrounding treatment and diagnosis without alienating stakeholders. This course of action will not necessarily solve the issue of Lyme disease, but would foster a greater understanding through dialogue that includes and validates the experiences of stakeholders, which is something that is currently missing.